'^^B. y — -.^ I :> Southern Branch of the University of California Los Angeles Form L-1 \*^\ cotk.8.. This book is DUE on the last date stamped below. '^0^ 3 192, APR 2 7 jggy MOV 8 1927 "^^ Mn 2 2 '.93t T^ I OCT 3 1 1941 m iM^v '%lsl mi 3m-8,'20 ^^^2 7 mo AUG 2 7 1962 .^ ,,.„,f°"THERN BRANCH UNIVERSITY OF CALIFORNIA LIBRARY LOS ANGEl'gS./CAtyn' ■ OUTLINES FOR EXPERIMENTAL PSYCHOLOGY BY H. L. HOLLINGWORTH, Ph.D. ASSISTANT PROFESSOR OF PSYCHOLOGY COLUMBIA UNIVKESITY tJi AT5S NORMAL SCHOOL 34 '17 ■ n: ORK A. G. ILER Copyright, 1914 By a. G. SEILER Press of J. J. Little & Ives Co.^ New York \ 19 I tin z CONTENTS PAGE Preface 5 PART I. General Outline for the Course 9 Topical Outlines and References 11 PART 11. General Laboratory Instructions 27 Laboratory Manual 29 Supplementary Experiments 108 PREFACE The only justification for the existence of an Outline for Experimental Psychology is to be found in its usefulness. In order to be useful, such a manual should serve several distinct piurposes. It should encourage rather than inhibit the enthusiasm of the student who is beginning the study of human nature imdei" controlled conditions; it shotdd assist in giving such a student a general and more or less systematic view of the wide field of psycho- logical inquiry; it should constitute a guide rather than an author- ity; it shoiild be detailed enough to enable the instructor to give his attention to the student rather than to the implements; with all this, it should allow sufficient freedom to avoid becoming itself the main object of investigation. The outline here presented has seemed to serve these various purposes in my own teaching. The system which it follows does not pretend to be a classifica- tion of psychological elements, processes or mechanisms. It is merely a convenient, and, in my experience, a suggestive classifica- tion of the topics or subject matter of the course. It affords a gradual transition from topics which may be studied by the purely objective methods of the physical sciences, through material related to the popular notion of psychology as the "interpretation" of conduct, to that more analytic and introspective type of inves- tigation which is sometimes held to be the only respectable psycho- logical pursuit. The Outline is primarily intended to serve as the basis of an introductory laboratory or practise course, rtmning throughout one academic year, with two or three lectures and three to five laboratory hours each week. Its arrangement is sufficiently flexible to permit of its being used in various other ways as well. It pre-supposes the use of a modest reference library rather than the study of any single text book. It avoids, so far as practicable, the introduction of special apparatus and intricate machinery. Its choice of subject matter is determined by an interest in the 6 Preface dynamics of thought and conduct, rather than in the analysis and description of the immediate contents of consciousness. Perhaps the only evidences of originality to be discerned in the Outline and Manual are to be found in the arrangement of subject matter and in the formulation of a few of the experiments. I have not hesitated to appropriate useful experiments from books and teachers, regardless of the time or place of their original de- scription. Wherever possible, my indebtedness to these sources is indicated by their inclusion among the references. In the formu- lation of instructions for several of the experiments on association and imagery I have profited by suggestions from unpublished laboratory outlines used by Prof. R. S. Woodworth in his courses on experimental psychology. H. L. HOLLINGWORTH Columbia University, New York City Part I. TOPICAL OUTLINE AND REFERENCES GENERAL OUTLINE FOR THIS COURSE (Laboratory, Lecttires, Collateral Reading, Demonstrations.) A — General and Introductory. I — The Problems and History of Experimental Psychology. 2 — Laboratory Methods — Technique of Measurement and Record, Sources of Error. 3 — Uniformities and Differences in Human Nature, The Curve of Distribution as Applied to Mental Traits, Statistical Methods. B — Externally Observable Behavior. I — Psychology of Work — Learning, Practise, Skill, Fatigue, Rest, External and Internal Conditions of Efficiency, Work Habits, Attitudes, Influence of Drugs, Motion Studies, Management, Periodicity, Dynamogeny, Correlation of Abilities, Tests, etc. 2 — Efficiency of Simple Nervous Arcs — Psychometric Measure- ments, Reaction Time Methods and Resvilts, Application of Reaction Methods. C — Semi-Observable Behavior. I — ^Attention — ^its Nature, Laws, Basis, Results, Types and Forms. 2 — Suggestion — Character and Laws, Basis, Individual Differ- ences, Pathology. 3 — Sleep — Nature and Causes, Experimental Studies, Drowsi- ness, Hygiene. 4 — Dissociation — Basis, Meaning and Applications of the Con- cept. S — The Unconscious and Subconscious — Descriptive, Theoretical and Critical. D — Expressive Behavior. I — Expressive Movements — their Origin, Character and Func- tion. 2 — Physiognomy, Phrenology and Character Estimation. 9 10 Outlines for Experimental Psychology 3 — Psychology of Speech and Language — Individual, Social, Pathological. 4 — Emotion, Mood and Temperament — Characteristics, Basis and Classification; the "Type" in Literature, History, Art, and Psychology. 5 — Symbolism and Expression of Inanimate Objects — Empathy, Feeling Tone of Design and Arrangement, Formal and Struc- tural Preferences, Psychology and Experimental ^Esthetics. E — Semi-Introspective Experience. I — Perception — Space, Time, Rhythm, Reading, Illusions. 2 — Kinsesthesis — Its Importance in Mental Life, Basis and Criteria. 3 — Association — Basis, Laws, Types, Forms, Classes, Individual Differences, Conditions and Applications. Psycho-analy- sis. 4 — Dreams — Character, Types, Origin and Significance. 5 — Memory — Recall and Recognition, Characteristics, Laws, Conditions, Methods, Types, Experimental Results. F — ^Purely Introspective Experience. I — Sensation — Character, Basis, Attributes, Measurements, Re- lations, Relative Esthetic Values. Intensive Study of one or two of the Special Senses. 2 — Centrally Excited Sensations (Imagery and Imagination) — Characteristics, Types, Laws and Fimction of Imaginal Experience. 3 — ^Affective Qualities (Feelings) — Affection and Sensation, Dimensions of Feeling, Basis of Affective Qualities, Classi- fication, Criteria and Fimction. Methods of Impression and Expression. 4 — Meaning and Relation — Concepts, Judgment, Thinking, "Imageless Thought". 5 — Impulsion — Desires, Wishes, Conation, Motive, Purpose, their Basis, Forms, and Varieties. Conflict, Repression, Rationalization. Experimental Studies of Volition and Choice. G — Review and Synthesis. I — The Psychological "Schools", their Differences and Agree- ments. Systematic Psychology. DETAILED TOPICAL OUTLINE AND REFERENCES A — General and Introductory. I— HISTORY OF EXPERIMENTAL PSYCHOLOGY. I — The Ancients — Democritus, Empedocles, Aristotle, Plato. 2 — The Middle Ages and the Scholastics. 3 — The Anatomy Movement, in Art and Science. Influence on Psychology. 4 — Philosophical Subjectivism — Locke, Berkeley, Hume, Kant, Mueller. 5 — The Association Psychology — Hartley, Hobbes, Herbart, Bain, Mill, Spencer. 6 — Phrenology, Physiognomy, etc. — Goll, Burdach, Mantegazza, Bell, Lombroso. 7 — Psychophysics — Weber, Fechner, Cattell, etc. 8 — Psychometry — Wundt, Helmholtz, Cattell, etc. 9 — Individual Differences — Galton, Binet, Stem, Cattell, Thorn- dike, etc. lo — Genetic, Animal and Comparative Psychology — Darwin, Morgan, Hall, Thomdike, Watson, Yerkes, Baldwin, Jennings, Washburn, etc. 11 — Systematic Psychology — Wtmdt, Kuelpe, James, Titchener, Stout, etc. 12— Abnormal Psychology— Kraepelin, Janet, Freud, Jung and many others. 13 — ^Applied Psychology — Gross, Stem, Muensterberg, Scott and many others. 14 — Neurology and Physiological Psychology. 15 — ^Anthropology, Sociology, Ethnology and related fields. References — Weber — History of Philosophy. Dessoir — History of Psychology. Ribot — German Psychology of Today. Ribot — English Psychology of Today. Klemm — History of Psychology. Scripture — The New Psychology. Villa — Contemporary Psychology. Baldwin — History of Psychology. Titchener — Experimental Psychology (Quantita- tive). Stratton — Experimental Psychology and Ctdture 11 12 Outlines for Experimental Psychology II— GRAPHIC AND STATISTICAL METHODS IN PSYCHOLOGY I — ^Various Types of Curves and Recording Devices. (Distribu- tion, Practise, Fatigue, Memory, Pulse, Breathing, etc.) The Meaning and Usefulness of the Graphic Methods. 2 — The Use of Statistics — Average, Median, Mode, Measures of Variability, Probable Errors, Constant and Variable Errors. Methods of Correlation. 3 — Standard Apparatus used in Psychological Laboratories. References — Myers — Experimental Psychology, Ch. X. Scripture — The New Psychology. Thomdike — Mental and Social Measurements. Davenport — Statistics . Titchener — Experimental Psychology. Judd — Laboratory Equipment for Psychological Experiments. Ill— UNIFORMITIES AND DIFFERENCES IN HUMAN NATURE. I — Nature and Amount of Individual Differences in Mental Traits. 2 — Conditions of Individual Differences — Trait, Age, Race, Training, Sex, etc. 3 — Correlation between Mental Traits. Nature and Conditions. 4 — Modifiability of Traits by Selection, Practise, Interest, etc. 5 — Tests of Intelligence — Tests for Defectives, Vocational Tests, etc. References — Thomdike — Individuality. Thomdike — Educational Psychology. Stem — Die Differentielle Psychologic. Boas — The Mind of Primitive Man. Whipple — Manual of Mental and Physical Tests. HoUingworth — Correlation of Abilities as Affected by Practise — Jour. Educ. Psych. Sept., 1913. HoUingworth — Individual Differences Before, Dur- ing and After Practise — Psych. Rev., Jan., 1914' Wells — Relation of Practise to Individual Differ- ences — Am. J. Psychol., 191 1. Outlines for Experimental Psychology 13 B — Externally Observable Behavior. IV— PSYCHOLOGY OF GENERAL EFFICIENCY. I — Methods of Measuring Mental and Motor Work. 2 — Learning a New Performance — Practise and the Practise Curve. Characteristics of Learning Curves of Men and Animals, Plateaus and their Significance, Methods of Work, Conditions of Improvement, Individual Differences. Inter- ference. 3 — Continued Work at a Perfected Performance — Bahnung, Spurts, Periodicity, Economical Distribution of Effort, Work Habits, Rhythm, Influence of Drugs, Inhibition, Fatigue, Dynamogeny, Suggestion, Rest. References — Book— The Psychology of Skill. Ruger — The Psychology of Efficiency. Swift — Mind in the Making, Chap. VI. Ladd and Woodworth, Physiological Psychology, Pt. II, Chap. VIII. Myers — Experimental Psychology, Chap. XIV. Scott — Increasing Human Efficiency in Business. Thomdike — The Psychology of Learning. Ladd and Woodworth, pp. 536-541. Mosso — Fatigue. Offner — Mental Fatigue. Myers — Experimental Psychology, Chap. XIV. Marsh — The Diurnal Course of Efficiency. Jones — Influence of Posture. Hollingworth — Influence of Caffein on Efficiency. Hollingworth (L. S.) — Functional Periodicity. James — The Energies of Men. Thomdike — Educational Psychology, Vol. III. V— EFFICIENCY OF SIMPLE NERVOUS ARCS. I — Chronometric Methods and Measurements. Factors Involved in Reaction. 2 — Types of Reaction Situation and Reagents. Reaction-time in Daily Life. 3 — Internal and External Determinants of Reaction-time. Appli- cations. 4 — The Use of Reaction-time Methods in Psychology — Individual Differences, Nervous Condition, Influence of Drugs, Diet, Disease, Practise, " Tatbestandsdiagnostik " and Associa- tion-reactions, Analysis of the "Higher Mental Processes. " 14 Outlines for Experimental Psychology References — Ladd and Woodworth — Physiological Psychology, Chap. VI. Myers — Experimental Psychology, Chap. XL Jastrow — Time Relations of Mental Phenomena. Titchener — Text-book of Psychology. Titchener — Experimental Psychology (Qualita- tive). Cattell — Psychological Researches, Chap. I. C — Semi-Observable Behavior. VI — ATTENTION — (As Mode of Behavior and State of Consciousness). I — Preliminary Facts — Selection, Prepotency of Stimvili, Scope and Span, Individual Differences, Interest, Absent-minded- ness, Distraction. 2 — ^Attention as Behavior — Characteristic Attitudes, Accommo- dation of Sense Organs, Re-enforcement, Variations in Ease, Speed, Uniformity and Amoimt of Work as Dependent on Stimulus and Situation, Facilitation. 3 — Introspective Characteristics — Distribution of "Clearness," Feelings of Effort, Rhythm and Periodicity in Clearness and Effort. 4 — Results of Attention — Changes in Clearness, Intensity, Duration, Steadiness, Scope and Speed of Process Attended to. Laws of Attention. 5 — Classifications of Attention — the Mechanical Devices, the Interest Incentives, Preperception. Characteristics, Laws, and Relative Values. 6 — Experimental Investigations of Attention. Methods of Measurement. 7 — Theoretical — Nervous Basis of Attention. Activity Theory, Motor Theory, Physiological Theories, Attention and Interest, Intensity and Clearness, Cortical Preparedness. Influence of Heredity and Training. References — Myers — Experimental Psychology, Chap. XXV. Ladd and Woodworth — Physiological Psychology, Special Sections. Titchener — Text-book of Psychology, Chap, on Attention. Titchener — Psychology of Feeling and Attention. Pillsbury — Attention. Washburn— The Animal Mind, Chap. XIII. Hollingworth — Advertising and Selling, Chap. II-VI. Outlines for Experimental Psychology 15 VII— SUGGESTION. I— Illustrations and Definitions. Long and Short Circuit Action. Motor Character of Ideas. Dissociation and Action. 2 — The Laws of Suggestion (Rivalry, Spontaneity, Intensity, Indirectness, Polarity, Prestige, Resistance, Summation, Attention) . 3 — Individual Differences in Suggestibility — Conditions, Correla- tions, etc. 4 — Suggestion and Hypnotism. Hysteria and Allied Disorders. References — Sidis — Suggestion. Moll — Hypnotism . Janet — The Major Symptoms of Hysteria. Ross — Social Psychology. James — Principles of Psychology, II., Chap. XXVII. Hollingworth — Advertising and Selling,Chap.XII. Scott — Theory of Advertising, Chap, on ''The Direct Command." VIII— SLEEP. I — Characteristics and Theoretical Explanations of Sleep. 2 — Experimental Studies — Depth, Influence of Drugs, Sleep of Animals, Loss of Sleep, Statistics. 3 — Drowsiness, the Hypnagogic State, Dissociation and Sleep. 4 — Individual Differences in Habits and Needs. Hygiene of Sleep. References — DeManaceine — Sleep. Sidis — Experimental Studies of Sleep. Howell— Physiology, Chap. XIII. Hollingworth — The Psychology of Drowsiness. Hollingworth — Influence of Caffein on Sleep. Terman and Hocking — Sleep of School Children— J. of Ed. Psych., March, April, May, 191 3. IX— DISSOCIATION. I — Illustrations, Concept, Basis and Applications. 2 — Habit Formation, Adaptation, Suppression of Double Images. 3 — Simple Forgetting, Amnesias, Anaesthesias, Aboulias. 4 — ^Absent-mindedness, Abstraction, Somnambulisms. 5 — Miiltiple Personalities, Hysteric Disorders, Logic-tight Com- partments. 16 Outlines for Experimental Psychology 6 — Dissociation and Hypnotism. Dissociation and Sleep. 7 — Meaning and Value of the Concept of Dissociation in Psy- chology. References — Hart — Psychology of Insanity. Coriat — ^Abnormal Psychology. Ribot — Diseases of the Personality. James — Principles of Psychology, Chap. XXVII. Jastrow — The Subconscious. Prince — The Dissociation of a Personality. Binet — On Double Consciousness. D — Expressive Behavior. X— EXPRESSIVE MOVEMENTS. I — Feeling and Emotion and Their Correlated Bodily Attitudes. The Origin and Function of Expressive Movements. 2 — Feeling and Emotion and Correlated Organic Changes (Tonus, Glandular, Respiratory and Electrical Reactions, Vaso- motor Changes). 3 — The Simple Feelings, the Typical Emotions, and their Ex- pressions. 4 — Mood and Temperament, The "Type", Physiognomy and Anthropometry. 5 — ^Judgments of Character and Type, Consistency, Correla- tions, Individual Differences. References — Wundt — Outlines of Psychology. Darwin — Expression of Emotions in Men and Animals. Ladd and Woodworth — Physiological Psychology, Chap. VII. Myers — Experimental Psychology, Chap. XXIV. James — Principles of Psychology, Chap, on " Emo- tion". Mantegazza — Physiognomy and Expression. XI— EXPRESSION AND INANIMATE OBJECTS. I — Feeling-tone of Design and Arrangement — Lines, Forms, Rhythm, Balance, Stability, Complexity and Unity. 2 — Formal and Structural Preferences. Experimental Aesthet- ics. 3 — ^Empathy and "Einfiihlung" — Nature and Basis, Criticism. 4 — Symbolism in Art, Language of Ornament, Synaesthesias. Outlines for Experimental Psychology 17 References — Gordon — Aesthetics. HoUingworth — ^Advertising and Selling, Chaps. IX andX. Witmer — Analytical Psychology. Puffer — The Psychology of Beauty. Allen — Physiological Aesthetics. Marshall — Pain, Pleasure and Aesthetics. Parsons — Principles of Arrangement. Ross — Theory of Pure Design. Him — Origins of Art. XII— SPEECH AND LANGUAGE. I — The Origin of Language, Primitive Languages and their Psychology. 2 — Psychological Laws in Language Formation and Change. 3 — Origin and History of Writing, The Alphabet. 4 — Language and Thought. 5 — Psycho-linguistic Problems. 6 — Speech Defects, their Varieties, Causes and Treatment. 7 — ^Aphasia, Agraphia, Alexia. References — Wundt — ^Volkerpsychologie. Mueller — Lectures on the Science of Thought. Mueller — Lectures on the Science of Language. Scripture — Stammering and Lisping. Elder — Aphasia. E — Semi-Introspective Experience. XIII— PERCEPTION. I — Nature and Laws of Perception — Perception as Behavior and as a Mode of Consciousness — Illustrated by Reading, Space and Time Perception. 2 — Reading as Perceptual Process — Eye Movements and the Reading Reaction, Reading Pauses and Fixations, Letter Perception and Word-Form, Determinants and Indiffer- ents, Psychological Process in Reading, Heirarchy of Read- ing Habits, Inner Speech, Meaning and Language. 3 — Space Perception — a — The Space Quale, Nativist and Empiricist Views; Voluminousness as Elementary Space Experience in Various Modalities of Sensation; Basis and Conditions of Extensity. 18 Outlines for Experimental Psychology b — Local Signature — Tactual, Visual and Auditory- Local Signs ; the Perception of Direction ; Criteria and Laws ; Fusion and Synthesis; Two-point Discrimination; Percep- tion of Change. c — Perception of Distance (Visual Space) — Monooilar Criteria — ^Accommodation, Size, Interference, Clearness, Elevation, Parallax, Light and Shade. Binocular Vision — Disparity of Images, Convergence and Divergence, Corresponding Points, Homonymous and Heteronymous Images, the Horopter, the Cyclopean Eye. d — Perception of Depth and Solidity (Stereoscopic Vision) — Images Indistinguishable — Fuse, Single Flat Object, Distinguishable but Consistent — Fuse, Composite Surface. Distinguishable but Inconsistent — Binocular Rivalry. Consistent on Supposition — Fuse, Solid Object, 3rd Dimension. e — The Stereoscope, Telestereoscope, Pseudoscope, Kinetoscope, etc. f — Space Perception (Tactual, Auditory, Kinaesthetic) — Tactual and Visual Space Correlations. Illusions. Criteria of Auditory Localization. Illusions. Perception of Extent, Duration and Speed of MovemenL. g — The Space System — Inter-modality Relations, Co- ordination, the Separate Space Worlds — their Fusion and Synthesis. 4 — Perception of Time — a — Attribute of Duration, and Temporal Character of Experience. b — Duration of Sensations. The Specious Present. c — The Criteria of Temporal Perception. d — Anomalies and Illusions in Perception of Duration and Interval. e — Rhythm, its Laws and Phenomena. References — Chapters on Perception in the general texts. Chapters on Space and Time in the general texts. Chapters on Vision and Hearing in texts on Physio- logical Psychology. Dearborn — The Psychology of Reading. Huey — Physiology and Psychology of Reading. Binet — The Psychology of Reasoning. Outlines for Experimental Psychology 19 XIV— KIN^STHESIS. I — Importance of Kineesthesis in Mental Experience — Space, Time, Rhythm, Optical and Other Illusions, General Perception. 2 — Origin and Topography of Kinaesthetic Impressions. 3 — Criteria of Judgments of Extent, Force, Speed and Duration of Movement. 4 — Methods of Studying Movement and its Psychology. 5 — Motor Accuracy and Inaccuracy. Kinaesthetic Illusions. References — Myers — Experimental Psychology, pp. 293-301. Ladd and Woodworth — Physiological Psychology, Chap. V. Hollingworth — The Inaccuracy of Movement. Woodworth — Le Mouvement. Woodworth — Accuracy of Voluntary Movement. Titchener — Text-book of Psychology, pp. 330-338. Titchener — Experimental Psychology (Qualita- tive), pp. 1 51-170. XV— ASSOCIATION. I — Characteristics, Conditions and Neurological Basis of Asso- ciation. 2 — Levels of Association and Associative Processes. 3 — Classifications and Laws — Principles of Connection and Re- vival. 4 — Measurements of Association Strength. 5 — The Association Methods and their Applications — ''Tatbestandsdiagnostik", Psycho-analysis, Clinical Diag- nosis. 6 — ^Association Reaction-types, their Determinants and Signifi- cance. 7 — Pathology of Association. 8 — Association in Daily Life. References — James — Principles of Psychology, Chap. XIV. Titchener, Text-book of Psychology — Section on "Association". Myers — Experimental Psychology, Chaps. XII and XIII. Kent and Rosanoff — Study of Association in Insanity. Jung — Miscellaneous Articles on Association Method. Calkins — Association (Psych. Rev. Mon. Suppl.) . Wells — Miscellaneous Articles on Association. Woodworth and Wells — Association Tests, Hollingworth — ^Advertising and Selling, Chap. XI. 20 Outlines for Experimental Psychology XVI— DREAMS. I — Characteristics, Varieties and History of Dreams. 2 — Causes, Conditions and Mechanisms of Dreaming. 3 — Drowsiness and Allied States. Hypnagogic Hallucinations. 4 — Interpretation and Meaning of Dreams. Freudian Psychol- ogy and Analysis. 5 — ^Analysis and Examination of Typical Dreams. References — Ellis— The World of Dreams. DeManaceine — Sleep . Freud — Die Traumdeutung. Coriat — Abnormal Psy chology . Hollingworth — The Psychology of Drowsiness. Special Articles in Journals of Psychology and Psychiatry. XVII— MEMORY. I — Definitions, Distinctions and Illustrations. 2 — ^Analysis of Memory Process and Memory Consciousness. Retention, Recall and Recognition. 3 — The Forms and Classification of Memory. 4 — Memorability of Different Kinds of Material. 5 — Mnemonic Types and Devices for Aiding Memory. 6 — Experimental Investigations of Memory — Methods, Tech- nique and Problems; Rate of Learning and Memorizing; The Curve of Forgetting, for Recall and Recognition ; Con- ditions of Efficient Memorizing; Individual Differences. 7 — Practical Applications of Experimental Results. 8 — Pathology of Memory. Diseases and Anomalies. References — Watt — The Economy and Training of Memory. Colegrove — Memory. Ebbinghaus — On Memory. James — Principles of Psychology, Chap. XVI. Ladd and Woodworth — Physiological Psychology, Chap. VIII. Myers — Experimental Psychology, Chaps. XII and XIII. Pillsbury — Attention, Chap. IX. Hollingworth — Obliviscence of the Disagreeable. Hollingworth — Characteristic Differences between Recall and Recognition — Am. J. Psychol., Jan., 1914. Outlines for Experimental Psychology 21 F — Purely Introspective Experience. XVIII— SENSATION. I — Elementary Characteristics, Basis and Classifications, 2 — The Problem of Attributes (Modality, Quality, Intensity, Extensity, Duration, Clearness, Locality, Feeling-tone). 3 — Modal and Qualitative Differences. Specific Energies. Genet- ic Problems. 4 — Qualitative Relations — Mixtures, Fusions, Complements, Contrasts, Range and Distribution of Qualities in the Various Modalities. 5 — Sensitivity and Discrimination — Minimal and Maximal Stimuli, Differential Thresholds, Psycho-physics, Individ- ual Differences in Sensitivity. 6 — Temporal Relations — Inertia, Duration, Perseveration, Adap- tation, Fatigue, After-sensations. 7 — Spatial Attributes — Extensity, Locality, Local Signature, etc. 8 — Clearness and Intensity as Attributes, Differences, Bases. 9 — Feeling-tone of Sensory Experiences — Affective Qualities, Value Aspect of Sensory Experiences, Relative Aesthetic Values of the Modalities, lo — Disorders of Sensation — Anaesthesia, Hypersesthesia, Par- aesthesia. References — Titchener — Experimental Psychology (Qualita- tive) (Quantitative). Titchener — Text-book of Psychology. Ladd and Woodworth — Physiological Psychology. Myers — Experimental Psychology. McKendrick and Snodgrass — Physiology of the Senses. Other General and Physiological Texts. XIX— IMAGINATION. I — Centrally Excited Sensations — Character, Basis, Classifica- tion. 2 — Structural Distinctions — Image and Sensation, Image and Affection, Differences of Intensity, Clearness, Texture, etc. 3 — Behavior of Images — Influence of General and Special Condi- tions, Habit, Practise, Age, Drowsiness, Drugs, Purpose and Intention, Types of Imagery, Reproductive and Crea- tive Imagination. 22 Outlines for Experimental Psychology 4 — Experimental Determination of Imaginal Type, Methods, Difficulties. 5 — Function of Imagery in Thought and Action — Imagination and Memory, Imagery in Perception, Discrimination, Thinking, Production of Voluntary Movement. 6 — Pathology of Imagination. Applications of Facts and Laws of Imagery. References — Titchener — Text-book of Psychology. Titchener — Experimental Psychology of Higher Thought Processes. Woodworth — The Cause of a Voluntary Move- ment. (Essays in Honor of William James.) James — Principles of Psychology, Chap. XVIII. Lay — Mental Imagery. Betts — Distribution and Function of Imagery. Galton — Inquiries into Human Faculty, pp. 57!!. Hollingworth — Vicarious Functioning of Irrele- vant Imagery — Jour. Phil., Dec, 1911. Special articles in the periodicals. XX— AFFECTION. I — Characteristics of Elementary Affective Qualities. Feeling and Cognition. 2 — Feeling as Attribute of Sensation. Evidences for and against. 3 — Feelings as Special Sensations. Various Views and Argu- ments. 4 — Feelings as Elementary Experience. Neurological Basis. Relation to Economy of Energy, to End of Action or Ten- dency, to Motor Attitudes and Kinaesthetic Complexes, to Intensity of Nervous Impulse, to Associated Elements, etc. 5 — Forms, Dimensions and Varieties of Feelings. Classifica- tion of the Simple and Complex Feelings. 7 — Methods of Experimentation — Methods of Impression and Expression, Typical Experimental Studies and their Results. 8 — Determinants and Conditions of Feeling. Individual Differ- ences. 9 — Genetic, Fimctional and Pathological Aspects. Outlines for Experimental Psychology 23 References — Titchener — Text-book of Psychology, Section on Affection, Emotion. Titchener — Psychology of Feeling and Attention. Myers — Experimental Psychology, Chap. XXIV. Ladd and Woodworth — Physiological Psychology. Stout — Analytic Psychology. Allen — Physiological Aesthetics. Spencer — Principles of Psychology. Marshall — Pleasure, Pain and Aesthetics. XXI— IMPULSION. I — Characteristic Experiences of Desire, Longing, Wish, Impulse. 2 — Determining Tendencies, Motives, Values, Conscious Atti- tudes, Awareness of Task and Instructions, etc. 3 — General Character of Conation. Nervous Basis. Tendency toward End. Consciousness as Process. 4 — Descriptive Psychology of Conation — Tendency, Conflict, Resolution. 5 — Belief, Doubt, Faith, Acquiescence, as Conation Complexes. 6 — Pathology of Will, Fixed Ideas and Obsessions, Abnormal Instincts, Insanity of Doubt, Negativism, Aboulias, Re- pressions, etc. References — Stout — Analytic Psychology. Ribot — Diseases of the Will. Hart — Psychology of Insanity. XXII— JUDGMENT. I — Nature and Mechanism of Judgment. Perception of Rela- tions. Basis. 2 — Forms, Varieties and Classification of Judgments and Rela- tions. 3 — Laws, Behavior and Conditions of Judgments. 4 — Criteria and Bases of Typical Judgments. 5 — Problems in the Individual Psychology of Judgment — Con- sistency, Correctness, Judicial Capacity, Correlations. 6 — Judgment Elaboration and Reasoning. Psychology and Logic. 7 — Disorders of Judgment. 24 Outlines for Experimental Psychology References — Binet — The Psychology of Reasoning. Pillsbury — The Psychology of Reasoning. Titchener — Psychology of the Higher Thought Processes. Hollingworth — Experimental Studies in Judg- ment. Dewey — How We Think. Part II. LABORATORY MANUAL. GENERAL LABORATORY INSTRUCTIONS. At the beginning of the term the class will be divided into pairs of laboratory partners, who will work together throughout the year. In the laboratory reports, A's book will contain the results which he has obtained from his experiments on B, and vice versa. A will thus be known as the "experimenter" or "operator" and B as the "subject" or "reagent", or vice versa. In some cases comparison of results with those secured by all the members of the class may be called for. Laboratory Books — Two records are to be kept. In one book (with non-detachable sheets) records and results, observa- tions, measurements, etc., are to be noted as soon as they are obtained. This book is to be kept in a rough but systematic way. It is to be presented only when called for. It may contain any notes, observations, remarks or data which are secured during the experiment. The Final Reports are to be kept in a separate book, with detachable sheets and in standard-sized cover, with your name on the outside. This book is to be kept intact (the reports written in ink) and is to be presented at regular intervals for inspection. The reports should be placed in the order in which the experiments occur in the laboratory Manual. Into this book are to be trans- ferred the results previously noted down in the rough data book described above. These reports are to be prepared outside of the regular laboratory hours. The report of each experiment should cover the following points : 1. A statement of the purpose of the experiment, or of the PROBLEM which it is designed to solve, or the question for which the answer is being sought. 2. Description of the apparatus employed. Use the appro- priate technical names. 3. An account of the procedure or method followed in the experiment. When detailed account of procedure or method is 27 28 Outlines for Experimental Psychology provided in the Manual, it will be sufficient to avoid purely me- chanical copying by referring to the appropriate sections in the Manual. 4. Plain STATEMENT OF RESULTS, in form of table, chart, map, list, data, reports, etc. Always keep these data free from other material and on separate sheets whenever possible. 5. Interpretation — free discussion of the results, in the light of information obtained from personal observation and reflection, or from the lectirres and the literature. What are your FINAL CONCLUSIONS? What general laws can be formu- lated? What is the solution of the problem or the answer to the question? etc. 6. A brief statement of the references and authorities con- sulted. Give the title of the book, the name of the author, and the chapters, topics or pages read, if these are called for by the instructor. Special References to be read at this point. Read any two. I — Seashore — Elementary Experiments in Psychology — Introduction. 2 — Judd — Laboratory Manual of Psychology — Introduc- tion. 3 — Myers — Experimental Psychology — Chap. I. 4 — Titchener — Student's Qualitative Manual — Introduc- tion. Outlines for Experimental Psychology 29 Introductory Experiments. A— INDIVIDUAL DIFFERENCES. Measure all the members of the class in the following traits or abilities. Plat the measurements for each trait in the form of a curve of distribution. Consult the instructor for directions as to units and scales for these curves. Find the average, median and mode for each trait. Which of these measures would afford the most representative statement of the character of the group? Having selected this most representa- tive measure, compute the variability (mean variation) of the group from the central tendency. Do individuals differ in the same way or to the same degree in all of these traits? Do you find any indications of bi-modality or of skewed distribution in the curves? What is the significance of these findings? What does it mean to be a normal individual? An abnormal individual? How would these conditions be represented on your curves of distribution? LIST OF TRAITS TO BE MEASURED. I — Time required for first solution of a mechanical puzzle. 2 — Steadiness, as indicated by the number of contacts in one minute with the motor-board apparatus. 3 — Cephalic index — found by dividing the width of the head, at its widest part, by the length of the head, in its longest line from the forehead directly backward. Use anthropometric calipers. 4 — Time required to make 25 words of the letters foimd in "psychiatry". 5 — Time required for some standard form of the "cancella- tion test". 6 — Strength of grip as registered by the dynamometer. 7 — Time required for first completion of the "form-board" test; let the reagent first examine the board visually; he is then to perform the test when blind-folded. Record time with stop watch. 8 — Time required to repeat the alphabet backward correctly. 9 — Suggestibility, as measured by the size-weight illusion, one trial. 10 — Time required for a standard "sorting test". 30 Outlines for Experimental Psychology B— INDIVIDUAL UNIFORMITIES. Inspect your fellow students as they work at their desks or in the library. How many are writing with the right hand and how many with the left hand? What conclusions are suggested? Ask your partner to tell you the first word that comes to his mind when you pronounce one of the following "stimulus words " — table, rose, color, flower, man. Do the same experiment on several other members of the class, using the same "stimulus word" in each case. What are the results? Draw up a list of traits or respects in which people will tend to resemble each other. On what factors will the degree of re- semblance probably depend? Draw up a similar list of traits in which people will tend to differ from each other more or less strikingly. On what factors will the amount of difference probably depend? Psychology of General Efficiency. DISCUSSION. We have seen that individuals show certain resemblances and certain differences, both with respect to performance and with respect to the constitution and behavior of their consciousness. The first problems of experimental psychology may then center about these facts. We may ask such questions, or set such prob- lems, as the following, and endeavor to answer or solve them by the application of experimental methods. I — How large are the differences which different people may show? 2 — What are the factors which determine the direction and the amount of these differences? 3 — To what degree and in what ways are the various traits modifiable by external conditions or by internal atti- tudes? 4 — What relations exist between differences in one trait and differences in other traits? How far does poor- ness, goodness, or other peculiarity in one trait in- volve similar standing in other traits? 5 — How do the various capacities fimction most efficiently? What is wrong when inefficiency of consciousness or of performance is present? Many similar questions might be asked, and the replies which are made to them might go a long way toward determining our judg- ments of others, our reactions toward them, and our expectations of reaction on their part toward us or toward the varied situations of daily life. Some such problems will be presented in the experi- ments to follow. Outlines for Experimental Psychology 31 The Effects of Practise. It is a familiar fact that practising any act leads to greater proficiency in its performance. An experiment in practise has for its object the determination of the exact course, rate and condi- tions of improvement. The "practise curve" is a means of pic- turing the course of improvement in a graphic manner. It is similar in principle to temperature curves, curves of barometric pressure, wind velocity, growth of population, etc., used in other sciences. The points in the horizontal line represent the successive trials. Points on the vertical axis represent the efficiency of the trials. For this reason it is convenient to plat the curves on co- ordinate paper. Certain essentials must be observed in practise experiments — I — The thing to be practised should be something unfami- liar, for otherwise the first part of the practise curve is not determined. 2 — The conditions shotdd be kept constant throughout, and the course of performance thus kept free from the influence of outside and irrelevant factors, or factors which are not under control. 3 — All trials should be recorded, there must be no "interim practise" — that is, practise between the experimental trials. 4 — Note should be made of the introspections of the per- former as he goes through the trials. He should report any changes in method, anything observed which might throw light on the conditions of effi- ciency, and give detailed account of what goes on in the mind during performance. 5 — The performer should be kept in ignorance of the records he is making until the experiment is completed. He should not be allowed to be influenced by any ex- ternal suggestions. 32 Outlines for Experimental Psychology EXPERIMENT i— PRACTISE AND TRANSFER IN PERCEPTIONAL REACTIONS (CANCELLATION). By a perceptional reaction is meant a movement whose char- acter and speed are determined by the accurate perception of some feature of the stimulus. The movement itself must be simple and of an automatic kind, but the stimulus may be of any kind or of any degree of complexity. For example, sorting a pack of cards into four suits as rapidly as possible involves a series of percep- tional reactions. Convenient material for studying this sort of behavior is also afforded by printed matter, out of which certain characters or groups of characters are to be cancelled. This sort of test is known as the "cancellation test". It is a much used test in experiments on fatigue, practise, transfer, interference, attention, perception, etc. Special blanks have been devised which permit of great variety in method and purpose of experi- ment. Among the problems which may be investigated by such ex- periments are the following — I — To what extent are perceptional reactions susceptible to improvement by practise? 2 — Does increased skill in one form of perceptional reaction show itself in other perceptional reactions? On what conditions or factors does the result depend? 3 — How do individuals differ in rate and amount of improve- ment by practise, and in the effect of such practise on other perceptional reactions? 4 — ^What are the internal and external conditions which determine skill in such a performance? 5 — What activities of daily life involve perceptional reactions? Procedure — 1. A special blank (Woodworth-Wells form) is provided, con- taining 1 68 six-digit combinations. Cover the blank with a sheet of paper and place it before your subject, in a convenient position. Provide the subject with a mediimi-soft lead pencil. At the "Ready, Go" signal the subject is to begin at the top of the blank, and check off all those combinations which contain both the digits 2 and, J. He is to pass from left to right, as in reading, is to make no errors, is to continue without pause until the blank is com- pleted, and is to finish the test as quickly as he can. Record, in fifth-seconds, the time taken. 2. After this test, provide yourself with lo blanks. Have your subject go through these ten in succession, checking off this time all combinations containing both the digits 8 and p. Take the time for each of the lo tests, and plat the practise curve for these ten trials, after the whole experiment is completed. Outlines for Experimental Psychology 33 3. After these 10 blanks have been marked, and the curve of practise for the perceptional reaction thus secured, give him a final blank, and ask him again to cross off all combinations con- taining both 2 and j, as in the first part of the experiment. Take the time required, and compare this with the record originally made in the 2-3 test. 4. Call for introspections from the subject as to the attitude, the method used, changes in method, etc., during the test. Precautions — Let a comfortable pause intervene after each blank so as to avoid eye strain, fatigue, etc. See that the sub- ject is not distracted. Conclusions — On the basis of this experiment, what replies are to be made to the preceding questions? Give full and detailed proof. What are the chief sources of error in such an experiment? EXPERIMENT 2— PRACTISE IN PUZZLE SOLUTION. Still more complicated than the simple perceptional reactions are such processes as involve "skill" — processes in which both the stimulus and the movement change from time to time, and in which the movement is to be accommodated to or directed by the change or the desired change in the stimulus. Such processes are to be found for example in handling the "novel situations" presented by the attempt to solve a mechanical puzzle. Here the movement will vary according to the different positions which the parts of the puzzle from time to time assimie. And the whole process will be directed by the desire to "change the stimulus" — ^that is, to arrange the parts of the puzzle in some definite position or relation. Do not forget that the psychological interest is not so much in the puzzle itself as in the process of solving it, and of acquiring com- plete mastery of the new reaction. Such questions as the following at once suggest themselves in this connection — I — Is the first solution accidental, partly understood, or thoroughly understood beforehand? 2 — Do any changes in method, variations in the "mode of attack" occur during the series of trials? What is the nature of such changes if they occur? To what degree are they successfiil? 3 — ^What part does imagination or "imagery" play in such a performance? 4 — Do individuals differ more in capacity (as shown by their final degree of skill) or in performance (as shown by their initial skill)? What does this mean in daily life? 34 Outlines for Experimental Psychology 5 — How do individuals differ in their ability to improve? 6 — ^Are individual differences disclosed in such a test as this likely to hold good of the individual performance in daily life? Give the reasons for your belief. Procedure — Select a puzzle which is wholly unfamiliar to your subject. Place it before him in a definite position, instructing him as to what is to be done with the puzzle (whether it is to be taken apart, put together, or placed in some definite relation, etc.). Let him then solve the puzzle as quickly as possible, and take his time with the stop watch. Leave him entirely to his own devices, and avoid any hints or suggestions. After each trial let him write down, under the number of that trial, all that he can remember of the process gone through during the trial — the methods used, the different things tried, the chief difficulties, whether the solution was accidental or planned and "seen through" beforehand, whether changes in method occur from trial to trial, whether imagery played any part in the process, and whether such imagery was helpful or detrimental, in his own mind. Repeat the experiment for trials. Do not allow the subject to replace the puzzle in its original position, after solution. Do this yourself, out of his sight, and place it before him, at each trial, in the original condition and position. Plat the practise curve on co-ordinate paper, laying off on the base line the successive trials, and on the vertical line the time required, in seconds or in minutes. On the basis of your data what replies are to be made to the questions suggested in the preceding discussion of the experiment? Give your proof in full, by means of figures, tables, curves, etc. References — Ruger, The Psychology of Efficiency. Royce, The Psychology of Invention (Psych. Rev. V, 113-144). Lindley, Article on Puzzles (Am. Jour, of Psychol.). Book, The Psychology of Skill. Bair, The Practice Curve. Outlines for Experimental Psychology 35 Individual Differences and Effects of Practise. Thinking is often said to be largely a matter of association of ideas. The objects of our experience are associated with their names ; ideas are associated with other ideas ; tasks and situations are associated with ideas which will handle or solve them effective- ly. In these processes three chief stages may be distinguished, which are illustrated in the following experiments. The three stages show interesting differences, both from the standpoint of the character of the processes, and from the point of view of indi- vidual differences in the efficiency of their performance. EXPERIMENT 3— FIRST STAGE. Association of Ideas and Words with Simple Objects of Experience. This process is illustrated by the color-naming test. The experiment is designed to measure the speed with which the name or idea can be brought to consciousness upon the sight of the object, which is, in this case, a color. In the beginning of the experiment the test measures the familiarity with colors and the accuracy of color discrimination as well as the absolute quickness of the thought process involved. As the experiment progresses the test measures the ability of the individual to improve by prac- tise, his degree of interference, as shown by the tendency of a pre- ceding idea to inhibit or interfere with the correct perception and expression of the next impression. It also measures the regularity of performance and the susceptibility to fatigue. Method — The card provided in the laboratory contains 100 colored squares. Name them through as rapidly as possible, beginning in the upper left hand comer, while your partner takes your time with the stop watch. Read every line from left to right. Then rest while you take your partner's time for the first reading in the same way. Continue this process until each has made 15 trials and thus has 15 measures of association speed, taken in succession. Plat these 15 trials on co-ordinate paper, so as to secure a practise curve for the experiment. Ask the in- structor what units to use in platting these curves. Include both the tables and the curves in your note book. EXPERIMENT 4— SECOND STAGE. Association of One Idea with Another Specific Idea. This process is illustrated by the test of naming opposites. To think of the exact answer to a question, the precise address of a friend, the exact shade of meaning of a word, delicate distinc- tions of connotation in the use of language, all involve a process of controlled association, a process in which, from many ideas which the stimulus calls up, the one appropriate idea is recognized, 36 Outlines for Experimental Psychology selected and expressed while the false or inadequate ideas are repressed or inhibited. Hence this test measures the ability of the individual to select the appropriate response from the host of ideas which follow in the wake of the stimulus word. It is thus an index of speed, accuracy, linguistic feeling and of the ability to suppress useless or irrelevant ideas. At the same time it shows the ability of the individual to improve by practise as well as indi- cates the regularity of his performance. Method — The cards provided contain a list of 50 words, each card presenting the same words, but in a new order. The test is to go down the list, naming, as quickly as possible, the opposite of each word (antonym), in the order in which they appear in the list. Let your partner take your time with a stop watch. Your partner should follow the list carefully as you proceed, and should say " No " if you give an unsatisfactory response. Never pass to a new word until the correct opposite of the preceding word has been given. Rest a moment while you take your partner's time for the test, then repeat it yourself as before. Continue this process until you have made 15 trials of the test, using a new card at each trial. Then plat your practise curve for the experiment, and in- clude it in your report, along with the table. EXPERIMENT 5— THIRD STAGE. Association of an Idea With a Specific Task or Situation. A still more complex stage in association is found when a specific task or situation calls for an appropriate and immediate response. The ideas themselves are not given. The individual must provide his own ideas or images, juggle them in his own way, but he must come out of the process with the right response. It is thus a case of evolving an idea to meet an unexpected situation. The question is — "How quickly can the individual manipulate his mental processes so as to call up the right idea in his conscious- ness and set up movements of artioilation which will express to an onlooker the result of his thinking?" Method — Without the aid of any graphic device, add 17 mentally to each of the nimibers on the card provided for the experiment. Let your partner check up your answers with the aid of the key card. Always give the right answer before proceeding to the next number. Repeat this test 15 times, alternating with your partner. Use a new card each time, the numbers being the same, but occurring in different orders on the various cards. Then plat your practise curve for the experiment, and include it with your table in your note book. As before, ask the instructor what imits to use in platting these curves. Outlines for Experimental Psychology 37 EXPERIMENT 6. Individual Differences. Using a different color for each individual, plat, on the same chart, the practise curves of 4 different people — yourself, your partner, and two other partners in your own laboratory section. Use a different chart for each of the three tests just described. You will thus have three charts, each bearing four curves. On the basis of these curves make out the answers to the following questions and point out the proof for the correctness of your answer to each question. Answer these questions for each of the three tests. I — How do individuals differ in the beginning of such an exper- iment in association? What is the ratio of the best to the poorest? 2 — How do individuals differ at the end of the experiment? Does practise decrease individual di_fferences, thus making people more alike in the end than they were in the beginning, or does practise accentuate these differences, so that people are more differ- ent after practise than they were before? (It is easy to make false assumptions or to commit various sorts of fallacies in answer- ing this question.) 3 — How do the four individuals differ in their rate of improve- ment — in the degree to which they can improve by practise, and in the rate of this improvement? 4- — Is improvement in such performances regular or uniform? 5 — Are there plateaus in these practise curves? If so, what do they probably mean? If not, why do they not appear? 6 — Are people who are quick also likely to be regular? Do you find any sort of correlation between speed and regularity? 7 — Do you find any relation between speed and ability to improve by practise? 8 — Make an intensive study of this experiment, writing it up carefully and completely. Add any other points noted. 38 Outlines for Experimental Psychology EXPERIMENT 7. Qualitative Differences. Average the results of 4 subjects for each of the three tests; thus getting a typical practise curve for each kind of performance. Plat these three curves, in different colors, on co-ordinate paper, using identical units. On the basis of your curves make out the answers to the following. I — Do the three stages of association yield to practise with equal rapidity? If not, in which is the improvement most rapid? How do you explain these facts? 2 — Do the three stages yield to practise with the same uni- formity? If not, what differences are disclosed? How can they be accounted for psychologically? 3 — Do the people who make the quickest records in one of these tests also show up well in the others? 4 — Are the people who are uniform and regular in one test also uniform and regular in the others? How about the irregular ones? 5 — ^What psychological explanations can you suggest for the relations shown under points 3 and 4? 6 — Make an intensive study of this topic, writing it up care- fully and completely. Add any other points or comments which may have occurred to you as having psychological interest. References for experiments 3 to 7. Whipple — Manual of Mental and Physical Tests, Chap. IX. Whitley — Tests for Individual Differences, pp. 98-136. Wells — Practice Effects in Free Association — ^Amer. Jour, of Psychol, January, 191 1. HoUingworth — Individual Differences as Affected by Practise — Psych. Rev., Jan., 1914. Brown — Habit Interference in Sorting Cards. Outlines for Experimental Psychology 39 Fatigue. DISCUSSION. After an unfamiliar act has been perfected, by means of prac- tise, performance in it may still show certain striking variations in speed, accuracy, regularity or quantity. These may be due to any one or more of a great variety of factors, among which may be mentioned fatigue, lack of incentive, sickness, daily rhythms and other forms of periodicity, conditions of the weather, etc. The most familiar of these factors, and perhaps one which, in its general character, includes many of the other factors, is fatigue. Fatigue has both its internal and its external aspects. From the point of view of performance, fatigue means diminution in the capacity for work. From the point of view of conscious- ness it means a certain complex mental state in which lack of interest, ennui, strain, soreness of muscles, impleasantness and aversion may be discerned as part factors. It is of psychological interest to know the cause and conditions the course of development, the meaning and function, the laws and types of fatigue, and the ways in which individuals may differ in these respects. Among the principal points of interest may be mentioned the following — I — The normal characteristics of the fatigue curve. 2 — The different forms or types of fatigue curves, and their meaning. 3 — The different kinds of fatigue, and their respective causes. 4 — Methods of relieving or avoiding fatigue. 5 — Methods of detecting and measuring fatigue. 6 — The fimction and consequence of fatigue. 40 Outlines for Experimental Psychology EXPERIMENT 8— FATIGUE IN THE TAPPING TEST. The tapping test measures the speed and endurance with which unloaded muscles can execute successive contractions of a rather narrow range. The subject holds in his hand a metal stylus, and rests the arm on the table, so that the forearm constitutes a lever, with the elbow as fulcrum. The stylus thus held may be made to strike a metal plate, and the two are so connected with an electric counter that each contact is recorded. The factor of accuracy is thus eliminated, and the performance may be measured in terms of speed and rate (by speed is meant the total time, and by rate is meant the distribution of the separate strokes within this total time). When the apparatus is in readiness, instruct your subject to start at your signal and to tap as rapidly as possible, without any rest pauses, until the muscles of the arm are fatigued and will ex- ecute no more contractions. I — With the stop watch record the time in seconds and fifth- seconds required for each group of 25 or of 50 taps (according to the directions of the instructor) until the subject is fatigued. 2 — Plat these records on co-ordinate paper, so as to show the curve of work. 3 — Compare this curve with other curves being made in the laboratory. 4 — On the basis of these data what may be said on the points of interest mentioned in preceding paragraphs? 5 — What additional information is yielded by the introspec- tions of your subject? References — M osso — Fatigue . Ladd and Woodworth — Physiological Psychology. Myers — Experimental Psychology. Offner — Mental Fatigue. Hollingworth — Variations in Efficiency During the Working Day — Psych. Rev., 1914. Outlines for Experimental Psychology 41 Efficiency of Single Sensori-Motor Arcs. DISCUSSION. Reaction Times — By a reaction time is meant the interval elapsing between the reception of a given stimulus and the pro- duction of a specified response. The character of the stimulus may vary according to the purpose of the experiment — thus it may be a sound, a flash of light, an electric shock, a touch, or the exposure of a colored disc, a word, an object, a statement of rela- tion, a logical proposition, etc. The response may also be varied and complicated in a variety of ways, according to the purpose of the experiment. Thus it may consist in pressing a telegraph key, moving a lever, squeezing a bulb, uttering a word, etc. The total reaction time includes the following processes — I — The latent time of the sense organ involved. 2 — Passage of the sensory impulse to the brain or spinal center. 3 — Communication between sensory and motor centers. 4 — Passage of motor impulse to the muscle. 5 — Latent time of the muscle or muscle group. Taken as a whole this reaction time is a measure of the abil- ity (speed, accuracy, uniformity, rate of adaptation) of the nervous system to respond to the situation in question, in a defi- nite way. The reaction may be a simple reflex, or it may or may not involve perception, discrimination, association, choice, judgment, decision, etc., depending on the conditions of the ex- periment, the nature of the task set, the attitude of the subject, etc. The method of measurement is simple in principle, al- though the apparatus, which is designed to facilitate precise meas- urement, may in some cases be very elaborate. In principle — the application of the stimulus sets going some mechanism which is stopped by the occurrence of the response. By appropriate means the interval between these two events is thus easily recorded, and this interval constitutes the "reaction time' >> Each experiment will require a considerable number of measurements, because different trials will result in slightly differ- ent reaction times. These times will vary about an average or norm. This will make possible the following significant meas- ures — I — The average time (or the median or mode). 2 — The uniformity (variability around the average, etc.). 3 — The degree and rate of adaptation (practise, etc.). 42 Outlines for Experimental Psychology Introspections should always be recorded and frequently asked for during the course of an experiment. The subject should be asked to tell what went on in his mind, what was in his conscious- ness, etc., just before, during, and immediately after the reaction. These introspections, when paralleled by the measurements them- selves, may often throw considerable light on the causes of differ- ences, changes, characteristics, etc., of the reaction times. Types of reaction experiments. Depending on the condi- tions of the experiment, the character of the stimulus and of the response, and the nature of the reaction process from the point of view of the subject, we may distinguish three principal forms of reaction-situations. I — The Simple Reaction. 2 — The Discrimination Reaction. 3 — The Discrimination-and-Choice Reaction. EXPERIMENT 9— THE SIMPLE REACTION. After having been instructed in the use of the chronoscope used in the laboratory, determine your partner's reaction times under the following typical situations. Make — trials in each experiment. In each experiment compute the average and the variability, and examine into the tendency to adaptation. Observe the standard precautions with respect to ready signal, interval between ready signal and stimulus, elimination of distractions, of suggestions, of expectations, etc. (a) Simple reaction to a visual stimulus. (b) Simple reaction to an auditory stimulus. (c) Simple reaction to a tactile stimulus. What differences in speed and in uniformity do the modalities of sight, sound and touch disclose? How are these differences to be explained? Do all the members of the class agree in these respects? Outlines for Experimental Psychology 43 EXPERIMENT lo— EXTERNAL DETERMINANTS OF REACTION TIME. Among these may be mentioned the quality, intensity, ex- tensity, duration, and abruptness of the stimulus. This type of influence may be well illustrated by an experiment on the influence of the intensity of a sound on the speed of the reaction. Using the sound-hammer provided in the laboratory, take the natural reactions ( — trials) to each of three intensities of sound stimulus, letting the three intensities occur in a random order. a — How does intensity influence the average reaction time? b — How does it influence the variability? c — Is the change in time proportionate to the difference in the intensity of the stimuli? How can you tell? d — How are these results to be explained? EXPERIMENT ii— INTERNAL DETERMINANTS OF REACTION TIME. Among these may be mentioned age, sex, practise, attitude, interest and attention, fatigue, drugs, expectation, etc. This type of influence may be illustrated by an experiment on the differ- ences between the so-called sensorial and muscular reactions. Using the sound stimulus, take one series in which the subject is instructed to direct his attention toward the stimulus, and an- other series in which he is instructed to direct his attention toward the movement to be made. The first type is called sensorial, the second muscular. Riui the two series simultaneously, giving now a sensorial, now a muscular group, with lo reactions in a group, and groups in the series. Compute averages and variabil- ities. a — What differences are fovmd between the two types? b — How are these differences to be explained? c — To which type does your subject's "natural" reaction most closely approximate? What does this indicate? SUMMARY OF EXTERNAL AND INTERNAL CONDITIONS. Enumerate all the factors in each group, in the order of their importance, placing the most important first. In connection with each factor, state the nature of its influence on the simple reaction time, as determined from experiment, reading, general observa- tion or inference. 44 Outlines for Experimental Psychology EXPERIMENT 12— THE DISCRIMINATION REACTION. The discrimination situation is produced by presenting a num- ber of stimuli, alternately, and instructing the subject to react only to a specified stimulus, making no reaction whatever when the stimulus presented is not the one specified. Determine, as an illustrative experiment in this class of reactions, the time re- quired to discriminate between a red and a blue stimulus card. Present the cards in a chance order, as in previous experiments. Require the subject to react whenever the red stimulus card ap- pears, and to do so as quickly as possible. Whenever the blue card appears he is to make no response whatever. Make — trials with each stimulus, and compute the average and M. V. a — How do these measures compare with the simple reac- tion times? b — How do you account for such differences as are found? Ask the subject to report what took place in his mind under the different circumstances. Does his testi- mony (introspection) throw any light on the differ- ences found? c — Secure the simple reaction time and also the discrimina- tion reaction time for all the members of the class. Are those whose simple reactions are quick also quick in this discrimination experiment? How are the facts to be explained? d — Do you observe any tendency on the part of this dis- crimination reaction to become reflex as the experi- ment proceeds? How could this happen, if it should be found in any case? EXPERIMENT 13— DISCRIMINATION AND CHOICE REACTIONS. Again present the blue and the red cards, each — times, in chance order. Instruct your subject to react as quickly as possi- ble, with the right hand when the red disc appears, and with the left hand when the blue appears. Caution him against making false reactions, such as reacting with the wrong hand, and record all such reactions if he should make any. a — How do the times and their variabilities compare with those of the simple, and those of the discrimination reactions? b — Does the introspection of your subject throw any light on the reasons for the characteristics of these compli- cated reaction times? — Does this type of reaction tend to become reflex? Outlines for Experimental Psychology 45 References on Reaction Times — I — Froeberg — Influence of Intensity on Reaction Time. 2 — Jastrow — Time Relations of Mental Phenomena. 3 — Ladd and Woodworth — Physiological Psychology. 4 — Myers — Experimental Psychology. 5 — Titchener — Text-book of Psychology. Experi- mental Psychology. 6 — Cattell — Psychological Researches, Chap. I. 7 — Scripture — The New Psychology. EXPERIMENT 14— FACILITATION AND INHIBITION. (Reenforcement, Dynamogeny, Distraction, Interference) At this point, if time allowed, a series of interesting experiments might be performed, which should be designed to demonstrate the way in which simultaneous mental or motor processes influence each other. The student may at once think of cases in daily life in which simultaneous processes, in consciousness or in per- formance, mutually aid each other, or in which one process goes on more efficiently because of the activity of the other. He may also think of situations in which the result may not be facilitation but inhibition — both processes are interfered with, or the one suffers because of the presence of the other. It would be of psychological interest to know under what cir- cumstances the result of simultaneous processes is facilitation, and under what conditions it is interference instead. Class room demonstrations of such situations may be made, and the student may then write up an account of what took place during the demonstration, reporting it after the manner of an individual experiment. References — Fere — Sensation et Mouvement. Ladd and Woodworth — Physiological Psychology. Todd — Reaction to Multiple Stimuli. McDougall — Physiological Psychology. Sherrington — The Integrative Action of the Nervous System. EXPERIMENT 15— EXPRESSIVE MOVEMENTS. Experiments on these topics do not admit of very satisfactory performance under general laboratory conditions. Conditions are hard to control, distractions likely to occur, and the necessary apparatus and technique may be complicated and delicate. Class room demonstrations of some of the principal facts may be given, and the student may then write up an account of 46 Outlines for Experimental Psychology what took place before him, after the manner of an individual experiment. The demonstration may include — I — Observation of one or more individuals in typical emo- tional, attentive, reflective and impulsive attitudes. (Anger, Surprise, Embarrassment, Doubt, etc.) De- scribe the expressive movements, postures, etc., and distinguish between the relevant and the irre- levant. Causes and function of these expressive reactions. Individual differences and types. 2 — Precise measurement of changes in some organic pro- cess (breathing, heart beat, volume, perspiration, etc.) under typical conditions. 3 — Experiments, by Methods of Impression, on judgments of character and capacity, as expressed by physiog- nomy, facial expression, pose, etc. References — Mantegazza — Physiognomy. Darwin — Expression of Emotions in Men and Animals. Ladd and Woodworth — Physiological Psychology. Titchener — Experimental Psychology (Qualitative). Myers — Experimental Psychology. James — Principles of Psychology, Chap, on Emotion. Physiognomy and Expression. DISCUSSION. An important factor in daily life is to be found in our constant attempts to "interpret" facial expression, gesture, bodily attitude and pose, inflection, and various other incidental aspects of ex- ternal behavior, such as blushing, hesitation, awkwardness, mis- speaking, etc. These external processes are felt to be in some more or less definite way correlated with states of consciousness — intentions, feelings, moods, temperaments, etc. In its extreme form this idea may develop into the absurdities of phrenology, clairvoyance, palmistry, etc. In its more reasonable and sensible form the idea is known in psychology as the doctrine of "expressive movements". States of consciousness are accompanied by characteristic reactions on the part of the muscles of the body. Indeed the consciousness of the moment may be largely constituted by the awareness of these reactions. At any rate, much of the significance of a stimulus or situation, as it comes to consciousness, depends on the reflex or instinctive reactions which are set up in response to it. Quite apart from the genuine and necessary correlation between these expressive movements and the transient or permanent char- Outlines for Experimental Psychology 47 acter of the consciousness which accompanies, precedes or follows them, it is of psychological interest to know what correlations people believe to exist between the two. We "size up" people on short acquaintance, and we do this chiefly on the basis of momen- tary expressive movements or on the basis of more or less per- manent facial sets, attitudes, or typical features. The purpose of the present experiment is to determine to what extent people agree on such "judgments of character", to what degree different judgments of the same individual are consistent, and on what external and internal factors these judgments depend. EXPERIMENT i6.— JUDGMENTS OF CHARACTER. A series of photographs or portraits is provided. These are to be arranged in an "order of merit" according to the degree to which they suggest such traits as beauty, himior, honesty, kind- ness, generosity, intelligence, etc., or their opposites. The in- structor will give specific directions for your own share in the ex- periment. From him you will also learn methods of handling your data so as to secure the information sought. The experi- ment will include the following points — I — Arrangement for a given trait by the same observer on two different occasions, and the determination of the "personal consistency" coefficient. 2 — Comparison of the records by this individual with the average judgments of the class as a whole, and the determination of the "judicial capacity" of the in- dividual in question. 3 — Determination of the relation between the personal consistency coefficient and the index of judicial capac- ity. Is the individual who is most sure of his own mind also the best judge of the opinions of others? 4 — Examination of the final average order and of the in- dividual orders for the purpose of determining what features of the faces are judged to be significant of the particular traits. 5 — Determination of the influence of the attitude of the observer on the outcome of his judgment. References — Mantegazza — Physiognomy. Norsworthy — Judgments of Character. HoUingworth and Strong — Influence of Form and Category on Outcome of Judgments of Character. Darwin — Expression of Emotions in Men and Animals. Scott — The Psychology of Public Speaking. 48 Outlines for Experimental Psychology EXPERIMENT 17— EXPRESSIONS OF MOOD AND EMOTION. Discussion. The purpose of this experiment is to study the facial expression of the various moods and emotions and the judgments we pass when we attempt to interpret the play of facial expression. The following questions may be noted as suggestive. Other questions will come to your mind as the experiment proceeds. a — What are the typical facial expressions of the various moods and emotions? How much variation is shown from person to person or from moment to moment, situation to situation in the case of the same individ- ual? b — How easily and quickly can we recognize the individual's mood or emotion on the basis of the expression of his features? c — Are some moods or emotions easier to identify and recog- nize than others? If so, what are the reasons for this? d — Are some moods or emotions easily confused with others, on the basis of their physical expressions? If so, which are these and what are the relatioiis, if any, between them? e — How consistent is a given person in judgment of this sort, on different occasions? f — How closely do people agree in their judgments of mood and emotion, as based on facial expression? g — ^At what age do children seem able to recognize the various emotional expressions? Do they recognize some of them earlier than they do others? Procedure — You will be provided with a set of 24 photo- graphs of the same person in different moods or emotional atti- tudes.* I — State in each case the emotion or mood represented or being experienced by the individual at the moment. Record your judgment alongside the nimiber of the photograph in your note book. 2 — Some time later (as the next week) repeat this process, without referring to the original records. Take a new and independent attitude toward the photographs, just as if you had never seen them before. 3 — Compare the two trials now, endeavoring to answer the questions suggested above, and others that have oc- curred to you. * A convenient set will be found in the paper by Feleky, in the Psycho, logical Review, January, 19 14. Sets of the photographs may be secured from Prof. E. L. Thomdike, Teachers College, Columbia University. Outlines for Experimental Psychology 49 4 — Bring together, under each number, all the judgments of the various members of the class, noting how closely they agree, and what the points of agreement and disagreement are. 5 — Suggest some new experiment that might be made with this material or in this field. Describe the experi- ment in detail, stating its purpose and its method of procedure. References — Darwin — Expression of Emotion in Men and Animals. Mantegazza — Physiognomy and Expression. James — Principles of Psychology, Chap, on Emotion. EXPERIMENT i8— FEELING AND ORGANIC PROCESSES. It has been suggested that not only the phenomena of attention but many things in the psychology of feeling as well may be closely correlated with organic changes and processes — such as modifica- tions in muscular contractions, in heart beat, volume of the blood vessels, rate and intensity of breathing, etc. Especially in connec- tion with the psychology of attention it would be interesting to know whether the attention wave and the fluctuations found in various conditions of perception can be correlated with any of these factors. It must be said that the various investigators are not yet agreed on the matter. This experiment will conse- quently be moving in a rather unsettled field. Procedure. — Familiarize yourself, by examination and pre- liminary practise, with the apparatus used for measuring respira- tion and heart action. Investigate the following problems as fully as the results seem to warrant. The influence of muscular effort on respiration (dynamo- meter). The influence of mental work on the breathing curve. The influence of disagreeable stimtdi (try various modali- ties). The influence of agreeable stimuli. The experiences of shock, surprise, amusement, pain. In these connections always secure a normal tracing at the beginning and end of the experiment. Observe the rate of inhala- tion and exhalation, the duration of the process, the depth of each, and the general level of the curve. Any or all four of these things may be foimd to be important things to compare. What is the typical modification produced by each of the ex- periences studied? 50 Outlines for Experimental Psychology Are the various sorts of consciousness really accompanied by characteristic bodily reactions? Include tables and curves in your reports. References — Ladd and Woodworth — Physiological Psychology, Chap. VIII. Titchener — Qualitative Manuals, Chap. VII. Kulpe — Outlines of Psychology — 225-276; 320-331. Titchener — The Psychology of Feeling and Attention. Wundt — Outlines of Psychology (Feeling and Emo- tion). James — Principles of Psychology (Emotion). Outlines for Experimental Psychology 51 Attention. Each of the following experiments is designed to illustrate one of the principal results or laws of attention. After solving the special problems presented in a given experiment, generalize your results into a statement which will express a fundamental law or result of attention. When you have completed all the experiments on attention, bring together these various laws, in the form of a synopsis or table. EXPERIMENT 19— ATTENTION AND CLEARNESS. A — Secure a set of puzzle pictures and try to find the concealed figures in each. Note that when once found they force themselves persistently upon you, although, on first observing the pictures, the special outlines were not even perceived as units or as forms. The outline of the hidden figure now seems more distinct than the other lines of the picture, and the "sense " of the picture as a whole recedes into the background. Does the change seem to be merely one of "intensity", or is "clearness" or "vividness" perhaps an unique and independent attribute or quality of the visual impression? B — Fixate a letter in the center of a printed page. How many adjacent letters can you clearly see while fixating this central point? While carefully maintaining this same point of fixation, can you direct your attention to the peripheral parts of the field of vision, thus clearly recognizing letters which lie at the edges of the page, or at some distance above or below the fixation point? As you shift your attention from point to point, what changes do you observe in the clearness of the various parts of the printed page? (To perform this experiment great care must be taken not to change the point of visual fixation, since in natural vision we are always inclined to direct our line of vision to the point to which our attention is directed.) Are the fixation point of the field of vision and the fixation point of attention identical, or can they by practise be separated, and the attention directed to the point in indirect vision? References — See last page of this section on "Attention". 52 Outlines for Experimental Psychology EXPERIMENT 20— ATTENTION AND INTENSITY. A — Strike a low tone upon the monochord. The resulting sound will seem to be a single tone, with definite pitch, loudness (intensity) and timbre or quality. While the string is vibrating, touch it with a feather at a point one-half, one-third or one-fourth the way along the string, from either end. Observe the rise of a fainter tone, which has a higher pitch than that produced by the vibration of the wire as a whole. This is an overtone. Now strike the string again, as before. Observe that these various overtones can be heard along with the main or fundamen- tal tone. Single out by attention some one of the overtones — does it seem to change in loudness? Now attend to the fundamental — is its intensity also increased by attention? B — Cite other illustrations of a simpler sort, which indicate the influence of attention on the intensity of an impression. C — Are you still convinced that intensity and clearness are identical (or different attributes, as the case may have been decided in Experiment i)? If you decide that they are different, what evidence can you offer? References — See last page of this section. EXPERIMENT 21— ATTENTION AND DURATION. Using the stereoscope, place before one eye a plain red field and before the other eye a plain green field. Hold the stereoscope steadily before the eyes and note the colors that appear, and any changes in the order in which they occur. Note that the colors do not mix or fuse, since they are on different eyes, nor do they both appear at once unless the slide is- out of focus. In this case the two colors are seen side by side. Adjust the stereoscope so that the two squares coincide. The colors will now alternate, the single combined square seeming now red, now green. This effect is known as "binocular rivalry". With the stereoscope adjusted in this way, work out the following problems — A — Can you hold either of the fields at will, so that it shall stay and not give way to the other field? Can you prolong the appearance of one of the fields, so that it remains longer than when you make no attempt to control the rate of fluctuation? (Call out the colors as they appear, so that yotir partner can record the duration of each with the aid of the second hand of a watch. Or, if there is time, record the changes more accurately, with the aid of a kymograph and time line.) Outlines for Experimental Psychology 53 B — What is the effect, on the persistence of one of the fields, of placing on it some simple figure, say, a small square, drawn in ink or pencil? Does this facilitate your attempts to control the fluctuation of the fields? Try a still more complicated figure on one of the fields. Can you now attend to this field as long as you please? Can you do the same with the field which bears no figure? What is the effect of placing equally complicated figures on each of the fields? Can you attend to either as long as you please? What further observations do you make as this experiment proceeds? C — What is the effect of "preparing the mind" beforehand, for one or other of the two fields? To determine this, proceed as follows. Use the plain fields again. Cover both with a sheet of black paper held by your partner. Before removing the screen, make up your mind which color you will see. Does this "determina- tion" have any effect on the relative frequency with which you see one or the other of the colors at the removal of the screen? Proceed as follows, in order to control your experiment adequately, and in order to avoid false and hasty inference. I — Make 20 trials, in which the fields are concealed by the black screen, but in which no thought of either color precedes the removal of the screen. Which color ap- pears at each trial? What is the total number for each color? (Make 10 of these trials first, and post- pone the remaining 10 until the series described in the following paragraph has been finished.) 2 — Select one of the colors. Now make 20 trials in which this color is determined on in advance of the removal of the screen. Note the number of times the chosen color really appears first. 3 — Now finish the control series, making the remaining 10 trials in which no color is determined upon in advance. Compare the results of the two experiments. What are your conclusions? Can you determine, by preliminary attention, the order of appearance of the two fields? Secure the results of 5 other students. What individual differences do you find in this respect? Cite cases in daily life in which this experimental situation is illustrated. What practical consequences are suggested in this connection? References — See the last page of this section. 54 Outlines for Experimental Psychology EXPERIMENT 22— THE SPAN OF ATTENTION. Within a given sense-field, as that of the visual field, for ex- ample, not all impressions are equally clear at a given moment. We may be vaguely aware of a large nimiber of them, but at the same time only a small ntmaber are clearly and distinctly perceived. The earlier experiment on attention and indirect vision has illus- trated this familiar fact. We may now ask — "What are the limi- tations of this central field of clearness? " How many impressions may be clearly grasped at a single effort or direction of attention? For the present we may well limit ourselves to simple and fairly meaningless impressions, of such a sort that each will constitute in itself an independent unit. When we come to study percep- tion, we shall find that the character of the impression, its meaning- ful or meaningless character, the ease with which it combines with other similar elements to form higher and more complex units, the familiarity of the material, etc., all assist in determining the clearness of the given unit, and the range of attention of such units. A — ^With the tachistoscope find how many dots (2 mm. square and 4 mm. apart) can be correctly perceived at a single exposure. You will be provided with a series of 10 to 12 cards, each bearing a nimiber of dots, the nvimbers ranging from i to 10 or 12. (Ob- serve carefully the oral directions concerning apparatus.) Expose these cards (being careful to follow a chance order), asking your observer to state the nimiber of dots on each card. Record replies in an appropriately planned table. After the series has been presented once, repeat the process, until each card has appeared 5 or 10 times. Now compute your results, and find the number of dots which is the largest that can be correctly perceived at least 4 times out of 5. Nimibers smaller than this should have been almost always perceived correctly, and nimibers larger than this will have been shown to be too large to be included in a single field of clearness, or in a single moment of attention. What is yotir partner's "span of attention" as thus measured? Secure the results of 10 other students. What individual differences are shown in these records? Is there a normal span of attention? B — After having determined in this way your partner's scope of visual perception, arrange the number of dots in several ways and positions, including in the series several miscellaneous cards bearing different numbers of dots, as control cards. Outlines for Experimental Psychology 55 Try each of the various arrangements 5 times, in the same way as before. Does the arrangement of the dots have any influence on the ease or certainty with which they are perceived? Which arrangement is the most favorable, in this case? What reasons can you suggest for this? Ask questions of your partner concern- ing the different arrangements, and the way in which they were perceived, thus endeavoring to learn from the introspective report, if possible, some of the reasons for the favorableness or unfavor- ableness of the various arrangements. Take some number of dots which, in the original experiment, was too large for the scope of visual attention. Can you, by arrang- ing this number of units in a more favorable way, enable your partner to perceive even this large number correctly? C — ^What conclusions do you draw concerning the span of attention? What determines it, in part? On what internal and external conditions does it in part depend? Do these conditions entirely explain it? References — See last page of this section. EXPERIMENT 23— FLUCTUATIONS IN CLEARNESS. (The Attention Wave.) Various optical illusions and geometric figures undergo, when observed continuously, intermittent changes in character, direc- tion or structure from moment to moment. These changes are often ascribed to fluctuations of attention and to the periodic or wave character of attention. (It must be said, however, that many of these fluctuations may be shown to be dependent on eye move- ment, changes in fixation, processes taking place in the sense organ, etc.) Auditory and tactile impressions display the same periodic character, and here perhaps the role of attention is even more complete. All very faint (minimal) stimuli show these periodicities — fluctuations which are for the most part beyond voluntary control. Many other phenomena show that changes in clearness (adjustments of attention) cannot occur instanta- neously, but require a certain time, show a certain waxing and wan- ing effect which we may conveniently term the "wave" of atten- tion. The purpose of this experiment is to demonstrate and meas- ure this attention wave. A — Materials — color mixer, Masson disc, kymograph, time marker, headrest, etc. When the disc is rotated, select a gray circle which is just visible. Note that you cannot always see it, 56 Outlines for Experimental Psychology but that it comes and goes, more or less regularly, alternately appearing and fading. Following the directions of the instructor, secure a graphic record of these waves of appearance and disappearance, on the smoked drum of the kymograph. The experiment may require care and patience, and considerable practise and skill in manipu- lating the apparatus. Measure the duration of lo or 20 of the periods of appearance, and the same number of the periods of disappearance. What is the average and the variability in each case? What are the shortest and longest times found? Calculate the ratio of the periods of appearance to the periods of disappearance. Compare these various records in the case of 5 students. Why do we choose this minimal stimulus difference instead of looking for fluctuations in more intense stimuli which would naturally hold the attention more easily? What evidence can you suggest as to whether or not these fluctuations are really changes in attention or, e.g., merely indica- tions of some periodic process in the sense organ? What are the chief sources of error in such an experiment? B — Select one of the geometrical figures provided in the labora- tory for illustrating such fluctuations. Note the changes in apperception which occur from moment to moment. Measure these by the same method used in the above experiment. Make the same computations and solve the same problems as in the above experiment. What similarities and differences do you find between the two cases? References — See last page of this section. EXPERIMENT 24— ATTENTION AND TIME OF PERCEPTION. Materials — the bell metronome, arranged with dial for a form of the "complication experiment". The instructor will give directions for the method of experiment. (Or see Titchener — Feeling and Attention.) A — Set the metronome pendulum for a fairly rapid beat (144 or 152 strokes per minute) and set the bell for sounding at every sixth stroke. What time relation does the ring of the bell bear to the corre- sponding stroke of the pendulimi? Do the two fall together, or does the ring come before or after the stroke? B — Set the bell for sounding at every second stroke. How are the ring and its stroke now heard? Is it possible by shifting Outlines for Experimental Psychology 5 7 ^he attention (now to the bell, now to the stroke) to shift the apparent time relation of the two simultaneous impressions? C — Use the cardboard dial, bearing colors or numbers. The pendulum now bears a pointer, which passes along the scale on the dial. Direct your attention toward the bell stroke, thinking of it beforehand, and letting the sight of the pendulum and its pointer "float" in the background of consciousness. But when the bell sounds, notice the position of the pointer on the dial. Record the number or color at which the bell stroke now seems to come. Now direct your attention to the pointer, following it with the eye, and letting the sound of the bell "float" in the back- ground of consciousness. At what point does the bell now ring? Can you shift the apparent time of occurrence of the bell by directing your attention back and forth from pointer to bell? What conclusions do you draw from these experiments? What is the effect of attention on the time of perception of impressions? The Laws and Results of Attention. At this point bring together, in tabular form, a statement of all fundamental laws or results of attention, as you have been able to derive them from the experiments you have just performed. There should be at least S to 7 such general laws derivable, and perhaps more. References on Attention — Myers — Experimental Psychology, Chap. XXV. Ladd and Woodworth — Physiological Psychology, special sections. Titchener — Text-book of Psychology, Chapter on "Attention". Pillsbury — Attention. Titchener — Feeling and Attention. Washburn — The Animal Mind, Chap. XIII. Hollingworth — Principles of Appeal and Response, 3 chapters. Wundt — ^An Introduction to Psychology. 68 Outlines for Experimental Psychology Perception. DISCUSSION. By perception we mean in psychology the interpretation of stimtili which come to us through one or more of the special organs of sensation. Sometimes the word perception is used to indicate the process of interpretation, and sometimes the resvilt. In or- dinary speech the result of this process is termed an object, thing, person, situation, attribute, etc., and is indicated by a concrete or abstract noun. The process by which the interpretation takes place has usually been so gradually perfected or so often repeated that its various steps have been overlooked in favor of the final outcome, and consequently it has become difficult if not quite impossible to give an introspective description of the process. Indirect examination and experimental variation of the conditions must then be relied on if the process itself is to be brought clearly into consciousness. By such means information concerning what takes place in perception has been secured, and is often expressed in such statements as the following — I — Perception always involves centrally aroused sensations (images) and memories, as well as sensations. 2 — The restilts of previous experiences cooperate in giving the object the character which it possesses. 3 — The object that is seen is the one that best serves to explain all the previous experiences along with the present ones. 4 — Perception is due to the interpretation of a present sensation by organized earlier experiences. 5 — Which one of several objects or interpretations shall be suggested depends upon the laws of association. Many experiments might be devised which might serve to bring to light the various steps of this process of interpretation or perception. The following experiment on "the perception of activity " may be taken as typical. Outlines for Experimental Psychology 59 EXPERIMENT 25— THE PERCEPTION OF ACTIVITY. An intrinsically interesting perception is that of a person, animal, machine, etc., in action. Much of the success of window demonstrations, street vending, etc., depends on this intrinsic interest. The " New York Herald " has no better advertisement than the sight of its presses through the windows on Broadway. A barber stropping his razor, a gang of men unloading a piano, a mason using his trowel, a lather slapping in the nails, anywhere, even in politics and the White House, the man in action attracts interest. Similarly, pictures or other representations of things in action are strongly attractive. But many attempts to portray or represent action are flatly unsuccessful. The attitude suggested is often rather one of inaction and pose. The problem of the present experiment is to discover what factors contribute toward the perception of action or suggested activity. A — Let your partner sit with closed eyes. Tell him that you are going to read to him a series of phrases, sentences or expressions, and request him, after each expression, to give you an accurate oral description of the visual picture which is called up in his imagination when he tries to represent, in his mind's eye, the mean- ing of the expression. Note down the chief points in his descrip- tion, paying particidar attention to the position of the object in the picture. The following expressions are only suggestive. Think of several new ones and include them. < I — "An athlete hurdling a fence". 2 — "A woodman felling a tree". 3 — "A pugilist striking a blow". 4 — "A brakeman leaping to catch a train". 5 — "A polevaulter in action". 6 — "An archer shooting at a target ". 7 — "A rattlesnake in the act of striking". 8 — "A man pumping water". 9 — "A blacksmith shoeing a horse". 10 — "A broncho trying to unseat a cowboy". Do you make out any common feature in the attitudes or posi- tions of these various actors? If so, how might this common feature be expressed in the form of a law? What evidence is there that this feature is a necessary factor in all such perceptions of suggested activity? 60 Outlines for Experimental Psychology B — You will now be provided with a series of pictures of the same person. All the pictures are intended to suggest strenuous activity. Are they all equally successful? If not, arrange them in an "order of merit" with respect to the degree to which they suggest activity, placing at the top of the series the picture which is most successful, or which suggests the greatest degree of activity. At the bottom of the series place the least successful picture, and arrange the others in their proper order between these two extremes. The pictures are numbered on the back. Indicate in your record the position assigned, in your own experiment, to each picture. Secure the records of lo other students and calculate the average position and the variability in the case of each picture. You have now secured an average position for each picture. Arrange the series in a final order of merit as determined by these average positions. Observe the M. V.'s of each of the pictures when arranged in this final order of merit. On which of the pictures do the lo judges agree most closely? On which do they disagree most? What is the significance of these facts? Do you observe any features in which the successful pictures, say the best two or three, differ from the unsuccessful ones? Can you make out any general law or principle which is more and more faithfully observed or approximated as one passes from the inferior through the mediocre to the superior pictures? If not, write out a verbal description of the typical posture portrayed in the pictures at the top of the list. Do the same for those at the bottom of the list. In what does the most striking difference between these two descriptions consist? Is this the same feature made out in the preceding section of this experiment on perception? How may the principle or law be best expressed? Is there any- thing paradoxical or unexpected in this statement? Discuss the psychological processes which underlie this law. What various psychological processes are exemplified in the per- ception of suggested activity? Show in detail how this experiment illustrates the typical process of perception. References — Chapters on Perception in the standard texts. Hollingworth — A New Experiment in Perception, Jour, of Phil., 1 913. — Advertising and Selling, Chap. VI. Outlines for Experimental Psychology 6 1 EXPERIMENT 26— PERCEPTION AND MEANING. (Scope of Perception.) You have already performed experiments (in the section on Attention) , which demonstrated the fact that the scope of a single act of perception is limited by the range of attention. It was there suggested that the "character" of the material is also an important factor in determining this scope. The present experi- ment is designed to demonstrate and measure the influence of "meaning" and of "familiarity", and to further illustrate the factors and processes involved in an act of perception. The problem may be stated in some such words as, "To what extent is perception determined by the objective properties of the stimulus, and to what extent by processes taking place in the mind of the percipient — expectation, association, mental set, imagery, supple- mentation, memory, etc."? • Use the tachistoscope already employed in measuring the range of attention. Using the same methods as in that experiment, satisfy yourself as to the correct replies to the following questions. Proceed carefully, using control experiments whenever these are appropriate. So far as possible keep your observer in ignorance of your method and purpose. A — How many letters (5 mm. square and 3 mm. apart) can be correctly recognized at a single exposure, when these letters occur in random order, or at least not forming a word or familiar combination? How do 10 individuals differ in this respect? B — Arrange similar letters so as to form words in the language most commonly employed by your observer. Find the largest number of letters which can now be reported correctly after a single exposure? How does this number compare with that of the preceding experiment? If there is any difference, how is this difference to be explained, and what light does this throw on the process of perception? C — Now try words in two foreign languages, one of which is more familiar to your observer than is the other. Determine the scope of perception for each language. How do your results compare with those of the experiment on the perception of meaningless combinations? How do they compare with those of the experi- ment in the commonly employed language? Tabulate your re- stdts in this order — 62 Outlines for Experimental Psychology Meaningless combinations of letters — Scope Unfamiliar foreign language — Scope Familiar foreign language — Scope Mother tongue, or most familiar. . . — Scope What general law or principle is now disclosed? How is the scope of perception influenced by the familiarity with, or by the meaningful character of, the material? D — Now prepare slides for a special experiment, imder the heading — "Supplementation and Correction". Ask the instruc- tor for directions for this experiment, and when your material is ready, proceed at once with the experiment without letting your observer know anjrthing about the nature of the material or the purpose of the experiment. Discuss your results, showing what light they throw on the process of perception. What light do they throw on the psychol- ogy of reading? References — Myers — Experimental Psychology, pp. 223-325. Titchener — Text-book of Psychology, pp. 287-290. Pillsbury — Attention, pp. 64-69. Huey — Physiology and Psychology of Reading. Outlines for Experimental Psychology 63 Visual Space Perception. EXPERIMENT 27— CO-ORDINATION OF VISION AND TOUCH. A — In the center of a sheet of co-ordinate paper make a filled-in circle of 2 mm. diameter. Place the sheet in the center of the table, immediately before your partner. With pencil in hand, let your partner strike at the circle at intervals of 5 seconds, each time bringing the hand back at once to the edge of the table in order to be ready for another trial. In this way make 10 trials, each time trying to strike the center of the circle. Number the trials as they are made. Measure the error of each trial, and plat the successive errors so as to form a practise curve. B — Prepare a second circle on a fresh sheet of paper. This time observe the target through a prism of 10 or 20 degrees angle, and attempt to touch the center by the same quick movement of the pencil hand as before. Make at least 20 trials at 5-second intervals, returning the hand at once to the edge of the table after each trial. Do not make groping movements, but strike at the circle with a sharp thrust. If after 20 trials the subject has not developed accuracy sufficient to hit the target, continue the trials until such proficiency is present. Number the trials as before, and plat the practise curve as a continuation of that secured from Experiment A. C — Now remove the prism, make a new target sheet and repeat Experiment A. Make again 10 trials, and plat the errors as a further continuation of the practise curve. General Instructions — Always use the right eye. In platting your curve, let errors to the right of the target be repre- sented by distance above the base line, and errors to the left by distance below the base line. Consult the instructor concerning units of measurement to be used in drawing the curves. In the light of the results secured from this experiment as a whole discuss the co-ordination of vision and touch. Do you think such co-ordination is innate? If so, why? If not, by what process does it seem to be acquired? What about its stability after it is once acquired? What are the chief means, processes or aids utilized in the acquisition or modification of such co-ordina- tions? Can you mention a similar co-ordination between vision and hearing? Do individuals dififer in the accuracy of the visual- tactual co-ordination? Do they differ with respect to its ease of modification or formation? If such individual differences are present, how may they perhaps be accounted for? References — Titchener — Text-book, pp. 303-339. Judd — Psychology, pp. 131-172. Ladd and Woodworth, pp. 461-469. 64 Outlines for Experimental Psychology EXPERIMENT 28— STEREOSCOPIC PERCEPTION With the truncated pyramid, stereoscope, and appropriate slides, work out for yourself the principles involved in the per- ception of depth in binocular vision. This experiment will have been already discussed in the class room. Demonstrate to your own satisfaction the principles developed in the class discussion. Make drawings illustrating the various points there presented, relying for suggestions and assist- ance on your notes and on the outlines, manuals or references provided in the laboratory. Classify the slides under the four headings representing the stages in binocular vision. These headings are — I — Images indistinguishable — fusion, single flat object. 2 — Distinguishable but consistent — fusion, composite object. 3 — Distinguishable but inconsistent — binocular rivalry. 4 — Consistent on supposition — fusion, solid object, third dimension. References — Titchener — Text-book of Psychology, pp. 306-326. Students Manual (Qualitative), pp. 137-144. Instructors Manual (Qualitative), pp. 257-295. Ladd and Woodworth — Physiological Psychology, pp. 413-427- Judd — Psychology, pp. 159-165. McKendrick and Snodgrass — Physiology of Senses, pp. 175-187. LeConte — Sight . Jastrow — Stereoscopic Vision. EXPERIMENT 29— OPTICAL ILLUSIONS. Examine carefully the illusion cards in Bradley's "Pseudop- tics", and determine as far as possible the principle of visual per- ception on which each illusion is based. Find illustrations of the principal types of optical illusions dis- cussed in the class room. So far as possible classify all these illusion cards under the various headings there proposed. Select a typical illusion for each principle or type and include it in your note book, along with a statement of the principle. Consult one or more of the following references before making your final write-up of the experiments. References — Myers — Experimental Psychology, pp. 293-307. Titchener— Text Book of Psychology, pp. 330-338- Students Manual (Qualitative), pp. 1 51-170. Ladd and Woodworth— Physiological Psychology, PP- 435-456. Witmer — ^Analytical Psychology. Outlines for Experimental Psychology 65 Space Perception — Tactual. EXPERIMENT 30— LOCAL SIGN. Touch yourself with the same object (pencil, pen, blunt stick) in several places, such as palm, knuckles, nails, wrist, elbow, fore- arm, forehead, cheek, lips, meatus of ear, eyelids, chin, and analyze out as far as you can the particular quality of sensation by which you recognize the place touched. Do all the touches feel alike? Use adjectives descriptive of such differences as you may find. How are you enabled to recognize a touch in one locality and dis- criminate it from similar contacts in other regions? This quality of the sensation is known as its "local sign". Of what various factors may it consist? References — Titchener — Text Book of Psychology, pp. 303-304, 335-339- Judd— Psychology, pp. 137-144. Kulpe — Outlines of Psychology, pp. 343-351. Ladd and Woodworth — Physiological Psychology, pp. 380-391-. Myers — Experimental Psychology, pp. 238-239. Witmer — Analytical Psychology, pp. 110-113. EXPERIMENT 31— ACCURACY OF LOCALIZATION OF TOUCHES. On a blank page in your note book make an accurate drawing of the outline of your partner's hand and wrist. Let the subject close his eyes and rest the hand on the table, palm down. Select any point on the back of hand, wrist or finger, and indicate it by a cross (X) on your drawing. Touch the point lightly with the point of the rubber pencil, and require the subject to touch the same point with another pencil immediately afterwards. Indi- cate this point of localization by a dot on your drawings, measuring the distance accurately in millimeters and being careful to observe the direction from the original touch. Make five trials on each of the following regions — wrist, hand, finger tips. Compute the average error for each region. Do the figures suggest any general law? Is the direction of error constant? 66 Outlines for Experimental Psychology Rhythm. EXPERIMENT 32— THE PSYCHOLOGY OF RHYTHM. A discussion of the experimental psychology of rhythm may be found in Titchener, Experimental Psychology, Qualitative, Student's Manual. Further references on the descriptive and theoretical features of rhythm are to be foimd at the end of this section. Taking Titchener's Manual as a guide, perform the typical experiments suggested there, making such modifications and selections as are suggested by the instructor. Before performing the experiments read carefvilly the series of suggestive questions to be found below. Plan your experiments so as to throw light on the questions suggested here, and bear them in mind when making your introspections. Experiments on rhythm are easily influenced by expectation, suggestion and prejudice. Therefore the student is advised not to consult the descriptive and theoretical references until his own experiments have been completed and recorded. Questions Suggested for Experiments on Rhythm. I — How rapid or slow may the series of clicks be in order for subjective accentuation still to be present? 2 — What is the most favorable rate? Does this differ with individuals? How great differences are found? 3 — Do the range and favorable rate vary with the intensity of the separate clicks? 4 — How long must the series continue, before subjective ac- centuation appears? In other words, what is the reaction time of the rhjrthm impression? 5 — Does this reaction time vary with individuals? Does it vary with the rate? Does it vary with the intensity of the clicks? 6 — ^Are there any indications that some people are more rhyth- mically minded than others — that some people get rhythmical impressions more easily and more quickly than others? 7 — Does the subjective rhythm persist, after it has once begun, or does it vary periodically or otherwise? If it varies, on what factors does the variation seem to depend? 8 — Does the rhythm affect the time relations of the clicks, or their intensity, or their duration, or more than one of these? Outlines for Experimental Psychology 67 9 — Do people have natural preferences for one or other rhythm grouping? 10 — What is the relative ease of securing the various groupings? II — Does the rate have any influence on this matter? Does the intensity of the clicks? If so, point out in detail. 1 2 — Do the different rates and groupings produce characteris- tically different feelings, emotions, or associations? 13 — Is there any evidence of involuntary motor accompani- ments or organic changes (such as respiration) during the percep- tion of the rhythm? 14 — ^When complex rh5rthmical groups are formed, are there any evidences of subordinate degrees of accentuation within the larger groups? If so, does this accentuation affect the intensity or the duration or the intervals? 15 — ^Where are the accents most likely to occur in these com- plex rhythmical groups — in the middle, at the beginning, or at the end? 16 — How does rhythm in music differ from rhythm in these qualitatively similar sound impressions? 17 — Is there such a thing as a visual rhythm? If not, how do you account for the rhythmical impression produced by beams of a vaulted ceiling, the rows of capitals on a fagade, etc. 18 — ^What are the characteristics of the consciousness of rhythm in the case of subjective accentuation? 19 — What is rhythm — is it perhaps a perception, a feeling, an emotion, etc? Give reasons for your answer. 20 — Suggest further experiments on rhythm that might have psychological interest. References on Rhythm — Titchener — Experimental Psychology (Qualitative Manuals) . Bolton — Rhythm (Amer. Jour, of Psychol.). Myers — Experimental Psychology. Gordon — Aesthetics . Brown — Time in English Verse Rhythm. Lipsky — Rhythm in Prose. Miner — Motor, Visual and Applied Rhythms. Baldwin — Dictionary of Philosophy and Psychology. 68 Outlines for Experimental Psychology Association. EXPERIMENT 33— THE TRAIN OF IDEAS— REVERIE. The classical illustration of one form of association is the *' train of ideas". "A consciousness is set up and allowed to work itself out, idea following idea along the line of least mental resist- ance, until the 'stream' of thought runs dry." The experimenter starts the subject off by pronouncing a few words, or by showing him some picture, object, etc. With this as a starting point the subject allows his mind to range freely where it will until the train of thought dies out. He then immediately goes through it again orally in outline, so as to catch everything before it is for- gotten. The outline is jotted down by the experimenter. The subject then goes through the reverie carefully, noting details. He also examines it to trace connections between the different parts or elements or members of the chain. Connections will be found between various successive ideas, suggesting that each idea was called up by a preceding idea. It may happen that the ap- parent cause is not the immediately preceding idea, but one further back in the chain. Draw a diagram of the train of thought, indicating by lines the connections between ideas. What sort of a diagram do you thus get? What light does such an experiment throw on the psychological process involved in reverie or random thinking? Do similar principles probably hold in the case of more controlled or deliberate thinking? Think of such cases as "deciding what to give a friend for Xmas ", "deciding where to spend a vacation", "deciding what to order for luncheon", etc. As the conditions of this experiment are somewhat artifiddal it is well to catch oneself in the midst of some spontaneous reverie or train of thought, and analyze this in the same way as above. References — Titchener — Qualitative Manuals, Chap. XH. See especially the Instructor's Manual. Outlines for Experimental Psychology 69 EXPERIMENT 34— FREE ASSOCIATION. Association is said to be "free" when it is not directed to any predetermined end but is allowed to run on just as it happens. It is said to be "controlled" when the ideas to be recalled have to meet certain requirements. An association may be rigidly con- trolled — as when there is only one idea which will satisfy the re- quirements — as for example in "3 5-1 9 equals?". OTitmay beloosely controlled, when any one of a class of ideas will satisfy the require- ments — as in "Give some number larger than 45". We may say that in controlled association the mind is set in a given way, whereas in free association there is no set of mind present. In case, however, it should introspectively appear that in an experi- ment which was intended to be one in free association there was really some involimtary set of the mind, this fact should be taken into account in considering the results. The experiment on "Re- verie" was intended to represent one case of free association. Another typical case is to be found in the study of single associative pairs of words, illustrated in the present experiment. Material and Procedure — A list of words is printed on a sheet of paper. This sheet is covered with another sheet which is moved along, thus exposing the words only one at a time. As soon as each word is seen, write down opposite it the first word that occurs, or some designation of the first idea that comes into the mind. (See Special Sheets.) It may not be a single word that comes, but may sometimes be an idea that requires several words for its expression. Whatever it be — take the first single word that comes into the mind, for this is an experiment in free association. After having filled out the lists, examine the material in the following ways. I — Is there any evidence of the presence of a particular mental set? If so, what is this evidence? 2 — Try to determine how far primacy, recency, frequency and vividness of experience may have been operative in making the particular idea come up in response to the printed word. How many cases of each do you find in the material? Tabulate these cases. Of course only the introspections of the subject can be relied on here, and it must be remembered that it is easy to read into events, after they have happened, explanations which were not really operative in the process when it occurred. 3 — In the class room the classification of association types will be discussed, and the following list given of the typical ways in which associated ideas or words may be related to each other. Such a table is of interest in determining ideational type, interest, characteristics, occupation, age, intellectual and emotional pecu- liarities, etc. Classify your associations according to this table. Make a table showing the proportion of associations of each of the classes. 70 Outlines for Experimental Psychology Table of Association Types. category example Emotional — I — Failure of response 2 — Egocentric succeed — I must. 3 — Egocentric predicate lonesome — never. 4 — Judgment of quality rose — beautiful. Intellectual — 5 — Simple predicate spinach — green. 6 — Subject relation dog — bite. 7 — Object relation deer — shoot. 8 — Causality joke — laughter. 9 — Co-ordination cow — horse. ID — Sub-ordination food — bread. II — Supra-ordination rat — animal. 1 2 — Contrast sunlight — shadow. 13 — Co-existence engine — cars. 14 — Identity expensive — costly. Superficial — 15 — Language (motor) town — state. 16 — Word-compounding side — board. 1 7 — Rhyme pack — tack. 18 — Syntactic change deep — depth. 19 — Miscellaneous (very few). Outlines for Experimental Psychology 71 4 — If possible, perform this experiment on some member of your family, or even on several of them. Coiint up the number of responses that are identical with your own. How much resem- blance do you find in this respect? Now compare your own tables with those of several of the other students with whom you are not very familiar or are at least not related. Do you find any considerable correspondence in responses? How does this cor- respondence compare with that found between yourself and your relatives? Do your mother or sisters resemble you in this respect more than your father or brothers? If you find interesting results on this point, how do you account for them? It will be still better if, instead of merely computing the nimiber of identical responses, you determine in each case the proportion of each type of reaction as based on the classification of the foregoing table. Such a qualitative comparison is likely to reveal interesting likeness and differences. 5 — By the standard methods, for which consult the instructor, determine the number of individual responses and the median of community for yourself and your partner. Compare these with similar records from other members of the class. What conclu- sions are suggested? 6 — Devise some new experiment or investigation in which this form of the association method might prove useful. State in detail the purpose and method of the experiment. References — A special set of references to articles in the American Journal of Psychology, the Psychological Review, the Journal of Philosophy and Psychology, and other periodical publications will be given out in the laboratory or class room. 72 Outlines for Experimental Psychology Free Association Experiment. (Special Sheet.) As quickly as possible and in regular order, write alongside each of the following stimulus words the first word or idea which comes into your mind as a result of having read the stimulus word. Begin at the bottom of the column, uncovering the words one by one. Do not pass over any words. STIMULUS WORD table music man soft mountain . black comfort . . . short butterfly. . command . sweet woman. . . slow river beautiful . . rough foot needle .... sleep carpet .... high sour trouble. . . cabbage . . . eagle ASSOCIATE STIMULUS WORD dark sickness. . . deep eating house mutton .... hand fruit smooth .... chair whistle. . . . cold wish white window. . . citizen. . . . spider red ASSOCIATE anger . girl working . earth soldier. . hard. . . . stomach . Outlines for Experimental Psychology 73 STIMULUS WORD ASSOCIATE STIMULUS WORD stem lamp dream .... yellow. . . . bread justice .... boy light health .... Bible sheep bath cottage .... swift blue hungry . . . priest ocean head stove long whiskey . . . chHd bitter hammer. . thirsty .... city square. . . . butter .... doctor. . . . loud thief lion joy bed heavy tobacco. . . baby moon scissors quiet green salt street king cheese blossom . . . afraid ASSOCIATE 74 Outlines for Experimental Psychology EXPERIMENT 35— CONTROLLED ASSOCIATION. A — Association forwards and backwards — Prepare columns of twenty letters, arranging the letters in irregtdar order, and omitting the letters A and Z. Make six such columns. Take the time required to write after the letters of the first column the letters following each of the given letters in alphabetical order; take the time required in the second column to write the letters preceding each of the given letters. Third and fifth coltunns do as the first; fourth and sixth as the second. Average the results of the like columns. B — Determine which is the quicker association — that between the sight of a color and saying its name, or that between the sight of the name of a color and saying the name. After doing the test, examine the material carefully, to see if it is really a fair test. Ease in this experiment is indicated by speed. C — Determine whether it is easier to keep the same control (problem, or ^'mental set^^) through a series of tasks, or to change from one control to another. A test blank is used in which are pairs of one-place numbers. In one blank the + sign is inserted between the members of every pair; in another blank the — sign is inserted; and in a third, sometimes the one and sometimes the other sign in irregular order. There should be four different blanks of each kind. Take the time for each of the twelve columns. Do them in irregular order, e.g., do the first column in the first sheet, next the second in the second sheet, next the third in the third sheet, and so on. Tabulate your results as follows — ADDING SUBTRACTING MIXED Coltmm I Column 2 Colimin 3 Column 4 Totals What inferences, if any, can you draw? Outlines for Experimental Psychology 75 Dissociation, Suppression, and Inhibition. General Remarks. According to some investigators, the failure to recall a really familiar name, or the failure of repetition of a previous or common association in response to a given stimulus word, points to the existence of some obstruction, or suppression, or complex. This obstruction or complex, it is maintained, may often be discovered by letting the thoughts play freely about the stimulus word or the response word, and following up every lead that suggests it- self — no matter how inconsequential in appearance — especially if the lead or train of thoughts or topics has an emotional tone. The obstruction to recall or repetition is conceived as equiva- lent to an unwillingness to recall the name or something associated with it. The subject is supposed to have driven something dis- agreeable from his mind, and the forgotten name has become en- tangled in this disagreeable "complex" and suppressed or dis- sociated along with it. Once the name is known, however, free associations may lead from it to the "complex " — that is, may bring back what has been driven from the mind, or ** suppressed." The process of discovering these relations is known as "psychanaly- sis". There is considerable evidence that many abnormal mental states, such as phobias, obsessions, fixed ideas, amnesias, aboulias, splits of personality, etc., are produced by these mechanisms of suppression and dissociation, in the case of people who have psychopathic personalities and who suffer from early shocks and suppressions, which develop into "complexes". It is said that the method of psychanalysis, when carefully and skillfully followed up, leads to the discovery of these "complexes ",and that, when they are once discovered and brought into the clear light of consciousness, the abnormal mental symptoms disappear. The subject may be interested to make further psychanalytic experiments on himself or others. It is further maintained by these investigators (the so-called Freudian school of psychologists, named after Sigmund Freud, their master) that dreams are but the disguised expression of these "complexes" which assert themselves when the censorship of waking consciousness is removed. All dreams are thus held to be the expression, in a disguised way, according to certain definitely stated laws of distortion, of suppressed wishes, fears, impulses, or other emotional experiences. The following experiments may be made by way of illustrating the methods of psychanalysis. They may also throw some addi- tional light on the question of the correctness or incorrectness of the generalizations of the Freudian psychology. 76 Outlines for Experimental Psychology EXPERIMENT 36— INHIBITIONS AND COMPLEXES. Repeat the Free Association experiment which you have already performed, using the same 100 stimulus words as before, with the same instructions and precautions. Cover up the re- sponses previously given by pinning a sheet of paper over them, not noticing any of them meanwhile. Record the new responses on this fresh sheet of paper. The experimenter may now compare the two lists, without letting the reagent see them. He will find that in some cases the same response to the stimulus word was given in both experiments. In other cases different responses will have been given in the two cases. The experimenter makes a list of all the stimulus words that gave different responses on the two occasions. Along with these stimulus words he intersperses a considerable number of the original stimulus words having identical responses in the two ex- periments. This composite selected list is now presented to the reagent, the words being given one at a time, with some such instructions as the following — "Let your mind play freely about this word, letting it call up anything and everything that it will. Tell me whether it suggests anything of personal significance to you — such as any topic which you would not care to talk about to everybody, any experience, event, desires or thoughts which you wotdd hesitate to reveal to others. " If such personal associations are foimd, the reagent need not report what they are, but he should indicate whether they are agreeable or disagreeable. The experimenter now compares the stimulus words which gave identical responses with those which gave different responses, in the two experiments on free association, and finds how many (how large a proportion) of each are connected with emotional topics. State the results as follows — NATURE OF STIMULUS WORD LATER ASSOCIATIONS I — Provoking identical responses and con- Agreeable % nected with emotional topics Disagreeable. . % 2 — Provoking different responses and con- Agreeable % nected with emotional topics Disagreeable.. % On the basis of these results, what conclusions, principles or suggestions are offered with respect to the mechanism of these free associations, and the factors which determine their stability or instability? References — Jung— The Association Method (Am. J. Psychol., 1910). Sutherland — Critique of Word Association Reactions. Outlines J or Experimental Psychology 77 EXPERIMENT 37— ASSOCIATION OF NAMES AND FACES. A — In this experiment the learning and recall of proper names in connection with human faces is to be studied by the "method of paired associates". The experimenter procures sets of 20 photographs of unknown persons. To each face he assigns a surname, employing a variety of names. Expose the portraits to the subject, one at a time, saying "This is Mr. ", "This is Miss ", etc. as the case may be. Allow the subject to examine the portrait for 5 seconds. Allow S seconds at least between the various portraits. After having presented a series of 20 portraits, show each pic- ture in turn, and in a random order, asking the subject to name each correctly. Here the portrait is the stimulus and the name is the response. Instruct the subject to respond by the first name that comes to his mind. If he is right, tell him so. If he is wrong, correct him, and continue until all 20 have been shown. Record all names that are given alongside the number of the picture. Then repeat the series of stimuli, calling again for the names and again correcting the false associations. Record all the names given, as before. Continue this process of repeating the whole series of 20, until all the pictures are named correctly as soon as they are presented. Now compare, in each case, the wrong responses with the cor- rect name, and see what you can discover as to the kind of errors made, the probable explanations of these errors, and in general — the mechanism of this sort of association. Do the false responses at all approximate or resemble the correct names? What is the the nature of the resemblance? Are there various kinds of resem- blance, and if so are some more common than others? What parts or characteristics of a name are most quickly or easily learn- ed? Use the method of psychanalysis with the difficult names, and discover, if possible, whether there is anything of an emotional character associated with these names in the experience of the subject. B — As a further development of this experiment, think of some person of your acquaintance whose name you cannot at once recall. Or the name of some literary or historical character may serve the purpose. Note down all the names that come to your mind, all words or ideas of any kind, as rapidly as they come, and con- tinue this process until the correct name comes to mind. Now compare the false responses with the correct name, and make out answers to such questions as those asked in the first part of the experiment. In some cases it will be found better to wait until some chance occasion arises, in which you find yourself unable to recall some name. Then carry out the experiment as here described. This will eliminate the artificial character which the experiment may have when tried in the laboratory. 78 Outlines for Experimental Psychology References — Freud — Psychopathologie des Alltagslebens, Hollingworth — Characteristic Differences Between Re- call and Recognition, American Journal of Psycho- logy, Oct., 1913, pp. 532-544. EXPERIMENT 38— QUANTITATIVE MEASUREMENTS OF ASSOC- lATION STRENGTH. The purpose of this experiment is to demonstrate the influence of frequency, recency, primacy and vividness of an experience on the probability of its recall, and to determine in an approximate way the relative strength of these several factors. The experi- ment is a modification of those described in Calkins, "Association", Monograph Supplement of the Psychological Review, No. 2. The material consists of colored frames or cards, each color or card being accompanied by a two-place niimber; a screen for con- cealing the experimenter's preparations from the subject; a pendu- lum or metronome beating seconds. There are frames or cards of various colors. The numbers comprise all the two-place nimi- bers that do not contain o nor a repeated digit. The colors are presented in connection with the nimibers, and at a later period or after a short time, depending on the plan of the experiment, the colors are shown alone, the subject being now asked to call up the number previously shown with each color. The psychological process involved is thus a process of association between number and color, this association being the basis of the recall when it occurs. In the experiment the following series are to be used — I — Normal Series — designated by the letter "N". In these series each of the frames will be filled by a different nimiber and the set will be shown in series, with about 3 seconds exposure of each, at about 2 seconds interval. As soon as the series has been shown, the colors are shown alone and the subject asked to think of some two-place number for each color. He will be unable to remember all the numbers, but should at any rate always say the first nimiber that is suggested to him by each frame, even if this number is felt to be merely a "guess". The number should be given promptly, the empty frame being exposed not over 3 seconds. Ten of these Normal series are to be taken, in an order described later. On the basis of these results, which are to be tabulated separately, the experimenter is to calculate the normal probability that a number shown in connection with a color shall be recalled by that color. These series will also afford data for the tables on primacy and recency. 2 — Frequency Series — To examine the effect of frequency on association strength introduce in the midst of the normal series, in the order suggested later on, some series in which one of the Outlines for Experimental Psychology 79 colors with its number shall be shown twice. Have five such series and designate them F2 (frequency 2). Have also five series in which some color and its number appear three times, and designate these series F3. Have also five series of F4. In summing up the results of the frequency series, compare the prob- ability of recalling a number that has occurred once only (N) with that of recalling one that has occurred twice, three times and four times. 3 — Vividness Series — Since we can reasonably assume from general experience that a vivid experience is more readily recalled than one that has nothing special to impress or characterize it, a question worth examining is — "What will make an experience vivid?" and another question is "How does vividness compare, in efhcacy, with frequency, primacy, and recency?" Apply these questions to the material in hand, and devise means cal- culated to make the experience of one number and its color vivid. Think up your own method of vivifying the experience. Try at least two devices, giving five series to each method. What sort of device is most successful? Try various schemes until you have found two that bring success — that is, that make the number recalled more times than in the normal series. Call these vividness series Vi and V2. In work of this kind it is advisable to make a plan for the whole course of the experiments, to have this plan well in mind and mapped out on paper, and to follow it methodically. A copy of such a plan will be found in the laboratory. Copy this plan in making out your preliminary tables, observing both the method of recording the data and the order in which the series occur. Models of tables of final results will also be found in the labora- tory. Follow these models in reporting your experiments. Dis- cuss all results in full. The discussion of results will fall under the following headings. Primacy and Recency — ^Assuming that the various colors are equally vivid, show how many times the first number in a series (N) will be recalled, how many times the second, and so on for each place in the series. Is there any indication of the effects of primacy and recency? What are these effects? How does pri- macy compare with recency, in its influence on association strength? Do these results have any practical applications? Frequency — What is the character of the effect of frequency on association strength? How does this effect vary with the degree of frequency? How does the effect of frequency compare with that of primacy? How does it compare with that of recency? Does mere repetition produce association strength? Give instances to support your answer. Suppose repetition to be unaccompanied by "the determination to learn". Would it still be effective? 80 Outlines for Experimental Psychology Vividness — What sort of devices will produce vividness in such an experiment as this? What factors most often produce vividness in daily life? What is the effect of vividness on asso- ciation strength? What is the relative value of the various de- vices used? How does the effect of vividness on association strength compare with the effect of Primacy? Recency? Fre- quency? Does mere vividness produce association strength? Need vividness be accompanied by the "determination to learn"? Do these facts have any application in daily life? References — Calkins — Association, Psych. Rev. Mon. Suppl. No. 2. Myers — Experimental Psychology, Chaps. 12 and 13. Titchener — Qualitative Manuals, Experiment XXXVII. in Chap. XII. James — Principles of Psychology, Chap. XIV. Outlines for Experimental Psychology 81 Memory. (Conditions that Influence the Efficiency of Memory.) EXPERIMENT 39— THE MASS METHOD AND THE SECTIONAL METHOD. Is it better, in memorizing a series of numbers or words, to read them over and over, reading each time the whole series, or to learn the series in parts of suitable length to be readily learned? To answer this question, take sets of 16 digits, and determine the time required to learn each set so as just to be able to repeat it once correctly. Take the time with the stop watch. Proceed as follows, to avoid the effect of practise, or rather to distribute these effects equally between the two methods of memorizing. Learn the first set of 16 digits as seems most natural; learn the second set by reading through and through, without any division into parts ; learn the third series by breaking it up into parts and learn- ing each of these before passing to the next. When the parts are learned, they must still be combined so that the whole series can be run off together without error or help. Learn the fourth set in the same way as the second, the fifth the same as the third, and so on alternately. It is best not to continue this sort of work too long at a time, if you feel yourself growing dull and in- efficient at it; but care should always be taken to make equal numbers of series by the two methods of memorizing, on each day on which such work is done. The subject should keep watch of the exact way in which he goes to work, and if he changes his way of working at all — though this is on the whole undesirable for the purposes of this experiment — he should make careful note of the change. In general, the subject's introspective observations shotild be recorded. Now perform a similar experiment, using stanzas of poetry instead of digits. Do you get different results in the two cases? What is the significance of your results? References — Myers — Experimental Psychology, Chaps. XII and XIII. Watt — The Economy and Training of Memory. "82 Outlines for Experimental Psychology EXPERIMENT 40— RHYTHMICAL MEMORIZING. There is still a third way of going to work in memorizing a series of niimbers, and that is to read them in a strongly marked rhythmical form, dividing the set of 16 digits into four groups of four, and, while reading the whole 16 right through each time, yet to make a pause after each group of four, and to accent the first digit in each group. This rhythmizing of the series should be avoided as far as possible in the preceding tests; but a special test may be made of its value, by comparing the time necessary to learn a set of 16 digits in this way and in the better of the two preceding ways. As this method will not have had the practise that has been given the other methods of memorizing in the preceding experiments, it will be well to begin by a few sets in which the rhythmic method is employed — enough of these preliminary trials should be taken to make the method about as familiar as the other one with which it is to be compared. Record should of course be kept of these preliminary trials. After that, make alternate experiments by the rhythmic method and by the other methods with which you wish to compare it. It is hard to say beforehand how many sets of digits must be memorized before the question shall be satisfactorily answered for a given individual. There is sure to be some variability between the times required to learn sets of 16 digits; and where there is variability not much can be inferred from a single pair of measure- ments. The greater the variability, the more trials must be made to determine the point at issue. The closer and more uniform the attention given to the act of memorizing, the less variable will be the results, and the fewer of them will be needed. Try to satisfy yourself of the validity of your results, and when you have done so, consult the instructor, and see if you can satisfy him. You should also be careful not to prejudge the restdts ; and not to allow yourself to work for any particular results; you should try just as hard in one method of memorizing as in the other. References — Watt — The Economy and Training of Memory. Myers — Experimental Psychology, Chaps. XII and XIII. Pillsbury — Attention, Chap. IX. Outlines for Experimental Psychology 83 EXPERIMENT 41— THE CURVE OF FORGETTING. I — Lists of Numbers. — Take the time for learning a set of 16 digits, as in preceding experiments, just sufficiently to be able to repeat it once correctly a moment later. Wait one-half minute and see how much time is necessary to releam it to this same de- gree. In another set wait 2 minutes, with another 5, another 20 and with still another 2 days. Do enough of the different sorts of experiment to be sure of the rate of disappearance of the reten- tion. How will you measure the rate of disappearance? Draw the curve of forgetting for numerals. 2 — Length of Lines. — In the same way test the ability to reproduce a standard line by drawing it with a pencil. Vary the interval between standard and reproduction through 5 seconds, 10 seconds, 15 seconds, 30 seconds, i minute, 5 minutes, 15 minutes, i hour, 2 days. Plat the curve of forgetting, taking 3 trials for each interval. References — Bean — The Curve of Forgetting. Myers — Experimental Psychology, Chaps. XII and XIII. Hollingworth — The Inacurracy of Movement, Chap. V. — Advertising and Selling, Chap. XI. EXPERIMENT 42— THE MEMORY SPAN. Find your partner's memory span for digits, letters, syllables, words and colors. Beginning with short series which he can al- ways remember on one reading or hearing, increase the length of the series until you are certainly beyond his range. How many of each of the different kinds of objects can he hold in conscious- ness at one time? This number is called the immediate memory span. Compare your records with those of other students. What individual differences do you find? On what factors do you suppose these differences to depend? References — Colegrove — Memory. Pillsbury — Attention. 84 Outlines for Experimental Psychology EXPERIMENT 43— AUDITORY AND VISUAL MEMORY. Using words, syllables and digits, find whether your partner can remember better when he hears the series or when he sees it. Make 5 trials for each kind of material, giving a series of 12 or 16 and recording the number of right cases. Do individuals differ in this respect? What practical suggestions does the experiment seem to aflord? References — Watt — The Economy and Training of Memory. Henmon — Psych. Rev., March, 191 2, pp. 79-96. EXPERIMENT 44— MEMORABILITY OF DIFFERENT KINDS OF THINGS. Some people find it difficult to remember faces, others names, or dates, etc., while other things are remembered with greater ease. Have you found any such peculiarity in yourself? Devise an experiment which will test the relative memor- ability of such things as nouns, digits, objects, colors, syllables, proper names, photographs, adjectives, places, etc. Work out a complete plan and report to the instructor for suggestions and criticism before performing the experiment. Work the problem out as thoroughly as possible with the material at hand. References — HoUingworth — The Obliviscence of the Disagreeable. Jour. Phil. Psych, and Sci. Meth., Dec. 22, 1910. — Advertising and Selling, pp. 208-214. Whipple — Manual of Mental and Physical Tests — chapter on "The Fidelity of Report". (Special paragraphs.) EXPERIMENT 45— RELATION BETWEEN QUICKNESS AND RETENTIVENESS. We often hear people say, "It takes me a long time to learn a thing, but when I once learn it I never forget it". Is it true that people who learn with difficulty remember best? Or do those who learn soonest also remember best? This experiment may be taken up by two or more students, using the members of the class as subjects. The results can be worked up by the class as a whole. The method will be to repeat after a given period material previously learned, taking time of learning, errors, etc. What are the weak points or sources of error in such an experiment? Outlines for Experimental Psychology 85 Visual Sensations. EXPERIMENT 46— VISUAL AFTER IMAGES. A — Look at the flame of a candle in the dark room for a second, then quickly close the eyes for a few minutes. What is the result? B — Fixate the catch on the window for several seconds, then close the eyes, cover them carefully so as to exclude all light, and observe what happens in the field of vision during the next five minutes or so. Try this several times, until you are able to write a detailed description of the character and order of succession of the bril- liantly colored after-images. C — Fixate small squares of various colors, then quickly trans- fer the gaze to a sheet of white paper or the gray wall. Describe what happens in the case of each of the following colors: red, orange, yellow, green, blue, violet, black; what colored after- image do you get for each? Why? D — Project the after-images of each color upon larger squares of the other colors, instead of upon the gray background. What color do you get in each case? Why? E — Lay a disc of bright red paper, i cm. in diameter, upon a white field. Close and cover the eyes, until there is no trace of after-images in the dark field. Open the right eye and fixate the red stimulus for five seconds. Then close and cover the right eye; blow away the red disc, and fixate an ink dot upon the white field with the left eye. What do you see? How is it to be ex- plained? References — Titchener — Experimental Psychology, Students Man- ual (Qualitative), pp. 22-30. — Text-book of Psychology, pp. 68, 72, 75, 92, 148 and 151. Ladd and Woodworth — Physiological Psychology, pp. 336-339- Myers — Experimental Psychology, pp. 89-91. Binet — Psychology of Reasoning, pp. 44-49; 52 ff. 86 Outlines for Experimental Psychology EXPERIMENT 47— COLOR MIXING. If the lights of two colors are simultaneously thrown on the same point of the retina, the sensation is not of two colors but of one, which is different from either of the lights used. There are several ways of color mixing, the best of which is to use spec- tral colors — ^i.e., portions of two spectra — but this is not so con- venient as some others. A transparent mirror may be used. Commonly we use a rotating disk or "color wheel". In this method the two colors to be mixed are not presented quite simul- taneously but succeed each other at short intervals (30 or more alternations per second are necessary to get complete fusion; it is worth while observing the curious effects produced by slower rotation). On account of retinal inertia, the effect of a brief stimulation holds over for a fraction of a second and so blends with the effect of an immediately following stimulation. This is the principle of the color wheel as a color mixer. "Color Equations". When two colors, mixed, give the same sensation as a third single color, an equation can be written, stating what proportion or percentage of each of the colors mixed was necessary to produce the required color. More generally, when the mixture of two or more colors gives the same sensation as another color or as a mixture of other colors, it is possible to write an equation expressing the proportions of each necessary in order to produce like sensations. It is often necessary to experiment for some time before finding the right proportions, and it is also often necessary to add white or black or both to one or the other mixtiire, in order to equate the brightness and the saturation. I — Mix black and white to produce a given gray. Write the equation. Are the black and white used in this experiment reaUy black and white? 2 — Determine the equation for a given orange and for a given purple in terms of standard red, yellow, green and blue. After getting each of these matches perfect, pull down the black cur- tains or otherwise diminish the illumination, and see whether the equation still holds good. 3 — Complementary Colors — One color is said to be comple- mentary to another when the two, on being mixed, produce white. "White", as here used, means colorless; what is produced, in ex- periments with the color wheel, is usually rather a dark gray. Of course the mixture can not be brighter than both of the colors mixed, by this method, and therefore the gray obtained will usually be dark. Taking the standard red, yellow, green and blue, determine the color complementary to each one of them. Also find the complementary to scarlet, grass green and violet. Observe carefully each pair of complementaries with reference to the spectrum, and also write the equation for each. Outlines for Experimental Psychology 87 4 — Mixing Complementary Colors — As just found, there is a certain proportion in which if two complementary colors are mixed, the result will be gray. What is the result of mixing them in other proportions? Mixing two colors that are not comple- mentary? Mix them in all proportions, starting with practically all of the first and almost none of the second, and gradually increasing the proportion of the second until you have almost none of the first; and describe the change in color tone and also in saturation. Try this with several pairs of colors, and, taking into account also the results of mixing complementary colors, frame a general law stating the results of mixing two colors. 5 — Mixing Three Colors — Primary Colors — It is possible, by using three properly selected colors, to get from their mixture all of the remaining color tones. Several such sets of colors can be determined. Determine such a set experimentally, guiding yourself as far as possible by the results already gained. Write the equation. References — Ladd and Woodworth — Physiological Psychology, pp. 330-334- Myers — Experimental Psychology, pp. 81-83. Titchener — Text-book of Psychology, pp. 67-71. — Students Manual, Qualitative, pp. 5-9. Rood — Text Book of Color. EXPERIMENT 48— COLOR CONTRAST. A — Lay a bit of white paper on a piece of black velvet. Where does the paper seem whitest? The velvet blackest? B — Examine the black-white contrast card and describe the effect produced. C — On a large colored field lay a small strip of gray paper and cover the whole with a piece of semi-transparent white paper. What happens to the strip of gray paper? Try this experiment using red, green, yellow, blue and orange backgrounds. D — Arrange two lights so that they shall cast a double shadow of a pencil upon a white surface. The daylight, if not too strong, will answer for one light. Introduce different colored glasses one after another before one of the lights, and notice the effect on the color of the shadow belonging to that light. How do you explain these effects? E — Ragona Scina's Experiment, if the appropriate apparatus is available. (Sanford, "Experimental Psychology," pp. 155- 157-) 88 Outlines for Experimental Psychology References — Read on "Color Contrast" in the following — Rood — Text Book of Color. Titchener — Text-book of Psychology. Also Stu- dents Manual, Qualitative. Myers — Experimental Psychology. Le Conte — Vision. Ladd and Woodworth — Physiological Psychology. EXPERIMENT 49— CAMPIMETRY. The distribution of the sensibility of the retina for color is unlike that for light. Surrounding the yellow spot are several zones, within each of which only certain colors can be perceived. The fixing of the boundaries of these zones of sensibility is known as campimetry. With the apparatus known as the perimeter, find at what angles from the center of vision on the vertical, horizontal and two main diagonal meridians of the eye the four principal colors, red, yellow, green, and blue can be recognized. Try white also. Keep the eye steadily fixed on the fixation mark of the instru- ment and have your partner slide the color slowly into the field from the outside. It will be well to move the paper slowly to and fro at right angles to the meridian, so as to avoid retinal fatigue. Ask the instructor for more specific directions. Record on a carefully prepared map, the point at which the color can first be recognized with certainty. What zones do you find? Compare your results with those of several other students. What individual differences are found? References — Howell — Text Book of Physiology, pp. 336-340. Titchener — Students Manual, Qualitative, pp. 9-14. — Text-book of Psychology, pp. 80-85. Myers — Experimental Psychology, p. 79. EXPERIMENT 50— THE BLIND SPOT. A — ^With the card provided in the laboratory, demonstrate the presence of the blind spot. B — Draw the projection of the blind spot in your own eye. Arrange a head -rest opposite a vertical sheet of white paper 15 inches distant. Put a dot on the paper for a fixation point. Fasten upon the end of a light rod a bit of black paper about 2 mm. square. Bring face into position, close one eye, and fix the other upon the dot. Move the rod slowly so as to bring the little square Outlines for Experimental Psychology 89 over the part of the paper corresponding to the blind spot, dotting on the paper the points where the square disappears or reappears. Repeat at various points till the outline of the projection of the blind spot is complete. Reproduce the map in your note book. From the size of the outline calculate the actual size of the blind spot on the retina, C — With appropriate apparatus demonstrate the effect of contours and the filling out of the blind spot. D — Why are we not inconvenienced in ordinary vision, by the presence of the blind spot — In binocular vision? In monocular vision? References — Titchener — Text-book of Psychology, pp. 326-328. Ladd and Woodworth — Physiological Psychology, pp. 193-194. Myers — Experimental Psychology, pp. 276 and 397. Sanford — Experimental Psychology, pp. 102-105. Howell — Physiology, pp. 316-317. EXPERIMENT 51— ENTOPTIC APPEARANCES. A — Light Dust: Close and cover the eyes so as to exclude all light, taking care not to press them. Experiment in the dark room. Let the after effects of objective light fade away, and then watch the shifting clouds, stars and crescents of retinal light. Describe them. How caused? B — Turn the closed eyes to the left, and press with the finger on the right eye, at the outer comer of the eyelid. Notice the colored ring that appears on the opposite side of the eye. What causes it? C — Concentrate a strong light (perferably in a dark room) with a lens, on the sclerotic in the outer comer of the eye of your partner, requesting him to turn the eye toward the nose and giving him a dark background to look at. Give the lens a gentle circular motion. Let your partner describe what he sees on the dark background. The dark branching figure is the shadow of the blood vessels in the retina. D — Look through a pin hole in a card, held close before the eyes, at the sky. Give the card a rather rapid circular motion. The finer retinal vessels in the region of the yellow spot will be seen and among them a small colored or slightly tinted disc-like spot. This is the macula. In its center find a shadowy dot which appears to rotate when the motion of the card is circular. This is the fovea, or point of clearest vision. 90 Outlines for Experimental Psychology References — Myers — Experimental Psychology, pp. 86-87. Howell — Text Book of Physiology, pp. 344-346. Ladd and Woodworth — Physiological Psychology, pp. 325-357- EXPERIMENT 52— SINGLE AND DOUBLE IMAGES. A — Hold up two fingers, one about a foot, the other about two feet from the eyes. Fixate the nearer finger; it will be seen single and the farther one will appear double. Fixate the farther one; it will be seen single while the nearer appears double. B — Fixate the near finger again and close one eye; which of the three images disappears? Fixate the farther finger and repeat the experiment; which image disappears? Draw figures explain- ing both cases. References — Sanford — Experimental Psychology, pp. 90-92. Myers — Experimental Psychology, pp. 274-275. Howell — Text Book of Physiology, pp. 350-353. Ladd and Woodworth — Physiological Psychology, pp. 423-426. Le Conte — Sight. EXPERIMENT 53— DURATION OF POSITIVE AFTER-IMAGES. Place the color mixer in such a position that the special disc shall be illiuninated by diffuse daylight only. Turn the driving wheel slowly and ascertain by counting, how many turns of the disc correspond to one turn of the wheel. Start the metronome and turn the wheel in time with its beats, making a turn every one, two, or four beats. Notice which of the rings, if any, is just blended into a uniform gray. If none is just blended, change the rate until one is found. From the rate of the metronome, the ntmiber of turns of the driving wheel, and the niunber of sectors in the just blended ring, find the number of stimuli per second required. Avoid eye movements which break up the uniformity of the gray. Outlines for Experimental Psychology 91 Cutaneous Sensation. (The next three experiments are based on similar ones as described in Titchener's Manual.) EXPERIMENT 54— TEMPERATURE SPOTS. Purpose I — To discover and accurately record the sense organs of temperature which lie scattered about the surface of the skin. 2 — and to become introspectively familiar with tempera- ture sensations in their purest forms. Materials — Metal cylinders, architects' paper, dyes, inks, writing points, hot water, and ice. I — Cold Spots. Procedure — The observer (O) lays out his left hand, lightly clinched, on the table, dorsal side upwards. On the smooth slightly strained skin surface in the region of the second and third metacarpals the experimenter (E) marks out with the indel- ible ink a parallelogram 1.5 by 2.5 cm. Draw upon the archi- tects' paper three corresponding parallelograms. E now moves one of the cooled cylinders, wiped dry, across the area, along the sides of the parallelogram, slowly and steadily. At some points a vivid sensation of cold will flash out. When such a spot is found, O says "There", and the spot is marked on the skin with a dot of green dye. If the sensation obtained be very intensive, one of the outline maps is laid over the skin and a tiny ink cross made on the paper at the point where the dye shows through. When one line has been worked over and its cold spots noted another line is begun, parallel to the first at a distance of i mm. and so on until the whole area has been explored. E now lays one of the outline maps over the area and makes ink dots at all the points (not already marked with crosses) where the green dots show through. This gives a permanent record of the sense organs of cold situated within this particular area. For references see later page. II — Warm Spots. This experiment is performed in the same way as the preceding, except that metal points perceptibly warm (but not uncomfortable) are used instead of the cold cylinders. Map out the warm spots, on this area. Make a final map containing both the warm and cold spots, differently marked. For references see later page. 92 Outlines for Experimental Psychology QUESTIONS. I — Are the cold or the warm spots the more niimerous? How are they distributed? Should both be marked by dots of the same size? 2 — ^Which are more easily verifiable, the intensive or the moderate spots? 3 — Did you experience nothing but cold at the cold spots and warm at the warm spots? 4 — Do cold and warm spots ever coincide? EXPERIMENT 55— PRESSURE SPOTS. Purpose — To map out the sense organs of pressure and to become familiar with the pressure quality. Materials — Inks, dyes, architects' paper, scale, scissors, lens, and wooden points about i mm. in diameter. Procedure — O lays out his hand, lightly clenched, on the table dorsal side upwards. Between the fourth and fifth meta- carpals E marks out a square of i cm. side. Draw four similar squares on the paper. Make a map of the hairs lying within the region. Cut each hair off short and mark with a tiny dot of dye the point where each shaft emerges. Transfer this map to the paper and wash the hand. With the hard wood point pass along the sides of the square not continuously as for tempera- ture, but with separate pressures, set as close together as possible. Do not jab the point. Apply it deliberately, making a noticeable depression of the skin at each pressure, and always holding the point vertical to the skin surface. Points of clear and sharp pressure will be found. When such a spot is touched O says "There " and the spot is marked with a dot of dye. If it is a very intensive spot, it may be marked on the map with a cross. Explore in this way the whole area, working in parallel lines about i mm. apart. For references see later page. Outlines for Experimental Psychology 93 QUESTIONS. I — What is the relation of the pressure spots to the hairs? Does stimulation of the hair itself give a pressure that is identical, for O's introspection, with those obtained from the pressiu-e spots? Do pressure spots occur in hairless regions? Do they give the same sensation as is given by the hair spots? 2 — Which set of spots is more easily verifiable, the intensive or the moderate? 3 — What introspective differences between the sensation evoked by strong and that evoked by weak stimulation of a pres- sure spot? 4 — Which of the sensations of temperature does the pressure sensation more nearly resemble? 5 — Did the pressure stimulus call out any other sensation than that of pressure? EXPERIMENT 56— PAIN SPOTS. Purpose — To map out the organs of cutaneous pain and to learn to distinguish the pain from the pressure quality. Materials — Bristles, millimeter paper, dye, ink, soap, water, reading glass. Procedure — On the area tested for pressure spots E marks out in indelible ink two parallelograms of twenty sq. mm. Reproduce these on enlarged scale on mm. paper, mapping the fine furrows that cross and recross the skin. Soften the skin with soap and water, shave the area carefully. The skin must remain moist and flabby throughout the experiment. Begin work on one of the areas, keeping the other moist by repeated appli- cation of the soap and water. When the first area shows signs of drying pass to the second and so on. E now passes one of the points along one of the sides of the area, dot by dot, as in case of pressure. Set the point down firmly so as to produce a distinct depression of the skin but not piercing the epidermis. When a pain spot is found O says ''There" and E locates the spot on the large map by means of the fur- rows. If the sensation is very intense, mark the spot with a cross instead of with a dot. Continue until both areas have been thoroughly explored. 94 Outlines for Experimental Psychology QUESTIONS. I — Which of the other three cutaneous sensations does that of pain most nearly resemble? 2 — Characterize the pain quality introspectively. 3 — How does the nimiber of pain spots compare with that of temperature spots? Are they related to any peripheral structure, as the pressure spots are to the hairs? 4 — Why do we moisten the skin in this experiment? References on Cold, Warmth, Pressure and Pain — Ladd and Wood worth — Physiological Psychology, pp. 1 78-181; 344-349. McKendrick and Snodgrass — Physiology of the Senses, pp. 41-69. Titchener — Text-book of Psychology, pp. 143-159. — Students Qualitative Manual, Chap. III. Instructors Qualitative Manual, Chap. III. Myers — Experimental Psychology, Chap. II. Outlines for Experimental Psychology 95 Mental Imagery. DISCUSSION. " If you ask yourself what you have in mind at a given moment, what is present in your consciousness, you find that there is often something present that is not a sensation, i.e. it is not caused by an external stimulus, but arises, as we say, within the mind. Some of these inner experiences are nevertheless like sensations to a greater or less degree: we may see with the mind's eye, or hear with the mind's ear, etc. What is experienced in this may be called imagery. An image has a sensory quality; seeing a person with the mind's eye is something like really seeing him; music running through the head has sound more or less like real music. Therefore images can properly be classed according to their kinship to different sensations. The following will do for a classification of sensations, and therefore of possible images: visual, auditory, smell, taste, touch, temperature, pain, muscular, labyrinthic, visceral. An image should be one of these or else a mixtiu"e of them." EXPERIMENT 57— VOLUNTARY CONTROL OF IMAGES. See whether you are able to summon up images of each of these sorts: e.g., for visual, your breakfast table this morning; for auditory, the sound of a friend's voice, or of familiar music; for smell, the odor of roast beef or of gasoline; for taste, sugar; for touch, the feeling of a hair-brush, etc; for muscular sense, opening and closing the fist (without actually doing it); for ''labyrinthic" diving, dizziness; for visceral, hunger. Keep record, as you go, of all your results; compare with the results of others, especially of your partner; determine, by mutual discussion, which of you has the better power of reproducing each sort of sensory quality. References — Galton — Inquiry into Human Faculty, pp. 57-58. Calkins — Introduction to Psychology, Chaps. 1 5 and 16. James — Principles of Psychology, Chap. 18. Binet — Psychology of Reasoning. 96 Outlines for Experimental Psychology EXPERIMENT 58— SPONTANEOUS IMAGERY. In the preceding experiment you tried to arouse certain images at will ; now you are to let whatever image come that will. The object is to see, in each individual, what sort of imagery is most readily called up. The material to he used consists of various words and phrases written on cards. The pack of cards is to be laid on the table, face downward; one card at a time is to be turned over, and as soon as the word or phrase is read, the subject is to notice what image arises first within his mind. Classify the images as before according to the sense to which they belong. If there is a second image immediately following the first, take note of that also. In case nothing that you can call an image occurs, note that fact. In many cases, it will be well to describe the experience a little more in detail than is implied in the simple classification of the image. The record should be kept as follows: after a preliminary description of the experiment, date, etc., turn over a card, get the image, then at once note the word and the image in your book; then proceed to the next. After one list of words has been gone through with, analyze the restdts as follows: in each case consider what different sorts of image might have been called up by the given word; each case affords a chance for different sorts of imagery to appear, and the one that does appear seems, so far, to be the more readily excited. Count up all the cases of visual preferred to auditory, auditory to visual, etc., and endeavor, from the total result, to arrange the different sorts of imagery in the order in which they are preferred, beginning with the most readily excited, and proceeding downward to the least readily excited. Present your resiilts in the form of tables. Plat these tables in the form of surfaces of distribution also. How does the result of this experiment compare with the result of the pre- ceding? What criticisms of the method and restdts occur to you? References — Betts — Distribution and Function of Imagery. Lay — Mental Imagery. Ribot — Creative Imagination. Outlines for Experimental Psychology 97 EXPERIMENT 59— IMAGERY OF WORDS. It appears that people differ in the ways in which they men- tally represent language to themselves — some always thinking in terms of sound, some in terms of printed or written characters, and some in terms of the movements of speech. We may thus speak of auditory, visual and articulatory imagery of speech. The aim of the present experiment is to ascertain what imagery of the names of objects spontaneously occurs to you, when you see the objects themselves, and think of their names without actually saying them. A pack of cards each having on it a color, picture or geometrical form, is laid face down on the table, and the cards are turned over one by one; as soon as you see what is on the card, name it mentally, and then observe whether the men- tal name was auditory, visual, motor, or whatever. After going through the series, count up the results, and determine in what form names most readily occur to you. In speaking, do you have a stream of images of words flowing along in advance of the spoken words? In listening to another person speak, do you mentally see the words he speaks? In reading, do you mentally hear the words as you read them? EXPERIMENT 60— THE DIFFERENTIA OF IMAGES. If we were not able, in some way, to distinguish between images and sensations, we should suffer from constant hallucinations. It is an interesting problem to discover what the criteria are that enable us to distinguish our images from sensations. But for the present, without speculating on the subject in a general way, it will be better to obtain some concrete, first-hand information as to the difference in special cases. The method suggested is to have at hand a set of objects — familiar and unfamiliar — and im- mediately after getting the image of an object, to get the sensations aroused by the same object, and note the difference. The materials include colors, forms, faces, tones, odors, feeling of objects held in the hand, movements of the members, etc. Keep all these objects behind a screen ; ask your partner to call up a mental image of one of the objects or experiences, and to note closely the characteristics of the image. Then present the object and ask him to state the introspective difference between the image and the actual sensa- tion or perception. Proceed until your results seem to you to be complete. How many and what criteria do you find? In how many ways do the two types of experience differ? How many of these differences do we utilize in daily life? Are all the differences always present? 98 Outlines for Experimental Psychology EXPERIMENT 61— SPEED OF IMAGERY. It has probably been noticed that some images came up more readily and promptly than others. In this experiment we wish to get an accurate measure of the "latent period " of different sorts of images. The method is as follows: The experimenter pre- pares a list of names of colors, tones, etc. He reads, for instance, the name of a color to the subject, and the subject makes a sign as soon as he mentally sees the color; the ex- perimenter meanwhile has kept track of the elapsed time — the time between the "stimulus" — here the name of the color — and the "response" — here the movement by which the subject indicates that he has the image. The experimenter may first attempt to take this time with a stop watch, but this will not succeed if the image comes very qmckly, and resort must then be had to the chronoscope, as used in the reaction time experiments. Some practise will here be necessary, on the experi- menter's part, to press his key at the same moment in which he pronounces the name, and on the subject's part, to open his key as soon as the image is clearly present, and not sooner. Considerable conscientiousness is demanded of the subject in this experiment. The experiment might be varied and extended almost indefinitely; but to answer the question whether visual, auditory, olfactory or tactile images come up most quickly it will perhaps be sufficient to make 5 sets of 50 tests each; one set to consist of 5 common colors, one of 5 faces or objects, one of 5 familiar sounds, one of 5 odors, and one of 5 familiar tactile experiences. The restilts of the experiment shovdd be carefully worked out and criticized. The subject should also be introspectively observant, and note anything that bears on the subject of the readiness with which imagery occurs. Present results in form of tables, gi\nng averages and mean variations. EXPERIMENT 62— THE FUNCTION OR USE OF IMAGES. In the early history of psychology great use was made of images in describing all the higher mental processes. For example, it is sometimes said that the thought of an individual person or thing consists in some form of image of it, and that an abstract idea — applicable to any one of a class of things — consists either of a vague, "generic" image, or else of the image of some individual of the class, which is taken as the representative of the group; that imagination (constructive) and reasoning are different waj^s of combining images; that perception and recognition are accom- plished by combining the present sensations aroused by an object Outlines for Experimental Psychology 99 with images of that or similar objects derived from past experi- ence. It should be noted that these explanations are more properly theories than directly observed facts; they should not therefore be taken for granted at the start, but submitted to the test of experiment. The following experiments supply a partial test. A — The Role of Images in Perception. The experimenter provides a number of objects, to be seen, heard or felt by the subject. The details may here be left to the ingenuity of the experimenter. These objects are presented, one at a time, to some sense of the subject. The subject has the following question to answer at each presentation: Did any image appear, in addi- tion to the presented object; and if so, what was the image? The experiment and its results should be carefully criticized. The Staircase Figure. This is a bare outline of a flight of stairs, without perspective. It may be seen in more than one way. Look at it steadily, and see if it changes its appearance. Note whether imagery, visual or motor, comes in at the moment of change ; also whether imagery of actual stairs is present during the persistence of either appearance. What, psychologically, is the difference between the two appearances? B — The Role of Images in Discrimination. Suppose that a person has to notice the likeness or difference of two things which are not presented to sense at the same time : how is it possible to do this? We say, in a general sort of way, that he must carry the first thing in mind till the second appears, and so compare the second with his memory of the first. But in what form does he carry the first thing in mind? Does he carry an image of it? This question may be approached by the following experiments. Individuals may perhaps differ here, as in other tests in imagery; and the same individual may get different results, according to the sort of things which are being compared. Brightness. A set of grays, ranging by small steps from white to black, is provided. These are concealed from the subject; the experimenter shows one card to the subject for two seconds, then waits ten seconds and shows another card (or else the same again) , and the subject has to say whether the second is lighter or darker than the first. Record is kept of the subject's answers, and the errors counted at the close of 20 trials. But, especially, the subject has to observe whether, in comparing the second card with the first, he has in mind an image of the first card. Answer in each trial. Try various degrees of difficulty, several trials for each. 100 Outlines for Experimental Psychology Lengths of Lines. Lines of two lengths are ruled on cards. The experimenter, as before, keeps them concealed from the subject; he shows one length for two seconds, waits lo seconds, then shows the other length; the subject has always to judge which is the longer, and also to report in each case whether he was con- scious of an image of the first line. Full record is kept, both of the subject's answers and of his right and wrong judgments. In case the subject has images sometimes and not at other times, see whether he made more errors proportionately, with or without the image. Try various degrees of difficulty, several trials for each. Tones. Two tuning forks, differing by 4 vibrations, are used. The subject sits with his side to the experimenter, 2 meters away from the forks, and with his eyes closed. If one of the subject's ears is better than the other, he sits with the better ear towards the forks. The experimenter sounds one fork, allows it to sound for 2 seconds, waits 10 seconds, and then sounds the other fork for 2 seconds. The subject has each time to say, or at least guess, which is the higher in pitch — 20 trials. The subject has also, as before, to report, after each trial, whether he had in mind, at time of comparison, an image of the first tone. As before, try various degrees of difference. Distances on the Skin. A "touch compass" is used, or rather two of them, the points of one being separated further than those of the other. The subject's eyes are closed; the experimenter ap- plies one of the compasses to the back of the subject's hand, in the longitudinal direction of the hand; he holds the points there for two seconds, waits 10 seconds, then applies the other to the same part of the hand. The subject has, as before, to judge which distance is the greater, and report the presence or absence of an image of the first impression at the moment of comparison. Try various degrees of difference, several trials for each. References — Woodworth — "The Consciousness of Relation", in Essays in Honor of William James. Titchener — Experimental Psychology of the Higher Thought Processes. Clarke — Conscious Attitudes, American Journal of Psychology, April, igii. Angell — Imageless Thought, Psych. Rev., 191 1. Hollingworth — Vicarious Functioning of Irrelevant Imagery, Journal of Philosophy, Dec, 1911. Betts — The Function and Distribution of Imagery. Outlines for Experimental Psychology 101 EXPERIMENT 63— THE ROLE OF ATTENTION AND IMAGERY IN PERCEPTION. Purpose — To discover by introspection the role played by imagery and attention in the interpretation of visual stimuli. Apparatus — A series of 12 puzzle pictures, in which the task is to find the "hidden" object. Procedure — The cards are numbered from i to 12. Take No. I, read the suggestion at the bottom of the picture, note the time and proceed to "find" the "hidden" object as quickly as possible. Observe meanwhile the process by which you discover the object. The visual stimuli — i.e., the marks on the card, the lines, spots, shadings, etc. — remain the same throughout, but the perception of the hidden object will not always be present — it will, more or less suddenly, "loom up" into consciousness. The question is — What factors produce, lead to, bring on, or facilitate the new interpretation of old stimuli? Careful introspection is required here, before a certain or trustworthy answer can be arrived at. Notice especially — I — Whether or not images come and go, in the process, and whether these images retain their original character or change from time to time. 2 — Was an image present at the moment of discovery? De- scribe the image. Do you think it played an essential part in the process of discovery? If so, point out how. 3 — What part does attention play in the process? Having once found the "hidden" object can you "hold it" — i.e., can you attend to it constantly — or does it come and go? What effect does a little practise have on such fluctuation, if it is present? Conclusions — Write up the results and introspections from each card, separately. Then, from a general view of the results, make such generalizations or final conclusions as you think are justified by your data, and present these conclusions in a separate paragraph. 102 Outlines for Experimental Psychology Judgment. DISCUSSION. A complete study of the topic of judgment would involve detailed examination into at least the following four chief sub- topics or aspects — A — The nature and mechanism of judgments, the qualitative differentia which distinguish judgments from other elementary or complex experiences, etc. Problems in this field are not easily investigated in an introductory laboratory course, since they require considerable practise in analysis and introspection. B — The formSj varieties and classification of judgments. This may be more properly a task for logical rather than for psychologi- cal investigation, and at any rate does not easily lend itself to objective and experimental examination. C — The basis or perceptual criteria of typical judgments — the data on which we rely in forming our judgments, and which de- termine the content, direction and outcome of the judgments of special varieties under given conditions. Study of these factors requires more intensive and prolonged work than is at our disposal in this course. D — The laws or behavior of judgments, the ways in which these laws are modified and the behavior conditioned by specific varia- tions in the judgment situation. By way of illustration of these variations may be mentioned such factors as individual differences, practise, the material or trait to be judged, the attitude or purpose of the judge, the influence of preceding judgments, the category or form of the judgment, etc. On this last topic (D) the following questions may be given as typical of a certain type of inquiry in psychology, and experi- ments may be performed for the purpose of throwing some light on them. Outlines for Experimental Psychology 103 SUGGESTED PROBLEMS IN JUDGMENT. I — How widely do people differ with respect to their judicial capacity under a given set of circumstances? What is the range from best to poorest, the average, the variability, etc.? Are there age differences, sex differences, etc.? 2 — When individuals are required to judge the same material for the same traits on different occasions, how consistent are their various determinations from time to time? How do people differ among themselves in this matter of personal consistency? To what degree do these factors depend on the material to be judged, the form or category of the judgment, the interval between trials, etc.? 3 — Is there such a thing as general judicial capacity — that is to say, is a person who is a good judge under one set of conditions, with a given kind of material, etc., also a good judge under other circumstances, with other material, etc.? 4 — Is there any relation between personal consistency and judi- cial capacity? Is the person who knows his own mind best and is most sure of his own opinions likely to be either a better or a poorer judge of the minds of others of his group than is a person who is not so self -consistent? How does this relation vary with the material? 5 — Are people more certain of their likes or their dislikes? Do people resemble each other more in their dislikes or in their pref- erences? If any definite tendencies are discoverable here, what is their probable significance? References — Hollingworth — Experimental Studies in Judgment. — Psychological Researches of J. McKeen Cattell, Chap. V. Thomdike — Mental and Social Measurements, Chaps. II and VIII. 104 Outlines for Experimental Psychology EXPERIMENT 64— EXPERIMENTS IN JUDGMENT. Procedure — Various sets of material are provided. Each set is to be arranged in order of merit for various traits or qualities (sensory, affective, relational, etc.) by each individual of the group. The instructor will indicate in each case the trait to be judged, the category or form of judgment, the mode of record, etc. Each individual arranges the material in strict order of merit (sometimes by the group method) on several different occasions, each arrangement being without reference to the previous arrangements. The record should show the position in the series assigned to each item by each individual. Once this is done the following procedure will throw light on the various questions asked in the foregoing section. A — Record the position assigned each item by each individual. Calculate the average position for each item on the basis of the various individual arrangements. Arrange the items in a final order of merit as determined by these averages. This final or average order may now be considered the correct or objective order. In some cases, as in weights, lines, etc., this order can be shown to be correct by comparing it with actual physical measure- ments of the items — that is, by comparison with some standard- ized scale or scales. In other cases no such standardized scales are available (as in the case of judgments of preference, beauty, similarity, interest, etc.) and a "correct" order will then mean the average order of the group of judges. B — The individual arrangements or judgments will not always agree absolutely with this final or objective order. In so far as a given individual's judgments agree with the objective order the individual may be said to be a "good" judge. In so far as his judgments differ from the objective scale, he may be said to be a "poor" judge, or a non-representative individual. By proper statistical methods, correlate the trials of each individual with the objective order, thus giving a numerical measure of his judicial capacity or representative character for the trait and material in question. C — The individual's judgments on a given occasion will not always be found to agree absolutely with his judgments for the same trait and material on other occasions. Correlate the indi- vidual's various trials with each other, or compute their variability. This will yield a numerical measure of his personal consistency. D — By comparing the variability of items at the top and bot- tom of the series the certainty and agreement of likes and dis- likes may be observed. E — By correlating the arrangements for various related traits, the influence of form and category of judgment may be studied. Outlines for Experimental Psychology 105 The Psycho-Metric Methods. DISCUSSION By way of introduction and general reference for the following experiments it will be well to read the following — Titchener — Text-book of Psychology, Chap, on Intensity of Sensation. — Experimental Psychology, Quantitative Man- uals. Ladd and Woodworth — Physiological Psychology. Appro- priate sections. Myers — Experimental Psychology, Chap. XV. Witmer — Analjrtical Psychology, Chap. VI. Hollingworth — Experimental Studies in Judgment. — Psychological Researches of J. McKeen Cattell, Chap. V. Fullerton and Cattell — Small Differences. PSYCHO-PHYSICAL MEASUREMENTS. Among the first problems investigated by experimental psychol- ogy was that of the relation between the magnitude (intensity, force, weight, etc.) of the stimulus and the corresponding degree of sensation. It was soon found that the relation was not directly proportionate — that is to say, doubling the stimulus does not result in twice as much sensation, nor does half the original stimu- lus produce a sensation only half as intense as the original sensa- tion. From the time of Weber and Fechner many attempts have been made to determine, within the various sensory modalities, the precise relation between increase in stimulus and increase in sensation, or to explain in other ways the characteristic results of psycho-physical experiments. This problem of course involves the whole question of the measurement of sensation intensity. It also affords opportunities for the study of many related problems, such as — individual differences in sensitivity; the possible range of sensations from minimiun to maximum; the psychology of discrimination, com- parison and judgment; illusions; constant errors; influence of fatigue and practise; and many other problems too ntunerous to mention. As the experiments proceed many of these problems will be suggested by your own results and observations, and some of them may seem important enough to merit further study. In the history of psycho-physical inquiry several methods have been evolved which have become standard methods of experiment in psychology. The various characteristics of these methods will have been indicated in the references to the general literature. They may be further discussed in the class room or in the labora- 106 Outlines for Experimental Psychology tory. Each of the methods is susceptible of application to a wide range of materials and situations. Some of them require con- siderable knowledge of mathematics and statistics before they are completely intelligible. These methods are of particular interest as being the first attempts to introduce accurate and controlled procedure into the field of psychology. They are usually to be supplemented by introspection, observation on the part of the operator, etc. Typical experiments by each method may be performed. THE METHODS ENUMERATED. Chief among these methods are the following. In parentheses are given the names of a few of the psychologists who have em- ployed the methods. These references are given for the sake of the more advanced student who may be interested in the problems and results of the various methods, as well as in the procedure itself. I — The Method of Limits, or The Method or Minimal Changes — (Fechner, Lipps, Wundt, Miiller, Merkel, Foucault, Cattell, Jastrow, Ebbinghaus, Sanford, Titchener, and many others) . 2 — The Method of Average Error — (Fechner, Kiilpe, Lipps, Wimdt, Cattell, Miinsterberg, Vierordt, Schirnianjn, Wood- worth, Hollingworth, and many others). 3 — The Method of Equivalents — (Weber, Fechner Wundt, Henri, Jastrow, Goldscheider, Helmholtz, and many others). 4 — The Method of Equal Sense Distances — (Plateau, Delboeuf, Hering, Wimdt, Boas, Lehman, Merkel, Cattell, and many others). 5 — Method of Right and Wrong Cases, sometimes called The Method of Constant Stimuli — (Muller, Fechner, Wtmdt, Angell, Cattell, Jastrow, Merkel, Kraepelin, Ebbinghaus, and many others) . 6 — The Order of Merit Method — (Cattell, Wells, Thorn- dike, Hollingworth, Strong, Downey, Norsworthy and Stunner). Outlines for Experimental Psychology 107 EXPERIMENTS 65 TO 70. Perform a typical experiment by each method. Use the fol- lowing materials and problems, consulting with the instructor concerning details. I — Method of Limits — Use the aesthesiometric compass to determine the two point threshold on several different areas of the skin. Suggest an original problem which might be investigated by this method. Plan the present experiment so as to throw light on several related problems. 2 — Method of Average Error — Use the kinaesthesograph, investigating some problem in the psychology of movement (per- ception of force, extent, constant errors, memory for kinaesthesis, etc). Suggest a new problem. 3 — Method of Equivalents — Use arm movements — one arm in front of the body and the other behind the back. Suggest some other experiment which might employ this method to ad- vantage. 4 — Method of Equal Sense Distances — Use lifted weights, lines ruled on cards, shades of gray, etc. How could this method be used to demonstrate Weber's Law? Suggest a new problem in which it might be used. 5 — Method of Right and Wrong Cases — Use the sound pendulum, to determine the least perceptible difference in inten- sity of sounds. Suggest an original problem for investigation by this method. 6 — Order of Merit Method — This is a relatively new method and is especially appropriate for studying complex material. Use photographs, handwriting, advertisements, etc. Suggest several new problems. 108 Outlines for Experimental Psychology Supplementary Experiments. If time allows, experiments of the following nature may be included. Their detailed character may be determined by the interests of students or instructor, and by the equipment of the laboratory. Affective Experience. I — A Typical Experiment by the Method of Impression. 2 — Introspective Analysis of the Affective Consciousness. 3 — Formal and Structural Aesthetic Preferences. 4 — Further Experiments by the Method of Relative Position. References — Gordon — Aesthetics. Pierce — Studies in Space Perception. Hollingworth — Advertising and Selling. — Professor Cattell's Studies by the Meth od of Relative Position. Titchener — Psychology of Feeling and Attentionx Experimental Psychology (Qualitative). Myers — Experimental Psychology, Chap. XXIV. Experiments in Judgment, etc. I — A Typical Experiment in Psychophysics. 2 — Perceptual Criteria of Typical Judgments. 3 — Judgments of Interval and Duration. 4 — Quantitative Measurement of a Typical Illusion. 5 — Introspective Analysis of Volition, Thought, Decision, etc. References — Titchener — Exper. Psychol, of the Thought Processes. — Experimental Psychology (Quantitative). Hollingworth — Experimental Studies in Judgment. Brown — The Judgment of Difference. Myers — Experimental Psychology, Chaps. XI, XIX, XXIII, XXVI. Outlines for Experimental Psychology 109 Books by H. L. Hollingworth. The Inaccuracy of Movement — Archives of Psychology, No. 13 (Columbia Contributions to Philosophy and Psychology, Vol. XVII, No. 3), pp. 87, June, 1909, New York. 80 cents. The Influence of Caffein on Mental and Motor Effi- ciency — Archives of Psychology, No. 22 (Columbia Contributions to Philosophy and Psychology, Vol. XX, No. 4), pp. 167, April, 19 1 2, New York. $1.50 (paper), $1.75 (cloth). Advertising and Selling — (Principles of Appeal and Re- sponse), pp. 315, New York, 1913. $2.00 net. By mail $2.16. Experimental Studies in Judgment — Archives of Psychology, No. 29 (Columbia Contributions to Philosophy and Psychology, Vol. XXII, No. 3), pp. 125, December, 1913, New York. $1.25 (paper), $1.50 (cloth). Outlines for Applied and Abnormal Psychology, pp. 25, July, 1914, New York. 25 cents. Outlines for Experimental Psychology, pp. no, Septem- ber, 19 14, New York. $1.00. Published and For Sale by A. G. 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