The study of moral cognition has been dominated by Kohlberg's stage theory, which emphasizes conscious deliberation as the source of moral judgments. More recently, researchers have proposed that moral judgments may be the product of certain implicit principles. The present study investigated whether 9th- and 12th-grade students would conform their judgments to three principles of harm, and the degree to which these principles would be available to conscious reflection. The present study also investigated the possibility of age-related differences with respect to the application and justification of these principles of harm. Results indicated that participants across age groups conformed their judgments to the principles of harm under investigation. However, participants had difficulty providing justifications for their judgments. This suggests these principles of harm operate outside of conscious control. Results also revealed age differences in the ability to provide justifications for one's judgments " with older participants providing more sufficient justifications.