Evolutionary psychology focuses on the study of adaptations. Its practitioners put little credence in the study of reproductive success in recent and current environments, and argue for an information-processing, cost-benefit conception of adaptation. Because ancestral and current environments differ, it is necessary to distinguish between innate and operational adaptations and between concurrently contingent and developmentally contingent behaviors. These distinctions lead to an evolutionary classification of behaviors into true pathologies, pseudopathologies, quasinormal behaviors, and adaptive-culturally-variable behaviors. I argue that a complete study of the functioning of a behavioral adaptation involves modeling ancestral selection pressures, cross-cultural research, experimental studies of mental processes, and studies of the proximate biological correlates of information-processing adaptations. Finally, I claim that evolutionary psychology can help us avoid making both naturalistic and moralistic fallacies.