Caring about others’ welfare, acting in ways that are helpful to others, feeling empathy, and behaving according to moral principles are all aspects of prosociality. This seminar covers the evolutionary, cognitive, and physiological bases for prosocial behavior as well as the roles of social and cultural institutions in shaping prosociality. In this class we will discuss 1) alternative views of what constitutes prosocial behavior and some of the challenges inherent in defining altruism, 2) potential explanations for the evolutionary origins of prosocial behavior, 3) the cognitive, neural, and endocrine bases for prosociality, and 4) the role of cultural, social, political, and religious institutions in promoting or eroding prosocial behavior.