Humans often act with caring, generosity, and benevolence, but can at times also be hostile, selfish, and malevolent. What motivates these different sides to human nature has been the focus of much recent research within self-determination theory (SDT). In this talk, Dr. Ryan will first review research on the intrinsic psychological satisfactions of benevolence, and how helping others satisfies basic psychological needs for autonomy, competence, and relatedness, and contributes to a sense of meaning. He will further show how social environments can either nurture or undermine people’s inherent prosocial propensities. Specifically, Ryan will discuss research showing how autonomy-supportive parents, schools, and organizations foster greater empathy and caring, whereas more controlling and need frustrating contexts yield more anti-social behaviors and aggression. At a more societal level, he will show the linkages between people’s experience of freedoms and capabilities with basic psychological need satisfactions, and in turn with enhanced prosocial and wellness outcomes. Finally, Ryan will comment on everyday activities and lifestyles that can meaningfully contribute to (or detract from) a person’s wellbeing and that of those around them. Self-determination theory thus offers an understanding of both the positive and negative sides of human behavior, and models for parenting, teaching, management, and leadership that can bring out the best in us.