It is widely accepted that humans are averse to performing harmful actions and that this emotional response explains important properties of moral judgment and behavior. The specific nature of this emotional response, however, remains poorly understood. Some past models have assumed that the aversion stems from empathy; that is, the anticipated outcome of a suffering victim. But in recent research, we have demonstrated that another powerful contributor is an intrinsic aversion to certain canonically harmful actions. Fiery Cushman is a Professor of Psychology at Harvard University