Recent research suggests that altruism can be surprisingly tenuous; minor situational variations can turn altruism on and off. For example, if provided with sufficient cover, “reluctant altruists” will often avoid situations that compel them to give, and they may even secretly renege on...

Why do some people engage in costly bystander intervention against norm violations without any personal direct or indirect gains? The present study investigates justice sensitivity and moral emotions as determinants of such altruistic punishment. We propose that the individual strength of...