One of the most important roots of persistent or extreme violence is an evolution or change in individuals and groups that results from their own actions. Once perpetrators begin to harm people, the resulting psychological changes make greater harm-doing probable. However, early public reactions can counteract these changes and inhibit further violence.

just-world thinking

One psychological consequence of harm-doing is further devaluation of victims. According to the just-world hypothesis, which has received substantial experimental support, people tend to assume that victims have earned their suffering by their actions or character. Perhaps we need to maintain faith that we ourselves will not become innocent victims of circumstance. However, blaming the victim is not universal; some people turn against the perpetrators. For example, a minority of individuals blame the experimenter instead of devaluing a student receiving electric shocks in an experiment. Prior devaluation should make it more likely that victims are blamed.

People believe in a just world with different degrees of conviction. Those whose belief is strong derogate poor people, underprivileged groups, or minorities. Strong belief in a just world is associated with rigid application of social rules and belief in the importance of convention, as opposed to empathy and concern with human welfare. It is ironic and seemingly paradoxical (although not truly paradoxical, because the belief that the world is just is not identical to regarding justice as an ideal or to the desire to promote justice) that the belief that the world is a just place leads people to accept the suffering of others more easily, even of people they themselves harmed.