Mama's Last Hug: Animal Emotions and What They Teach Us about Ourselves

by Frans de Waal

In an early study, eleven-year-old boys at a summer camp were divided into two groups to compete against each other. In-group cohesiveness increased, as did reinforcement of social norms and leader-follower behavior. The experiment demonstrated that status hierarchies have a unifying quality that is reinforced as soon as concerted action is called for. This is the paradox of power structures: they bind people together.