Keeping the benefits of group cooperation: domain-specific responses to distinct causes of social exclusion

Some people are especially physically adept, others carry dangerous pathogens, some have valuable and rare knowledge, and still others cheat or deceive those around them. Because of these differences, and the costs and benefits they pose, natural selection has crafted mechanisms of partner choice that are selective: some people are chosen as social partners, others are not. When people are not chosen as partners—when they are socially excluded—they lose access to important fitness benefits. Thus, the mind should have adaptations to recapture these benefits by regaining inclusion. Is there one best way to regain inclusion? This is unlikely because there are multiple causes of exclusion; a single response is unlikely to be successful across all possible causes. Instead, distinct causes of exclusion might require adaptively tailored responses. We test whether there are tailored responses to five possible causes of exclusion from a cooperative group: inability to contribute, pathogen infection, free riding, disrupting group coordination, and exit from the group. Our results show that different causes of exclusion lead to distinct profiles of emotions and behavior. Each emotion and behavior profile is adaptively specialized to reverse or mitigate its specific cause of exclusion. Our research shows how taking an evolutionary view of human sociality can help map the psychology of cooperation and exclusion.