Stress, Ethnicity, and Prosocial Behavior

While observational evidence suggests that people behave more prosocially toward members of their own ethnic group, many laboratory studies fail to find this effect. One possible explanation is that coethnic preference only emerges during times of stress. To test this hypothesis, we pharmacologically increase levels of the stress hormone cortisol, after which participants complete laboratory experiments with coethnics and non-coethnics. We find mixed evidence that increased cortisol decreases prosocial behavior. Coethnic preferences do not vary with cortisol. However, in contrast to previous studies, we find strong and robust evidence of coethnic preference.