Social Taste Buds: Evidence of Evolved Same-Sex Friend Preferences from a Policy-Capturing Study

Abstract

Despite the importance of friendship, the traits that people seek in a friend are not well understood. Here, we pursue the hypothesis that same-sex friendships evolved as ongoing cooperative relationships, so friend preferences should at least partially focus on those traits that would have made someone a good cooperative partner within the conditions of the human ancestral environment. We tested this hypothesis in a face perception paradigm in which undergraduate participants rated the friend desirability of target faces that were also rated on several traits hypothesized to be relevant to friend choice. This allowed us to test the actual predictors of attraction, rather than relying on self-reported preferences. Consistent with our hypothesis, we found that judgments of a target person’s desirability as a friend depended on perceptions of their ability to create material benefits in the ancestral environment (e.g., skill as a hunter or gatherer). These effects were not due to an attractiveness “halo effect” or a preference for intelligence more generally. In addition, we found mixed evidence for sex differences that match the typical hunter-gatherer division of labor. We discuss implications of these findings for the study of friend choice, and for understanding social preferences more broadly.