Adaptive cooperation in the face of social exclusion

The extent to which socially excluded individuals are willing to collaborate with others is an important theoretical and practical question. We consider four contrasting predictions based on the existing psychological literature. The first two are derived from the need-threat literature: Following social rejection individuals may withdraw from cooperative interaction in general (aggression hypothesis), or cooperate more in general (reconnection hypothesis). Alternatively, performance of the excluded individuals in cooperative tasks may worsen reflecting reduced ability to deliberate (cognitive depletion hypothesis). Finally, excluded individuals may cooperate less with those who rejected them (revenge hypothesis). We tested these hypotheses in three incentivized experiments. In each, we first varied whether participants were excluded or included in a virtual ball-passing game. In the second part, participants entered a two-player investment game, in which their earnings were partly dependent on the cooperativeness of their partner. We varied how cooperative the co-player was, and measured whether our participants were willing to cooperate or not. All participants entered the game twice, once with an unknown player, and once with a person who they previously encountered during the ball-passing task. Our findings were consistent with the revenge hypothesis – excluded participants were less cooperative when they were paired with the individual who previously excluded them. Interactions with unknown players were unaffected – excluded and included participants were equally cooperative. We propose a straightforward explanation of our findings: People do not like to cooperate with those who previously rejected them, but the experience of rejection does not have broad implications for people's overall willingness to cooperate.