Disentangling the Effects of Acute Stress on Affiliation and Prosociality

It has been suggested that acute stress increases prosociality in humans, indicating a tend-and-befriend response, but empirical findings are yet mixed. Although most prior studies operationalized prosociality with economic games, we argue that befriending is primarily characterized by affiliation and, therefore, cannot be shown in such anonymous settings. We investigated effects of acute stress on both prosociality and affiliation in two pre-registered studies. In an experimental laboratory study (N = 74), participants played a cooperative video game involving face-to-face interactions before and after the Maastricht Acute Stress Test. In a quasi-experimental field study (N = 168) we assessed affiliation and prosociality before a university exam (stress condition) versus a regular lecture (control condition). In line with the tend-and-befriend theory, acute stress increased affiliation in both studies. Moreover, in our laboratory study, higher affiliation in response to the stressor was associated with a stronger decrease in subjective stress, suggesting that affiliation might be an effective coping mechanism. We did not find a main effect of stress on prosociality in either study. Instead, Social Value Orientation predicted changes in prosociality under stress. A more prosocial orientation (i.e., higher values in Social Value Orientation) was associated with higher prosociality under stress as compared to non-stressed.