A social and physical stressor increases later punishment in healthy males

Existing literature suggests that stress in early life can influence or trigger later aggressive and punishment behaviors during social interactions. However, only a few human studies have addressed this link in controlled experimental settings. Here, we assessed the impact of biological and behavioral markers of stress on economic and social interactions in healthy men using a between-group design. The Socially Evaluated Cold Pressor Test (i.e., supervised hand immersion into cold water) was applied to one group of participants (n = 19), while a second group underwent the Warm Water Test (n = 21). After the stressor or control procedure, all participants played the Inequality Game, a paradigm in which they could engage in punishment, cooperative, or aggressive behaviors towards a fair and an unfair counterpart player. Compared to the control condition, participants in the stress condition engaged in more punishment behaviors towards the unfair player and less cooperative behaviors towards both players. Critically, higher levels of cortisol in the stress group were associated with more punishment behaviors towards the unfair player. In contrast, aggressive behavior did not differ between participants in the stress vs. control condition. Overall, our findings showed that situationally induced stress might facilitate punishment behaviors in provoking situations. Further research should elucidate the role of inter-individual variables that may encourage or prevent stress-related punishment in social contexts.