Arno Riedl (Maastricht University) – Prosociality under acute stress: exploring the role of sex and baseline social preferences

Humans are a social species and many decisions we make are inherently driven by our social preferences. However, these decisions are frequently made in the presence of stressors, ranging from mild inconveniences, such as missing the bus, to severe events, such as the death of a loved one. Existing evidence regarding the effects of acute stress on social decision-making paint an inconsistent picture. These studies suffer from a male bias and do not control for baseline preferences. We experimentally investigate the effects of acute stress on social preferences, focusing on the moderating role of baseline social preferences and sex. Using a sex-balanced sample (N=271), we randomly assigned participants to either the stress or control (placebo stress) treatment. Participants underwent the (placebo) Maastricht Acute Stress Task and successful stress induction was evaluated through salivary cortisol and blood pressure. Distributional social preferences were elicited using a series of incentivized binary dictator games. Results indicate that stress-response-induced cortisol changes predict differences in social preferences, with stressed individuals exhibiting more selfish behaviors than their non-stressed counterparts. Interestingly, this effect appears to be driven primarily by individuals with low or no cortisol response displaying increases in prosocial behavior. Results further suggest that the cortisol effect is weaker for individuals with more generous baseline social preferences and appears to be present in males only. Our results highlight the relevance of baseline social preferences and sex in explaining the relationship between stress and prosociality.