EFFECTS OF ADVERSE EXPERIENCES ON SOCIAL DECISION-MAKING ACROSS SEXES

Social decision-making refers to the processes by which individuals evaluate options and make choices within a social context. Disruptions in these processes contribute to neuropsychiatric disorders characterized by social dysfunction, many of which show marked sex differences in vulnerability and expression. Yet how adverse social experiences shape social decision-making in a sex‑dependent manner remains poorly understood. Here, we investigated the impact of chronic social isolation and social defeat on choice behavior in male and female mice using a two‑choice social reward task. In this paradigm, mice could choose to deliver a reward to both themselves and a partner (prosocial option) or obtain it solely for themselves (selfish option). Based on baseline behavior, animals were categorized as prosocial or selfish, and changes in their preferences were assessed following exposure to social stress. We found that chronic social isolation reliably diminished prosocial preference scores across all baseline phenotypes and in both sexes, indicating a broad suppressive effect on prosocial tendencies. In contrast, social defeat produced pronounced sex‑dependent effects: it eliminated choice preference in males, leading to marked behavioral disruption, whereas females were largely resilient, showing minimal alterations except following repeated defeat. Together, these findings demonstrate that distinct forms of social adversity differentially influence social decision-making in a phenotype‑ and sex‑dependent manner. This work provides a behavioral framework for dissecting the neural mechanisms through which social experiences shape prosocial behavior and its dysregulation in disease.
This work is supported by HKRGC-CRF Grant C4052-24G, HKRGC-GRF grant 14124525; CUHK 3110198