Acute isolation increases reward responsiveness in human adolescents

Abstract Social connection is a basic human need and particularly important during adolescence. How a lack of connection impacts adolescent behaviour is unclear. To address this question, we employed experimental short-term isolation, first, to assess how isolation affects reward seeking and learning in adolescents aged 16-19 years and, second, to investigate whether neural reward sensitivity predicts vulnerability to isolation. Additionally, we assessed whether virtual interactions remediate isolation effects. Isolation caused faster decisions to exert effort for rewards and faster learned reward contingencies, especially from social feedback. These effects were stronger in participants who experienced higher loneliness following isolation. Participants with lower neural reward sensitivity showed stronger effects of isolation. Virtual interactions remediated effects only partially and decreased learning from social feedback. These results demonstrate that in adolescence isolation increases reward responsiveness, a key driver of motivation and decision-making.