Daily social isolation maps onto distinctive features of anhedonic behavior: A combined ecological and computational investigation

Background. Loneliness and social isolation have detrimental consequences on mental health and act as vulnerability factors for the development of depressive symptoms, such as anhedonia. The mitigation strategies used to contain the Coronavirus 2019 (COVID-19), such as social distancing and lockdowns, allowed us to investigate putative associations between daily objective and perceived social isolation and anhedonic-like behavior. Methods. Reward-related functioning was objectively assessed using the Probabilistic Reward Task (PRT). One hundred and fourteen unselected healthy individuals (71% females) underwent both a laboratory and an ecological momentary assessment. Computational modelling was applied to performance on the PRT to disentangle reward sensitivity and learning rate. Results. Findings revealed that objective-but not subjective-daily social interactions were associated with motivational behavior. Specifically, higher social isolation (less time spent with others) was associated with higher responsivity to rewarding stimuli and a reduced influence of a given reward on successive behavioral choices. Conclusions. Overall, current results broaden our knowledge on the potential pathways linking (COVID-19-related) social isolation to altered motivational functioning.