PROJECT SUMMARY Social isolation is associated with excessive alcohol use, depression, anxiety, and other poor outcomes (e.g., Daeppen et al., 2013; Moos et al., 2001; Muller et al., 2017; Zuckermann et al., 2020). Substantial variability also exists in these associations, such that individuals with limited social ties do experience positive outcomes and socially connected individuals similarly do experience negative outcomes (Bond et al., 2007; Bryan et al., 2017; Eddie & Kelly, 2017; Spohr et al., 2019). Despite the importance of social factors in alcohol use and related outcomes, the mechanisms via which social connectedness or isolation yield positive and negative outcomes remains largely unexplored, in part due to difficulties eliciting and quantifying interpersonal processes in a parametric manner. We have previously shown that sensitivity to social signals may be parameterized in the context of interactive behavioral economic games and provide powerful tools with which to examine sources of variability and potential mechanisms through which social preferences are related to mental health (Chung et al., 2015; Chiu et al., 2008; King-Casas et al., 2005, 2008; King-Casas & Chiu, 2012). Here, we use these tools to test the possibility that sensitivity to social signals in the context of social interaction influences how social ties yield variability in alcohol use, mood, and anxiety. To examine associations among social connectedness, sensitivity to social signals, and outcomes, we combine a longitudinal cohort design including time-lagged mediation analyses, functional neuroimaging, and a behavioral economic social exchange task. We will assess these associations (i) contemporaneously in Aim 1, (ii) over time in Aim 2, and (iii) following social restrictions related to COVID-19 in a large online sample in Aim 3. The broad hypothesis is that sensitivity to social signals (as measured by neurocomputational indices) will both moderate and mediate associations between social ties and alcohol use and related outcomes. The work is submitted in response to PAR-19-373 requesting applications addressing basic mechanisms of social connectedness, connection, and isolation, including those related to COVID-19. The application further is in line with specific interests of NIAAA and NIMH and in “mechanistic studies of the biopsychosocial causes and effects of social connection and isolation” and “behavioral [and] neurobiological mechanisms of social connection and isolation leading to alcohol use, addiction, or cessation of consumption.”

PROJECT NARRATIVE Human social interactions are important to maintaining our physical and mental health. However, some people experience undesirable outcomes (e.g., alcoholism, depression, addiction) despite having many social ties, and other people report high life satisfaction despite being socially isolated. Here, we use a computational and statistical model-based approach to test how brain sensitivity during social interactions, a measure of how important an interaction is to an individual person, may protect from negative outcomes of social isolation or confer vulnerability despite social connectedness.