Loneliness and social isolation are not associated with executive functioning in a cross-sectional study of cognitively healthy older adults

The empirical literature on the relationship between social interaction and executive functions in older age is mixed, perhaps stemming in part from differences in executive functioning measures (e.g., a single test or a test battery) and differences in conceptualization and measurement of social interaction (e.g., loneliness and/or social isolation). Our study investigated the relationship between social interaction and executive functions in a sample (N = 102) of cognitively unimpaired, functionally independent older adults (ages 65 - 90). Participants received a comprehensive executive functioning battery with measures of working memory, inhibition, shifting, and global executive functioning. We measured loneliness subjectively through survey (NIH Toolbox Loneliness Scale) and social isolation objectively through naturalistic observation (percentage of time alone captured from ambient sound sampling using the Electronically Activated Recorder). Loneliness was not significantly related to working memory, inhibition, shifting, or global executive functioning (p-values = .13 - .65). Time spent alone was also not significantly related to working memory, inhibition, shifting, or global executive functioning (p-values = .11 - .69). Corresponding Bayes factors indicated anywhere from moderate to extremely strong evidence (BF01 = 8.70 to BF01 = 119.49) in support of no relationship and the effect sizes were at best modest (β values = -.17 - .10). These findings suggest that, among cognitively healthy older adults, there may not be a robust cross-sectional relationship between multiple aspects of executive functioning and either subjectively experienced loneliness or objectively observed social isolation.