Daily social interactions related to daily performance on mobile cognitive tests among older adults.

The lack of social contact or good social relationships has been linked with cognitive decline and higher risk for Alzheimer's disease and related dementias. One important but unexamined question is how daily social interactions relate to older adults' cognitive function in daily life. The present study examined how changes in daily social interactions related to fluctuations in older adults' performance on mobile cognitive tests from day to day. Using an ecological momentary assessments approach, 312 older adults (aged 70 to 90 years) completed surveys on social interactions and mobile cognitive tests five times a day for 16 consecutive days using smartphones. Multilevel modeling was used for analyses. Results demonstrated that having more daily social interactions, especially more pleasant social interactions, related to better cognitive performance the same day and over the subsequent two days. Cognitive performance, however, did not predict subsequent changes in social interactions across days. At the between-person level, older adults who had more (vs. less) frequent interactions with close partners on average, especially with their friends, had better cognitive performance. Finally, the average levels of social interactions also moderated the within-person associations between daily social interactions and the same-day cognitive performance. In sum, results from this study highlight the importance of having pleasant social interactions and frequent interactions with friends for older adults' cognitive function in daily life, and have important implications for future behavioral interventions targeting certain features of daily social interactions to reduce risk of cognitive decline and Alzheimer's disease and related dementias.