That's what friends are for: How years, days, and minutes of social engagement relate to cognition in older and younger adulthood

Author: Daniele Antoniou

Antoniou, Daniele, 2022 That's what friends are for: How years, days, and minutes of social engagement relate to cognition in older and younger adulthood, Flinders University, College of Education, Psychology and Social Work

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Cognitive functioning plays a fundamental role in healthy ageing. Although slowing of cognition is a somewhat normal part of the aging process, neurodegenerative illnesses such as dementia are not typical and currently have no effective treatments. As cognitive decline is a risk factor of developing dementia, recent years have seen an increasing focus on identifying lifestyle factors that can slow cognitive decline across the lifespan. The purpose of this thesis was to consider associations of social resources with cognitive performance across different timescales analysed within a Bayesian statistical framework.

The first study used longitudinal data to examine whether social resources (social activity engagement and loneliness) play a compensatory role in buffering the effects of ageing on cognitive decline among those with limited opportunity to develop cognitive reserve (proxied by low educational attainment). A meaningful four-way interaction indicated the most vulnerable group of older adults (in terms of decline in processing speed over time) were those who had low education, were lonely, and had low levels of social activity participation. In contrast, there was a meaningfully slower rate of processing speed decline for those who had low education, were not lonely, and had high levels of social activity participation. However, the four-way interaction was no longer meaningful when participants who were classified as having dementia subsequent to baseline were excluded from the analysis. Finally, cross-sectional analyses demonstrated that meaningful activity in general (regardless of whether the activity was social in nature) was associated with better verbal fluency performance.

The second study used daily diary data to examine whether older adults' cognitive performance on a given day was related to the activities they engaged in, the degree of enjoyment they attributed to a positive social exchange, or the severity of a negative social exchange experienced on that day. No within-person associations of activity engagement or affective social exchanges and processing speed performance were found. Moreover, tests of between-person x within-person social exchange interactions did not reveal meaningful results, indicating that the novelty of the activity or affective social exchange did not impact the strength of the daily covariation.

The final study used an experimental design with young adults to investigate whether perspective-taking was a mechanism explaining acute boosts between social interaction and cognition that have been reported in previous research. Findings suggested perspective-taking benefiting processing speed above and beyond effects of practice. Specifically, perspective- taking conditions (social and alone) showed a larger increase in simple scores when compared to a passive control condition. There was no observable difference in improvement scores between the two perspective-taking conditions (social or alone).

Overall, the empirical findings did not provide strong evidence of social resources impacting cognition. Specifically: (a) where it appeared that social resources protected those with low educational attainment from the effects of cognitive decline, there was a high possibility of this effect reflecting reverse causality, (b) no reliable covariation between social activities or affective social exchanges and cognition were observed among older adults at the daily level, and (c) social interactions boosted processing speed in the short-term relative to a control group, however did not appear to be of additional benefit above and beyond the effects of perspective-taking. Finally, the few associations of social resources with cognitive performance that emerged tended not to generalise across multiple cognitive domains. In the final chapter, possible explanations for the discrepancies between the findings of this thesis and the broader literature are discussed.

Keywords: social engagement, older adulthood, cognition, bayesian

Subject: Psychology thesis

Thesis type: Doctor of Philosophy
Completed: 2022
School: College of Education, Psychology and Social Work
Supervisor: Tim Windsor