The Effects of Age-Related Cognitive Change on Social Engagement: An Exploration of Cohort and Electrophysiological Data

Abstract

Ageing brings about a number of functional changes across many cognitive domains; slowed language production (Horton, Spieler, & Shriberg, 2010), reduced ability to effectively direct attentional behaviours and monitor conflict (Wascher, Schneider, Hoffmann, Beste, & Sänger, 2012; West & Schwarb, 2006), and most well-known are drastic declines in memory (Burke and MacKay, 1997). These cognitive abilities support our ability to create social bonds: communicating, effectively directing behaviour, and recalling past experiences (Diamond, 2013; Krueger et al., 2009; McHugh Power, Steptoe, Kee, & Lawlor, 2019). Preservation of cognitive health becomes increasingly important in later life to prevent social isolation and loneliness (Evans et al., 2019), which can have significant impacts on mental and physical health during old age (Cacioppo & Cacioppo, 2014; Cacioppo & Hawkley, 2003; Christiansen et al., 2021; Hawton et al., 2011). This thesis investigated effects of age-related changes in cognition on the experience of social engagement and inclusion. Study 1 used factor analyses and Structural Equation Modelling (SEM) on data from the first wave of data collection for the Cam-CAN dataset (Shafto et al., 2014). The factor analysis uncovered differences in the underpinnings of cognition and social engagement in young and old adults. Structural Equation Modelling then revealed the interactions between these factors, as influenced by socioeconomic status (SES). This established a number of interactions between SES, cognition, and social engagement in both young and old adults, though only in the older group were cognitively mediated associations found. This study established the framework of differential representations in young and old adults, and highlighted facets of cognition that supported social engagement in later life. The second study investigated these associations further using the second wave of Cam-CAN data, where cognitive measures were more targeted. Structural Equation Modelling in this study showed more discreet relationships between cognition and social engagement that suggested older adults relied on mediation of specific cognitive abilities for social engagement. These findings highlight specific cognitive domains that can be targeted in interventions that address social isolation and loneliness among older adults, including supporting cognitive development in early adulthood or working to maintain cognitive skills throughout life. The third study of this thesis used electroencephalography (EEG), to investigate age differences in neural markers of language and executive function, as well as probing feelings of social inclusion in young and older adults. Several differences were found across the cognitive domains; older adults had a significantly reduced P300 amplitude in tests of inhibition, showed little correct/incorrect differences in mid-frontal theta (3-7Hz) in mental-shifting and showed a reduced left-frontal positivity in correct verbal responses. These findings demonstrate age-related differences in neurological measures across the three cognitive domains explored, suggesting that these cognitive processes are more effortful and recruit more global neural resources in older adults. The research identified age-related differences in cognition, at behavioural and neuronal levels, and associated such differences with social engagement. By utilising both a large-scale, dataset and extremely targeted neurocognitive measures I have been able to establish a broad model of associations between social engagement and cognition at different life-stages, then elaborate on the underlying neurocognitive mechanisms of language and executive functions. This provides strong evidence for cognitive-social engagement associations that become more impactful in later-life and highlight neuro-cognitive differences in older people across multiple domains.

Date of Award	31 Dec 2023
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Pamela Qualter (Supervisor) & Jason Taylor (Supervisor)