Date of Award
Doctor of Philosophy
Studying older adults who are aging ‘successfully’ (i.e., avoiding disease/disability; maintaining high cognitive and physical functioning; engaging in meaningful interpersonal/social engagement) may offer insight into variables that contribute to cognitive change throughout the lifespan. Successful aging is related to levels of engagement, which may be promoted by the problem solving and reevaluation encouraged by the creative process (Fisher & Specht, 1999). Creative thinking requires the consideration of diverse concepts and strategies (e.g., generating many solutions), as well as the regulated filtering of these possibilities (e.g., neither too permissive nor too narrow when eliminating ideas; Baas, De Dreu, & Nijstad, 2011). Cognitive inhibition is necessary for goal-directed behavior, and may also promote creativity by influencing abilities such as plasticity and innovation. Performance on executive control tasks, especially those that draw on inhibition, are impacted by age. Performance on inhibitory (but not excitatory) tasks may be sensitive to arousal levels that fluctuate with circadian rhythm (synchrony effect). The current study examined performance on a variety of neuropsychological and creativity measures at two times of the day in a sample of successfully aging adults aged 70-79. Assessments of executive function, inhibition, and creativity (i.e., verbal and non-verbal divergent thinking) were administered to older adults twice, once at a time when inhibitory performance was expected to be ideal (synchronous) and another at a time when inhibitory performance was expected to be reduced (non-synchronous). We hypothesized that morning testing (synchronous) trials of inhibitory tasks would exhibit lower latency and error rates than evening testing (non-synchronous) trials; morning testing (synchronous) trials of creative potential tasks would exhibit lower fluency, flexibility, and originality scores than evening testing (non-synchronous) trials; and that Need For Cognition (NFC) scores and Information-Orientation ISI subscale scores would be positively correlated with overall (AM + PM) creativity scores (fluency, flexibility, originality). Participants were expected to demonstrate time of day effects on Stroop and TMT performance. Synchrony effects were not observed in this study. There was a significant relation between creative potential and Need for Cognition scores but not between creative potential and scores on the Information-Orientation subscale of the ISI. The current sample may have compensated with cognitive challenges such as those induced by testing time effects. These findings may suggest that a successfully-aging cohort is not impacted by synchrony effects. No previous research has used synchrony to compare aging trajectories (pathological, usual, successful) on cognitive performance. It is feasible that a successfully aging population would have significant cognitive reserve, brain reserve, or scaffolding strategies to compensate for the additional cognitive challenge of non-optimal testing time (Düzel, Schütze, Yonelinas, & Heinze, 2011; Reuter-Lorenz & Park, 2014). Indeed, a marker of successful aging is to compensate well with age-related changes and demonstrate minimal- to no- deficits in performance (Rowe & Kahn, 1997). Synchrony changes in cognitive performance may not be evident in a successfully aging population. The current study provides evidence that motivates intriguing questions about successful aging, inhibition, creativity, and time of day.
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