| dc.description.abstract | Declines due to cognitive aging can significantly impact day to day living, and those who have higher levels of cognitive persistence can potentially mitigate some of that decline (Li et al., 2024). An example of this could be shown by observing the relationship between cognitive persistence and discerning difficult to hear speech. The theory of cognitive reserve (CR) proposes that individual differences in life experiences such as education, occupation, and mentally or socially stimulating activities, can prevent dementia/brain damage from having as strong as an effect on an individual compared to someone with different experiences (Harrison, Sajjad, Bramer, Ikram, Tiemeier, & Stephan, 2015). It has been suggested by several studies that grit is a predictor of CR (Rhodes & Giovannetitti, 2021, Rhodes, et. al, 2017). Persistence, which involves engaging effort to overcome difficulty during cognitive tasks, is conceptually similar to grit but can be measured using cognitive assessments, rather than self-report. Chapter 1 provides an overview of the literature on cognitive aging and factors that might contribute to CR to offset age-related declines in cognition. The first project, discussed in Chapter 2, was designed to investigate the relationship between age, levels of persistence, and accuracy of discerning speech that has been time compressed at three different rates. Older adults showed steeper declines in accuracy with increased time-compression, despite higher cognitive persistence improving accuracy overall. This resulted in poorer speech recognition for fast speech in older compared to younger adults. Pupillometry indicated older adults had larger initial changes in pupil diameter across compression conditions than younger adults, suggesting high baseline effort regardless of task difficulty. Older adults also showed a delayed pupil response to rapid speech, suggesting age-related declines in recruitment of effort in response to challenging listening conditions. The second project, discussed in Chapter 3, investigated the relationships between persistence, grit, and CR to evaluate whether grit builds CR directly, or indirectly by increasing persistence. The hypothesized structural model linking grit to persistence to CR was not supported. However, project 2 established that grit was correlated with persistence on the Anagram Persistence Task (APT), and there was a trend toward a correlation between persistence on the Wisconsin Card Sorting-64 task (WCST-64) and CR. As the APT and WCST-64 measures of persistence were not correlated with each other, these results suggest independent time- and effort-based persistence components. These separate persistence components merit further investigation to determine if they differentially support grit and CR in healthy aging. Finally, Chapter 4 concludes that persistence may act as a compensatory mechanism to benefit performance in challenging task conditions. However, its effectiveness in aging may be limited by age-related constraints on the timely deployment of cognitive resources. | en_US |
