PhD Oral Exam - Heather Herriot, Psychology

When studying for a doctoral degree (PhD), candidates submit a thesis that provides a critical review of the current state of knowledge of the thesis subject as well as the student’s own contributions to the subject. The distinguishing criterion of doctoral graduate research is a significant and original contribution to knowledge.

Once accepted, the candidate presents the thesis orally. This oral exam is open to the public.

Abstract

The aging population is the fastest growing segment of the population. With aging, there is an increase in the number of uncontrollable stressors that arise. Stress is known to have an impact on biological processes (e.g., HPA axis function) and downstream physical health outcomes (e.g., chronic illness). However, the exact pathophysiological patterns of HPA axis dysfunction that arise from chronic stress experiences is vastly understudied. In addition, little is known about psychological factors that promote adaption to stress and reduce the negative consequences of stress on health in old age. This dissertation sought to investigate the impact of stress experiences on older adult’s physical health and the benefits of the psychological trait self-compassion. Study 1 examined how chronic stress levels and changes predicted trajectories of diurnal cortisol (AUC and slope) over 12 years. Results indicated that older adults with high levels of chronic stress were likely to have significantly steeper declines in cortisol levels over the study. In addition, older adults with high and increasing stress levels displayed increasingly flatter cortisol slopes. Study 2 investigated cross-sectional associations between age-related stressors and diurnal cortisol, and whether self-compassion could buffer the impact of stress on cortisol patterns. The results found no association between age-related stress and diurnal cortisol. However, self-compassion moderated the association between age-related stress and cortisol. Specifically, older adults with higher levels of age-related stressors who were more self-compassionate were protected from higher levels of stress-related diurnal cortisol. Study 3 sought to explore the longitudinal health benefits of self-compassion across four years, and whether they vary for older adults in early vs. advanced old age. The results revealed that self-compassion predicted lower levels of daily physical symptoms on average for those in advanced old age (but not early old age). Self-compassion also predicted fewer increases in chronic illness over four years among those in advanced, but not early old age. Overall, this dissertation provides significant contributions to theory and research on stress, aging and health.