Theses and Dissertations

Date of Award

8-1-2026

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Clinical Psychology

First Advisor

Grant Benham

Second Advisor

Philip Gasquoine

Third Advisor

Ruby Charak

Abstract

Sensory Processing Sensitivity (SPS) is a temperament trait characterized by greater environmental attunement and deeper cognitive-emotional processing. Though associated with heightened emotional reactivity, the physiological mechanisms of SPS remain unclear. This study tested whether SPS is associated with parasympathetic nervous system (PNS) functioning, indexed via heart rate variability (HRV), during rest, stress, and recovery. A sample of 274 female undergraduates completed the Highly Sensitive Person Scale and participated in a laboratory stress protocol involving a resting baseline, a psychosocial stressor (the Montreal Imaging Stress Task), and a recovery period. HRV was measured via electrocardiogram and quantified using RMSSD and high-frequency HRV (HF-HRV), with respiration-adjusted scores examined as well.

Results showed no significant correlations between SPS and HRV during rest, stress, or recovery. SPS was also unrelated to change scores across these phases. Exploratory regressions revealed a significant model predicting RMSSD during recovery, but this effect was not replicated across indices and did not persist in bivariate analyses. In contrast, SPS was consistently and positively associated with self-reported stress, tension, and nervousness during the task, even after accounting for negative affect. However, SPS was not associated with greater changes from baseline to task on these subjective ratings. These findings suggest that SPS influences emotional perception more reliably than parasympathetic reactivity.

This study is among the first to assess SPS and PNS activity across rest, stress, and recovery in a single design. While the null HRV findings challenge early hypotheses about direct physiological sensitivity in SPS, they are consistent with a growing literature suggesting that SPS may operate more strongly through cognitive-affective appraisal mechanisms than through vagal modulation. Strengths include high-fidelity physiological measurement, careful control of respiration, and multi-method stress assessment. Future research should examine contextual moderators, explore alternative physiological systems (e.g., sympathetic activity), and evaluate within-person variation in emotional and physiological sensitivity to clarify the stress responsivity profile of SPS.

Comments

Copyright 2026 Jordan Kenemore. All Rights Reserved. https://proquest.com/docview/3409025087

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