The Relationship between Heart Rate Variability, Lay Theories of Self-Regulation, and Ego-Depletion: Evidence of Psychophysiological Pathways of Self-Regulation

Self-regulation (SR) is defined as the process by which people adopt and manage various goals and standards for their thoughts, feelings, and behavior, and then ensure that these goals and standards are met. Strong evidence shows that SR is a limited resource that when depleted, the individual experiences ego-depletion, a state where SR is operating at less than full capacity. However, to date, research has not examined the association between ego-depletion and physiological indices of SR capacity. The characteristic variability in the time series of heartbeats, or heart rate variability (HRV), has been considered a biomarker of SR capacity. One study found that individuals with high HRV did not experience task fatigue – a concept related to ego-depletion. Recent investigations also show that an individuals’ lay theories of SR predict ego-depletion, such that those who think that SR is a limited resource experience ego-depletion, while those who think SR in an unlimited resource do not differ in performance. Drawing on these studies, the present investigation attempts to replicate and extend previous findings. It was hypothesized that only those with low resting HRV will experience depletion. Moreover, the present investigation was designed to examine the direct relationship between lay theories of SR and HRV. Using an electrocardiogram (EKG), baseline-resting period HRV data were collected in 61 (42 White, 42 Women) participants that later completed a set of questionnaires, a depletion manipulation task, the Stroop task, and a second set of questionnaires. Lay theories of SR were assessed using the Implicit Theories of Willpower Scale (ITWS). Participants were randomly assigned to a depletion or non-depletion group: in the depletion manipulation, participants completed a task that required SR, presumably, depleting resources for later use. In contrast, those in the non-depletion manipulation completed a task that did not require SR. All participants then completed the Stroop task. Accuracy on the Stroop task was used to assess the degree of depletion between conditions and at varying levels of ITWS scores and baseline HRV. In line with previous studies, individuals in the depletion condition performed worse on the task than those in the non-depletion condition. Interestingly, this effect was independently moderated by both resting HRV and lay theories of SR. Individuals with low resting HRV or who think SR is limited experienced ego-depletion, where their respective counterparts did not show similar patterns. Additionally, analyses revealed a strong relationship between resting HRV and ITWS scores such that those with higher resting HRV were more likely to have unlimited theories of SR. These observations have important implications – throughout daily life, individuals are often faced with situations that require repeated SR behaviors. The present study suggests that having low HRV and/or holding limited-theories of SR may undermine successful prolonged SR. Limitations, implications, and future directions are…