Date of Award

August 2017

Degree Type


Degree Name

Doctor of Philosophy



First Advisor

Raymond Fleming

Committee Members

Diane Reddy, Susan D. Lima, Han Joo Lee, Shawn P. Cahill


Affect, Cardiovascular Responses, Emotion, Parasympathetic Activity, Self-affirmation, Value Affirmation


Self-affirmation is the act of focusing on important aspects of the self, such as personal values and characteristic. Benefits of self-affirmation have been documented in past research. However, the immediate impacts of self-affirmation on cardiovascular responses have not been fully explored. Therefore, the present study examined such effects both during and consequent to the practice of self-affirmation. One hundred and twenty-five participants completed the study. A within-subject design was used, in which each participant went through both the control and self-affirmation conditions (the order of presentation was counterbalanced). In the self-affirmation condition, participants were asked to write about their top-ranked personal value for 5 minutes, whereas a writing exercise unrelated to personal values was used in the control condition. After each writing exercise, the International Affective Picture System (IAPS) was used to induce positive and negative emotion. Cardiovascular measures and self-reported affective responses were collected throughout the experiment. Results showed that self-affirmation produced lower cardiovascular arousal, less negative affect, and higher levels of self-worth. Compared to the control condition, when practicing self-affirmation, participants had higher high frequency component of heart rate variability (HF-HRV) and respiratory sinus arrhythmia (RSA). During negative emotion induction, self-affirmation also led to lower maximum heart rate, higher RSA, and lower ratings of negative affect. Moreover, affirmational thinking was found to be associated with self-resources such as self-esteem, optimism, and one’s perceived worthiness in a group. These findings suggest that the act of focusing on an important aspect of self has beneficial effects on psychological and physiological well-being. The present study is one of the few that have examined self-affirmation’s impacts on vagal tone using HF-HRV, RSA, and direct manipulation of emotion. Not only has self-affirmation shown to be valuable, its positive effects appear quickly, and it is easy to practice with low to no cost.