Document Type



Doctor of Philosophy (PhD)



First Advisor's Name

Erica Musser

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Jonathan Comer

Second Advisor's Committee Title

Committee Member

Third Advisor's Name

Jeremy Pettit

Third Advisor's Committee Title

Committee Member

Fourth Advisor's Name

Barbara Thomlison

Fourth Advisor's Committee Title

Committee Member


selective mutism, emotion regulation

Date of Defense



Selective mutism (SM) is associated with considerable individual and family burdens, significant long-term functional impairment, and risk for later psychopathology. However, literature examining the phenomenology of SM has been scant, and it remains unclear which mechanisms are related to the development or maintenance of SM. Multiple theoretical perspectives have been proposed, and it appears that several pathways may be involved and interact to lead to the development of SM. Emotionrelated processes, such as negative emotion reactivity, disruptions in emotion regulation, and parental behavior and emotionality have been proposed to be involved in the etiology and/or maintenance of SM. The present study examined each of these factors using a multi-method approach among a sample of children with SM, and typically developing children. Specifically, a mother-child dyad participated in a protocol of tasks in the laboratory. Behavioral coding and psychophysiological recording indexed emotion reactivity and regulation during tasks, as well as maternal report of these abilities. Expressed emotion, maternal behavior and self-report on emotionality was evaluated in mothers. Between-group comparisons were conducted using ANCOVAs and logistic binary regression, as well as linear regression to examine associations with a continuous measure of SM symptom severity.

The study provided preliminary evidence in the presence of heightened negative emotion reactivity indexed behaviorally, via maternal report, and sympathetic-based activity and reactivity (i.e., EDA and PEP) among children with SM. Disruptions in emotion regulation were also present in children with SM as indexed behaviorally, via maternal report, and parasympathetic-based dysregulation (RSA). Mothers of children with SM also demonstrated increased control and accommodation behaviors. In addition, mothers of children with SM demonstrated high negative affect and disruptions in emotion regulation abilities as evidenced via ratings on self-report measures. No differences were observed with respect to maternal expressed emotion. Findings suggest emotion-related processes are important to consider in the phenomenology of SM. Future directions are discussed with respect to longitudinal designs to assess temporal causality, and to contribute to the etiological theory of SM.





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