A functional assessment of selective mutism

Jessica Katherine Masty, Fordham University


The purpose of this study was to develop and implement a behavioral coding system to describe interactions between children with selective mutism and their parents in order to identify external variables that impact communication behaviors. The data consisted of archived video recordings of 30 families engaging in a structured play task at a pre-treatment clinic visit. A confederate "stranger" entered the room in alternating ABAB conditions, parent prompts were systematically varied, and child and parent verbal and nonverbal behaviors were coded. The Selective Mutism Behavioral Observation Coding System had excellent interobserver reliability. It was a useful tool for behavioral assessment of selective mutism. Frequency counts and conditional probabilities of communication behaviors were computed and compared across conditions for each participant. Results were pooled across the sample to examine larger trends. In this study, children spoke frequently during the task; 82% of their communication was verbal. There was individual variation regarding which antecedents were most likely to elicit speech, but some general patterns were discovered. The presence of the "stranger" significantly decreased child verbalizations, including spontaneous verbalizations, but did not increase the use of nonverbal gestures. There was not a significant increase in talking in the presence of the "stranger" over time, but the task provided only brief exposures to the "stranger." Children produced significantly more spontaneous speech than prompted speech, although the rate of prompted speech was high (mean conditional probability = .76). Open-ended questions were most effective at inducing verbalizations. Prompts that "pull" exclusively for verbal responses had high specificity for speech. Clear operant factors for maintaining mutism were not determined. A lack of positive reinforcement after child verbalizations and punishing statements from parents were not significant variables. Positive reinforcement of children's speech avoidance did not appear to be significant, but this analysis was confounded by problems operationalizing positive reinforcement. The functional assessment approach was helpful in understanding how external variables impact verbal and nonverbal communication in families of children with selective mutism. Clinicians should use this behavioral assessment method to tailor their treatments according to patterns identified in each family's functional assessment.

Subject Area

Developmental psychology|Psychology|Clinical psychology

Recommended Citation

Masty, Jessica Katherine, "A functional assessment of selective mutism" (2014). ETD Collection for Fordham University. AAI3630169.