Catching a (sine) wave: Temporal dynamics of nonverbal synchrony in social anxiety disorder.

Individuals with social anxiety disorder (SAD) experience a range of interpersonal problems and studies have found that nonverbal synchrony (the coordination between interaction partners' movements) may be impaired in dyads in which one individual has SAD (Asher et al., 2020). In the present study, we examined the temporal dynamics of nonverbal synchrony during "getting aquatinted" conversations of individuals with and without SAD. Specifically, participants (n = 146) formed either SAD dyads (dyads in which one individual had SAD and the other did not; n = 37 dyads), or control dyads (dyads in which both individuals did not have SAD; n = 36 dyads). Dyads were randomized to either small talk or closeness-generating (i.e., intimate) conversations. We found that during conversations, nonverbal synchrony followed a repeating pattern of increases and decreases that was best modeled by a sinusoidal wave (explained variance = 63.74 %). We found significant Diagnosis × Social Context interactions in the temporal dynamics of nonverbal synchrony (i.e., in the parameters of sine waves). Specifically, we found that for SAD dyads (but not control dyads), the average sine wave amplitude which indicates increases and decreases in nonverbal synchrony was greater during small talk conversations compared to closeness-generating conversations. In addition, we found that among control dyads (but not SAD dyads), the average vertical offset of sine waves (i.e., the average level of nonverbal synchrony) during closeness-generating conversations was greater compared to small talk conversations. The findings are interpreted within the context of the social anxiety literature as capturing two distinct social-anxiety related processes, and suggest that when examined temporally (rather than averaged), nonverbal synchrony may be an important implicit biomarker of SAD.

Nonverbal synchrony in diagnostic interviews of individuals with social anxiety disorder.

The present study examined nonverbal synchrony (i.e., synchrony between individuals' movement) during diagnostic interviews of individuals with and without social anxiety disorder (SAD). Specifically, 42 individuals with SAD and 42 individuals without SAD underwent a structured clinical interview, and videos of clinical interviews were analysed using Motion Energy Analysis (an objective machine-based video analysis) to quantify each individuals' movement as well as dyadic synchrony. Results indicated that interviews of individuals with SAD had significantly lower levels of nonverbal synchrony compared to interviews of individuals without SAD. In addition, interviews of individuals with SAD had lower levels of pacing compared to interviews of individuals without SAD (pacing refers to synchrony in which the interviewer initiates movement to which the participant responds). Analyses with social anxiety represented as a continuum of severity (vs. a diagnostic dichotomy) resulted in similar findings. Thus, individuals with SAD synchronized with interviewers' movement to a lesser extent compared to individuals without SAD, and social anxiety was associated with diminished synchrony. Implications for psychopathology and diagnosis of SAD are discussed.