Nonverbal Sensitivity in Individuals with Autism Spectrum Disorders

Background: Differences in face processing have been identified in individuals with autism spectrum disorders (ASD; Jemel et al., 2006), but little ASD research has examined the broader concept of nonverbal sensitivity, which includes processing of facial expressions, body language, and vocal prosody, and has been implicated as important for social interaction in individuals with typical development (TD; Burgoon & Bacue, 2003). 

Objectives: The current study investigated understanding of facial expressions and body postures/gestures in individuals with ASD in order to expand our understanding of the nonverbal basis for their social deficits.
Methods: Participants included 19 males with high-functioning ASD and 19 males with TD, matched on age and verbal ability.  Participants watched a series of 3-second video clips of women’s faces and women’s bodies (with the faces covered) and were asked to identify the corresponding emotion. 
Results: All participants performed more accurately with face, rather than body, stimuli.  The group with ASD was significantly less accurate in responding to face stimuli than the group with TD (d = .84).  There was not a significant difference between diagnostic groups in accuracy of response to body stimuli (d = .36).  However, for the group with ASD only, there were significant correlations between accuracy on face and body stimuli and verbal reasoning skill (r = +.78 and + .79), as well as between accuracy on face stimuli and lifetime social deficits (r = -.44). 
Conclusions: Results replicated findings of face processing impairments in ASD.  Relative impairment in a broader range of nonverbal sensitivity in ASD was not supported by the current methodology.  However, the strong relation between nonverbal sensitivity and verbal reasoning in participants with ASD suggests that they may be able to use verbal reasoning to compensate for weak nonverbal sensitivity.  Weak nonverbal sensitivity may also underlie social skills impairments.