When people try to communicate with others, they may use different types of gestures to make their meaning clear. Individuals with Autism Spectrum Disorder (ASD) have been thought to gesture less than others, but recent research suggests whether that is true depends on the type of gesture. Deictic gestures include actions such as pointing and reaching. Emblematic gestures communicate semantic meaning such as nodding the head to mean “yes” or shrugging the shoulders to mean “I don’t know.” Iconic gestures visually represent an object, action, or concept such as forming a circle with the hands to represent a ball, sliding a hand rapidly from left to right to indicate a car racing past, and so on.
Nicola McKern and colleagues conducted a meta-analysis of 31 articles comparing the gestures of over 700 ASD individuals to those of 860 neurotypical individuals. They found that autistic individuals do indeed exhibit fewer deictic and emblematic gestures than others, but that they do not generally differ from others in the production of iconic gestures.
These researchers believe the most important conclusion from their analysis is that we should not prematurely rule out a diagnosis of Autism Spectrum Disorder simply because a person gestures normally to communicate.
Abstract
While diagnostic assessments for autism routinely screen for reduced frequency of gestures, evidence supporting reduced gesture production in autism is inconsistent. This systematic review and meta-analysis aimed to clarify differences in frequency of gestures between autistic and neurotypical individuals. Included studies compared frequency of gestures between autistic and neurotypical individuals. Database searches (APA PsycInfo, ERIC, MEDLINE, ProQuest Dissertations and Theses Global) and a call for unpublished data on the International Society for Gesture Studies listserv identified research from January 1994 to March 2023. Study quality was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Quasi-Experimental Designs. Quantitative synthesis involved a narrative review of all findings and meta-analysis of articles allowing effect size calculations, stratified by the type of gesture. Thirty-one articles comparing frequency of gestures between 701 autistic and 860 neurotypical individuals were included in the narrative review, 25 of which were also included in the meta-analysis. Compared to neurotypical individuals, meta-analyses found that autistic individuals produced significantly less total, deictic, and emblematic gestures. While the number of iconic gestures appeared comparable between groups, studies investigating iconic gestures exhibited an almost equal trend of both positive and negative effect sizes, which were mostly nonsignificant. The way gesture production was measured, age, observer familiarity, and task structure (but not overall study quality) moderated the effect size, albeit inconsistently across the types of gestures. Findings have implications relating to profiling gesture use in diagnostic assessments for autism and highlight gaps in our understanding of differences in gesture production in autism.
Citation
McKern, N., Dargue, N., & Sweller, N.(2023). Comparing gesture frequency between autistic and neurotypical individuals: A systematic review and meta-analysis. Psychological Bulletin, 149(11-12), 724–745.
Dr Martin Fracker 