Eye-tracking measures of social attention in ASD: Systematic reviews and meta-analyses
Determining whether social attention is reduced or atypical in Autism Spectrum Disorder (ASD) and what factors influence social attention is important to our theoretical understanding of developmental trajectories of ASD and to designing targeted interventions for ASD. However, so far no consensus has been reached on whether social attention is fundamentally reduced or absent in individuals with ASD, with some studies showing significantly diminished attention to social information in ASD compared to typically developing (TD) controls (e.g. Klin et al., 2002) while other studies show no differences (e.g. Parish-Morris et al., 2013).
Similarly, no consensus has been reached regarding whether attention is allocated atypically to social stimuli in ASD. Some eye-tracking studies have found that, relative to TD controls, individuals with ASD spend a reduced amount of time attending to the eyes area of interest (AOI; e.g. Sterling et al., 2008) while other studies have found no significant differences (e.g. Fletcher-Watson et al., 2009). With regards to looking at mouths, studies have previously found both reduced looking time for individuals with ASD (e.g. Rice et al., 2012), increased looking time for individuals with ASD (e.g. Asberg Johnels et al., 2014) and no statistically significant differences (e.g. Birmingham et al., 2011). Studies have found both reduced attention to faces in ASD (e.g. Rice et al., 2012), and no significant differences (e.g. Birmingham et al, 2011). With regards to the body AOI, results are again very mixed with studies finding reduced attention to the body (e.g. Fletcher-Watson et al., 2009), increased attention to the body (e.g. Hanley et al., 2013) and no significant differences (e.g. Birmingham et al, 2011). Mixed results are reported for looking time to non-social AOIs as well, some studies finding no differences between ASD and TD controls (e.g. Norbury et al., 2009) and others finding increased attention to non-social AOIs in ASD (e.g. Klin et al., 2002). Finally, some but not all studies have reported reduced attention to the screen overall (e.g. Shic, Chawarska, Bradshaw, & Scassellati, 2008).
This poster shows results from two meta-analyses (see below) examining data from 38 and 68 papers, respectively, that used eye-tracking methods to compare individuals with ASD and TD controls. Results show that individuals with ASD spend less time attending to social stimuli than typically developing (TD) controls, with a mean effect size of 0.55. Also, social attention in ASD was most impacted when stimuli had a high social content (showed more than one person). Results also suggest the presence of atypical attention allocation in ASD, indicated by small but significant effect sizes: overall reduced attention to the eyes (d=0.38), mouth (d=0.24) and face (d=0.45), increased attention to the body (d=-0.48) and non-social elements (d=-0.34), and reduced attention to the screen (d=0.64).
Other eye-tracking measures of social attention, in addition to looking time such as measures of prioritization, exploration and persistence have also indicated atypical social attention processes in ASD. Compared to TD controls individuals with ASD prioritize social information less when non-social stimuli are competing for visual attention, they explore fewer novel areas of a scene and persist in attending to restricted areas. This pattern of findings suggests less accessing of social information by individuals with ASD.
Chita-Tegmark, M. (2016).Social attention in ASD: a review and meta-analysis of eye-tracking studies. Research in developmental disabilities, 48, 79-93.
Chita-Tegmark, M. (2016). Attention allocation in ASD: a review and meta-analysis of eye-tracking studies. Review Journal of Autism and Developmental Disorders, 3(3), 209-223.