Let Us Face It! a Meta-Analysis of Atypical Viewing Patterns in Individuals with ASD
Objectives: Instead of yet another empirical study evaluating the fixation patterns of individuals with ASD, the field is in need of a systematical and quantitative overview of all the evidence. We therefore wanted to examine and combine all available empirical data on this topic, by means of a meta-analysis, in which the effect size across different studies was calculated, evaluating the overall evidence for differences in social attention between individuals with and without ASD.
Methods: Our literature search yielded over 2,500 articles, of which all abstracts were further reviewed, applying a set of strict inclusion and exclusion criteria. The remaining set of 57 articles was included in our quantitative meta-analysis. Several moderator variables, such as participants’ age, gender, stimulus and task characteristics, and region of interest, were incorporated as moderator variables in our analysis. Hedges’ geffect sizes were examined.
Results: Overall, results provided evidence for a reduced saliency of faces in individuals with ASD (Hedges’ g effect size = -0.52, p < .0001), which was stronger for upper (g = -0.79, p < .0001) compared to lower (g = -0.32, p = .0341) face regions. These viewing pattern differences were partially overcome by using task instructions, compared with free-viewing tasks (F(1,208) = 5.96, p = .0154). Group differences appeared strongest in age groups between 12 and 25 years old, and for individuals with average IQ scores between 85 and 115.
Conclusions: This meta-analysis provided evidence for atypical viewing patterns in individuals with ASD, characterized by a reduced saliency of faces and – more specifically – all internal facial features, with moderate to strong effect sizes. The impact of several moderator variables will be discussed.