Reduced visual exploration when viewing photographic scenes in individuals with Autism Spectrum Disorder

Individuals with Autism Spectrum Disorder (ASD) often display enhanced attention to detail and exhibit restricted behaviour. However, due to a lack of comprehensive eye-movement modelling techniques, it is currently unknown whether these behavioural effects are also evident during scene viewing (i.e. detailed visual inspection and restricted visual exploration). Free viewing eye-tracking data from observation of everyday photographic scenes were recorded during two experiments involving high functioning adolescents with ASD and matched typically developing (TD) controls (Experiment 1 ASD n=14; TD n=22; Experiment 2 ASD n=16; TD n=23). Data from both experiments were combined and analysed using five novel methods of eye-tracking time-course analysis, enabling detailed characterisation of viewing strategies. Participants’ verbal descriptions of scenes were also assessed. Scenes either contained a centrally positioned person whose face was in full view or contained no centrally positioned face. For both types of scene, ASD participants displayed significantly less exploration of new areas over time compared to their TD peers. Analyses of scanpath length and recursion suggested a greater tendency to explore areas close to the current fixation in the ASD group, termed visual persistence. Differences were not accounted for by fixation rate. Significantly more areas within the scenes were also missing from the verbal descriptions in the ASD group. Differences were observed for both scene types suggesting a domain-general difference rather than a specific impairment related to face processing. The observed characteristic viewing patterns may explain relative superior processing of local level information in individuals with ASD.