Objectives: The aims of this study were threefold: (1) to assess whether children with ASD show superior large-scale search compared to typical children, as evidenced in small-scale contexts, (2) to identify differences in search strategies between clinical and comparison groups, especially with regard to the systematic or otherwise nature of search, and (3) to determine the relative consistency in search behaviour within individual children.
Methods: Twenty-one children with ASD aged between 8 and 13 years, and 21 typically developing children, of similar age, nonverbal ability, verbal ability, participated in an engaging, ecologically-valid large-scale search task. Children searched within a unique laboratory, an isolated space without landmarks, in which an array of search locations (LED lights) was embedded into the floor. On each trial, children were instructed to look for a (red) target by pressing the (green) switch at each location. Children completed a total of 40 trials. The distribution of target locations across trials was probabilistically manipulated so that they appeared on one particular side of the array for 80% of trials.
Results: Comparative analysis of the microstructure of the search behaviour of the two groups revealed striking differences in three respects. First, children with ASD were less sensitive to the spatial probability manipulation compared with typical children. Second, the search patterns that children with ASD followed were further from the optimal route than comparison children. And third, there was less internal consistency in the search patterns for individual children with ASD, further suggesting that they were searching in a less systematic fashion.
Conclusions: Previous studies have suggested that children with ASD show enhanced small-scale visual search and “systemising” behaviour. Contrary to these reports and to anecdotal evidence, we discovered that search and foraging behaviour in ASD is in fact disorganized and non-optimal. These findings have important implications for current theoretical accounts and for our understanding of autistic individuals’ everyday functional behaviour.