Sorting preference in children with autism: the dominance of concrete features.

The current study investigates preference to sort objects on the basis of either concrete or abstract features in children with and without autism. Participants were asked to sort a set of books into two groups that could be differentiated according to concrete (color, size) or abstract criteria (category membership: sports/games). The results showed that those with autism, unlike controls, were significantly more likely to sort according to a concrete criterion. In a further phase of testing, those with autism still did not sort according to abstract criteria, even when this was the only basis for sorting systematically. The findings are interpreted as evidence for a preference in autism to process concrete over abstract features of stimuli.