Enhanced visual search for a conjunctive target in autism: a research note.

Children with and without autism were compared on two visual search tasks in which a letter target appeared among two sets of letter distracters. In one task, the target shared colour with one set of distracters but was unique in shape--the feature search task. In the other, the conjunctive search task, the target shared colour with one set and shape with another set of distracters. Although search was slower in the conjunctive task than the feature task in normally developing control children, children with autism showed no significant slowing in reaction time in the conjunctive task and were faster than control children in this task. This result is discussed in the light of theories of visual search which state that rate of search is determined by the degree of similarity between target and distracters.