Abstract
Introduction: Visual search is a most-studied cognitive behavior. Anne Treisman introduced classification of easy, “pre-attentive” feature search, (search for elements which differ greatly from distractors in simple features), which leads to rapid target “pop-out,” versus more difficult search with focused attention, (e.g. search for feature conjunction), where target detection depends on set size (number of display items). This search-type dichotomy has been found also in children. Finding that conscious vision is initiated through representations at higher cortical levels, Hochstein & Ahissar (2002) suggested Reverse Hierarchy Theory, whereby initial “vision at a glance” depends on higher cortical representations suggesting, and later found (Hershler & Hochstein, 2005, 2006) that fast, easy feature search is associated with higher cortical levels so that faces, too, pop out. Disorders on the autism spectrum (ASD) are often characterized by difficulties in face recognition, while there is some evidence of speeded visual search in children with ASD. Methods: We presented displays with 4, 16, 36, or 64 pictures of different category objects, including one target picture of a face, car, house, or animal, dog or lion faces and measured response time (RT) to touching the target item on the screen – for neurotypical and ASD children, matched for age and IQ (block-design: WISC-IV; WAIS-III). Average Autism Spectrum Quotient test (AQ) was 27 for the ASD group vs. 11 for the NT group; t-test p<0.0001. Results: Face detection is different for the two groups, with average set-size slope of 16 (ASD) vs. 11 (NT) ms/item, t-test p<0.005. Face detection is only slightly affected by IQ. Detection of other categories is not affected on average by ASD, with an average set-size slope of 78.6 vs. 78.2; p=0.48. Conclusions: Children on the autism spectrum have more difficulty than neuro-typical children in finding a face among pictures of other categories.