Parallel processing of same and different form arrays in children and adults

A simultaneous same-different task in which the number of identical forms varied was given to younger children, older children, and adults. Same and different reaction times of older subjects did not increase as the number of forms increased, while younger children's reaction times on different trials did increase, probably due to difficulty in scanning the larger arrays. The results for older subjects on same and different arrays and for younger children on same arrays are consistent with parallel, independent processing, but this conclusion is complicated by the possibility of wholistic processing in this task. However, the slower reaction times obtained for same arrays relative to different for the youngest group are inconsistent with wholistic processing and indicative of a strategy in which all feature comparisons are completed before making a same decision. A strategy to check for differences first among the younger children may have been induced in this task by the perceptual saliency of the single, odd different form.