Socially relevant visual information has been implicated as an object of specific and automatic attentional biases in normal visual cognition; conversely, inattentiveness to social agents and information comprises one of the central impairments in autism. The overarching aim of this research is to determine the scope of such prioritized social attention, in two ways: Beyond specific features such as faces and eye-gaze (as studied in previous research), does such prioritization (1) encompass more subtle features such as emotional expression, and (2) prioritize the processing of animate individuals - people and animals - as a general category? These questions will be studied in normally developing adults, children with autism spectrum disorder, and matched developmental controls using a series of 'change detection' tasks that are able to assess spontaneous prioritization of social information, without the explicit guidance to such information which is present in most previous studies. Participants must "spot the difference" between two alternating versions of a scene, and their response times serve as a measure of the spontaneous allocation of attention (1) to various types of stimuli involving changes to people, animals, and artifacts; and (2) to aspects effaces including identity, eye gaze direction, head direction, and emotional expression. Such results will help to determine the nature and extent of the impairment of social attention in individuals with autism spectrum disorder, and also the scope of 'social prioritization' in intact visual cognition. [unreadable] [unreadable] [unreadable]