We confirm that low-functioning autistic children are impaired in the processing of physical environmental movement, particularly rapid movement (3), while high-functioning autistic children are much less impaired in the same type of tasks. When biological movement is concerned, autistic children perform relatively adequately in emotional and nonemotional expression-recognition tasks when facial expressions are displayed slowly on video (4). Along the same line, low-functioning autistic children better recognize dynamic facial expressions when displayed slowly than when presented at normal speed. Considering these arguments and others, we proposed the rapid visual-motion integration deficit hypothesis in autism (5). According to this hypothesis, some autistic individuals having major movement-processing disorders from early in their lives will avoid rapid physical and biological movements (considered as aversive stimuli), thus disrupting secondarily social interaction. Some of these individuals, or some autistic persons having minor motion-processing disorders, will search for, habituate themselves to, and learn to handle and cope with such kinds of stimuli. To summarize, rapid visual-motion processing deficits constitute a core neuropsychological marker of autism and secondarily account for the deficit in social interaction.