Based on the hypothesis that cognition and sleep are linked, this study compared the sleep patterns of nine children (ages 6-16) with autism with those of children with mental retardation and no disabilities. The children with autism were observed for two consecutive nights at a laboratory where their sleep patterns were recorded. Results found differences between the sleep patterns of the children with autism and other children. Children with autism exhibited reduced frequency of rapid eye movements, which is an index of organizational capacity. The sleep patterns support the idea that autistic children exhibit major deficits in organizing information. The findings are felt to explain the effectiveness of the TEACCH method proposed by Scopler and others, which presents information to autistic children in a highly organized and structured way. The paper concludes that the psychological differences found between children with autism and with intellectual disabilities suggest that these children should not be mixed together for their education. (CR)