Background: Down syndrome (DS) has been the focus of much cognitive and developmental research; however, there is a gap in knowledge regarding sustained attention, particularly across different sensory domains. This research examined the hypothesis that children with DS would demonstrate superior visual rather than auditory performance on a…

In this paper, we summarize some of our findings from a series of three meta-analyses and discuss their implications for autism research. In the first meta-analysis, we examined studies addressing the theory of mind hypothesis in autism. This analysis revealed that theory of mind disabilities are not unique to autism, although what may be unique…

Surveys 30 studies involving 104 separate tests of the "similar structure hypothesis" which holds that, when nonorganically impaired retarded and nonretarded persons are similar in developmental level, they are also similar in the processes and concepts by which they reason. (Researchers distinguished between studies that excluded…