Sigman and Ruskin (1999) conducted a series of studies examining the emotional development of children with Down syndrome and other developmental delays. In contrast to the children with autism, when confronted with an experimenter who showed distress, the children with developmental delays looked frequently at the experimenter’s face. They also were rated as showing greater empathy than the children with autism and were rated similarly to the typically developing children in the sample.

Substantial research has documented the social interactions and social competence of young children with developmental delays. Guralnick (2001) found that, in comparison to typically developing peers, children with developmental delays generally show more solitary play, are more negative with their partners during play, and have less success with peers when they make social bids. Hestenes and Carroll (2000) found similar results. The preschool children with disabilities that they studied spent more of their time in solitary and onlooker play than their peers. They did, however, spend about 30% of their play time in cooperative play.