Differences in social signals produced by children with developmental delays of differing etiologies.

Clarity of referential looks (either a focus on parent's face or other focus) produced by preschool children with delays of differing etiologies and children without delays was examined. Adults (with and without experience with children with delays) viewed videotaped segments in which children's looks did or did not occur. Adults judged whether a look occurred and rated their confidence in each judgment; latency to respond was measured. Adults' experience with children with delays did not influence outcome measures. When viewing looks focusing on parents' faces, participants were more accurate and more confident judging looks by children with typical development, less accurate when viewing face-directed looks of children with developmental delays, and least accurate when viewing children with Down syndrome. Discriminability of social looks differed by etiological group, and judges' decision criteria, confidence, and speed of responding also differed.