Children with autism spectrum disorder (ASD) have often been observed to express affect (feeling or emotion) either weakly, only in one modality at a time (e.g., choice of words), or in multiple modalities but not in a coordinated fashion. However, studies conducted to date have not conclusively determined whether crossmodal integration of affect expression indeed is impaired in ASD and what its detailed behavioral characteristics are. The goal of the project is to detail crossmodal integration of affect expression in ASD (with typical children and children with developmental language disorder as comparison groups) using an innovative method in which researchers independently measure affect expression in multiple expressive modalities (i.e., facial, gestural, and vocal). Findings from this study could provide a detailed picture of impairments in affect in ASD, deepening the understanding of impairments in social reciprocity and providing a basis for future studies to specifically target brain areas responsible for affect expression or design remedial programs for intensive training of under-used or uncoordinated expressive modalities. This study thus contributes to autism etiology, diagnosis, and treatment.