Date of Award


Degree Type


Degree Name

Master of Science (MS)


Human Development and Family Studies

Committee Chair

A.J. Schwichtenberg

Committee Member 1

Germán Posada

Committee Member 2

Bridgette Tonnsen


In families raising a child with an autism spectrum disorder (ASD), infant siblings are at elevated risk for ASD and other developmental concerns including subclinical ASD features, often called the Broader Autism Phenotype (BAP). Recognizing the importance of parent-child social interactions in early development and the known social difficulties associated with BAP, the present study aimed to expand our developmental understanding of the BAP by (1) examining performance on standardized measures, and (2) describing dyadic characteristics to determine if the BAP group is distinguishable from the TYP group on select dyadic constructs. As part of a prospective study, dyads were recruited from families with at least one older child with ASD and families with no history of ASD. Mother-child play interactions were coded when children were 12, 15, 18, and 24 months of age for dyadic synchrony, responsiveness, and joint engagement, respectively. By 36 months, children received outcome classifications for BAP (n = 22) and TYP (n = 52). A series of ANCOVAS were conducted, with terms for infant sex and maternal education, and primarily revealed significant group differences on joint engagement measures by 15 months of age. However, these results were not consistent across visits. Overall, this study provides preliminary support for the importance of dyadic exchanges in the BAP, which may inform later developmental outcomes and early intervention efforts. Recognizing the increasing demand for elevated-risk interventions, these findings highlight several social constructs through which interventions may promote optimal development in children developing at risk.