Date of Award


Level of Access Assigned by Author

Campus-Only Dissertation

Degree Name

Doctor of Philosophy (PhD)




Cynthia A. Erdley

Second Committee Member

Douglas W. Nangle

Third Committee Member

K. Lira Yoon


Children with High Functioning Autism Spectrum Disorder (HFASD) have marked deficits in social functioning (Carter et al., 2005). Influences from both family and peer contexts contribute to the socio-cognitve development of typically developing (TD) individuals and children with HFASD (Beyer, 2009). An important part of family interaction for many children is their relationships with siblings. Specifically, TD children with high quality sibling relationships experience greater levels of warmth and companionship, and thus higher levels of teaching and nurturance behaviors, within the sibling dyad (Volling, 2003). This study investigated siblings' role in the social functioning of children with HFASD among those with affected, TD, or no siblings.

Participants were 154 children and adolescents (M= 8.58, SD = 3.32) with HFASD who had an affected (n = 29), a TD (n = 63), or no siblings (n = 62). Individuals across groups were matched on gender, age, and Full Scale IQ (FSIQ) and compared on measures of social functioning and friendship experiences. In addition, addition, sibling relationship quality was investigated for participants with TD siblings.

Results found that participants with a reciprocal friendship had higher levels of social functioning than those without a friendship. In addition, findings indicated that as individuals with HFASD age, they become more socially adept. No evidence was obtained in support of group differences on measures of social competency among children with HFASD as a function of sibling status. This is contrary to previous findings wherein children with HFASD with affected siblings displayed worse social skills than those with TD or no siblings (Baroni, Erdley, & Hanson, 2013). However results revealed a pattern in which children with HFASD with affected siblings were less likely to have reciprocal friendships than children with TD siblings or no siblings, albeit differences were not statistically significant.

Despite the lack of significant findings, the social processes of children with HFASD continue to be an important area for investigation. Improved knowledge regarding siblings' roles could help in the development of more effective, naturalistic social skills programs for children with HFASD. Future directions and study implications are discussed.