Publication Date




Embargo Period


Degree Type


Degree Name

Master of Science (MS)


Psychology (Arts and Sciences)

Date of Defense


First Committee Member

Daniel S. Messinger

Second Committee Member

Heather A. Henderson

Third Committee Member

Jeffrey P. Brosco

Fourth Committee Member

Christine E. Delgado


Infant-initiated joint attention (IJA) typically emerges during the first year of life and is an important precursor of later social competence. Children with Autism Spectrum Disorders (ASD) have impairments in referential communication, such as IJA, that involve sharing experiences with others through gaze and gesture. A specific pattern of smiling occurring during IJA, anticipatory smiling, may communicate preexisting positive affect to a social partner through looking at an object, smiling, and then turning the smile toward a social partner. In typically developing infants, anticipatory smiling increases from eight to 12 months of age. The current study compared the development of anticipatory smiling at eight, 10, and 12 months of age between infant siblings of children with ASD (high-risk siblings), who are at heightened risk for ASD, and infant siblings of children without ASD (low-risk siblings). While there were no risk group differences in reactive smiling and no smiling, high-risk siblings produced less anticipatory smiling between eight and 12 months than low-risk siblings. These findings indicate that communicating preexisting positive affect may be a specific early impairment in children at risk for developing ASD, with possible implications for social and emotional outcomes.


anticipatory smiling; autism; infant siblings