“…Importantly, infant social engagement with parents has been well-characterized in studies of typical development (e.g., Feldman, Greenbaum, and Yirmiya, 1999; Tamis-LaMonda, Bornstein, and Baumwell, 2001), thereby providing a logical focus for possible early markers of autism in high risk infant siblings. Research on parent-infant interaction demonstrates that typically-developing children engage enthusiastically with their parents during shared play activities, both initiating interaction and responding to parents’ scaffolding and teaching (e.g., Bigelow et al, 2010; Bornstein, Tamis-LaMonda, Hahn, and Haynes, 2008; Mendive, Bornstein, and Sebastian, 2013). In contrast, lower levels of social interest, social engagement, and the use of communicative gestures have been identified in retrospective studies of infants who later received an autism diagnosis (Osterling, Dawson, and Munson, 2002; Werner, Dawson, Munson, and Osterling, 2005), underscoring the importance of prospective studies of early social engagement in HR infant siblings.…”