Systematic longitudinal observations were made as typically-developing toddlers and young children with autism and with Down syndrome interacted with their caregivers in order to document how joint engagement developed over a year-long period and how variations in joint engagement experiences predicted language outcome. Children with autism displayed a persistent deficit in coordinated joint attention; children with Down syndrome were significantly less able to infuse symbols into joint engagement. For all groups, variations in amount of symbol-infused supported joint engagement, a state in which the child attended to a shared object and to language but not actively to the partner, contributed to differences in expressive and receptive language outcome, over and above initial language capacity.
KeywordsAutism; Down syndrome; joint attention; language; parent-child interactionThe early development of joint engagement and the acquisition of language are usually intertwined. As infants acquire joint attention skills, they gain entrance into "primordial sharing situations" (Werner & Kaplan, 1963) that serve as "zones of proximal development" (Vygotsky, 1978) where caregivers can facilitate their introduction to symbols during affect-laden and intention-filled social interactions (Adamson, 1996;Hobson, 2000;Tomasello, 1995). Then, as the child acquires a vocabulary, the scope of joint engagement increasingly expands as the focus of shared attention is displaced from present objects to symbols that refer to them, to future and past events, and to internal states (Adamson & Bakeman, 2006). Developmental disorders may disrupt the mutual relation between joint attention and language. Problems sustaining joint attention may alter and even curtail a toddler's access to language facilitating interactions. For example, the early deficits in joint attention skills in young children with autism that have been documented in home videotapes (e.g., Baranek, 1999;Werner & Dawson, 2005), standardized tests (Lord, 1995;Mundy, Sigman, & Kasari, 1990; Wetherby, Watt, Morgan, & Shumway, 2007), screening questionnaires (Baron-Cohen et al., 1996;Robins, Fein, Barton, & Green, 2001), and laboratory-based studies (McArthur & Adamson, 1996;Sigman & Ruskin, 1999;Stone, Ousley, Yoder, Hogan, & Hepburn, 1997; see Leekam & Moore, 2001, for a review) likely play a pivotal role in their problems acquiring and using Correspondence concerning this article should be addressed to Lauren B. Adamson, Department of Psychology, Box 5010, Georgia State University, Atlanta, GA 30302-5010, USA. Electronic mail may be sent via Internet to ladamson@gsu.edu.
NIH Public AccessAuthor Manuscript J Autism Dev Disord. Author manuscript; available in PMC 2010 January 1. NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author Manuscript language (Charman, 2004;Dawson et al., 2004;Happe, 1998;McDuffie, Yoder, & Stone, 2005;Sigman & Ruskin, 1999, Smith, Mirenda, & Zaidman-Zait, 2007Toth, Munson, Meltzoff, & Dawson, 2006). Thus, although older estimate...