Social Orienting and Joint Attention in 9 to 12 Month Old Children with ASD with and without Intelectual Disability: A Study with Family Home Movies

Background: Studies analyzing family home movies of young children later diagnosed with autism spectrum disorder (ASD) indicate that social orienting behaviours (looking at faces/people and responding to name) are the earliest identifiable specific symptoms (Baranek, 1999; Osterling et al., 2002). The Social Motivation Model (Dawson et al., 2002, 2005a,b) considers the social orienting deficit observed in autism at the end of the first year as the earliest behavioural consequence of an alteration in the dopamine reward system balance. This model predicts that the imbalance in the social reward system has developmental consequences for social perception as well as for complex behaviours such as imitation, attention disengagement, intentional communication and especially, joint attention (Dawson, Toth, Abott et al., 2004).

Objectives: (1) To compare the early social and communicative development of children between 9 and 12 months old, later diagnosed with ASD, with and without intellectual disability (ID); (2) to test the predictions from the Social Motivation Model (Dawson et al., 2005a,b) that at the end of the first year of life all ASD groups will show social orienting deficits, which will contribute to joint attention impairment.

Methods: We coded family home movies from children with typical development (TD, n=16), ASD with ID (ASD-ID, n=17) and ASD with normal IQ (ASD-N, n= 12). First, we coded the general content from the videotapes (e.g., setting, contexts, type of social activity, number of people in the frame) using an adaptation of Baranek’s (1999) code. Then, using Noldus, The Observer 5.0, we analysed several social orienting (social gaze and responding to name) and joint attention (gaze alternation and gestures) behaviours using a coding system based on Dawson’s (Osterling et al., 2002).

Results: There were no significant differences in the general content of the tapes. There were no significant differences found in any of the social orienting behaviours coded or total time the children expressed positive or negative emotions. Children with TD used significantly more vowel vocalizations than both ASD groups. Compared with TD, the ASD-ID group showed significantly fewer initiations of joint attention (IJA). The ASD-N group tended to show the same pattern but differences from the TD group did not reach statistical significance. There were no significant differences in any behaviour between the two ASD groups. Social orienting behaviours were not significantly correlated with IJA gazes or gestures in either the total sample or within any of the groups. A discriminant analysis using a dichotomous classification (TD vs ASD) showed that the combination of IJA and orienting behaviours was the best predictor of diagnosis, correctly classifying 73.3% of the participants. Individually, IJA classified 71.1% of the participants, while orienting behaviours 62.2%.

Conclusions: We did not find social orienting difficulties between 9-12 month olds with TD and those who went on to develop ASD but we did find significant differences in IJA development. Thus, our results don’t support the predictions of the Social Motivation Model, implying that IJA impairment in ASD is developmentally independent of and not preceded by social orienting deficits.