The Adaptive Value of Attending to Social Stimuli Differs for Toddlers with Autism Spectrum Disorder and Williams Syndrome
Objectives: To investigate: (1) clinical profiles and patterns of visual fixation to social stimuli in children with ASD, WS, and control groups and (2) whether and to what extent fixation patterns are related to communicative competence.
Methods: Eye-tracking data were collected while 63 toddlers (20 ASD, 11 WS, 12 DD and 20 TD; refer to Table 1 for group characterization details) watched video scenes of an actress caregiver engaging in child-directed communication. Visual fixation was quantified as the percentage of time spent looking at 4 regions of interest (eyes, mouth, body, object). Between-group comparisons of assessment scores on the Autism Diagnostic Observation Schedule (ADOS) and the Mullen Scales of Early Learning were made, and within-group analyses tested for correlations between assessment scores and percentage of fixation time to each region of interest.
Results: Clinical profiles of toddler groups are presented in Table 1. For children with WS, percent fixation on the mouth was positively correlated with expressive (p = .003) and receptive (p = .04) language scores (Figure 1). The same significant positive correlations were found for both DD and TD control groups (all p’s < .05). By contrast, mouth-looking was not correlated with either expressive or receptive language for children with ASD (all p’s > 0.2).
Conclusions: This research reveals a disorder-specific developmental process that may contribute to the social and cognitive phenotype of ASD. Visual engagement with the mouths of others is positively associated with language competence for WS, DD, and TD groups alike. However, this type of visual engagement does not share the same adaptive value for children with ASD, who show no association between mouth-looking and language scores. This suggests that toddlers with ASD may seek and attend to the mouths of others for very different reasons than do TD, DD, and WS children. These very different goals likely yield different learning experiences and expertise that may contribute to the unique presentations of both neurodevelopmental disorders, and ASD in particular.