The Effects of Social Context On Perception of Audiovisual Synchrony in Infants with Autism

Background: In recent research, we found that two-year-olds with autism failed to give preferential attention to point-light displays of human biological motion. Instead, they oriented towards non-social, physical contingencies—contingencies that were disregarded by control children in favor of preferential attention to biological motion.  These results showed that a skill present in two-day-old, typically-developing infants, as well as in chronologically-, verbally-, and nonverbally-matched control children, was derailed in young children with autism.  In its place, toddlers with autism demonstrated intact processing of a physical contingency: audiovisual synchrony.

Objectives: The goal of the current project is to understand how attention to audiovisual synchrony is modified by the social context in which stimuli are perceived. Our aims are (1) to assess baseline sensitivity to audiovisual synchrony in both infants with ASD and in control children; and (2) to measure, in the same children, the effect of varying social context upon preferential looking to synchronous stimuli.

Methods: Three groups of children – infants with ASD, typically-developing infants (TD), and infants with non-autistic developmental-delays (DD), ages 12-24 months – participated in two series of experiments based on a preferential looking paradigm. We used stimuli that varied in degree of social context: pure tones, sine wave speech, and naturalistic speech in the auditory modality, and circles, ellipses and dynamic faces in the visual modality. The first series of experiments tested baseline sensitivities to audiovisual synchrony. The second series of experiments tested how sensitivity to audiovisual synchrony was affected by varying the social context of the stimuli.  Infants’ looking was measured by eye-tracking.   

Results: Results show that infants with autism and typically-developing peers do not differ in their baseline sensitivity to audiovisual synchrony.  However, audiovisual synchrony detection in infants with autism was less influenced by accompanying social context: while the introduction of biasing social context altered the preferential viewing patterns of TD and DD controls—who showed a strong preference for synchronous faces—the change in contextual information did not alter the viewing patterns of infants with ASD. 

Conclusions: The present study suggests that in the developmental experience of children with autism, the perception of physical contingencies is not altered by accompanying social context.  This gives insight into a way of learning about the world in which sensory stimuli are experienced as coincident patterns of light and sound, unmoored from their social adaptive context.  Future investigations will benefit from studies, starting still earlier in life, of the developmental unfolding of this process.  Exactly which signals are spontaneously attended to and which are missed, and the consequences thereof for structural and functional brain development, may shed light on the neurobiological anomalies that predispose these altered avenues of learning.