The Influence of Perceived Gaze Cues on Elementary Sound Perception In Individuals with Autism

Background: Prior research has shown that our brains are pervasively social and multisensory. Remarkably, perceived social cues such as eye gaze influence even basic sensory sound perception in typical adults: if a brief burst of sound is presented immediately after a face displaying averted gaze, typical adults systematically, and erroneously, perceive a shift in the direction of the sound’s location.  The shift in perception is in accordance with the direction of the perceived gaze cue: left-looking eyes bias listeners to perceive sounds as if coming from the left, while right-looking eyes bias perception to the right. This shift in sound localization also occurs when subjects are cued with arrows. At the neural level, human lesion studies demonstrated distinct neural pathways for the initial processing of arrows and gaze cues, while fMRI studies reported only subtle differences between networks cued by gaze and arrows. Thus, the extent to which the observed phenomenon is uniquely social is unknown. Past research with individuals with autism has documented atypical gaze cueing and impaired gaze following but intact following of non-social directional cues.

Objectives: The current study aims to use a psychophysical paradigm to explore the extent to which visually perceived social and non-social cues influence elementary sound perception in individuals with autism and matched controls.

Methods: Fifteen individuals with autism and fifteen age-, IQ-, and handedness-matched controls volunteered for the study. The psychophysical experiment was based on a variant of the Posner attention-cuing paradigm. A directionally-tuned broadband noise stimulus of brief duration was delivered via headphones to the participant’s ears. The sound stimulus was presented 300ms after the presentation of a visual cue: a face with neutral affect gazing 30^o to the left or right; a double-headed arrow pointing to the left or right; or a directionally-neutral fixation cross. Participants were instructed to gaze steadily towards the screen and, as quickly and accurately as possible, indicate by button press whether the sound came from their left or right. At this time, the visual cue disappeared. Reaction time and performance data were collected and analyzed.

Results: While ASD subjects consistently fail to engage in joint attention in real-world settings, past laboratory studies of gaze following in ASD have reported mixed results.  We quantify both the average magnitude and intersubject variability in perceptual shift to social and non-social cueing, examining whether ASD participants differ systematically from neurotypical subjects. Preliminary data suggest that ASD participants show higher variability in individual response to the task.

Conclusions: Preliminary results indicate a high degree of variability among individuals with autism in their responses to the performed multisensory perception task. This heterogeneity is consistent with the inherent variability exhibited across the autism spectrum. By considering both intergroup and intragroup differences in sensitivity to social signals, we will be able to investigate the mechanisms of such heterogeneity. As autism tends to have wide-ranging effects on individual function, the variety of individual task performance implicates a myriad of neural coping strategies used by the brain to mediate perception and interactions in the world.