Saturday, May 14, 2011
Elizabeth Ballroom E-F and Lirenta Foyer Level 2 (Manchester Grand Hyatt)
10:00 AM
J. M. Bebko1, M. Slusarczyk2, L. N. Hancock1 and S. M. Brown3, (1)York University, Toronto, ON, Canada, (2)Psychology, York University, Toronto, ON, Canada, (3)Department of Psychology, York University, Toronto, ON, Canada
Background: Intermodal perception involves the simultaneous integration of information from different sensory modalities into a coherent conceptual unit. Audio-visual intermodal processing has been largely studied using a visual preference method known as preferential looking (Spelke, 1976), used as a means of detecting audio-visual temporal invariants, namely rate and synchrony. Individuals who are able to discriminate between the visual stimuli and show non-random preferential looking patterns are considered to be intermodally processing the incoming audio-visual information. Bebko et al. (2006) examined intermodal processing in children with autism using the preferential looking paradigm and found that children with autism showed a deficit in the processing of complex linguistic information compared to their typically developing peers. Initial eye tracking studies have revealed distinct scanning patterns in adults with autism compared to typically-developing controls (Klin et al, 2002) indicating that there is an attentional component to audio-visual processing. Modern eye tracking technology offers the ability to look at the role of differential attention during scanning of stimuli, providing a more subtle interpretation of what is occurring during preferential looking. Eye tracking recordings can provide additional data about pupil dilation. Pupils have been shown to dilate under stress (Hicks et al, 1967), cognitive difficulty (Beatty, 1981), arousal and pain (Chapman et al, 1999 & Oka et al, 2000). The current study aims to extend our previous findings by more closely examining pupillary responses of children with autism spectrum disorder (ASD) as well as typically developing controls when viewing audio-visual stimuli.
Objectives: To determine if eye-tracking responses (pupil diameter) would differentiate young children with ASD from the mental-age matched controls during the presentation of congruent and incongruent audiovisual stimuli within a modified preferential looking model.
Methods: Children between 6 and 10 years of age diagnosed with ASD were matched to typically developing controls based on mental age. Both groups were shown a series of linguistic and non-linguistic videos displaying four visually identical video recordings, one in each quadrant of the screen. Each quadrant differed only in its synchrony or asynchrony with a single auditory track, the audio track temporally matched to only one of the four videos.
Results: Data analysis is ongoing. Individual pupillary responses will be analyzed and an average pupil size will be computed for fixations among the four screens (within trial) as well as for between trial comparisons. All participants are predicted to demonstrate significant increases in pupil diameter towards the temporally synchronous screens, supporting the previous findings of Bebko et al. (2006). However, it is predicted that the ASD group will show pupillary constriction when viewing a person’s face (linguistic stimuli), while the control group will show an overall pupillary dilation for the same stimuli.
Conclusions: The identification of distinctive pupillary responses as a measure of attentional engagement between children with ASD and control groups may help to extend the understanding of intermodal processing deficits found in previous studies (Klin et al, 2002; Bebko et al, 2006).
