TITLE:
Studying gaze abnormalities in autism: Which type of stimulus to use?
AUTHORS:
Ana Saitovitch, Anne Bargiacchi, Nadia Chabane, Anne Phillipe, Francis Brunelle, Nathalie Boddaert, Yves Samson, Monica Zilbovicius
KEYWORDS:
Autism; Eye-Tracking; Social Perception
JOURNAL NAME:
Open Journal of Psychiatry,
Vol.3 No.2A,
April
16,
2013
ABSTRACT: Background:
Eye-tracking has been used to investigate social perception in autism
spectrum disorder (ASD) with variable results. This heterogeneity may be due to
the types of stimuli used. In this study, we investigated whether the use of
moving vs static stimuli or human actors vs cartoons characters would be more
sensitive in detecting gaze abnormalities and discriminating children with ASD
from typically developing children. Methods: We studied 18 children with ASD
(mean age = 12.9 ± 2.9) and 21 typically developing controls (mean age = 11.3 ±
2.5). Gazes were tracked using Tobii-T120 eye-tracker. Four different types
of stimuli were presented: movie with human actors, cartoon movie, picture with
human actors and cartoon picture. To identify the type of stimuli that best
discriminate the ASD group from the control group, a two-way ANOVA was
performed using ecological dimension [human-actors/cartoon] and presentation
form [movie/picture] as factors. Results: Children with ASD presented
significantly less fixations to eyes and faces in the movie with human actors
and in the picture with human actors. Children with ASD also presented
significantly more fixations to non-social backgrounds in the movie with human
actors and in the cartoon movie. A significant ecological effect was observed
for the reduction in fixations to the eyes [human-actors > cartoon]. A significant presentation form effect was observed for the
increased fixations to the non-social background [movie > picture]. Conclusions:
The direct comparison of gaze behavior across four different types of stimuli
demonstrates that gaze abnormalities in ASD depend on the type of stimuli that
is used. Our results suggest that general gaze abnormalities in children with
ASD are better detected when using dynamic stimuli, and finer details of these
abnormalities, especially looking less to the eyes, are better detected in a
more ecologically relevant situation presenting human characters.