Deficits in joint attention development characterize autism and are thought to hinder social development and early language acquisition (Mundy & Burnette, 2005), therefore response to gaze cueing -the ability to shift visual attention in response to the observed eye gaze direction of another person- has been investigated in autism using different paradigms: Posner-style gaze-cueing tests demonstrated that purely reflexive perceptual aspects are intact even in very young children with autism (Chawarska et al., 2003; Swettenham et al. 2003) while performance in explicit gaze direction detection judgment tasks is impaired in older ones (Riby & Doherty 2009). However the use of verbally demanding tasks and explicit judgments about gaze-direction can be problematic when testing young children with autism.
Objectives:
We aimed to evaluate spontaneous response to gaze cueing of attention in young children with autism by means of an experimental stimulus in which an implicit goal elicits spontaneous response to gaze-cueing, while free visual explorations of the stimuli are recorded with an eye tracker.
Methods:
18 children with high-functioning autism (mean age 6.4 years, SD 2.1) and 18 age-matched controls (mean age 6.3 years, SD 1.10) participated. Participants were simply instructed to look at the videos presented with a Tobii-T60 eye-tracker. Each child saw 2 demonstrations and 2 test videos depicting an actor hiding an object under one of two identical opaque glasses, rotating them and then looking laterally for three times (without head turn) towards the glass that covered the object, before lifting it up. The hiding process was either visible (2 demonstrations) or hidden behind a screen (2 tests) thus in the demonstrations the observer could ignore the gaze-cue in order to find the object, while in the experimental conditions the gaze cue was the only visible feature leading to it. Statistical analysis compared fixations to key areas of the stimuli, namely Eyes, Gaze-Target and Non-Gaze-Target, qualitative analysis on gaze patterns evaluated response to gaze cueing.
Results:
The group comparison found statistically significant differences in attention towards the Gaze Target: Children with autism showed shorter fixations on the Gaze Target (p= 0.035) and spent lower time exploring it (p= 0.054). The qualitative analysis of the visual fixation patterns confirmed that children with autism as a group had a reduced tendency to follow the gaze cue (37% accuracy ), compared to typical controls (82% accuracy). Finally, paired samples t-tests within groups showed that control children made a significantly higher number of fixations to the Target Vs the Non Target (p=0.007), spent a significantly higher time on the Target rather than on the Non Target (p= 0.002) and made longer fixations to it (p<0.001) while no statistically significant differences were found for children with autism suggesting an inefficient differentiation between Target and Non target.
Conclusions:
Our data suggest that even though children with autism were less efficient than controls in perceiving and flexibly following the eye gaze cue they showed considerable residual gaze following abilities. Implications for treatment and further research will be discussed.
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