Background: In our previous study (Fadda, Doneddu, Striano et al., 2010) investigating children with ASDs' sensitivity to the orientation of an adult’s eye gaze towards an object located within the child’s field of view, in static images, children with autism appeared as successful and as accurate as controls in locating the object although they paid less attention to the eyes and over-explored non relevant areas of the stimulus. This led to the hypothesis that children with ASDs might use compensatory strategies to locate the gaze target rather than understanding the referential meaning of the gaze. Objectives: Our study aims to extend our previous results, exploring the strategies used by children with ASDs to locate a gaze target by analyzing the time-course of their visual attention, in comparison with a group of chronological age matched controls, and with a group of adults, that represent respectively typical immature and mature patterns of visual attention toward static gaze-direction cues. Methods: We compared 20 children with ASDs (13 M), mean age=57 mths (range: 36-101; sd=21.37), mean non verbal mental age=39 mths (Leiter-R scale), with a group of 20 typically-developing children, matched for chronological age (7 M) and a group of typically-developing adults (10 M), mean age=22.65 (sd=1.98). The stimuli, presented with a Tobii T60 Eye Tracker, were those used in Fadda et al. 2010: a human face looking right or left at one of two visible target objects positioned next to the head. We defined 5 areas of interest for all the 8 stimulus images: eyes, gaze target, non-gaze target, mouth, not-AOI (that is the area of the screen external to the other AOI). In order to define the strategies used to perform the tasks, we calculated the mean proportion of Fixation Count (FC: the number of fixations to an AOI) for each AOI during 3 different time slots, each lasting one second: 1st , 2nd and 5th second of stimulus presentation. Results: Paired sample t tests revealed that adults showed a preference to the gaze target versus the non-gaze target at t1 (t=3.35.; df=19; p=0.003), t2 (t=2.54; df=19; p=0.02) and at t3 (t=1.78; df=19; p=0.09). Neither children with ASDs nor typical controls showed such a preference. Adults preferred the eyes rather than not-AOI at t1 (t=5.63; df=19; p=0.000), at t2 (t=4.10; df=19; p=0.001) and at t3 (t=2.15; df=19; p=0.044). The same preference was found in young typical controls but not in children with ASDs. Conclusions: While adults were quickly and stably oriented by the eye-gaze direction toward the gaze target, both children with ASDs and typical controls were not, meaning that this phenomenon might be due to immature visual orienting patterns rather than being specific to ASDs. Contrary to previous studies (Ristic et al. 2005; Chawarska et al. 2003) we didn’t find intact basic gaze cueing in ASDs, indeed children with ASDs showed poor attention to the eyes, suggesting that they generally miss important information conveyed by the eyes and this is also likely to hinder later understanding of the referential value of looking.
How Attention to Gaze-Direction Is Captured by Static Pictures In Very Young Children with ASDs: a Time-Course Analysis
Fadda, R.;Congiu, S.;
2011-01-01
Abstract
Background: In our previous study (Fadda, Doneddu, Striano et al., 2010) investigating children with ASDs' sensitivity to the orientation of an adult’s eye gaze towards an object located within the child’s field of view, in static images, children with autism appeared as successful and as accurate as controls in locating the object although they paid less attention to the eyes and over-explored non relevant areas of the stimulus. This led to the hypothesis that children with ASDs might use compensatory strategies to locate the gaze target rather than understanding the referential meaning of the gaze. Objectives: Our study aims to extend our previous results, exploring the strategies used by children with ASDs to locate a gaze target by analyzing the time-course of their visual attention, in comparison with a group of chronological age matched controls, and with a group of adults, that represent respectively typical immature and mature patterns of visual attention toward static gaze-direction cues. Methods: We compared 20 children with ASDs (13 M), mean age=57 mths (range: 36-101; sd=21.37), mean non verbal mental age=39 mths (Leiter-R scale), with a group of 20 typically-developing children, matched for chronological age (7 M) and a group of typically-developing adults (10 M), mean age=22.65 (sd=1.98). The stimuli, presented with a Tobii T60 Eye Tracker, were those used in Fadda et al. 2010: a human face looking right or left at one of two visible target objects positioned next to the head. We defined 5 areas of interest for all the 8 stimulus images: eyes, gaze target, non-gaze target, mouth, not-AOI (that is the area of the screen external to the other AOI). In order to define the strategies used to perform the tasks, we calculated the mean proportion of Fixation Count (FC: the number of fixations to an AOI) for each AOI during 3 different time slots, each lasting one second: 1st , 2nd and 5th second of stimulus presentation. Results: Paired sample t tests revealed that adults showed a preference to the gaze target versus the non-gaze target at t1 (t=3.35.; df=19; p=0.003), t2 (t=2.54; df=19; p=0.02) and at t3 (t=1.78; df=19; p=0.09). Neither children with ASDs nor typical controls showed such a preference. Adults preferred the eyes rather than not-AOI at t1 (t=5.63; df=19; p=0.000), at t2 (t=4.10; df=19; p=0.001) and at t3 (t=2.15; df=19; p=0.044). The same preference was found in young typical controls but not in children with ASDs. Conclusions: While adults were quickly and stably oriented by the eye-gaze direction toward the gaze target, both children with ASDs and typical controls were not, meaning that this phenomenon might be due to immature visual orienting patterns rather than being specific to ASDs. Contrary to previous studies (Ristic et al. 2005; Chawarska et al. 2003) we didn’t find intact basic gaze cueing in ASDs, indeed children with ASDs showed poor attention to the eyes, suggesting that they generally miss important information conveyed by the eyes and this is also likely to hinder later understanding of the referential value of looking.
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