The Eye Movement Study On Influence Of Facial Information On Attentional Orienting Processes In Young Children With Autism Spectrum Disorder

Facial information have been shown to have an important influence on individual’s involuntary and voluntary attentional orienting systems,which is reflected in the tendency for this information to attract more attention automatically(involuntary level)and to delay the attentional disengagement voluntarily(voluntary level).This attentional bias to faces serves as the underlying mechanisms for people to detect and identify facial information efficiently,and then supports the normal development of social interactions in the typically developing(TD)population.Populations diagnosed with autism spectrum disorder(ASD)have obvious deficits in social adaptation and communication.Abnormal performances in social attention in ASD have the potential to impact on social function in this group.However,few studies have attempted to explore the influences of facial information on both the involuntary orienting and voluntary orienting levels in individuals with ASD.In order to reveal the potential attentional mechanisms related to atypical social adaption of ASD group,the current study investigated how facial information could influence the attentional orienting at both the involuntary and voluntary levels in young children(4-7 years old)with ASD.Specifically,the current study explored the role of facial information(face and non-faces,expressional and neutral faces)in capturing attention involuntarily and retaining attention at the voluntary level when participants have to ignore facial stimuli in young children with ASD.In answer to the above questions,the remote distractor paradigm(RDP)was adopted in the current study,whereby facial stimuli were selected as irrelevant distractors.In RDP,subjects were instructed to look to a pre-defined target accurately and rapidly,which was presented in isolation,or with a central,parafoveal,or peripheral distractor synchronously.Three measures were analysed in this study,which were the saccadic errors(the proportion of trials where participants’ first saccades were directed to the distractor instead of target),saccade latency(time taken to begin to move the eyes towards the target),and the disengagement failure rate(DFR,proportion of trials whereby participants failed to disengage from the centrally presented distractors in the first saccade),to examine the influence of the facial distractors on voluntary(saccade latency and DFR)and reflexive(saccadic errors)attentional orienting respectively in ASD.Furthermore,the current study investigated the influence of emotional faces on gaze following effect in ASD using the gaze cueing paradigm,in which participants were required to look to the target presented laterally at the same or the opposite direction with the gaze shift of neutral or emotional faces shown in the centre of the display screen.The task was also adopted to compare the attentional disengagement from emotional faces under the gaze-averted condition between both groups.Noteworthy,before investigating the distractor effects of facial information on attentional orienting,the current study firstly examined the basic eye movement characteristics and the eye movement control ability to inhibit non-social distractors in ASD during visual orientation.The current study selected the high functioning autistic children as participants.The first study investigated the basic eye movement and eye movement control characteristics in the ASD and TD children,including two experiments.Experiment 1presented a single target in the pro-saccade task whereby participants had to look to the target upon its appearance.The eccentricity of the target from the center of the display screen is 4°,8° and 12° respectively.The results showed similar performances in relation to basic eye movement characteristics,which are saccade amplitude,saccade peak velocity and saccade duration in both groups in any eccentricity condition.Moreover,both groups exhibited the same main sequence effects,saying that the saccade peak velocity and saccade duration increased linearly as saccade amplitude increased.Experiment 2 adopted the RDP paradigm and selected simple shapes as the target and the distractor.Experiment 2 found the expected remote distractor effect(RDE)on the saccade latency in both groups,showing that the saccade latency was largest in the central distractor condition and least in the peripheral distractor condition.In addition,results showed that the ASD children needed longer in the central distractor condition compared to the TD group.On the saccadic errors,both groups made a high level of error rates towards the distractors.Therefore,the first study showed the RDP paradigm was suitable to investigate eye movement control in young children.Basic eye movement function of the autistic children were intact,however,the ability to disengage from the centrally presented non-social distractors was affected in the ASD children.The second study investigated the impacts from facial and non-facial stimuli on attentional orienting systems in children with and without ASD in the RDP task.Face-like and non-face like shapes were utilised as the distractors in Experiment 3,and results showed that face-like distractors triggered higher saccade errors compared to a non-face like condition in both groups.However,this distractor type effect was not present on saccade latency(voluntary level)in either group,and only the RDE effect were present for this measure in both groups.In Experiment 4,real neutral faces and the disorganised neutral faces—scrambled and blurred faces,were adopted as distractors in the RDP.Neutral faces showed increased interference on both the involuntary(errors)and voluntary attentional control(saccade latency and DFR)levels compared to blurred faces in both groups.Detailed analysis reveal that children without ASD showed greatest distractor effects from scrambled faces on saccade latency compared to the other two conditions.However,the ASD group failed to show this effect.Direct comparisons between neutral and blurred face conditions revealed significant group differences on the DFR,which showed that the ASD group had a greater magnitude of distractor type effect relative to typical children.The findings from the second study suggested an intact involuntary orienting system towards faces relative to non-faces,but revealed atypical disengagement processing from neutral faces at voluntary level in ASD,which pointed to a delayed attentional disengagement from the centrally fixated neutral faces in this group.The third study investigated the influence of emotional and neutral faces on attentional orienting in the ASD and TD children.In Experiment 5,angry faces,happy faces and neutral faces was adopted as distractors in the RDP paradigm.Emotional faces triggered more saccadic errors compared to neutral faces in both groups.In terms of saccade latency and DFR,the ASD group suffered greater interference from centrally presented angry faces compared to neutral and happy faces.However,this result was absent for the TD children.Experiment 6 manipulated the expression(angry or neutral face)of the central faces and the congruency between the gaze direction and the position of the target(incongruent vs congruent)in the gaze cueing task.Experiment 6found that the gaze cueing effect,whereby participants took longer to look to the incongruent target compared to the congruent target,was reduced in the ASD group compared to the TD group.Moreover,there was no enhanced effect of the gaze cueing effect for angry faces relative to neutral faces in the ASD children,which was different from the TD group.For the DFR,the ASD children was found to show higher DFR at both the angry and neutral conditions compared to the TD group,and this difference was partly modulated by the social anxiety level of all the participants(the ASD group had higher level of anxiety traits).This study indicated an intact involuntary orienting tendency towards emotional faces in the ASD children,but revealed a delayed disengagement speed from the central angry faces in ASD regardless of the direction of facial gaze.Moreover,young children with ASD did not show an enhanced orientation for the angry gazes compared to the TD children.Based on the above findings,the main conclusions of this study were presented as below:(1)Young children with ASD are not impaired in the involuntary orientation towards faces compared to non-faces.However,the ASD group show disengagement difficulties from the centrally presented neutral human faces.(2)Similar to the TD group,the ASD group have a bias to look to angry and happy faces involuntarily relative to neutral faces,whereas,they need longer time to disengage from the central angry faces compared to TD group at the voluntary level.(3)Delayed disengagement from neutral and angry faces in the ASD group is related to higher level of anxiety traits of this group.This atypical attentional profile could reflect hypervigilance for threats in individuals with ASD.(4)Young children with ASD are inefficient in utilising expressions from faces when following the gaze of others.(5)In total,young children with ASD have the ability to involuntarily orient to facial information,but they have difficulties in disengaging from centrally fixated faces at the voluntary level and have deficits in gaze following behavior.These differences have the potential to impact upon the typical development of higher-level social and communicative functions in ASD.