The Role Of Directional Cues In Animacy Perception Of Individuals With Autism Spectrum Disorder

Autism Spectrum Disorder is a group of neurodevelopmental disorders that are characterized by persistent deficiencies in social interaction,social communication,and behavioral patterns,repetitiveness,and limitation of interest activities(American Psychiatric Association,2013).A number of studies have shown that it's difficult for individuals of ASD to identify the intention of simple moving shapes,and their animacy perception has shown abnormalities in different motion modes(Cook,Saygin,Swain,& Blakemore,2009;Miller & Saygin,2013).But their ability to handle simple motion cues is similar to that of typically developing people,which shows that they just have difficulty dealing with social cues.The enactive mind hypothesis indicates that the reason for the abnormal animacy perception of individuals of ASD is that when they observe moving objects,they will perform low-level processing on physical stimuli such as speed and direction,but lack high-level cognitive processing of social meaning contained in these attributes.This view became a reasonable explanation for such phenomena.Recently,some researchers have discovered an interesting phenomenon called directional advantage,that is,when the direction of an object is consistent with its direction of movement,it will significantly improve the individual's perception of animacy,and this phenomenon has been proven to be stable in a variety of motion modes.The existence of directional advantage reflects the effective processing of directional cues by the individual's visual system,and the impact of the relationship between object orientation and movement direction on the individual's implicit social inferences.Therefore,this study explores the effect of directional advantage on the animacy perception of individuals of ASD,and reveals in detail how individuals of ASD visually process this kind of cues that imply animacy based on social information processing defects.This study uses the chase detection paradigm which regards chase as a sign of animacy.When the participants found that there is a chasing relationship between two moving objects with the same appearance,it means that it has animacy perception.The chase detection accuracy rate is used as an index to quantify animacy perception.In Experiment 1,three types of object orientations and movement directions were designed as clues: non-directional clues,directional clues,and non-directional clues,that is,the ball always "gazed" at this static object and would not change with thedirection of motion.This kind of non-directed cues can effectively weaken the chase detection ability of individuals of TD,a phenomenon known as the "wolf pack effect" in the study of Gao et al.(2010).They believe that the wolf pack effect proves that animacy perception is a reflective and automatic perception,and at the same time confirms the stability of directional superiority from the negative side.In order to further explore the participants' visual search process,we used Eyelink 1000 to record their eyes movements.The Experiment 1 explored whether there is a directional advantage between the two groups,so we designed three directional cues in different orientations in Experiment 2 to further explore the effect of different orientation of the directional cues on animacy perception.The three types of directional cues are: forward cues,reverse cues,and vertical cues.Previous studies have confirmed that TD participants do not show a directional advantage for vertical cues(Gao et al.,2009),which may be due to the social processing of such directional cues by individuals.They rounded the two dots on the ball as eyes.Under forward cues,looking forward during the movement helps participants to identify the direction of motion;but when the eyes keep looking at the side,it will interfere with their perception of the direction of motion.Thereby it will reduce the accuracy of their chase detection.However,no research has investigated the effect of the reverse cues on animacy perception.We believe that the physical characteristics of reverse cues are more similar to those of forward cues.If participants of ASD tend to use compensatory strategies for physical attribute processing in chase detection,then their accuracy of chase detection under forward cues and reverse cues will be correct similarly.The results show that in the case of high chasing accuracy,the two groups of subjects have directional advantage.Participants of ASD have a search strategy of local processing and lack of attention.Their visual sensitivity was generally higher than that of participants of TD,while their cognitive sensitivity was generally lower than that of participants of TD.The directional cues with different orientations had no significant effect on the animacy perception of participants of ASD.But compared with the vertical cues,the reverse cues improve their ocular sensitivity.It has been preliminarily proved that the role of directional cues in animacy perception of ASD participants is significantly different from that of TD participants.The physical and chemical processing methods of individuals of ASD make it difficult for them to use the social information contained in the directional cues to improve the accuracy of the chase detection.