An Eye-Tracking Study on Biological Motion Perception in Children with High-Functioning Autism Spectrum Disorder

Background: Literature had been demonstrated that children with autism spectrum disorder (ASD) revealed atypical perceptual pattern in biological motion with eye-tracking paradigm. However, some methodological issues such as subject characteristics and the strategy of data analysis are needed to explore.

Objectives: This study investigated the preferential attention and attentional processing on the basic motion perception, animal biological motion perception, and human biological motion perception in children with High-Functioning ASD (HFASD). It aimed to explore the processing of biological motion perception in children with HFASD. Moreover, concerning the heterogeneity within ASD, the study examined the biological motion perception in intellectually gifted children within HFASD.

Methods: Fifty children aged 7 to 10 years with HFASD and twenty-five children with typically development（TD）matched on age and IQ were recruited. The current study utilized preferential looking paradigm and motion point-light displays, demonstrating three visual comparisons: (1) basic motion perception: object motion paired with scrambled motion; (2) animal biological motion perception: animal motion paired with object motion; (3) human biological motion: human motion paired with animal motion. Eye-tracking techniques were applied to measure proportion of dwell time and time course of fixation probability on each motion stimuli.

Results: In basic motion perception, children with TD and HFASD preferentially attend toward scrambled motion. In biological motion perception, generally, children with TD and HFASD preferentially attend toward animal motion and human motion. Time-course analysis revealed that children with TD and HFASD attended toward animal motion and human motion at the same time window. Moreover, in animal biological motion perception, children with HFASD showed lower preferential interest in animal motion than children with TD at the early stage of time course, and there were no significant difference between groups at the late stage of time course. In human biological motion perception, children with TD and HFASD showed similar level of preferential interest in human motion at the early stage of time course; however, children with TD maintained preferential interest in human motion across time, but children with HFASD reduced preferential interest in human motion across time. At the late stage of time course, children with HFASD showed significantly lower level preferential interest in human motion than children with TD. Concerning the heterogeneity within the study sample of HFASD, results indicated that there was no difference on the level of preferential interest in animal motion between intellectually gifted HFASD (IG-HFASD) and TD group; however, in human biological motion perception, IG-HFASD and nonIG-HFASD group reduced preferential interest in human motion across time course compared to TD group.

Conclusions: Findings suggested that children with HFASD exhibit the equivalent preferential interest and speed of attending to biological motion as did TD children. However, children with HFASD reduced referential interest in human biological motion across time course compared to TD children, and not influenced by the intellectually gifted advantage with compensation. The results implicated that biological motion perception may play an important role to understanding the social deficit in children with ASD.