Eye movement pattern during global-local perceptual processing and their relationship with autistic and schizotypal traits

Abstract

Besides executive functions, past and recent research found abnormalities in globallocal processing in individuals with autism and individuals with schizophrenia compared to the healthy population. Nonetheless, the findings and mechanisms remained equivocal and unclear. This study examined global-local processing in relation to autistic traits and schizotypal traits in the non-clinical population to minimize confounding effects such as that of medication and illness duration. 120 college students without a history of neurodevelopmental or mental health history were recruited. They were administered the Autism Quotient, Schizotypal Personality Questionnaire, Embedded Figures test, Contour Integration task, Face Recognition task, four cognitive/ executive function tasks, and a battery of questionnaires related to mental health. In addition to performance indicators in perceptual processing tasks, eye movement patterns and consistency were measured and analyzed using the Eye Movement analysis with Hidden Markov Models (EMHMM). While two distinctive eye movement patterns were generated for each global-local processing task, they were not significantly correlated with autistic and schizotypal traits. Nevertheless, stepwise regression analysis revealed that autistic traits were best predicted by the reaction time in the Contour Integration task and the eye movement consistency in the Face Recognition task, while schizotypal traits were best predicted by accuracy in the spatial 2- back task, the reaction time of the Contour Integration task, and eye movement consistency in Face Recognition task. Notably, the higher the autistic and schizotypal traits, the more consistent the eye movement in face recognition. This relationship may be related to a more consistent compensatory strategy adopted by individuals with high autistic or high schizotypal traits relative to a more flexible and exploratory strategy adopted by those lower in these traits. This study concluded that in addition to performance indicators of global-local processing tasks and cognitive tasks, eye movement consistency in face recognition also predicted autistic and schizotypal traits. In particular, eye movement consistency was more predictive of autistic and schizotypal traits than eye movement patterns, which may be unique to the non-clinical population. Further analyses on eye movement consistency and studying it with a broader range of global-local processing tasks and more trials may further contribute to the identification of promising objective biomarkers.