Marcel Linka¹, Sanna Stroth², Inge Kamp-Becker³, Jutta Billino¹, Benjamin de Haas¹; ¹Experimental psychology, Justus Liebig University Giessen, Germany, ²Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Philipps University, Marburg, Germany, ³Department of Child and Adolescent Psychiatry, Center for Psychosocial Medicine, University Hospital Heidelberg, Heidelberg, Germany.

Natural gaze is strongly driven by semantic object characteristics, such as faces and text. People with neurodevelopmental disorders, such as Autism (ASD) and Attention deficit hyperactivity disorder (ADHD), exhibit atypical gaze patterns, including a reduced focus on faces and eyes in ASD. This study investigated how free-viewing behavior toward faces differs among individuals with ASD, ADHD, and individuals with no diagnosis as controls. Additionally, we examined the free-viewing behavior of first-degree relatives of each group to explore potential genetic factors. Participants with ASD (N = 13), ADHD (N = 14), controls (N = 22), and first-degree relatives, freely viewed a set of 40 complex scenes. Both, the ASD and ADHD groups exhibited a lower proportion of first fixations and dwell time on faces compared to controls, with no significant differences between the ASD and ADHD groups. Notably, the ASD group demonstrated a lower proportion of dwell time and first fixations on eyes relative to controls and there was a similar tendency in the ADHD group. Gaze patterns of first-degree relatives fell between the tendencies observed in the corresponding groups with diagnoses and controls, suggesting a heritable component. Recent findings indicate that individuals fixating lower within faces (and thus avoid the eye region) also tend to fixate lower within inanimate objects (Broda & de Haas, 2024). This suggests potential domain-general mechanisms, possibly involving individual visual field geometry. Building on this, we plan to analyse whether eye avoidance in ASD also generalises to lower fixations within inanimate objects, or is domain-specific in this group. Either outcome can inform us about potential underlying mechanisms and efficient strategies for eyetracking as a diagnostic tool.