Preserved and non-preserved social attentional processes in Autism and developmental language disorder at early ages

Differentiating between Autism Spectrum Disorder (ASD) and Developmental Language Disorder (DLD) in early childhood, when language and behavioral repertoires are not yet fully developed, remains a major challenge in clinical practice. This study aimed to examine which aspects of social attention are preserved or altered in each condition, using eye-tracking. We analyzed how children explored faces and objects in three groups: children with ASD, children with DLD, and non-clinical children. A paired-preference task was used in which children viewed images with one face and one object. Variables included stimulus type (face vs. object), object interest (related vs. unrelated to autistic circumscribed interests), and facial emotional expression (neutral, happy, angry). The sample included 69 children aged 32 to 74 months (23 per group). Eye-tracking measures captured how quickly children oriented to each stimulus (time to first fixation; prioritization index), how long they looked at it (total fixation duration; preference index), and how sustained their visual engagement was (visit duration; duration index). The ASD group showed preserved orientation toward social stimuli, with no differences relative to the non-clinical group. The ASD and DLD groups differed in the duration index, indicating stronger visual engagement with objects in the ASD group. Both prioritization and preference indices differentiated between clinical and non-clinical groups. These findings characterize how children in each group attend to social and non-social information, highlighting distinct patterns that may inform early differential diagnosis and clinical assessment.