The main aim of the present study is to examine eye-tracking based markers for social processing deficits in children with autism spectrum disorder (ASD). To this end a battery of five eye-tracking paradigms will be administered to young children with ASD and typically developing children. To additionally evaluate the specificity of the eye-tracking markers a group of children with disorders of delayed development other than ASD will be included.

During an initial screening session all participants will undergo the Autism Diagnostic Observation Schedule (ADOS). ASD-related symptomatology and levels of impairments will be further characterized using the Social Responsibilities Scale 2 (SRS 2), Caregiver Strain Questionnaire (CSQ), Aberrant Behavior Checklist (ABC), Social Communication Questionnaire (SCQ), and Repetitive Behaviour Scale Revised (RBS-R).

Subsequently all participants will be administered the following eye-tracking paradigms: (1) dynamic social and non-social visual preference paradigm during which dynamic geometric images (DGI) and dynamic social images (DSI) will be presented, (2) non-biological versus biological motion paradigm, (3) social attention and sharing of enjoyment paradigm, (4) preference for real versus schematic emotional face stimuli paradigm during which photographs of human faces and emoticons will be presented, (5) shared social attention and gaze direction paradigm.

Exclusion criteria for all participants:

• visual, auditory or motor impairments
• use of medication

Inclusion criteria for all participants:

• written informed consent from parents / caregiver
• age: 1-10 years

Additional inclusion criterion for the ASD group:

- diagnosis of Autism Spectrum Disorder according to DSM-5

Additional inclusion criteria for typically developing children in the control group:

• no symptoms of developmental disorders
• no current or history of psychological disorder

Additional inclusion criterion for the unspecific disorder of delayed development children in the additional control group:

- disorder of delayed development other than ASD

Children with ASD according to DSM-5 criteria will be compared with typically developing children and a group of children with unspecific delayed development disorders.