A Multi-site Comparison of Social Visual Engagement to Clinical Diagnosis for Autism Spectrum Disorder

Inclusion Criteria: Subjects must meet all of the following inclusion criteria to participate in this study: 1. Boys and girls between 16 and 30 months of age 2. Generally healthy with no acute illnesses by physical examination 3. Normal or corrected-to-normal vision, in terms of visual acuity and oculomotor function, sufficient to watch short videos. Adequate hearing to hear material presented in videos 4. Subject and parent can communicate meaningfully in English with the principal investigator and the clinical study site staff 5. Subject's parent or guardian is able to read and understand the informed consent form 6. Parent voluntarily provides written informed consent Exclusion Criteria: Any subject who meets any of the exclusion criteria will be excluded from participation in this study: 1. Known genetic disorders (e.g., Fragile X, Williams Syndrome, Tuberous Sclerosis, Muscular Dystrophy, Neurofibromatosis, Down Syndrome) 2. Severe hearing or visual impairment as determined on physical examination (e.g., congenital nystagmus, congenital cataracts, previous diagnosis of severe hearing deficits by otoacoustic emissions or auditory brainstem response) 3. Acute illnesses likely to prevent successful or valid data collection, i.e., conjunctivitis, fever, uncontrolled allergy symptoms, etc. 4. Uncontrolled epilepsy or seizure disorder 5. History or presence of a clinically significant medical disease, or a mental state that might confound the study or be detrimental to the subject as determined by the investigator 6. Acute exacerbations of chronic illnesses likely to prevent successful or valid data collection 7. Receiving therapies that may affect vision, i.e., currently receiving or have received the following therapies within 2 weeks of screening: topiramate, chlorpromazine, thioridazine, prednisone, prednisolone (including ophthalmic solutions and ointments), diphenhydramine, or hydroxyzine; or have received ophthalmic antibiotics within 3 days of screening: tobramycin, ciprofloxacin, gatifloxacin, levofloxacin, moxifloxacin and ofloxacin solutions and/or bacitracin ointment 8. Receiving therapies that may affect the ability to focus attention on the videos, i.e., if on central nervous system (CNS) stimulants, CNS depressants, or anticonvulsants, dose must be stable (same dose for at least 2 weeks). 9. Known allergies or sensitivity to the plastic, leather, or metal components used in the materials of the Social Developmental Testing Device seat 10. Unable or unwilling to sit in a car seat, e.g., child has tantrums on nearly all occasions when placed in a car seat and tantrums do not subside within 5 minutes