Early Developmental Impairment

The goal of this observational study is to assess the effectiveness of a machine-assisted system for early screening of autism. The main questions it aims to answer are: * Does the machine-assisted system including 5 main behavioral paradigms identify toddlers with autism from those with other neurodevelopmental disorders and typical development? * Are there any differences in the early symptoms of autism among toddlers over the whole mainland China? Participants will receive some developmental and social communicational evaluations for clinical diagnoses. They will also receive the behavior evaluations of the machine-assisted system. The above evaluations will be performed just once.