Early symptoms of autism in infants and toddlers mainly include language disorders, lack of attachment and stereotyped behavior. 1. Language disorder: the language disorder of autism in infants and toddlers manifests itself in the absence of teething, inability to be amused, absence of gaze following, and frequent crying and shouting. 2. No attachment: Autistic infants and toddlers cannot establish a close and dependent relationship with their parents or caregivers, do not like to cuddle with their parents or caregivers, and prefer to be alone. 3. Stereotyped behavior: Autistic infants and toddlers will repeat the same action over and over again, such as clapping their hands and stamping their feet. If an infant or toddler exhibits any of the above behaviors, he or she should go to the hospital in time for the doctor to determine if he or she is autistic based on the test results.