Dou Dou, a 4-year-old, is all smiles as he pets a golden retriever sitting quietly at his feet in a barely furnished treatment room at the Beijing Rehabilitation Center for Autism.

The autistic child is unable to understand social norms and can easily become upset and violent.

The dog acts as a comfort to him and also entertains him. During treatment, Dou Dou hugs it, touching specific parts of the animal's body as his therapist asks him to.