Autism is a developmental disorder that is marked by the appearance of three, broad behavioral symptom categories. These behavior characteristics of autism include a number of actions that are common among a wide range of children and adults. The presence of any single behavior does not necessarily mean someone has autism. However, the appearance of behaviors in all three areas is generally seen as a sign that the disorder is present.

These three areas are:

• social impairment -- people along the autism spectrum have difficulty with social interaction and related physical behaviors. They may have difficulty making eye contact, tend not to smile and cannot correctly interpet the feelings of others.
  
• communication -- between one-third and one-half of people with autism will not naturally develop sufficient skill with speech to meet their basic daily needs. In such cases, intervention is required if the autistic individual is to learn to communicate with others. In some situations, autistic people will exhibit very communication disorders such as echolalia, in which the autistic person repeats the words of others.
• restrictive and repetitive activity --autistic people exhibit many behaviors marked by ritual, order and control. Among these are the seemingly purposeless movements, sometimes called self-stimulation, self-stim, or stereotypy. These include body rocking, hand flapping, etc. Also common are compulsive behaviors such as the lining up of toys in a particular order, ritualistic behaviors such as requiring that clothes always be put on in the exact same order, and restrictive behaviors, such as a preoccupation with a particular television show.

For more information on the behavior characteristics of autism, visit Autism Resources.