Stimming is a repetitive body movement that self-stimulates one or more senses in a regulated manner. Stimming is known in psychiatry as a "stereotypy", a continuous, purposeless movement.
Stimming is one of the symptoms listed by the DSM IV for autism, although it is observed in about 10 percent of young children without autism. Many autistic children have no stims. Common forms of stimming among autistic people include hand flapping, body spinning or rocking, lining up or spinning toys or other objects, echolalia, perseveration, and repeating rote phrases. 
There are many theories about the function of stimming, and the reasons for its increased incidence in autistic people. For hyposensitive people, it may provide needed nervous system arousal, releasing beta-endorphins. For hypersensitive people, it may provide a "norming" effect, allowing the person to control a specific sense, and is thus a soothing behavior. 
Some common examples indulged by an autistic person is presented below :
|Visual||Flapping hands, blinking and / or moving fingers in front of eyes; staring repetitively at a light|
|Auditory||Making vocal sounds; snapping fingers|
|Tactile||Scratching; rubbing the skin with one's hands or with an external object|
|Vestibular||Moving body in rhythmic motion; rocking front and back or side-to-side|
|Taste||Licking body parts; licking an object|
|Smell||Smelling objects or hands; other people|
The above is only an illustrative list, and there may be several other stimming actions displayed by an autistic person.
- ↑ "Prevalence of stereotypy among children diagnosed with autism at a tertiary referral clinic", K.A. Crosland, presented at the Association for Behavioral Analysis annual conference, May 25, 2001.
- ↑ "Stereotypic (Self-Stimulatory) Behavior (Stimming)", Stephen M. Edelson, 1995.