Stimming

Stimming is a jargon term for a particular form of stereotypy, a repetitive body movement (often done unconsciously) that self-stimulates one or more senses in a regulated manner. It is shorthand for self-stimulation, and a stereotypy is referred to as stimming under the hypothesis that it has a function related to sensory input. Stereotypy is one of the symptoms listed by the DSM IV for autism and is observed in about 10% of non-autistic young children. Many people with autism do not exhibit stereotypy. Common forms of stereotypy among people with autism 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 part of their sensorium, and is thus a soothing behavior.

Sometimes self-injury is viewed as a form of stimming. Usually, self-injury is very different from stimming, but people with decreased pain sensitivity may injure themselves because they like the feel of it, similar to other stims. For example, they might like the way their hand feels in the mouth when they bite themselves, while not feeling the pain of the bite. Or they might like pressure on their forehead and bang their head without it hurting, even if they are risking brain damage.