Stereotypy or self-stimulatory behavior refers to repetitive body movements or repetitive movement of objects. This behavior is common in many individuals with developmental disabilities; however, it appears to be more common in autism. In fact, if a person with another developmental disability exhibits a form of self-stimulatory behavior, often the person is also labeled as having autistic characteristics. Stereotypy can involve any one or all senses. We have listed the five major senses and some examples of stereotypy.
Stereotypic Behaviors Related to Senses
- Visual staring at lights, repetitive blinking, moving fingers in front of the eyes, hand-flapping
- Auditory tapping ears, snapping fingers, making vocal sounds
- Tactile rubbing the skin with one’s hands or with another object, scratching
- Vestibular rocking front to back, rocking side-to-side
- Taste placing body parts or objects in one’s mouth, licking objects
- Smell smelling objects, sniffing people
Researchers have suggested various reasons for why a person may engage in stereotypic behaviors. One set of theories suggests that these behaviors provide the person with sensory stimulation (i.e., the person’s sense is hyposensitive). Due to some dysfunctional system in the brain or periphery, the body craves stimulation; and thus, the person engages in these behaviors to excite or arouse the nervous system. One specific theory states that these behaviors release beta-endorphins in the body (endogeneous opiate-like substances) and provides the person with some form of internal pleasure.
Another set of theories states that these behaviors are exhibited to calm a person (i.e., the person’s sense is hypersensitive). That is, the environment is too stimulating and the person is in a state of sensory-overload. As a result, the individual engages in these behaviors to block-out the over-stimulating environment; and his/her attention becomes focused inwardly.
Researchers have also shown that stereotypic behaviors interfere with attention and learning. Interestingly, these behaviors are often effective positive reinforcers if a person is allowed to engage in these behaviors after completing a task.
There are numerous ways to reduce or eliminate stereotypic behaviors, such as exercise as well as providing an individual with an alternative, more socially-appropriate, forms of stimulation (e.g., chewing on a rubber tube rather than biting one’s arm). Drugs are also used to reduce these behaviors; however, it is not clear whether the drugs actually reduce the behaviors directly (e.g., providing internal arousal) or indirectly (e.g., slowing down one’s overall motor movement).
iance, as well as a tendency to be inappropriate in nature (Turner, 1999). Insight into the function (e.g., sensory, social, tangible) of the behavior is neither diagnostic nor invoked. In other words, membership into the group of behaviors is based on meeting criteria for the physical and observable form alone.
Stereotypic behaviors are highly heterogeneous in presentation. Behaviors may be verbal or nonverbal, fine or gross motor-oriented, as well as simple or complex. Additionally, they may occur with or without objects. Some forms involve stereotyped and repetitive motor mannerisms or use of language. Common examples of stereotypy are: hand flapping, body rocking, toe walking, spinning objects, sniffing, immediate and delayed echolalia and running objects across one’s peripheral vision (Schreibman, Heyser, &Stahmer, 1999). Other forms involve more complex behaviors, such as restricted and stereotyped patterns of interest or the demand for sameness. These forms may involve a persistent fixation on parts of objects or an inflexible adherence to specific, nonfunctional routines or rituals. For example, a child engaging in stereotypic behavior may attend only to specific parts of objects (e.g., car wheels, doll eyes). Alternatively, a child may insist on playing with his or her toys in a very specific fashion (e.g., lining blocks up in identical rows repetitively).
Stereotypic behaviors are not isolated to autism. They are common to individuals with other sensory, intellectual, or developmental disabilities. For example, research indicates that a large majority of individuals with mental retardation exhibit stereotypies. However, in comparison to individuals with mental retardation, those with autism tend to display more varied topographies, along with increased severity and overall occurrence (Bodfish, Symons, Parker, & Lewis, 2000). Stereotypies also occur in typical individuals from infancy through adulthood. Some examples of stereotypic behavior in typical adults include tapping feet, nail biting, smoking, organizing, playing sports, and watching TV. Alternatively, stereotypies in typical infants and toddlers often resemble behaviors seen in individuals with autism across the lifespan (Smith & Van Houten, 1996). Stereotypies in autism are distinguished by their lack of developmental and social appropriateness. In one study, stereotypic behaviors in children with developmental delays (DD) were compared to stereotypes in two control groups of children, matched on chronological age (CA) and mental age (MA) respectively. Although no systematic differences were found between groups in the percentage of occurrence or variety of displayed behaviors, the stereotypic behaviors observed in children with DD were rated as more bizarre overall compared to their CA matches. Children with DD exhibited higher levels of obvious gross motor mannerisms, as well as behaviors with higher visual intensity and focus. Behaviors exhibited by children with DD were perceived as similar in comparison to those displayed by children matched on MA (Smith & Van Houten, 1996).
