Abnormal, compulsive behaviors that are an expression of the stress that primates in labs experience. Stereotypies are often a direct result of trauma, confinement, and isolation (i.e. the deprivation of many of an individual's social, emotional, intellectual, and physical needs). Some nonhuman primates exhibit highly repetitive and abnormal behaviors, involving abnormal locomotion (pacing, flipping, circling) or other movements (including but not limited to eye-poking, saluting, slapping, floating limbs (the individual momentarily fails to recognize a hand or foot as part of his own body). Finger or penis sucking, eating or smearing feces, excessive masturbation, and self-mutilation (see above) are also common stereotypies. Once a primate develops a stereotypical behavior it is very difficult to eliminate it.

Constantly repeated meaningless gestures or movements such as hand flapping. Stereotypy is common in autism and in self-stimulatory behaviors seen in individuals with severe mental retardation.