automatism(redirected from automatic behaviour)
Also found in: Dictionary, Thesaurus, Medical, Encyclopedia.
An involuntary act such as sleepwalking that is performed in a state of unconsciousness. The subject does not act voluntarily and is not fully aware of his or her actions while in a state of automatism. Automatism has been used as a defense to show that a defendant lacked the requisite mental state for the commission of a crime. A defense based on automatism asserts that there was no act in the legal sense because at the time of the alleged crime, the defendant had no psychic awareness or volition. Some American jurisdictions have recognized automatism as a complete, Affirmative Defense to most criminal charges. An Insanity Defense, by comparison, asserts that the accused possessed psychic awareness or volition, but at the time of the offense, the accused possessed a mental disorder or defect that caused them to commit the offense or prevented them from understanding the wrongness of the offense.