What is Automatism?

Legal Definition
In medical Jurisprudence, this term is applied to actions or conduct of an individual apparently occurring without will, purpose or reasoned intention on his part; a condition sometimes observed in persons who, without being actually insane, suffer from an obscuration of the mental faculties, loss of volition or of memory or kindred affections. "Ambulatory automatism" describes the pathological impulse to purposeless and irresponsible wanderings from place to place often characteristic of patients suffering from loss of memory with dissociation of personality.
-- Black's Law Dictionary