APA Dictionary of Psychology

reflexive action (Latin): the term used by René Descartes to explain bodily movements that are not under volitional control but instead occur as a response to the surrounding environment. The concept arose from Descartes’s notion of the body as a machine that is wholly distinct from the mind (see Cartesian dualism). It served as a basis for later psychological theories that took the reflex arc as the basic unit, as well as the basic model, of behavior.