The four models have parallel developmental lines as well. Splitting in each of the models is an immature experience. In drive theory it occurs in the oral/ anal stage-the earliest psychosexual stages-as one of the immature ego defenses used by young children. Ego psychology sees splitting as an attempt to defend the ego against anxiety by keeping good and bad as separate qualities. Object relations theory conceptualizes splitting as the early form of object relations that later consolidates into mature object relations. Self-psychology also views splitting as an early self-object experience in which the distinction between self and object is poorly developed and is at times precariously maintained in adulthood by violently splitting the two.