Unlike Freud, Erikson believed that sexual impulses were not the only conflicts within the child's developing psyche: a desire for autonomy, for example, was equally important at most stages of development. Freud's most famous contribution to the study of development is his theory of the Oedipus Complex, which suggests that after a period of polymorphous perversity, or the ability to be sexually stimulated by a number of undifferentiated means, the child begins to desire the mother as its first love object. In the case of a boy, he begins to despise and feel murderously towards his father as a rival for the mother's affection, while the young girl begins to resent the mother for making her 'incomplete' (without a penis) and tries to 'have' her father as a way of 'having' what she lacks. Eventually, the girl tries to resemble...

The boy tries to seem like his father to please the opposite-sex parent. Coming to sexual maturity for Freud was thus a traumatic process of negotiating a 'family romance' and disturbances could create psychological wounds that would result in difficulties later on. Although biology clearly had an influence upon the child in terms of their sexual status, Freud's philosophy is usually viewed as stressing nurture, or experiences, over nature: the unconscious mind affects the body and actions of the individual in the present.
Erikson believed that Freud over-emphasized the impact of sexual jealousy on the mind of the developing child. He believed that other individuals, such as teachers and peers, could play just as potent an influence upon the life of a child.