the structure of personality
the id=pleasure principle, primitive aspects of behaviour aim for immediate gratification(birth to 18 months)
the ego=reality principle,mediator between id and superego and involved in defence mechanisms(18 months to 3 years old)
super ego=morality principle, formed at end of the phallic stage, internal sense of wrong and right and punishes/praises the ego based on this(3-6 years)