Freud has made many contributions to the development of psychology, firstly the Oedipus/Electra complexes. The Oedipus complex involves the male child, and his desire to have his mother to himself and his father out of the way. However he fears castration by the father. To avoid this, he identifies with the aggressor (father), to adopt his attitudes and traits. The Electra complex on the other hand, is relevant to the female child, and concerns her fear of the loss of her mothers' love, therefore identifying with her mother and adopting her attitudes and traits. Successful resolution of the Oedipus/Electra complex is when gender identity is formed.
The second contribution by Freud to the development of Psychology I am going to mention is about the Psychodynamic Theory, or the structure of the personality. This is split into three parts, ID, ego, and superego. The ID is described as the inner child, and is the only part of the personality that is innate.
This part of the personality is self-centred, demanding, pleasure seeking, and wants immediate gratification, as well as being ruled by the pleasure principle. ID functions on the unconscious level, and is inaccessible except via therapy.
The ego is the inner adult part of the personality. It emerges at around 2 years old, and deals with reality and is fairly logical. This part of the personality is also prepared to listen, prepared to wait for pleasures, and deals with responsibilities. This part is ruled by reality, and operates on the conscious level, which makes it immediately accessible.
The third and last part of the personality is the superego, which is the inner parent part. This emerges at around 5/6 years, when the child is more mature. This part of the personality deals with responsibility, moral values...