When it comes to psychoanalysis criticism two figures spring in our mind Freud and Lacan. Freud’s psychoanalysis is simple to understand than the analysis of Lacan. According to Freud whose contribution in psychoanalysis is great says human mind is composed of 3 elements: ID, ego superego. ID is the basic level common to humans and animals, babies and grownups. It is regulated by pleasure-pain principle. ID is instinctual, when a baby sees something; he/she wants to have it but does not know how it comes.
When the baby grows from the level of ID into ego, he/she is conscious of her/his identity. The ego keeps the person active to look/become heroic. It develops ‘I am beautiful, I am handsome.’ Ego brings desire of things; it is the sense/feelings that motivates a person to work hard to prove that he/she is great/important. Desire of something and loss of it hurts the person. Same applies to Great Gatsby who has ego to win Daisy as sweetheart. When Tom marries Daisy, Gatsby feels hurt and bails with rivalry. It is now that he realizes how inferior he is to Tom.
Superego filters out wild wishes and desire and sends then back to the unconscious section. The presence of ego/unconscious would make on individual a social misfit and shatter his/her image. The superego prevails over the unconscious and allows only those activities and expression which are socially acceptable. Yes, there goes a punch and pull (conflict) between ego/unconscious and superego/conscious. The superego or the conscious controls the human behavior.
That every individual is a psycho has already been accepted. It is also clear that individuals have wishes and desires. They work hard to fulfill those wishes but only a few wishes are fulfilled and many of them remain unfulfilled. The unfulfilled desires sty and stay in our mind and push us to fulfill those desires by unfair ways. No matter what the result. There goes a long push and pull between the two the unconscious and the conscious. Some people use unfair way to fulfill their desires and thereby spoil their career.
When the unconscious prevails over conscious, the person plays guilty thoughts all the time. But when the conscious wins over the unconscious the person becomes alert. The conscious has a mechanism of controlling wishful thinking and prevents the individual from becoming violent.
Lacan comes to give a totally different set of psychoanalysis criticism. According to him there are two major stages in the psychological development of a person. Before the child without language and after the child learning language. When a baby is born, it is without language. Slowly and gradually the baby grows and bigger and starts to learn language. Before learning the language the baby is happy and satisfied because the baby has no sense of companions. The baby has no language so it cannot think/imagine or compare. But when the child learns language, s/he passes through a mirror stage. In the stage the child indentifies himself/herself with the type of sex boy or girl. When the child sees female sex in herself and male sex in her brother a kind of negativity or rivalry develops in her mind. The female child wonders at the difference of sex between her and her brother. Slowly and gradually she learns that she and her mother are of same sex and her brother and her father are of the other sex. The child gains mastery over language and argues a lot. She associates love, closeness, possessions, gifts etc. with presence or absence of certain sex. If parents give gifts to her brother first, she grows angry and jealousy of his sex. But if the girl child grows into teen age just the opposite stage develops. She becomes closer to male sex. She makes many boyfriends and other girls appear as a rival.