Self-understanding

Life instincts. Freud theorized that each person has life instincts or eros. These instincts urges seek to preserve life. Each of us is motivated to satisfy our hunger, thirst, and sexual needs. Without food and water, we couldn’t survive. The energy associated with these instincts he termed libido.
Death instincts. Just like life instincts, there are death instincts or thanatos. He believed that “the goal of all life is death” – that human beings strive to return to a state of balance that started life, in which there is no painful struggle to satisfy biological needs. The life instincts operate to ensure that death is delayed as long as possible, so that human beings can obtain many other satisfactions.
Psycho sexual development(심리-성적 발달이론)
According to the famous psychoanalyst Sigmund Freud, children go through a series of psychosexual stages that lead to the development of the adult personality. His theory described how personality developed over the course of childhood. While the theory is well-known in psychology, it has always been quite controversial, both during Freud's time and in modern psychology.
Freud believed that personality developed through a series of childhood stages in which the pleasure-seeking energies of the id become focused on certain erogenous areas. An erogenous zone (성감대) is characterized as an area of the body that is particularly sensitive to stimulation. During the five psychosexual stages, which are the oral, anal, phallic, latent and genital stages, the erogenous zone associated with each stage serves as a source of pleasure.
The psychosexual energy, or libido, was described as the driving force behind behavior.
Oral stage (구순기적 성격) - During the oral stage, the infant's primary source of interaction occurs through the mouth, so the rooting and sucking reflex is especially important. The mouth is vital for eating, and the infant derives pleasure from oral stimulation through gratifying activities such as tasting and sucking. Because the infant is entirely dependent upon caretakers (who are responsible for feeding the child), the child also develops a sense of trust and comfort through this oral stimulation.