The ego comprises the organized part of the personality structure that includes defensive, perceptual, intellectual-cognitive, and executive functions. Conscious awareness resides in the ego, although not all of the operations of the ego are conscious. Originally, Freud used the word ego to mean a sense of self, but later revised it to mean a set of psychic functions such as judgment, tolerance, reality testing, control, planning, defense, synthesis of information, intellectual functioning, and memory. The ego separates out what is real. It helps us to organize our thoughts and make sense of them and the world around us.
Jung included the ego in a broadly comprehensive theory of complexes, often referring to it as the ego-complex as illustrated when he said "I understand ego as a complex of ideas which constitutes the center of my field of consciousness and appears to possess a high degree of continuity and identity".
According to Jung, the Ego - the "I" or self-conscious faculty - has four inseparable functions, four different fundamental ways of perceiving and interpreting reality, and two ways of responding to it. The four ego functions postulated by C.G. Jung in Psychological Types are Sensation, Thinking, Feeling, and Intuition. Jung suggested that people start life developing one of these four ego functions, and at various stages throughout their life may develop others, the undeveloped ones having less effect on their cognition. Typically, the second ego function might become developed during adolescence, and the development of a third accounts for mid life crises.
Jung proposed four main functions of consciousness:
The functions are modified by two main attitude types: extraversion and introversion. Jung theorized that the dominant function characterizes consciousness, while its opposite is repressed and characterizes unconscious behavior.
The eight psychological types are as follows: