A psychoanalytic term denoting the part of the personality which carries on relationships with the external world.The ego is conceived as a group of functions that enable us to perceive, reason, make judgments, store knowledge, and solve problems. It has been called the executive agency of the personality, and its many functions enable us to modify our instinctual impulses (the id), make compromises with demands of the superego (conscience, ideals), and in general deal rationally and effectively with reality. It operates largely but not entirely on a conscious level, and in a mature person is guided less often by the pleasure principle than by the reality principle—that is, the practical demands of life. It may, however, be torn between these two opposing forces.The ego, unlike the id, is not readymade at birth. It develops slowly as the child learns to master his impulses, know what behavior the world requires, and use intelligence in meeting difficulties. A person who develops a “strong ego” successfully integrates the demands of the id, superego, and reality. He therefore does not have to resort to rigid defenses or escape mechanisms in handling the stresses of life. An individual with a “weak ego” is dominated by unconscious impulses and may disintegrate under strain, with the result that mental symptoms or character defects are likely to develop.