The ego is the center of consciousness and is concerned with perceiving thinking feeling and remembering. Part of our conscious perception is determined by the attitudes of introversion and extraversion in which libido is channeled internally or externally. The psychological functions include thinking feeling sensing and intuiting. Thinking and feeling are rational. Function sensing and intuiting are non-rational only one attiude and function can be dominant. The eight psychological types are formed by combinations of the attitudes and functions,