The comparative analysis of when and how animals become aware of themselves has at least two levels of focus. One has to do with a conceptual awareness. It implies some representational memory and is reflected in some self-referencing behavior that discriminates unique features of the individual (Gallup, 1970; Lewis & Brooks-Gunn, 1979). Lewis and Brooks-Gunn call this level the “categorical self”. The other level of focus has to do with a perceptual sensitivity. It implies some detection mechanism and is reflected in some self-referencing behavior that discriminates self from nonself at least momentarily. Lewis and Brooks-Gunn call this level the “existential self”. This paper will be limited to a consideration of how infants detect their existential selves. It is the simpler of selves, but it has been none the less elusive in the history of developmental psychology.

Theoretical concern for detection of self

Self-discovery in Freudian and Piagetian theories

The two major developmental theories of this century, Freud's and Piaget's, each assume that normal development in humans requires an initial investment in the task of differentiating the self from its external environment. The theories differ as to when and how the task is accomplished. As for timing, Freud proposed a relatively speedy accomplishment within the first few months, whereas Piaget proposed that the task would take two or three times as long (Wolff, 1960). As for how the distinction between self and nonself is accomplished, the two theorists differed fundamentally.

Freud (1911/1946) attended to why we would be motivated to do so.