Gordon Gallup's significant contribution to the psychological study of the self is twofold: He introduced an objective empirical method to examine selfrecognition in nonverbal organisms through the mirror self-recognition (MSR) test, and he developed a challenging theoretical account that postulates an inherent link between the ability for MSR and the capacity to infer mental states in others, that is, for having a theory of mind (ToM). Briefly, Gallup's model states that

1. MSR implies self-awareness;

2. this “self-awareness is tantamount to being aware of being aware” (Gallup, 1991, p. 123); and

3. being aware of one's own “mental states and their relation to various external events” allows one “to gain inferential access” to the mental states of others (Gallup, 1991, p. 123).

Thus, because Gallup's model attributes to the organism showing MSR a level of self-awareness that satisfies the representational preconditions for inferring beliefs in others, he predicts a developmental synchrony between the appearance of MSR and “introspectively based social strategies”, such as intentional deception, that implies a ToM.

Evidence demonstrating that organisms that seem to possess a ToM – such as young children (Astington, Harris, & Olson, 1988) and chimpanzees (Povinelli, Nelson, & Boysen, 1990; Woodruff & Premack, 1979) – also show MSR (Gallup & Suarez, 1986), is clearly in line with this prediction.