The order of the 6 possibilities outlined above corresponds to an increasing complexity in the perception and representation of mirror self-reflection: from mere perceptual discrimination to explicit recognition, identification, and ultimately to evaluation. This progressive order corresponds also, I will contend, to the order in which self-awareness develops between birth and 3 years of age.
Next, I present this development in its chronology and as it appears to unfold in the first 3 years of life. For illustration, I selected empirical evidence that support each of these proposed developmental steps. Table 1 below summarizes these steps, in the chronology of their manifestation early in life, with approximate age onset. Note that these ages are only indicative, varying across individual infants and depending on the experimental and cultural context of the child, as well as the kind of tests used to probe the development of self-awareness. Rather than exact timing, what is important here is the putative invariant developmental progression in terms of emerging processes, behavioral expression, and motives that seem to underlie the ontogeny of self-awareness.
