mind, self, and young children
There are some powerful arguments to the effect that children less than about three years of age don't have a concept of a self. This is because one can have a concept of the self only if one has a concept of what a mind is. But empirical experiments on identifying what are the mental states of others indicate that young children do not recognize the concept of other minds; hence, they have no recognition of the concept of a self. Eventually, of course, virtually all do come to such a recognition of other minds, though some children, such as acute autisitcs, never come to gain such a recognition.