Introspection Plays an Early Role in Children's Explicit Theory of Mind Development.

This study assessed children's (N = 236) ability to introspect the mental states of seeing and knowing relative to their ability to attribute each state to others. Children could introspect seeing 10 months before they could introspect knowing. Two- and 3-year-olds correctly reported their own seeing states, whereas 3- and 4-year-olds correctly reported their own knowing states. For each mental state, there was a 7-month difference before children could correctly attribute that state to another. These findings indicate that knowing is more difficult to introspect than seeing and that the ability to introspect each mental state emerges prior to the ability to correctly attribute them to others. Theoretical implications for self-other differences in theory-of-mind development are considered.