Development of children's knowledge about unconsciousness.

Children of ages 5, 6, 7, 8, and 10 years, and adults were asked whether people who are sound asleep and not dreaming could or would: (1) see, hear, listen, notice, think, wish, pretend, and feel things (primary-consciousness activities), (2), know that they are asleep, and know whether they are or are not engaged in primary-consciousness activities such as perceiving and thinking (reflective-consciousness activities), (3) deliberately decide to or try to perform mental or physical actions (control activities). Results indicated that the recognition that people do not engage in conscious mental activities when unconscious is still developing during the late middle-childhood years. We speculate that a developing understanding of consciousness may assist the development of an understanding of unconsciousness and vice versa, and that sensitivity to the phenomenology as contrasted with the content of mental states may be a late acquisition in the theory-of-mind area.