Developmental aspects of consciousness: how much theory of mind do you need to be consciously aware?
Consciousness and cognition March 1, 2003 Josef Perner, Zoltán Dienes
Children likely become consciously aware of events in the world between 12 and 15 months of age, with a possible range of plus or minus 3 months. This conclusion emerges from evaluating five strategies: three look for signs of verbal communication, executive control, or explicit memory—activities that require conscious awareness in adults; two consider when children can engage in the minimal higher-order thought needed for access consciousness and phenomenal consciousness. The answer is tentative, based on converging evidence from these different approaches.