The deceiving brain

     When does a child learn to lie? Three-year-olds don’t seem to have the ability to report their own past belief states. In other words, if they believe there’s a monster in the shed, and then learn that’s not true, they’ll deny ever having believed in the monster at all. Is that lying? Not if “lying” means knowing that what you say isn’t true. Three year-olds haven’t developed the cognitive ability to impute false beliefs to others when they themselves know what the truth is. The ability to understand alternative mental representations, or other minds, is sometimes called a theory of mind, which children don’t develop until about age four. Other facts about the gradual development of memory and the brain also shed light on why the concept of “lying” may just not apply to a very young child.