It is as his own mind comes into contact with others that truth will begin to acquire value in the child's eyes and will consequently become a moral demand that can be made upon him. As long as the child remains egocentric, truth as such will fail to interest him and he will see no harm in transposing facts in accordance with his desires.

Ch. 2 : Adult Constraint and Moral Realism - The Moral Judgment of the Child (1932)