In my lab, which studies the cognitive development of children, we have found
that even 1½-year-olds can understand that someone else might want something different from what they want.
They understand that someone else might like broccoli, even though they themselves prefer crackers, and they will help that person get what he wants.
They understand and care about how other people feel and think, and recognize that other people can feel and think differently from them.
Children as young as 2½ say that hurting another child is always wrong, even if an authority figure were to say otherwise.
But Mr. Trump doesn’t just lie; he seems not even to care whether his statements are true.
