They thought he was stupid

The friends of Johnny, a five-year Australian boy, give him a choice between two coins, one bigger, of $1, and one smaller, of $2, telling him that he can choose anyone. He chooses the bigger coin of $1. His friends think he is stupid for not knowing that the smaller coin is double-valued. When they want him to look like dumb, the friends offer him the same choice, and he always choose the $1-coin, appearing to never learn.

One day, an adult that has observed the transaction calls Johnny aside and tell him that the smaller coin in fact is more valued than that bigger one - though it may seem the opposite.

Johnny hears him politely and say: "Yes, I know that. But how many times you thing they would offer me the coins, if I have chosen the $2-coin at the first time?

Edward de Bono

In Serious Creativity: Using the Power of Lateral Thinking to Create New Ideas

Translated from Portuguese edition: Criatividade Levada a Sério by V. V. Vilela.