Every child, by nature, likes learning just as he likes eating. Children reluctant to eat, and parents using promises and threats in order to make them eat, are not rare, yet they constitute perhaps rather an exception than a rule. In teaching, the situation is worse: to attach rewards and punishments to learning is more a rule than an exception. It is an institutionalized practice supported by social conditioning and by decrees. This practice exerts an unfavorable influence on the natural process of learning.