In Psychology, the reinforcement is a process which increases the Probabilité of repetition of a Comportement. B.F. Skinner was the first studied systematically the effects of them, using rats and of pigeons.

The positive reinforcement consists in giving to the subject a pleasant Stimulus, it is an event which increases the frequency of appearance of a behavior thanks to a pleasant stimulus. The negative reinforcement consists in removing a stimulus unpleasant or painful, it is an event which increases the frequency of appearance of a behavior thanks to a withdrawal or to the stop of an unpleasant stimulus.

The primary education reinforcers are stimuli which increase the probability of an answer and which, like food, fill a biological need. The secondary reinforcers are stimuli which increase the probability of an answer and which, like the Argent the material and goods, do not have an intrinsic biological value.