Deprivation is a condition that increases the value (effectiveness) of a reinforcer. Specifically, deprivation refers to the length of time elapsed since a particular reinforcer has been available. The more time elapsed, the greater the deprivation, and the greater the deprivation, the more effective the withheld reinforcer will be.

A clear example of the principle of deprivation can be seen in the early work of B. F. Skinner. In a series of experiments on the basic principles of learning and behavior conducted with pigeons, Skinner used food as a reinforcer. To make sure that food would be an effective reinforcer when the experimental sessions were conducted each day, the sessions were held only when the subjects (the pigeons) had been deprived of food for ...