The strengthening of behavior which results from reinforcement is appropriately called ‘conditioning’. In operant conditioning we ‘strengthen’ an operant in the sense of making a response more probable or, in actual fact, more frequent. — B. F. Skinner — Reinforcement refers to “the process by which a stimulus or event strengthens or increases the probability of a behavior or an event that follows” (Santrok, 2003, p. 280). In other words, a reinforcer is anything that strengthens the behavior that leads to it. Reinforcement can be further subdivided into categories…