The principle of reinforcement is, when a given act is followed closely by areinforcer, the organism tends to increase the frequency of that actunder the same or similar conditions (Carpenter 1974)

Reinforcer - the object or the event which increases the frequency of theperformance it follows (Ferster 1968).

Reinforcement - the condition - when a stimulus follows a performance,reinforcement has occured (Ferster 1968).

For example, two students are offered a set amount of money for everyhour that they study after school. If there is no increase in the frequency ofstudying after school, the money is considered a reward. If the studentincreases the hours of study, the money is considered a positivereinforcer.

There are two basic models of reinforcement, both of which are designed toincrease a target behavior:

1. Positive Reinforcement
2. Negative Reinforcement
3. Non Reinforcement