ABSTRACT
The concept of motivation deals with the fact, that, even for the same individual, a given reinforcer may be effective sometimes and ineffective at other times. The effectiveness of a given primary reinforcer in establishing and maintaining behaviour, and in providing backup for a conditioned reinforcer, is a function of several variables. A variable that affects the effectiveness of a primary reinforcer is called a motivational variable. There are two types of motivational variables, appetitive and aversive, that corresponds to positive and negative reinforcement. These two classes of motivational variables correspond to the distinction between positive and negative primary reinforcement. Negative reinforcement appears to produce certain emotional effects that are produced either to a lesser extent or not at all by positive reinforcement. There are a number of similarities between responding under appetitive motivation and responding under aversive motivation, suggesting that similar processes underlie both types of responding. Aversive motivation tends to produce more emotional behaviour than appetitive motivation.
