The negative reinforcer increases the likelihood of that behavior occurring again under the same circumstances. Primary Reinforcer A primary reinforcer is a reinforcer that is biologically pre-established to act as reinforcement. Food, water, and sex are all primary reinforcers because they satisfy biological desires. Conditioned Reinforcer A conditioned reinforcer is a previously neutral stimulus . If the neutral stimulus is paired with a primary reinforcer it acquires the same reinforcement properties associated with the primary reinforcer.
Money is a conditioned reinforcer.
The actual paper bills are not themselves reinforcing. However, the paper bills can be used to acquire primary reinforcers such as food, water, and shelter. Therefore, the paper bills become reinforcers as a result of pairing them with the acquisition of food, water, and shelter.