Why do animals behave as they do?

Figure 1: Behavior is a function of its consequences: positive consequences increase, and aversive consequences decrease, the likelihood of a behavior recurring.

If the probability of a behavior increases by delivery of some item or event, then that item or event is a positive reinforcer and the procedure is called reinforcement. For example, when animals eat nutritious foods or find nutritious foods in a particular location, the likelihood increases that they will eat the foods and return to the location.

If the probability of a response decreases after delivery of some item or event, that consequence is considered aversive and the procedure is called punishment. For example, if an animal is poisoned after eating a food or is attacked by a predator in a particular location, the likelihood decreases the animal will eat the food or return to the location.

Thus, positive reinforcement increases the likelihood of a behavior reoccurring, and punishment decreases the likelihood of a behavior reoccurring. Nothing is simpler or accounts for so much behavior at so many levels with so few assumptions (see BEHAVE booklet, page 35).

If behavior is a function of consequences, and it is, then what causes consequences to be positive or aversive?

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