Associative learning (also called conditioning) occurs when an animal learns to link (or associate) two events. Perhaps the most famous example of conditioning is the response of Ivan Pavlov’s dogs. Pavlov first presented the dogs with meat powder, and they salivated in response. He then presented the dogs with an additional cue, a ringing bell, whenever he presented the dogs with meat powder. After repeatedly experiencing the two stimuli together, the dogs salivated at the sound of the bell alone, in expectation of the meat reward. This form of conditioning, in which two stimuli are paired, is called classical conditioning. In this case, a stimulus that leads to a behavior (the meat powder) was paired with a neutral stimulus (the bell) that initially had nothing to do with salivation. Eventually, a novel association is made between the sound of the bell and food, and the sound of the bell alone elicits salivation.
A second form of associative learning links a behavior with a reward or punishment. If the behavior is rewarded (positively reinforced), it is more likely to occur the next time around. It is not just out of the goodness of her heart that the trainer at Sea World gives a sea lion or dolphin a fish reward at the end of each trick that the animal performs. However, if the behavior is punished (negatively reinforced), the response becomes less likely. This form of associative learning is called operant conditioning.
In classical conditioning, an association is made between a stimulus and a behavior, whereas in operant conditioning, an association is made between a behavior and a response. Operant conditioning involves a novel, undirected behavior that becomes more or less likely over time. Consider a rat in a cage with some levers in it, each a different color. The rat has no impulse to press any of the levers, but by chance, it presses the red one. A food reward tumbles into the cage. Eventually, the rat learns to associate pressing the red lever with the food reward; it has been operantly conditioned. It is thought that play in young animals provides them with the opportunity to explore their environment much in the same way as the rat does when first placed in the cage. Like the rat, they may find that some behaviors are more rewarding or more punishing than others.
Quick Check 2 Both classical and operant conditioning involve learning to associate two events. What then is the difference between the two kinds of conditioning?
In classical conditioning, one stimulus is exchanged for another (in the case of Pavlov’s dogs, the smell of food is exchanged for the sound of a bell). As a result, a novel stimulus evokes a behavior. In operant conditioning, a behavior is associated with a reward or punishment, so the behavior becomes more likely (with a reward) or less likely (with a punishment). Therefore, in the case of classical conditioning, an association is made between a stimulus and a behavior, and in operant conditioning, an association is made between a behavior and a response.