Research on learning has been heavily influenced by behaviorism, which accounts for behavior in terms of observable events, without reference to mental entities such as "mind" or "will." Behaviorists have focused on two types of conditioning: classical and operant.
Classical conditioning
classical conditioning was for study by Russian physiologist Ivan Pavlov. In this type of learning, when a neutral stimulus is paired with an unconditioned stimulus (US) that elicits some reflects of unconditioned response (UR), the neutral stimulus comes to elicit a similar or related response. The neutral stimulus is then called a conditioned stimulus (CS), and the response it elicits, a conditioned response (CR). Nearly any kind of involuntary response can become a CR.
An extinction, the conditioned stimulus is repeatedly pre-sentenced without the unconditioned stimulus, and the conditioned response eventually disappears -- although later it may reappear (spontaneous recovery). And higher order conditioning, a neutral stimulus becomes a conditioned stimulus by being paired with an already established conditioned stimulus. In stimulus generalization, after he stimulus becomes a conditioned stimulus for some response, other, similar stimuli may produce the same reaction. In stimulus discrimination, different responses are made to stimuli that resemble the conditioned stimulus in some way.
Many theorists believe that what an animal or person learns and classical conditioning is not just an association between the unconditioned and conditioned stimulus, the information conveyed by one stimulus about another. Indeed, classical conditioning appears to be an evolutionary adaptation that allows an organism to prepare for a biologically important event. Considerable evidence exists to show that a neutral stimulus does not become a CS unless it reliably signals or predicts the US.
Classical conditioning in real life
classical conditioning helps account for positive emotional responses to particular objects and events, fears and phobias, the acquisition of likes and dislikes, and reactions to medical treatments and placebos. John Watson showed how fears may be learned and then may be unlearned through a process of counterconditioning. Human beings and other species are biologically primed to acquire some adaptive responses easily, such as conditioned taste aversions and certain fears.
Classical conditioning is now integrating findings on motivation, learning, and biology. For example, a recent study explored brain changes in the amygdala and orbitofrontal cortex that occur in response to conditioned stimuli for appetite or pleasure, and how those responses may affect motivation eat.
Operant conditioning
In operant conditioning, behavior becomes more likely to occur or less so depending on its consequences. Responses are generally not reflexive and are more complex than in classical conditioning. Research in this area is closely associated with B.F. Skinner, who called his approach "radical behaviorism."
In the Skinnerian analysis, reinforcement strengthens or increases the probability of a response and punishment weekends or decreases the probability of a response. Immediate consequences usually have a greater effect on response than do delayed consequences.
Reinforcers are called primary when they are naturally reinforcing (because they satisfy a biological need) and secondary when they have acquired their ability to strengthen response through association with other reinforcers. A similar distinction is made for punisher's.
Reinforcement punishment may either be positive or negative, depending on whether the consequence involves a stimulus that is presented or one that is removed or avoided. In positive reinforcement, something pleasant follows a response; and negative reinforcement, something unpleasant is removed. In positive punishment, something unpleasant follows the response; and negative punishment, something pleasant is removed.
Using the Skinner box and similar devices, behaviorists have shown that extinction, stimulus generalization, and stimulus discrimination occur in operant as well as in classical conditioning. A descriptive stimulus signals that a response is likely to be followed by a certain type of consequence.
The pattern of responding in operant conditioning depends in part on the schedule of reinforcement. Continuous reinforcement leads to the most rapid learning. However, intermittent reinforcement makes a response resistant to extinction and therefore helps account for the persistence of superstitious rituals. Different animated patterns of reinforcement produced different patterns of responding. What are the most common errors people make is to reward intermittently the responses they would like to eliminate.
Shaping is used to train behaviors with a low probability of occurring spontaneously. Reinforcers are given for successive approximations to the desired response until the desired response is achieved.
Biology places limits on what an animal or person can learn through operant conditioning. For example, animals sometimes have trouble learning a task because of instinctive drift.
Operant conditioning in real life
behavior modification, the application of operant conditioning principles, has been used successfully in many settings, but reinforcement punishment both have their pitfalls.
Punishment, when used properly, can discourage undesirable behavior, including criminal behavior. But it is frequently misused, and may have unintended consequences. It is often administered inappropriately because of the emotion of the moment; and may produce rage and fear; its effects are often only temporary; it is hard to minister immediately; it conveys little information about the kind of behavior that is desired; and may provide attention that is rewarding. Sanction of undesirable behavior, combined with reinforcement of the desired behaviors, is generally preferable to the use of punishment.
Reinforcers can also be misused. Rewards are given out indiscriminately, as in efforts to raise children's self-esteem, do not reinforce desirable behavior. An exclusive reliance on extrinsic reinforcement can sometimes undermine the power of intrinsic reinforcement. But money and praise do not usually interfere with intrinsic pleasure when a person is rewarding for succeeding or making progress rather than for merely participating in activity, or when a person is already highly interested in the activity.
Learning and the mind
even during behaviorism's heyday, some researchers were probing the "black box" of the mind. In the 1930s, Edward Tolman studied latent learning, in which no obvious reinforce or is present during learning and a response is not expressed until later on, when reinforcement does become available. What seems to be acquired in latent learning is not a specific response, but knowledge about responses and their consequences.
The 1960s and 1970s saw the increased influence of social cognitive theories of learning, with focus on observational learning and the role played by beliefs, interpretations of events, and other cognitions. Social cognitive theorists argue that in observational learning, as in latent learning, what is required is knowledge, rather than a specific response.
Because people differ in their perceptions and beliefs, in a long different lessons from the same event or situation. For example, some people become more aggressive after exposure to violent images in the media, but most people do not. Moreover, cause-and-effect also work in the opposite direction: aggressive individuals tend to be drawn to violent images and more affected by them than other people are.
