Classical Conditioning and Operant Conditioning

Classical Conditioning and Operant Conditioning

There are two primary classifications of animal learning:  
Classical Conditioning and Operant Conditioning. These classifications of learning theory also apply to humans, not just animals.

Classical Conditioning (also Pavlovian or Respondent Conditioning) is a form of associative learning that was first demonstrated by Ivan Pavlov. The typical procedure for inducing classical conditioning involves presentations of a neutral stimulus along with a stimulus of some significance. The neutral stimulus could be any event that does not result in an overt behavioral response from the organism under investigation. Pavlov referred to this as a Conditioned Stimulus (CS). 

For example, when you smell a favorite food, you may start to feel hungry. The smell of the food is the unconditioned stimulus. 

Conversely, presentation of the significant stimulus necessarily evokes an innate, often reflexive, response. Pavlov called these the Unconditioned Stimulus (US) and Unconditioned Response (UR), respectively

For example, the feeling of hunger in response to the smell of food is the unconditioned response.

 If the CS and the UR are repeatedly paired, eventually the two stimuli become associated and the animal begins to produce a behavioral response to the CS. Pavlov called this the Conditioned Response (CR).

For example, when you smelled your favorite food, you simultaneously heard the sound of a bell. The bell is unrelated to the smell of the food, but if the sound of the bell was paired many times with the smell of the food, the sound of the bell eventually would trigger the conditioned response. In this case, the sound of the bell is the conditioned stimulus.

Operant conditioning is the use of consequences to modify the occurrence and form of behavior. "Consequences" in this context, means to connect certain responses with certain stimuli. Operant conditioning is distinguished from classical conditioning in that operant conditioning deals with the modification of "voluntary behavior" or operant behavior. Operant behavior "operates" on the environment and is maintained by its consequences, while classical conditioning deals with the conditioning of respondent behaviors which are elicited by antecedent conditions. Behaviors conditioned via a classical conditioning procedure are not maintained by consequences.

Reinforcement is a consequence that causes a behavior to occur with greater frequency. 

Punishment is a consequence that causes a behavior to occur with less frequency. 

Extinction is the lack of any consequence following a behavior. When a behavior is inconsequential, producing neither favorable nor unfavorable consequences, it will occur with less frequency. When a previously reinforced behavior is no longer reinforced with either positive or negative reinforcement, it leads to a decline in the response. 

Four contexts of operant conditioning

Here the terms "positive" and "negative" are not used in their popular sense, but rather: "positive" refers to addition, and "negative" refers to subtraction. What is added or subtracted may be either reinforcement or punishment. Hence positive punishment is sometimes a confusing term, as it denotes the addition of punishment (such as spanking or an electric shock), a context that may seem very negative in the lay sense. The four procedures are:

Positive reinforcement occurs when a behavior (response) is followed by a favorable stimulus (commonly seen as pleasant) that increases the frequency of that behavior. In the Skinner box experiment, a stimulus such as food or sugar solution can be delivered when the rat engages in a target behavior, such as pressing a lever. 

Negative reinforcement occurs when a behavior (response) is followed by the removal of an aversive stimulus (commonly seen as unpleasant) thereby increasing that behavior's frequency. In the Skinner box experiment, negative reinforcement can be a loud noise continuously sounding inside the rat's cage until it engages in the target behavior, such as pressing a lever, upon which the loud noise is removed. 

Positive punishment occurs when a behavior (response) is followed by an aversive stimulus, such as introducing a shock or loud noise, resulting in a decrease in that behavior. 

Negative punishment occurs when a behavior (response) is followed by the removal of a favorable stimulus, such as taking away a child's toy following an undesired behavior, resulting in a decrease in that behavior. 

(permission to reprint through Wikipedia on Operant Conditioning)