Tuesday, November 3, 2009

Operant Conditioning


*The organism performs a voluntary behavior that produces either reinforcement or punishment, which influence whether the response will occur again in the future.



**Reinforcement: Strengthens a response and makes it more likely to reoccur


**Punishment: Weakens a response and makes it less likely to reoccur

Thorndike and Skinner's Contributions


*Edward Thorndike was the first to examine how voluntary behaviors are influenced by their consequences.
**Law of Effects: the probability of an action being repeated is strengthen if it is followed by a pleasant or satisfying consequence.



*Skinner extended Thorndike's theory to more complex behaviors.

SKINNER BOX:

Reinforcement



Strengthening a Response

Types of Reinforcers:
*Primary Reinforcers: stimuli that increase the probability of a response because they satisfy a unlearned biological need.
**Examples: Food, Water, and Sex
*Secondary Reinforcers: stimuli that increase the probability of a response because of their learned value.
**Examples: Money and Material Possessions


Types of Reinforcement:
*Positive Reinforcement: adding a stimulus which strengthens a response and makes it more likely to reoccur
**Example: You tickle your baby and he or she smiles, where the smile is the positive reinforcement
*Negative Reinforcement: taking away a stimulus which strengthens a response and makes it more likely to reoccur.
**Example: You pick up a baby in order to stop the crying


Negative Reinforcement vs Punishment
Reinforcement strengthens a behavior while punishment weakens a behavior.
**Premack's Principle: uses a natural occurring high frequency response to reinforce an increase low frequency responses.

Four Partial Schedules of Reinforcement

Ration Schedules

*Fixed Ratio: Reinforcement occurs after a predetermined set of responses the ratio is fixed
The response rate produces a high rate of response, but a brief Drop off.
*Example: a car wash employee receives $10 for every 3 cars washed.
*Variable Ratio: Reinforcement occurs unpredictably the ratio varies.
It produces a high response rate and no pause after reinforcement. Very resistant to extinction.
*Example: Slot Machines are designed to pay out after an average number of responses.

Interval Schedules

*Fixed Interval: Reinforcement occurs after a predetermined time has elapsed so the interval or time is fixed.
The response tends to increase as the time for the next reinforcer is near but drop off after reinforcement and during interval.
*Example: You receive a monthly paycheck
*Variable Interval: Reinforcement occurs unpredictably the interval varies
The response is relatively low but steady.
*Example: In class with pop quizzes you study at a slow but steady rate because you cannot anticipate the next quiz.

Shaping


Shaping teaches a desire response by reinforcing a series of successfully improving steps leading to the final goal response.


*Skinner believed that shaping explains a wide variety of skills. For example playing an instrument or driving a car.



**Another example, as discussed in class, would be a baby's first steps learning to walk. The first step, the parent claps. As the baby begins to take the next step the parent elicits the desired response by pausing and waiting for the next step, then clapping again once completed.

How to Weaken a Response


Positive Punishment: adding a stimulus that weakens a response making it less likely to occur
*Example: A parent adds extra chores following a child's misbehavior



Negative Punishment: taking away a stimulus that weakens a response that makes is less likely to occur.

*Example: A parent taking away a child's cell phone after coming home after their curfew

Operant Conditioning in Everyday Life


Prejudice: Negative perceptions of others. This may be acquired through operant conditioning.




Biofeedback: "Feeding back" biological information for control of normally automatic body functions.



Superstitious Behavior: Develops from accidental rewarding of specific behavior.

*Example: Knocking on Wood- People knock on wood when they are speaking of good fortune or making predictions because down through the ages, people have believed that trees were homes of gods, who were kind and generous if approached in the right way. A person who wanted to as a favor of the tree god would touch the bark. After the favor was granted, the person would return to knock on the tree as a sign of thanks.