Download Ch. 5: Learning

Chapter 5: Learning
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Learning is a relatively permanent change in behavior brought about by experience.
Remember-- some learning simply occurs as a result of maturation and it doesn’t involve experience.
We do know that humans are primed for learning as infants. Infants habituate to toys after the novelty wears-- they get tired or lose interest
in the same toy. We refer to this as habituation.
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Classical Conditioning
Ivan Pavlov was a Russian physiologist; in 1904 won Nobel Prize or his work on digestion and learning research.
He studied secretion of stomach acids and salivation in dogs in response to the ingestion of varying amounts and kinds of food.
He saw that sometimes dogs would salivate when they didn’t eat food.
Just seeing the experimenter bring the food would lead to salivation
So-- he developed classical conditioning: a type of learning where a neutral stimulus (like seeing the experimenter) elicted a response after
being paired with a stimulus (like food) that naturally brings about the response.
He then rang a bell-- and the dog salivated when hearing the bell.
Neutral Stimulus - a stimulus that before conditioning, does not lead to the response (the bell)
UCS - unconditioned stimulus: a stimulus that naturally brings about a particular response without having been learned (this is the meat)
UCR - unconditioned response: a response that is natural and needs no training (salivation at the smell of food)
CS - conditioned stimulus: what used to be the neutral stimulus is now paired with the unconditioned stimulus to bring about a response
formerly caused by the unconditioned stimulus (meat was the UCS)
CR - conditioned response: a response, that after conditioning follows a previous neutral stimulus Salivation that occurs as a response to the
bell is now the Conditioned Response.
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Extinction occurs when a previously conditioned response decreases in frequency and eventually disappears.
So-- you end the association between the conditioned stimuli and unconditioned stimuli.
After training the dog to salivate to (conditioned response) at the ringing of a bell (conditioned stimulus) we produce extinction by
repeatedly ringing the bell but not providing the meat.
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Spontaneous Recovery
The re-emergence of an extinguished conditioned response after a period of rest and with no further conditioning.
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Extinction
Generalization and Discrimination
Pavlov noticed that the dogs salivated not only to the ringing of a bell-- but also to the sound of a buzzer-- which he called Stimulus
Generalization.
The greater the similarity between the stimuli-- the greater the likelihood of stimulus generalization.
The opposite is Stimulus Discrimination where the two stimuli are sufficiently distinct from one another that one evokes the conditioned
response and the other one doesn’t.
B.F. Skinner and Operant Conditioning
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B.F. Skinner was a famous behavioral psychologist (1904 - 1990) who experimented in lab settings with animals. He created the Skinner
Box where there’s a lever for the animal to press to obtain food.
The rat learns connections between pressing a lever and receiving food. At first though-- the rat will not learn because it happens randomly.
At some point, however it learns that pressing the level gets the food pellet-- and the frequency of lever pressing increases. So-- we say the
rat learned that getting the food pellet is contingent of pressing the lever.
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Reinforcement
Reinforcement is a process by which a stimulus increases the probability that a preceding behavior will be repeated. Food is a reinforcer
because it increases the probability that pressing the lever will occur. Bonuses, toys and outstanding grades are reinforcers.
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Schedules of Reinforcement
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Continuous Reinforcement: where behavior is reinforced every time it occurs.
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Partial/Intermittent Reinforcement: where behavior is reinforced some but not all of the time.
Partial/Intermittent reinforcement can be categorized as:
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1) schedules with number of responses before reinforcer is given is called fixed and variable ratio; reinforcement
given after a fixed number of responses; rat receives a food pellet after every 10th time it presses lever; garment
workers operate like this when they get paid for every blouse they sew; here one likes to work fast and produce to
get paid more-- but quality may suffer.
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For the variable-ratio schedule-- reinforcement occurs after a varying number of responses rather than a fixed
number; it varies here but hovers around a specific average; a telephone salesperson’s job is like this where he/she
makes sale on the 3rd, 8th and 20th call; they make as many calls as possible in as short a time as possible. This
schedule is resistant to extinction-- like those of us who gamble in Las Vegas. The machines operate on a varibale
ratio schedule. Yes or no? Why?
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2) schedules with amount of time before reinforcer is given are called fixed and variable interval
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Fixed Interval would be receiving a weekly paychek; but you need to work to receive the check
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Variable Interval would be where the time between reinforcement varies; like if I were to give quizzes but not tell
you when I’m giving the quiz. I don’t do this because you’d dislike me. So-- I tell you when the quizzes are.
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Positive Reinforcer: a stimulus added to the environment that brings about an increase in a preceding response. If food,
water, money or praise is given after a response-- then it’s more likely that the response will occur again in the future.
Receiving a paycheck is an example-- you’re likely to return to work next week.
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Negative Reinforcer: an unpleasant stimulus whose removal leads to an increase in the probability that a preceding
response will be repeated. If you have an itchy rash (the unpleasant stimulus) you will use an ointment. Using the
ointment is negatively reinforcing because it removes the unpleasant itch.
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Punishment: a stimulus that decreases the probability that a previous behavior will occur again. Punishment is different
from negative reinforcement. Negative reinforcement produces an increase in behavior and punishment decreases a
behavior.
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Two types of punishment:
– 1) Positive Punishment: weakens a response through applying an unpleasant stimulus such as going to jail for
doing a crime, spanking a child for misbehaving.
– 2) Negative Punishment: here you remove something pleasant like when you ground your child for misbehaving.
– In treating Autism - sometimes self-injurious behaviors are seen, so the child may receive a quick, intense electric
shock to prevent self-injurious behaviors from re-occurring.
– But-- punishment can have disadvantages: parents hitting child conveys to child it’s OK to hit; those who use
physical punishment may think others fear them; it may lower self-esteem of the child if he/she doesn’t understand
the purpose/reason for it.
– Punishment will be ineffective if it’s not delivered immediately after the misbehavior.