Classical Conditioning

Pavlov’s experiment - psychic secretions.

Pavlov was a Russian physiologists who studied digestion.

He won the Nobel prize in physiology in 1904 for his work on the digestive system in dogs.

Classical Conditioning

Psychic Secretions.

Some of Pavlov’s work with his dogs involved placing objects on the dog’s tongue and measuring the amount of saliva produced. Sand more than marbles amnt’s of food.

He noticed that some of his dogs began to salivate before food powder was put on their tongues. Psychic secretions. Similar to your pet getting excited at the

sight of you picking up it’s food bowl. He found that stimuli associated with

food produced similar amounts of saliva as did actual food

Pavlov recognized that this salivation to stimuli associated with food was just as reflexive (out of the animals control) as was food on the tongue. The conditioned reflex. Pavlov set about trying to understand

how conditioned reflexes occur.

The Unconditioned Response (UCR)

This is a reflexive response to certain stimuli that animals are born with Food = salivation tapping knee = knee Jerk puff of air on eye = eye blink

The Unconditioned Stimulus (UCS)

The stimulus that causes an unconditioned response is the unconditioned stimulus. It is a stimulus animals are born to respond to. Food = salivation tapping knee = knee Jerk puff of air on eye = eye blink

The Conditioned Stimulus (CS). The conditioned stimulus is some

stimulus that the experimenter presents that predicts an unconditioned stimulus. Pavlov paired the sound of a bell (CS) with

placement of food (UCS) in a dog’s mouth. If you sound a bell and then immediately

put food in a dog’s mouth what happens? It salivates (UCR).

The conditioned response (CR). If you sound a bell (CS) and

immediately place food (UCS) in a dogs mouth, several times, what will happen if you just ring the bell? Test = Bell (CS) alone = salivation Salivating to the bell in the absence of

food powder is called a conditioned response (CR).

This reflects learning.

Summary of Classical Conditioning

CS -->UCS = UCR bell -->food = salivation

do this several times and then test with the CS alone

CS = CR bell = salivation

Twitmeyer’s patellar conditioning Twitmeyer was examining the human

knee jerk reflex at the same time Pavlov was studying salivation in dogs.

UCS - hammer on knee UCR - Knee Jerk

He had a bell (CS) that sounded when the hammer’s fell.

One day he accidentally rang the bell without dropping the hammer (What happened)?

Classical conditioning phenomena

Acquisition Extinction Spontaneous recovery Stimulus Generalization

train with one tone test with others Discrimination

One tone means food, one does not.

Instrumental Conditioning

Thorndike Chicks and Mazes Cats and puzzle boxes

Were there signs of reasoning abilities?

The law of effect

A response followed by a pleasant consequence will become more likely Satisfying state of affairs

A response followed by an unpleasant consequence will become less likely Dissatisfying state of affairs

Reinforcement - an event that increases the future probability of the most recent response. RF stamps in a response

Punishment – an event that decreases the future probability of the most recent response. Punishment stamps out a response. Very mechanistic

Skinner and the operant chamber (Skinner box).

Rats get levers Pigeons get keys

Now you had an easily quantifiable response.

Operant conditioning (Instrumental conditioning)

The process of changing behavior by following a response (operant) with reinforcement. What’s the difference between

operant and classical conditioning?

Operant vs. Classical Conditioning In operant conditioning the subject’s behavior

determines an outcome and is affected by that outcome.

Response – stimulus change in behavior Touch stove – get burned less likely to touch the

stove In classical conditioning, the subjects learn that

two stimuli go together. Usually that some stimulus (sight or sound) that is paired with something the organism likes (food) or dislikes (pain).

Stimulus – Stimulus change in behavior See Stove – get burned fear stove

Reinforcement vs Punishment

Skinner defined these terms by their outcomes. Anything that increases the likelihood

of a response is a reinforcer Anything that decreases the

likelihood of a response is a punisher. Is food a reinforcer?

Reinforcement Positive reinforcement

Negative reinforcement

Both increase behavior but for positive Reinforcement something

good happens. for negative Reinforcement something bad

is taken away.

Punishment Positive punishment

Negative punishment

Both serve to decrease behaviors positive punishment involves giving something to

you for your behavior (something bad) whereas negative punishment involves taking

something away (something good).

Try these Rat stops pressing a bar because each

time he does he gets shocked Rat presses a bar to stop shock from

occurring Rat presses a bar because each time he

does he gets food Rat stops pressing a bar because

pressing the bar causes food to be delayed from when it would normally occur