Operant Conditioning I

Priscilla the Fastidious Pig http://www.youtube.com/watch?v=y6tpXC2mwlQ

Thorndike and Law of Effect Rewarded behavior is likely to occur

B. F. Skinner “Operant conditioning shapes behavior as a sculptor shapes a lump of clay” It’s all a matter of consequences

Operant Conditioning Learning where responses come to be controlled by their consequences Classical conditioning = regulating reflexive, involuntary responses Operant conditioning = voluntary responses

Skinner = Pigeons http://www.youtube.com/watch?v=vGazyH6fQQ4

What the what!? How did he do that? http://www.youtube.com/watch?v=TtfQlkGwE2U Shaping and reinforcement Shaping – operant technique, reward for closer and closer approximation of desired response

Skinner says… Organisms tend to repeat responses that are followed by favorable consequences Understood best through idea of reinforcement – response is strengthened because it leads to rewarding consequences Defined AFTER THE FACT

Tendency to patronize Chipotle increases Rewarding stimulus presented: Most delicious meal you will ever have… ever Response: Go to Chipotle for a meal REINFORCEMENT IN OPERANT CONDITIONING Tendency to tell jokes increases Response: Tell jokes Rewarding stimulus presented: Friends laugh

Primary vs. Secondary Reinforcers

Generalization vs. Discrimination Which is which? Kids only ask parents for sweets when they know the parents are in a good mood. A cat runs into the kitchen whenever a can opener is being utilized

Basic Processes in Classical and Operant Conditioning VS. Acquisition, Extinction, Stimulus Generalization, Stimulus Discrimination

Operant Conditioning II

Fixed-ratio schedule A rat is reinforced for every tenth lever press A salesperson receives a bonus for every fourth gym membership sold

Variable-ratio schedule A slot machine in a casino pays off once every six tries on the average. The number of winning responses between payoffs varies greatly from one time to the next.

Fixed-interval schedule A man washing his clothes periodically check to see whether each load is finished The reward (clean clothes) is available only after a fixed time interval The man who checks his laundry before it is completed in the cycle does not receive reinforcement of clean clothes… because they’re not done yet

Variable-interval schedule Person wants to win a radio contest, so calls the station and gets a busy signal Getting through to the DJ is the reinforcer A rat is reinforced for the first lever press after a 1 minute interval, but the following intervals are 3 min, 2 min, and 4 min (average of 2 min)

Conclusion: Faster responding leads to reinforcement sooner when ratio is in effect Variable schedules tend to generate steadier response rates Greater resistance to extinction

Operant Conditioning II

Positive vs. Negative Reinforcement Study hint – THEY BOTH HAVE THE WORD REINFORCEMENT IN IT – so it has to REINFORCE the behavior either way

Positive reinforcement: response is strengthened because it is followed by the presentation of a rewarding stimulus Ex: good grades, tasty meals, paychecks, scholarship, promotions, nice clothes, attention, flattery

Negative Reinforcement: occurs when a response is strengthened because it is followed by the removal of an aversive stimulus ex: you rush home in winter to get out of the cold, you clean a house to get rid of a mess, you give in to an argument to avoid an unpleasant situation

REINFORCEMENT IS REINFORCEMENT Both positive and negative reinforcement involve a favorable outcome that STRENGTHENS a response tendency

Positive vs. Negative Reinforcement in a Skinner Box Behavior Consequence Rewarding stimulus presented: food delivered Response: Press lever + Tendency to press lever increases Aversive Stimulus removed: shock turned off Response: Press lever Tendency to press lever increases -

Negative reinforcement applications 1. Escape learning: organism acquires a response that decreases or ends some aversive stimulation Ex: you leave a party where you were getting picked on by peers

2. Avoidance learning: organism acquires a response that prevents some aversive stimulation from occurring Ex: you quit going to parties because of your concern about being picked on

How does avoidance learning present an example of how classical conditioning and operant conditioning work together to regulate behavior? Ex: Rat, shuttle box, shock

Punishment: Consequences that weaken responses Punishment: occurs when event following a response weakens the tendency to make that response Super easy to mix-up How is this different from negative reinforcement?

Punishment examples: If you wear a new outfit and your classmates make fun of it, your behavior will have been punished and your tendency to wear the same clothing will probably decline. 2) If you have a bad meal and a restaurant, your response will have been punished, and you will be less likely to go to the restaurant again.