Operant ConditioningOperant Conditioning

IntroductionIntroductionThrough classical (Pavlov) conditioning, an organism associates different stimuli that it does not control. Through operant conditioning, the organism associates its behaviors with consequences. Behaviors followed by reinforcements increase; those followed by punishers decrease. This simple but powerful principle has many applications and also several important qualifications.

Operant means…Operant means…

….Explain and train

Operant ConditioningOperant Conditioning•A type of learning in which

responses can be controlled by their consequences

i.e. rewards or

punishments

Reward vs. PunishmentReward vs. Punishment

Reward = more likely behavior will repeat

Punishment = less likely to repeat behaviorsWhich is better?

BehaviorBehavior

• Respondent Behavior

– Behavior that occurs as an automatic response to some stimulus

Ex: food when hungry; water when thirsty

• Operant Behavior

– The act operates on the environment to produce rewarding or punishing stimuli

Ex: good grades = MONEY; bad grades = grounded

Important People in Operant Conditioning

B.F. Skinner

Edward Thorndike

Radical Behaviorism

Skinner BoxPuzzle Box

Law of Effect

SkinnerSkinner• Operant Chamber-

– “Skinner Box”– Soundproof– Bar or key that an animal presses or pecks to

release a rewards of food or water– Device that records these responses

• Shaping--Procedure in which reinforcers (like food) gradually guide an animal’s actions toward a desired behavior-Operant Conditioning

Edward L. ThorndikeEdward L. Thorndike• Law of Effect:

– Rewarded behavior is likely to recur– Puzzle Box

Operant Conditioning Chamber

Skinner BoxSkinner Box

Puzzle BoxPuzzle Box

Two important concepts used in Operant Two important concepts used in Operant ConditioningConditioning

• ReinforcerReinforcer– A stimulus or event that increasesincreases the odds of

repeating the behavior that led to it• I give my kids money when they clean their room…this

stimulus increases the odds they will do it again

• PunisherPunisher– A stimulus or event that functions to decreases the

odds of repeating the behavior that lead to • I spank my kids when they throw food at the dinner table…

this event decreases the odds they will do it again• Remember…Remember…

– It is often the learner that determines if something is a reinforcement or punishment

– This is called the Premack PrinciplePremack Principle– I might give Ryan broccoli after he did a chore and if he likes it

he will do more chores– Or I might give Ryan broccoli after he did a chore and he may

never do that chore again– My feelings toward broccoli make no difference

Reinforcer

Two Types of Reinforcement:Positive and Negative

Anything likely to increase a behaviorAnything likely to increase a behavior

Positive Reinforcement

• Something desirable is addedadded to the environment and this encourages (reinforces)(reinforces) behavior– Behaviors are strengthened when they are followed

by the introduction of a stimulus

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Negative Reinforcement• Something undesirable is subtractedsubtracted from the

environment and this encourages (reinforces)(reinforces) behavior– NR are aversive stimuli such as loud noise, cold, pain,

or nagging• We are more likely to repeat behaviors that lead to their

removal

– Example• Say I have a headache• The NR is the pain of the headache• I take aspirin and the headache goes away• Headache pain (stimulus) - - aspirin (response) - - consequence

(headache gone)• I will take aspirin again because it removed something

unpleasant So…positive and negative do not mean good or So…positive and negative do not mean good or bad. Instead, positive means bad. Instead, positive means addingadding a stimulus, a stimulus,

and negative means and negative means removingremoving a stimulus. a stimulus.

The SimpsonsThe Simpsons

Reinforcement Schedules

The pattern (schedule) in which reinforcement (reward

or punishment) is given.

These schedules influence learningThese schedules influence learning

Continuous Reinforcement

• Reinforcing the desired response every time it occurs.– Example – vending machine

Quick Quick AcquisitionAcquisition

Quick Quick ExtinctionExtinction

Partial Reinforcement• Reinforcing a response only part of the Reinforcing a response only part of the

time.time.– slot machine– You don’t expect to win every

time but hope to win sometime– The acquisition process is slower, but… – Greater resistance to extinction.

• 4 different partial reinforcement schedules

– Two focus on timetime between reinforcement

(interval schedule)(interval schedule)– Two focus on numbernumber of responses between

reinforcement (ratio schedule)(ratio schedule)

Fixed-Interval Schedule

• Reinforcement of a behavior after a specified or fixed time (interval)time (interval) has passed.

• You get paid every two weeks• A worker gets a bonus once a year

– After receiving a reward (a reinforcement) the worker has to wait one year for another reward (fixed interval)

Variable-interval Schedule• Reinforcement of a behavior

at unpredictable (variable) timetime intervals.

• You don’t know when the reinforcement is coming so you keep trying or have to be prepared to take action

Pop Quizzes

Fixed-ratio Schedules

• Reinforcement of a behavior only after a specified (fixed) numbernumber of responses

• Movie rentals that say rent 5 get one free

• A worker gets a bonus after every three items he sells

Variable-ratio Schedule• Reinforcement of a behavior after an

unpredictable (variable) number number of responses.– Working on sales commission

• Sometimes called the gambler’s gambler’s scheduleschedule– Back to the lottery…– You don’t know when you will win but you

do know the more you buy the better your chances

Overjustification EffectOverjustification Effect• When external rewards undermine the

intrinsic satisfaction of performing a behavior – Makes people only do something for reward

or prize and not for pure joy– Usually the reward may lesson and replace

the person’s original, natural motivation so that the behavior stops if the reward is eliminated

• Pizza for reading– “what, I don’t get a free pizza for reading 10

books?”

Before we move on…• Operant Conditioning uses much of the same

terminology as classical conditioning…(acquisition, extinction, generalization, discrimination, etc…)

• For example, if I want a child to increase his bathing behavior, I can give him an extra 30 minutes of TV time after he bathes.

• The reinforcer is extra TV time and acquisition occurs when he links together the idea that bathing gives him more Cartoon Network.

• Extinction would occur if I stop giving him TV time for bathing and he stops seeing the association.

Types of Reinforcers

Types of ReinforcersTypes of Reinforcers

• Primary Reinforcers- reinforcements that happen naturally; not learned (i.e. getting food when hungry, taking your hand off a burning stove to relieve pain)

• Conditioned Reinforcers- (secondary reinforcers) are learned. (i.e. if a rat in Skinner’s box learns that when a light signal goes off it signals food, the light becomes on the secondary reinforcer

Primary Reinforcer• Things that are in themselves rewarding and

satisfy biological needs

• Like food, warmth, or water

Secondary (or Conditioned) Reinforcer

• Something that you have learned to value through classical conditioning – Money, fines or grades

• Secondary reinforcers can loose their effectiveness

Intrinsic vs. Extrinsic Motivation

PunishmentPunishment• Flip side of reinforcement• The introduction of a bad

stimulus or the removal of a reinforcing stimulus after a response occurs– Weakens a behavior or

makes it less likely to occur again in the future

Does punishment Does punishment work?work?

Yes, Yes, but…but…Often tells the learner what behavior should NOT

be exhibited and not what behavior should be

And…don’t forget the Premack Principle

Difference between Negative Difference between Negative Reinforcement and PunishmentReinforcement and Punishment

Punishment Punishment the introduction of a negative the introduction of a negative

consequence after a behavior weakens consequence after a behavior weakens the behaviorthe behavior

Time out for hitting other childrenTime out for hitting other children

Negative ReinforcementNegative Reinforcement the removal of a negative stimulus after a the removal of a negative stimulus after a

behavior strengthens the behaviorbehavior strengthens the behavior Picking up a crying babyPicking up a crying baby

Observational Observational LearningLearning

Learning by ObservationLearning by Observation Learning occurs not Learning occurs not

only through only through conditioning but conditioning but also from our also from our observation of observation of others. others.

““We are, in truth, We are, in truth, more than half what more than half what we are by imitation”we are by imitation”

Lord Lord ChesterfieldChesterfield

Observational Learning: Observational Learning: DefinitionDefinition

Observe and imitate Observe and imitate othersothers

ModelingModeling- Process of - Process of observing and observing and imitating a specific imitating a specific behaviorbehavior

We learn all kinds of We learn all kinds of social behaviors by social behaviors by observing and observing and imitating othersimitating others

Mirror NeuronsMirror Neurons

Mirror neurons provide a neural basis for Mirror neurons provide a neural basis for observational learningobservational learning

Example: when a baby imitates a face an Example: when a baby imitates a face an adult is making, mirror neurons are firingadult is making, mirror neurons are firing

Bandura’s ExperimentBandura’s Experiment

Albert BanduraAlbert Bandura Pioneer of research Pioneer of research

in observational in observational learninglearning

BoBo Doll BoBo Doll ExperimentExperiment Reinforcement and Reinforcement and

punishment leads punishment leads to imitating a to imitating a behaviorbehavior

Social Influence on Social Influence on Observational LearningObservational Learning

Columbine High School- Columbine High School- “copycat threats”“copycat threats”

Prosocial- models can have Prosocial- models can have positive effectspositive effects

Gandhi and Martin Luther King Gandhi and Martin Luther King Jr.Jr.

Television:Television: More hours children spend More hours children spend

watching violent TV or playing watching violent TV or playing violet video games, more at risk violet video games, more at risk for aggression and crime as for aggression and crime as teens and adultsteens and adults

Homicides doubled between Homicides doubled between 1957 and 1974, coinciding with 1957 and 1974, coinciding with the introduction of televisionthe introduction of television

Aversive ConditioningAversive Conditioning In aversive conditioning, client is exposed to an In aversive conditioning, client is exposed to an

unpleasant stimulus while engaging in the unpleasant stimulus while engaging in the targeted behaviortargeted behavior

Goal- create an aversion to it. Goal- create an aversion to it. In adults, aversive conditioning is often used to In adults, aversive conditioning is often used to

combat addictions such as smoking or alcoholism. combat addictions such as smoking or alcoholism. Examples-Nausea-producing drug while the client Examples-Nausea-producing drug while the client

is smoking or drinking so that unpleasant is smoking or drinking so that unpleasant associations are paired with the addictive associations are paired with the addictive behavior. behavior.

Also used to treat nail biting, sex addiction, and Also used to treat nail biting, sex addiction, and other strong habits or addictions.other strong habits or addictions.

Observational Learning influenced debates on the effect of television violence and

parental role models

Studies have shown the amount Studies have shown the amount of violent TV watched by children of violent TV watched by children

in elementary school is correlated with in elementary school is correlated with their aggressiveness as teenagers their aggressiveness as teenagers

and with their criminal behavior as adultsand with their criminal behavior as adults

Antisocial models vs. prosocial models