Lesson 8 operant conditioning

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Lesson 8: Operant Conditioning Reward and Punishment

Transcript of Lesson 8 operant conditioning

Page 1: Lesson 8   operant conditioning

Lesson 8: Operant Conditioning

Reward and Punishment

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From last lesson…….

Marnie is a nurse at a country hospital. Jimmy, an 8-year-old boy, attends the hospital each fortnight for treatment. On his first visit, Marnie gave him an injection which was very painful. Now he screams when he is approached by a nurse, even if he does not need an injection. According to the classical conditioning model of learning, identify the i. unconditioned stimulus

     ii. conditioned stimulus     iii. unconditioned response  iv. conditioned response

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The answer…….

  i. unconditioned stimulus: Pain from the needle (pain)  

  ii. conditioned stimulus: Approach of nurse (nurse/sight of approaching nurse)  

  iii. unconditioned response: Fear of pain from injection (scream because of pain) 

iv. conditioned response: Fear of nurse (scream at approach of nurse)

In previous assessment reports it has been emphasised that it is necessary to distinguish between the unconditioned response and the conditioned response.

Therefore, in parts iii. and iv., responses were required to be differentiated by identifying the origin as in ‘fear from the pain of the injection’ and ‘fear due to the approach of the nurse’.

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Today’s Lesson

Explain the three-phase model of operant conditioning as informed by B.F. Skinner: positive and negative reinforcement, response cost, punishment and schedules of reinforcement

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Operant Conditioning

A learning process by which the likelihood of a particular behaviour occurring is determined by the consequences of that behaviour

Theory of Operant Conditioning - Behaviour operates on the environment and our behaviour is instrumental in producing the consequences - Rewards/Punishments

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Three-phases model of operant conditioning

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Operant Conditioning - Skinner American Psychologist, B.F Skinner

(1904 – 1990) believed behaviour can be reduced to the relationships between the behaviour, its antecedents (the events that precede it), and its consequences

Operant - a response (or set or responses) that occurs in the absence of any stimulus and acts upon the environment in the same way each time

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The Skinner Box

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The Skinner Box

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Reinforcement

Any stimulus (event or action) that subsequently strengthens or increases the likelihood of the response (behaviour) that it follows.

The reinforcer comes after the response (behaviour)

Reinforcement makes things stronger

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Positive Reinforcement GOOD

Positive Reinforcer PLUS something GOOD A stimulus which strengthens a

response by providing a pleasant or satisfying consequence

Skinners experiment = food pellets Money Grades Applause

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Negative Reinforcement BAD

Negative Reinforcer MINUS something BAD A stimulus that strengthens a response by

the reduction, removal or prevention of an unpleasant stimulus

The behaviour that removes reduces or prevents and unpleasant stimulus is strengthened by the consequence

Skinners experiment = electric shock Taking Panadol for headache Driving slow to avoid fine

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Pos vs Neg Reinforcement Positive reinforcement add good

Negative reinforcement take away bad

Both STRENGTHEN a response Overall outcome is desirable to

organism, just have achieved it in different ways

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Punishement BAD GOOD Positive punishment - the delivery of a stimulus following an

undesirable response PLUS BAD

Negative punishment – the removal of a stimulus following an undesired response

MINUS GOOD

Punisher – an unpleasant stimulus that when paired with a response weakens the response or decreases the rate of responding over time

Punishers reduce unwanted behaviour

It is usually more effective to reinforce alternative desirable behaviour than it is to punish undesirable behaviour

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Response cost – negative punishment GOOD

MINUS GOOD Negative punishment often referred

to as response cost When a valued stimulus removed Eg. If you drink drive we will take

away your liscence

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Schedules of Reinforcement

Continuous Reinforcement necessary for a response to become learned

Partial Reinforcement can be more effective at maintaining a response

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Schedules of Reinforcement

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Schedules of ReinforcementFixed Ratio Fixed number of correct responses Being paid $5 for every 100 newspapers delivered

Variable Ratio Variable number of correct responses Poker machines

Fixed Interval Fixed time period Teachers at Woodleigh pain every fortnight

Variable Interval Variable time period Fishing

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Variable Ratio

The variable ratio schedule is the most resistant to extinction

It leads to the fastest rate of responding

Gambling addiction is explicable through variable ratio reinforcement

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Schedules of Reinforcement

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Factors Effecting Reinforcement Order of presentation – reinforcement needs to

occur after the desired response not before! So the organism associates the reinforcement with the behaviour

Timing – Reinforcers need to occur as close in time to the desired response as possible. Most effective reinforcement occurs immediately after the desired response

  Appropriateness of the reinforcer – For a

stimulus to be a reinforcer it must provide a pleasing or satisfying consequence for its recipient.

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Stimulus Generalisation and Discrimination

Stimulus generalization - occurs when the correct response is made to another stimulus which is similar to the stimulus for which reinforcement is obtained

Stimulus discrimination - organism makes response to a stimulus for which reinforcement is obtained but not for any other similar stimulus

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Extinction and Spontaneous Recovery

Extinction – the gradual decrease in the strength or rate of responding after a period of non- reinforcement. Extinction occurs after the termination of reinforcement

Spontaneous recovery – the response is (after a rest period) again shown in the absence of reinforcement