Operant conditioning week 2 pt2

Conditioned Emotional responses in humans: The little albert study

• Albert was exposed to two instances of the rat followed by the loud sound in an initial session and another five instances a week later

• This was sufficient to produce an extreme conditioned fear response to the white rat alone

• Generalisation also occurred to other furry animals, and Santa’s white beard

• They did not get a chance to extinguish the response

Operant conditioning

behaviour is shaped by the learner’s history of experiencing rewards and punishments for their actions

Studying operant conditioning: the skinner box

• a ‘microworld’ in which he could control the animal’s experience of reinforcement and punishment

• pressing the lever was the target behaviour which could be strengthened through reinforcement and weakened through punishment

Reinforcement

• a behaviour is reinforced (strengthened) whenever a desirable outcome is the consequence

• behaviours that are reinforced are more likely to be repeated

• a reinforcer is any consequence of a behaviour that makes that behaviour more likely to recur in future

• reinforcers can either positive (+) or negative (-)

Positive reinforcement

• an animal will learn to reproduce a behaviour if the consequence is receiving something pleasant

• positive reinforcer

  • something pleasant that is added to increase behaviour

Negative Reinforcement

• An animal will learn to reproduce a behaviour if the consequence is that something unpleasant will stop

• negative reinforcer

  • something unpleasant that is removed to increase behaviour

Continuous Reinforcement

• Continuous reinforcement rarely occurs in natural environments

• continuous reinforcement leads to rapid extinction once the reinforcer is withheld

Partial Reinforcement

• Behaviour is usually reinforced on a partial ‘schedule’

• Partial reinforcement leads to more persistent learning because the learner becomes accustomed to reinforcement occurring on some occasions and not others

Extinction of a reinforced behaviour

• its occurs when reinforcement is withheld

• not immediate - sometimes there is a brief increase in responding referred to as an extinction burst followed by decrease in trained behaviour

• The figure shows that responses that are reinforced partially will be harder to extinguish than those reinforced continuously

Shaping behaviour: Pigeons playing ping-pong

shaping reinforces successive approximations to the desired behaviour (reinforcing small steps)

• start by reinforcing a high frequency component of the desired response

• then drop this reinforcement behaviour becomes more variable again

• await a response that is still closer to the desired response then reintroduce the reinforcer

• keep cycling through as closer and closer approximations to the desired behaviour are achieved

• Enables the modules of a response that is not normally part of an animal’s repertoire

punishment

• behaviour is punished (weakened) whenever the learner experiences an undesirable consequence for that behaviour

• behaviours that are followed by punishment are less likely to be repeated

• a punisher is any consequence of a behaviour that makes that behaviour less likely to recur in future

• punishers is any consequence of a behaviour that makes that behaviours less likely to recur in the future

• punishers can also be either positive (+) or negative (-)

Positive punishment

• an animal will stop producing a behaviour if the consequence is the presentation of an unpleasant stimulus

• positive punisher

  • an unpleasant stimulus that weakens behaviour when added as consequence of the behaviour

Negative punishment (response cost)

• an animal will stop producing a behaviour if the consequence is that something desirable is taken away

• Negative punisher

  • a pleasant stimulus that weakens behaviour when removed as a consequence of a behaviour

When is punishment effective? the three Cs

• Contingency: the relationship between the behaviour and the punisher must be clear

• Contiguity: the punisher must follow the behaviour swiftly

• Consistency: the punisher needs to occur for every occurrence of the behaviour

Drawbacks of punishment

• positive punishment rarely works for long-term behaviour change

  • it tends to only supress behaviour

• it does not teach a more desirable behaviour

• produces negative feelings in the learner, which do not promote new learning

• Harsh punishment may teach the learner to use such behaviour towards others (social learning)

Alternatives to punishment

• stop reinforcing the problem behaviour (extinction)

• reinforce an alternative behaviour that is both constructive and incompatible with the undesirable behaviour

• reinforce the non-occurrence of the undesirable behaviour

• generate your own examples for each of these

Antecedents

• is a cue that signals the availability of a reinforcer

• Note that the antecedent-reinforcer relationship is based on a classically conditioned CS-UCS association

• Classically conditioned associations become cues for operant behaviours

ABC model of operant conditioning

• Antecedent → Behaviour → Consequence

Discriminant stimuli

an antecedent becomes a () when it signals which of two or more behaviours will be rewarded in a particular context

is based on a classically conditioned CS-UCS association

is used in animal training