Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Educational psychology wikipedia , lookup
Insufficient justification wikipedia , lookup
Psychophysics wikipedia , lookup
Learning theory (education) wikipedia , lookup
Behaviorism wikipedia , lookup
Eyeblink conditioning wikipedia , lookup
Psychological behaviorism wikipedia , lookup
Learning theory Classical conditioning, operant conditioning and social learning theory 25th September 2012 Dr Susannah Redhead Clinical Psychologist North Cambridge Intake and Treatment Team, CPFT [email protected] Objectives 1. To provide an introduction to the main concepts and terminology relating to classical conditioning, operant conditioning and social learning theory 2. To evaluate these approaches with regard to their implications for our understanding and treatment of mental health difficulties. 3. To enable you to do well in your MCQs! Plan Classical conditioning - Describe and evaluate Operant conditioning - Describe and evaluate Social learning theory - Describe and evaluate With an emphasis on clinical implications Learning is... • ...”the process by which relatively permanent changes occur in behavioural potential as a result of experience” (Anderson, 1995). • What kinds of changes? - Overt, behavioural changes? - Covert, cognitive changes? Classical conditioning Or.... Pavlovian conditioning Ivan Pavlov (1849-1936) A Russian physiologist Before working on classical conditioning, he already had won a Nobel prize for his work on digestion. Primarily worked with dogs. Developed a surgical technique for developing a dogs salivatory secretions which incorporated a tube attached to the side of its cheek so the drops of saliva could be easily measured. What Pavlov (1927) noticed... - The dogs would start salivating before the food was given to them, on the basis of visual stimuli (seeing the feeding bucket) and auditory prompts (hearing the footsteps of the laboratory assistant approaching) – “psychic secretions” - Pavlov resolved to explain this phenomenon. Classical conditioning Higher order conditioning – a cynical example UCS – Dessert/ pressies UCR - Pleasure NS/ CS - Grandma CR - Pleasure NS/ CS – Grandma’s perfume CR - Pleasure Some more concepts from classical conditioning... • Generalisation – A CR can be elicited to stimuli that are similar but not identical to the original UCS...however the strength of the CR is different (e.g. For Pavlov, less saliva). • Discrimination – The strength of the CR to one CS is strengthened at the same time as a second CS is weakened – i.e. Learning to respond differently to slightly different stimuli Some more concepts from classical conditioning... • Experimental extinction – The repeated presentation of the CS in the absence of the UCS removes the conditioned response • Spontaneous recovery – The re-emergence of responses over time following experimental extinction e.g. Dogs brought back into the experimental situation after extinction has occurred demonstrate some salivation in response to the tone. Four types of classical conditioning... 1. Delayed or forward The CS is presented before the UCS an remains present while the UCS is presented and until the UCR appears. Conditioning has occured when the the CR appears before the UCS is presented. A half-second interval produces the strongest learning. As the interval increases, learning becomes poorer. 2. Backward The CS is presented after the UCS. Produces very little, if any learning in laboratory animals. However, much advertising uses backwards conditioning. Four types of classical conditioning... 3. Simultaneous – The CS and UCS are presented together. This often occurs in real life situations (e.g. The sound of the dentists drill accompanies the contact of the drill with your tooth). 4. Trace – The CS is presented and removed befoe the UCS is presented, so only a memory trace of the the CS remains to be conditioned. The CR is usually weaker then in delayed or simultaneous conditioning. Classical conditioning – Little-known facts... • A wide variety of stimuli were recorded in Pavlov’s writings, including electric shocks, whistles, metronomes, tuning forks, and a range of visual stimuli. • Pavlov's experiments extended to children, some of whom apparently underwent surgical procedures, similar to those performed on the dogs, for the collection of saliva. • CR does not necessarily equal the UCR – Pavlov found the content of the dogs saliva was different • Classical conditioning is a widely recognised process accross organisms. Occurs in dogs, rats, the human foetus, neurons Evaluation of classical conditioning 1. Clinical relevance and utility - Explanation of development of specific phobias, trigger generalisation in PTSD - Implications for intervention: Implosion therapy, flooding , Systematic desensitisation, aversion therapy, exposure and response prevention for OCD, prolonged exposure therapy for PTSD Critiques... 2. Assumes passivity, irrelevance of cognition 3. Ethics?! Ecological validity. 4. One trial learning – Garcia, Ervin and Koelling (1966) 5. Natural associations 6. The role of language Explanation of development of specific phobias The Little Albert example – Watson (1920) Fear of white rat and other stimuli conditioned in 9m old child UCS – Clanging metal bars (!) CS – White rat UCR – Fear CR – Fear Generalisation of fear response to fluffy white beards (or higher order conditioning?) Similar process in PTSD – conditioned responses, generalisation Implosion therapy and flooding Premise – if the stimulus evoking a fear response is presented without the aversive experience that accompanies it, the fear response will be lost • Implosion therapy - The therapist exposes the client to vivid mental images of the feared stimulus. - Stimulus augmentation – the therapist encourages the client to consider the most extreme form of contact with the feared stimulus - After repeated trials, the stimulus loses its anxiety-provoking power (“implodes” – extinction takes place) • Flooding - The individual is forced to confront the object or situation evoking the fear response in vivo, e.g. Wolpe (1973) – adolescent girl forced into the back of a car...! * For many people, these procedures would be too traumatic* Systematic desensitisation and aversion therapy Systematic desensitisation - Relaxation training then gradual exposure to anxiety hierarchy - Based on the concept of reciprocal inhibition – fear and anxiety are mutually exclusive Aversion therapy - Pairing an unpleasant stimulus with a desired but socially undesirable behaviour - E.g. Treatment of alcohol abuse – alcohol paired with vomit-inducing substance - A Clockwork Orange More recent developments in interventions based on classical conditioning Exposure and response prevention for OCD - Less emphasis on relaxation as an alternative response then SD, as this can be undertaken in a ritualistic manner - Purpose – gradual reduction in anxiety response, alleviating need to rely on compulsions • - Prolonged exposure therapy (Foa, 2007) Exposure to traumatic memories in PTSD. Imagined then audio-recorded. Played and replayed until anxiety level subsides. Monitoring essential (role of cognition?) Critiques of classical conditioning • • • • Assumes the passivity of the learner. The cognitive aspect of learning is not incorporated into the model The role of language in learning is not taken into account – e.g. Just telling a person the UCS will not be repeated again can cause extinction (Davey, 1983) Assumes repeated exposure necessary to explore learning. However... -One trial learning – Garcia et al. (1966), rats rapidly conditioned to avoid sweet tasting emetic substance • Natural associations – CC does not explain how some associations are more easily made than others • Operant conditioning Or.... Instrumental conditioning Classical vs. Operant conditioning Premise of operant conditioning: Much behaviour is controlled by its consequences (future stimuli), by events that precede it such as in classical conditioning. Operant conditioning: Behaviour Classical conditioning: UCS Unconditioned behaviour CS Conditioned behaviour Consequences – reinforcement/ punishment Thorndike’s law of effect (1898) •Cats had to learn to operate a latch to retrieve a piece of fish •Each time they were returned to the puzzle box, it took less time to escape •Trial and error learning •What was being learnt –a connection between the stimulus (manipulative contents of box) and the response (behaviour allowing cat to escape) Thorndike’s “puzzle box” The stimulus-response connection is “stamped in when pleasure results from the act and stamped out when it doesn’t” B. F. Skinner (1904-1990) BF – Burrhus Frederic Founder of radical behaviourism Inventor of numerous creations including the controversial “air crib”, cumulative recorder, operant conditional chamber, teaching machine and pigeon-guided missile. Skinner’s “analysis of behaviour” (1904) Skinner developed his own version of Thorndike’s “puzzle-box” The animal presses the lever (in the case of rats) or pecks an illuminated disk (for pigeons) The experimenter decides what the relationship will be between the pressing/ pecking, and the subsequent consequences. The experimenter has complete control over the animal’s environment What Skinner found... The “law of reinforcement” – a response is more likely to be repeated if it is followed by a reward or “positive reinforcer” The rats soon learnt the lever could result in food pellets being released (continual reinforcement), so pressed the lever more and more often. The effects of a positive reinforcer are greater if it follows immediately after the behaviour. The probability of a response decreases if not followed by the positive reinforcer (experimental extinction). There is usually some spontaneous recovery after extinction has occurred. Skinner (1938) identified several different schedules of reinforcement apart from continual reinforcement – collectively referred to as partial reinforcement schedules. Please refer to Appendix A for more detail Primary and secondary reinforcers Primary and secondary reinforces are the two main type of reinforcers in operant conditioning. Primary reinforcers are stimuli that are needed to live e.g. Food, water, sleep, air. Secondary reinforcers are reinforcing because we have learnt to associate them with primary reinforcers, e.g. Money, praise, attention. Some more concepts from operant conditioning... • How do we condition an animal to produce a response it would not produce naturally? By shaping – in which the animal moves towards the right behaviour with successive approximations E.g. if we happened to want to train pigeons to play table tennis... • Latent learning - It is possible for learning to occur without any obvious impact on performance...until positive reinforcement is provided The rats in mazes example Negative reinforcement and punishment Lever pressing Lever pressing Lever pressing Positive reinforcement Negative reinforcement Food is presented Electric shock is switched off (escape learning) OR Avoided altogether (avoidance learning) Punishment Electric shock is switched on Negative reinforcement and punishment Negative reinforcement The removal or avoidance of a negative stimuli Escape learning: Learning that occurs in order to cause a negative stimulus to cease Avoidance learning: Avoidance of the negative stimulus altogether e.g. Stopping at traffic lights to avoid an accident. The shuttle box example – electric shocks can be delivered to one compartment of the shuttle box independently of the other. Warning signal – pigeon jumps to the other compartment. Punishment The probability of a response being made is reduced by following it (quickly) with an aversive stimulus e.g. Telling off. Learned helplessness Seligman (1975) - - Dogs exposed to aversive stimuli they couldn’t avoid, in the form of electric shocks Afterwards, put in a shuttle box; they could escape by jumping over to the other side. In fact, most of the dogs passively accepted the shocks. The term learned helplessness is now used to refer to passive behaviour in situations when appropriate action could be taken, e.g. Depression, domestic violence situations. Classical vs. Operant conditioning Similarities Both types of associative learning Both involve generalisation, discrimination, extinction and spontaneous recovery In practice, it can be hard to tell them apart Differences CC – Behaviour involuntary, OC – voluntary CC – Process works the same regardless of whether stimulus is pleasurable or aversive. OC – likelihood of response depends on the extent to which it’s pleasurable. CC – new stimulus response connections are formed. OC – more concerned with the strengthening or weakening of behavioural tendencies already exhibited by the animal. Classical vs. Operant conditioning Differences cont. CC – reinforce presented irrespective of what the animal does, before the response. OC – reinforcer presented only if the animal behaves in a certain way, after the behaviour CC – strength of conditioning measured in terms of response magnitude and or latency. In operant conditioning – response strength is measured as response rate. Evaluation of operant conditioning 1. Clinical relevance and utility - Explanation of development of depression and the maintenance of phobias. - Implications for intervention – Therapies based on extinction, therapies based on punishment, Token economies, Applied behavioural analysis (ABA), behavioural activation/ activity scheduling Critiques... 2. Other critiques relevant to classical conditioning are also relevant here (and these are also relevant to classical conditioning). 3. Does not take account of insight learning (the aha moment) or observational learning 4. Equipotentiality An explanation of the development of depression - Lewisohn (1974) – Life events involving loss induce depression due to reduced opportunities for positive reinforcement, which in turn leads to increased withdrawal. - Lewisohn suggests that social withdrawal leads to concern and attention, which can reinforce the depressed behaviour. When the concern wanes, the depression is exacerbated. - Depression is associated with a reduction in pleasant activities/ opportunities for positive reinforcement (pleasure/ mastery – Padesky). An explanation of the maintenance of phobias Mowrer’s (1947) two-factor theory - Phobias are acquired through classical conditioning (factor 1) and maintained through operant conditioning (factor 2), as the avoidance of phobic stimulus/ reduction in anxiety is negatively reinforcing. - Rachman (1984) sees avoidance as being maintained by positive feelings of safety. - Rosenhan and Seligman (1984) – Prepared conditioning – we are genetically predisposed to acquire phobias towards certain stimuli, e.g. Snakes rather than flowers. Interventions based on extinction/ punishment/ token economies Premise – If a difficulty has been acquired through operant conditioning, it can be eliminated through it. • Interventions based on extinction - Identify then eliminate the reinforcer e.g. Attention...but ensure the underlying need is met through another source. • Interventions based on punishment - E.g. In a secure hospital – time in solitary. - Not common as not effective as strategies using positive reinforcement for bringing about behaviour change. • Token economies Tokens are provided to exchange for priviledges, in order to encourage desirable behaviour ? Institutionalisation ABA/ behavioural activation • Applied behavioural analysis (ABA) Primarily used with people with autism, and those with a learning disability/ challenging behaviour. Functional analysis involving ABC monitoring Interventions – e.g. shaping, teaching communication skills, identifying other outlets for functions served by the behaviour… •Behavioural activation/ activity scheduling Goal setting around increasing levels of activity to ensure increased pleasure and mastery (positive reinforcement). Activities rank-ordered by difficulty. Critiques of operant conditioning 3. Does not take account of insight learning (the “aha” moment) or observational learning Several types of learning do not appear to depend on conditioning principles. Kohler (1925) – Insight learning – chimps suddenly able to reach the banana. Observational learning…see next slide! 4. Equipotentiality Skinner seems to have believed that any response could be conditioned in any stimulus situation Not the case, due to “instinctive drift” – pigs push a coin around in the mud rather than drop it in a piggy bank Social learning theory Or…. Observational learning Albert Bandura, born 1925 Key proponent of social learning theory Based on studies of children, in particular the observation that children tend to imitate their parents People learn by observing the behaviour of others and the outcome of those behaviours, which does not necessarily involve direct exposure to reinforcement The expectation of reinforcement influences cognitive processes that promote learning. Therefore attention and memory play a critical role in learning. Particularly influential in the understanding of aggressive behaviour Bandura et al.’s Bobo doll studies (1963, 1965) 1963 -Children were allocated to one of two groups, either watching an aggressive film or a non-aggressive film featuring an adult interacting with a Bobo doll. The children were left to play with the Bobo doll… Guess what happened next? 1965 – Three groups – 1. violence, 2. violence with reward, 3. violence with punishment Children in the punishment group demonstrated equal learning, but least likely to apply this to their bahviour. Bandura’s (1974) five conditions 1. Attention: the person must first pay attention to the model. 2. A visual image or semantic code for the modelled behaviour is stored in the memory. 3. Retention: the observer must be able to remember the behavior that has been observed, e.g. through rehearsal. 4. Motor reproduction: the third condition is the ability to replicate the behavior that the model has just demonstrated. 5. Motivation: the final necessary ingredient for modeling to occur is motivation, learners must want to demonstrate what they have learned, e.g. due to the anticipation of positive reinforcement. Evaluation of social learning theory • Influential in explaining aggressive behaviour e.g. children who watch violent TV programs are more likely to behave in an aggressive way (is watching violent TV a correlation of lack of boundaries/ discipline…?) • The majority of forensic psychologists would maintain that people’s internal emotional state, interpretation of the current situation and personality amongst other things are also important factors • HCR-20 – exposure to violence is not a predictor of violence (although this would be hard to quantify) • Ethics/ ecological validity yet again – would the children have attacked another child? To finish… • Have we met our objectives? • Any questions? Good luck with the rest of your training!