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Chapter 5 Ivan Pavlov Ivan Pavlov (1849-1936) Pavlov, a Russian physiologist, first described classical conditioning in 1899 while conducting research into the digestive system of dogs. He was particularly interested in the role of salivary secretions in the digestion of food and was awarded the Nobel Prize for Medicine or Physiology in 1904. Pavlov’s Research Pavlov used an apparatus to measure the amount of saliva produced when a dog ate. The flow of saliva occurred naturally whenever food was placed in the dog’s mouth, as salivation is an involuntary, reflex response. Pavlov’s Method Dog was restrained in a harness to avoid extraneous variables. Meat powder was placed directly on the dog’s tongue or in the bowl. A tube was surgically attached to the dog’s cheek near one of the salivary glands and a fistula was made so that the saliva drained straight out into a measuring device. Further on, more sophisticated measuring devices were used to measure the speed of saliva flow. What did Pavlov observe? Pavlov observed that the dogs A stimulus is any event or salivated not only at the sight of the food, but also at the sight or sound of the lab tech who had been preparing the food. Pavlov was intrigued by these unintentional observations & he decided to conduct further experiments. His subsequent experiments provided clear evidence of a form of learning based on the repeated association of 2 different stimuli. object that elicits a response from an organism. A response is a reaction by an organism to a stimulus. In Pavlov’s experiment, the stimulus of food initially produced the response of salivation. Eventually the sight or sound of the tech became the stimulus. How is this response explained? The salivation response This process is in essence is controlled by the autonomic division of the PNS. Involuntary. The salivation had become associated with, and conditioned to, a new stimulus – the lab tech. the process of classical conditioning. What is Classical Conditioning? Also known as respondent conditioning refers to a form of learning that occurs through the repeated association of 2 or more different stimuli. Learning is only said to have occurred when a particular stimulus consistently produces a response that it did not previously produce. In classical condition, a response that is automatically produced by one stimulus becomes associated, or linked, with another stimulus that would not normally produce this response. There are 4 key elements that are used to describe the process of classical conditioning. 1. Unconditioned Stimulus The unconditioned stimulus (UCS) is any neutral stimulus that consistently produces a particular, naturally occurring, automatic response. In Pavlov’s experiment, the UCS was the food (meat powder). 2. Unconditioned Response The unconditioned response (UCR) is the response that occurs automatically when the UCS is presented. A UCR is a reflexive, involuntary response that is predictably caused by a UCS. In Pavlov’s experiments, the UCR was the salivation. 3. Conditioned Stimulus The conditioned stimulus (CS) is the stimulus that is neutral at the start of the conditioning process and does not normally produce the UCR. Yet, through repeated association with the UCS, the CS triggers a very similar response to that caused by the UCS. Association refers to the pairing or linking of 1 stimulus with another stimulus. In Pavlov’s experiments, the bell and subsequently other stimuli were initially neutral, but each became associated with the meat powder. Once conditioning has occurred and the originally neutral stimulus produces the response of salivating, then it is called the CS. 4. Conditioned Response The conditioned response Pavlov’s dogs displayed a (CR) is the learned response that is produced by the CS. The CR occurs after the CS has been associated with the UCS. The behaviour involved in a CR is very similar to that of the UCR, but it is triggered by the CS alone. CR (salivation) only when they began to salivate to a CS. When the dog responded to a CS, such as the sound of a bell, classical conditioning had taken place because salivation would not be a usual response to the sound of a bell. Another example… https://www.youtube.com/watch?v=hhqumf pxuzI https://www.youtube.com/watch?v=OwBQI hg6CvE Pavlov distinguished several key processes that are involved in classical conditioning. These are known as: •Acquisition, extinction, stimulus, generalisation, stimulus discrimination and spontaneous recovery. Acquisition Each paired presentation of the CS with UCS is referred to as a trial. Acquisition is the overall process during which the organism learns to associate 2 events. The rate of learning is often very fast in the early stages of the acquisition phase. Timing of the CS and UCS pairing is critical. Pavlov found that a very short time between presentations of the 2 stimuli was most effective. Acquisition is more rapid when the CS occurs and remains present until the UCS is presented. The end of the acquisition stage is said to occur when the CS alone produces the CR. Extinction A conditioned stimulus- E.g. Pavlov’s dogs eventually response association can fade over time or disappear altogether. Extinction is the gradual decrease in the strength or rate of a CR that occurs when the UCS is no longer presented. Extinction is said to have occurred when a CR no longer occurs following presentation of the CS. ceased salivating (CR) in response to the bell (CS) presented alone after a number of trials in which the food (UCS) did not follow the sound of the bell). There is some variation between individuals in the rate at which extinction of the same conditioned response will occur. There is also considerable variation between the rates at which different response will be extinguished. Spontaneous Recovery Extinction of a CR is not Spontaneous recovery always permanent. In CC, spontaneous recovery is the reappearance of a CR when the CS is presented, following a rest period after the CR appears to have been extinguished. does not always occur and when it does it is often short-lived. Furthermore the CR tends to be weaker than it was originally. Stimulus Generalisation Pavlov observed that his dogs salivated to other noises that sounded like a bell. This is known as stimulus generalisation which is the tendency for another stimulus to produce a response that is similar to the CR. The greater the similarity between stimuli, the greater the possibility that a generalisation will occur. E.g. is a stimulus generalisation to the sounds of a bell occurred with one of Pavlov’s dogs, the dog might also salivate in response to the ringing of the front-door bell. However, the amount of saliva produced by the dog would tend to be less than the amount produced by the original bell to which the dog was conditioned. Stimulus Discrimination Stimulus discrimination occurs when a person or animal responds to the CS only, but not to any other stimulus that is similar to the CS. E.g. in a CC experiment, stimulus discrimination would be observed when a dog salivated only in response to the sound of the ‘experimental bell’, and not in response to any other similar sound such as a door bell. Experimental Neurosis Ability of the dog to discriminate between the shapes Circle (CS) was accompanied by feeding (UCS)and salivation (CR and UCR) was measured. When Ellipse was introduced dog did not salivate still salivated at the circle. When ellipse was made to closely resemble circle discrimination disappeared It created emotional reactions in the dogs such as restlessness, frustration-because of lack of control and predictability EXAMPLES OF CLASSICAL CONDITIONING Using electric wires to keep cows in a field - Electric shock - Jump back - wire - Stay away EXAMPLES OF CLASSICAL CONDITIONING Using electric wires to keep cows in a field UCS - Electric shock UCR - Jump back CS - wire CR - Stay away ELECTRIC CAN OPENER / CATS - food - Run into the kitchen - Or sound of opening the can or can opener - Run into the kitchen ELECTRIC CAN OPENER / CATS UCS - food UCR - Run into the kitchen CS - Or sound of opening the can or can opener CR - Run into the kitchen Real-Life Examples of Classical Conditioning Mowrer & Mowrer (1938) Treatment for enuresis (bed-wetting) -Child sleeps on a pad (a wire mesh that is connected to a bell has been sewn) - Child wets the bed electrical circuit causes bell to ring (UCS) -Child wakes up (UCR) After several repetitions of this cycle (bed-wetting causes him to be awakened by the bell), the child begins to associate the sensation of pressure in his bladder (a previously neutral stimulus) with waking up -In a short time, the need to urinate (now a CS) becomes sufficient in itself to awaken the child (now a CR) so he or she can get up and go to the bathroom - no need for PAD with Bell Real-Life Examples of Classical Conditioning Gustavson and Gustavson (1985) – Conditioned Taste Aversion Coyotes killing sheep – problem to sheep farmers Study conditioned coyotes not to eat the sheep Sheep meat sprinkled with a chemical that would produce a stomachache After coyotes ate the treated meat, they avoided the live sheep This humane application of conditioned taste aversion might be used to control other predators as well Real-Life Examples of Classical Conditioning Gustavson and Gustavson (1985) – Conditioned Taste Aversion Coyotes killing sheep – problem to sheep farmers Study conditioned coyotes not to eat the sheep Sheep meat (CS) sprinkled with a chemical (UCS) that would produce a stomachache (UCR) After coyotes ate the treated meat, they avoided the live sheep (CR) This humane application of conditioned taste aversion might be used to control other predators as well Real-Life Examples of Classical Conditioning Metalmikov & Chorine (1926, 1928) – Immune System Injected Guinea Pigs with Foreign agents (non lethal) antibodies boost their immune system Then paired injections with Lights Lights + Injections = better immunity Lights alone = better immunity Later Injected Cholera: animals with prior conditioning better survival vs controls with no conditioning In A Clockwork Orange, a brutal sociopath, a mass murderer, is strapped to a chair and forced to watch violent movies while he is injected with a drug that nauseates him. So he sits and gags and retches as he watches the movies. After hundreds of repetitions of this, he associates violence with nausea, and it limits his ability to be violent. Conditioned Emotional Response An emotional reaction such as fear of a specific stimulus is learned through CC. A conditioned emotional response is an emotional reaction that usually occurs when the autonomic nervous system produces a response to a stimulus that did not previously trigger that response. E.g. fearing the sound of the dentist’s drill. Founder of Behaviorism: Only study behavior…not concerned with the mind…focus on relationship between environment and behavior VH1 “Behind the Science” -Born South Carolina -Wild & impulsive -Trouble with law -16 yrs – to college -21 yrs – masters -Supported himself totally through college -4th year turned in a paper back to front – “F” -Grad school – Univ. of Chicago -Ph.D. in 3 years -1907 offered position - Johns Hopkins $2500 -1915 APA President (37 yrs) “Little Albert” – first CC in humans "Give me a dozen healthy infants, wellformed, and my own specialized world to bring them up in, and I'll guarantee to take any one at random and train him to become any type of specialist I might select – doctor, lawyer, artist, merchant chief and yes, even beggarman and thief, regardless of his talents, penchants, tendencies, abilities, vocations and race of his ancestors.” Watson’s ‘Little Albert’ experiment American psychologist John B. Watson and his graduate student, Rosalie Rayner first used CC to elicit an emotional response. Aim to test the notion that fears can be acquired through CC. The research participant was Albert B. (Little Albert), the 11 moth old son of a woman who worked at the same clinic as Watson. How was Little Albert conditioned to hate the rat? They placed him on a mattress in a room where a white lab rat (CS) was within reaching distance. Albert showed no initial fear of it and played with it. They then struck a hammer on a steel bar behind Albert (loud noise, UCS) and Albert began to cry. For the next 17 days Watson and Rayner began a series of fearconditioning experiments. They also conducted tests to find out if Albert’s fear response could be generalised. Albert also seemed to fear a white rabbit, a dog and a seal skin coat. During Conditioning (Association & Acquisition) CS Is associated with Which automatically leads to the UCS UCR After Conditioning CS Leads to a conditioned response CR Ethical considerations? Albert’s mother left her job and Informed consent is not Watson and Rayner reported that they were denied the opportunity to remove the conditioned emotional responses. This has been disputed, as it is believed they were aware of Albert’s departure a month in advance. Some believe Albert’s mother may not have been fully aware of the experimental condition and effect on her son. mentioned in Watson original article, so a judgement cannot be made about this ethical issue. Also possible that Albert was vulnerable to psychological harm as a result of the experiments. Yet Albert was subjected to severe anxiety and distress & the experimenters made not attempt to end the experiment and attend to his distress in an appropriate way. Never Published again…Private Industry CC is used in a range of different settings, many of which are concerned with therapeutic benefits. These include: Aversion therapy and systematic desensitisation. Elimination of Motivated Behaviours Counterconditioning Negative CS paired with positive UCS by no longer paired with negative UCS. e.g removes phobias ….ghost movies Elimination of Motivated Behaviours Developed on the 1950s by The client associates being psychiatrist Joseph Wolpe, systematic desensitisation is a kind of behaviour therapy that attempts to replace an anxiety or fear response with a relaxation response through a classical conditioning procedure. relaxed with the anxiety or fear-arousing stimulus by means of a series of graded steps. Basic principle is that the client is gradually desensitised to anxiety or fear-arousing objects, activities or situations. Wolpe’s procedure: Person is taught to relax. 2. Break down the fear arousing situation into a logical sequence of steps (steps are ranked from least to most fearinducing). 1. Case study: fear of flying. Most frightening •Experiencing mid air turbulence •Taking off •Taxiing down the runway •Boarding the plane •Waiting to get on the plane •Travelling to the airport in a car •Buying a place ticket. Least frightening Procedure cont… Once the steps are ranked, The best results seem to the therapist then teaches the person deep muscle relaxation and asks them to imagine the least frightening scene on the list and so on… In the end the person learns to imagine the most frightening scene without becoming afraid. occur using real life desensitisation, such as the therapist sitting in a plane with the person or introducing them to the pilot for reassurance. By allowing the client to confront the phobia under such supportive circumstances, the fear of flying is eventually overcome. Interoceptive Conditioning Razran (1961) CS, UCS, or both are applied to internal organs Intero-exteroceptive conditioning: CS is applied internally UCS is applied externally Intero-interoceptive conditioning: CS and UCS applied internally Extero-interoceptive conditioning: external CS paired with an internal UCS Learned Aversions A taste-aversion is a conditioned This tends to happen with one response that results from a person or animal establishing an association between a particular food and being or feeling ill after having consumed it at some time in the past. The association is usually the result of a single experience & the particular food will be avoided in the future. There is an association between a CS( smell/taste of food) and the UCS (nausea producing substance). trial. One-trial learning is a form of learning involving a change in behaviour that occurs with only one experience. Garcia’s st 1 Experiment Thirsty rats were allocated to 1 of Rats who had flavoured water 2 experimental groups. Whenever rats in 1 group licked the tube, a bright light was flashed and a clicking noise sounded (bright –noisy condition). Rats in the other condition were offered saccharine-flavoured water to drink from a tube. Later, rats in one group received a painful shock to their feet, while those in the other group received a dose of illnessinducing X-rays. and X rays avoided the water. Rats in the shock group did not associate shock with water. Rats in bright noisy condition did not develop aversion to water as a result of X ray. But had the rats learned to avoid all parts of the CS, or just some of them? (CS – combo of saccharine flavoured water, bright light and clicking noise). Garcia’s nd 2 Experiment Tested same rats under a Result: rats that had different condition. The rats were given either saccharineflavoured water that was not paired with either light or noise, OR unflavoured water that was paired with the same light and noise that had been present during the previous condition. become ill because of the effects of the X-rays avoided the saccharine flavour, but were quite content to drink water accompanied by the same light and noise. In general, results indicate the UCS influenced what the rats had learned. Learned aversions Biological constraints-predisposition to learn certain associations Prepared associations-reflexes Contraprepared associations-cannot learn Unprepared associations-can be learnt Learned Aversions in Cancer Progressive Muscle Relaxation Guided Imagery Anxiety, nausea, and vomiting IntroductionInstrumental/Operant Conditioning Thorndike and his puzzle boxes Freddie! Coined the phrase ‘Operant conditioning’ The animal operates on the environment Unlike ‘respondent conditioning’ (Pavlovian) Pioneered the use of free operants Pioneered the use of respone rate The Skinner Box Basically this allowed the researcher to walk away Allowed for a dependent variable that could be easily measured and compared across species too Criticisms of the Skinner box Is it artificial? Well duh… But Many species can be tested Real world applications Therapy Who cares? Instrumental Conditioning Pavlovian Conditioning = Stimulus learning Instrumental Conditioning = Response learning Instrumental behavior = behavior that occurs because it was previously instrumental in producing certain consequences Also called ‘goal-directed’ behavior Instrumental Conditioning Thorndike interpreted the results of his experiment as reflecting the learning of an S-R association Thorndike believed the cats learned an association between the stimuli inside the puzzle box and the escape response The consequence of the successful response – escaping the box – strengthened the association between the box stimuli and that response On the basis of his work, Thorndike formulated the law of effect Quantity, Quality, and Contrasts of Reinforcement Crespi’s rat experiment (1942) AOR: positive association between reinforcement (reward) and performance QOR: Quality of reinforcement Negative contrast Positive contrast History of reinforcement Latent learning Reinforcers Increases the probability that response will occur Primary Reinforcers-More innate linked to basic needs Secondary Reinforcers-Acquired through experience-money, status etc Generalized conditioned reinforcers-gains reinforcing properties through pairing with primary reinforcers Schedules of Reinforcement Fixed Interval First response after a given interval is rewarded FI Scallop Variable Interval Like FI but varies with a given average Scallop disappears Schedules of Reinforcement Fixed Ratio Reinforcement is given after a given number of responses A little less smooth Variable Ratio After a varying number of responses Reinforcement Occurs when a stimulus change immediately follows a response and increases the future frequency of that type of behavior in similar circumstances Reinforcement can also strengthen the duration, latency, magnitude, and/or topography of behavior How immediate? The behavior closest in time to the reinforcer will be strengthened When behavior is affected by a delayed consequence, language is probably playing a role and not simply reinforcement Positive Reinforcement Occurs when a behavior is followed immediately by the presentation of a stimulus that increases the future frequency of the behavior in similar conditions Positive reinforcer: a stimulus whose presentation or onset functions as reinforcement Negative Reinforcement Occurs when a behavior is followed immediately by the removal, termination, reduction, or postponement of a stimulus that increases the future frequency of the behavior in similar conditions Negative reinforcer: a stimulus whose termination or reduction functions as reinforcement Can be unconditioned (e.g., pain) or conditioned (e.g., dirty look) Note: Negative Reinforcement is not punishment! https://www.youtube.com/watch?v=Mt4N9GSBoMI Applications Work with autistic kids Prompts Fading Secondary reinforcers Token economies I/O applications Behaviour therapy Token Economies “Tokens” considered currencies or credit Given in exchange for appropriate behavior Classical-Operant Interactions Acquired Fear Conditioned Emotional Responses Stimuli associated with positive emotional or motivational states. Learned Helplessness A typical case of demotivation Symptoms-Passivity, retardation of learning, somatic effects, reduction of helplessness with time Causes & prevention–lack of control and depression Observational Learning Vicarious learning/Modelling-learned through observation Self reinforcement-self regulation of behavior Modelling process Attention Retention Reproduction Classical Conditioning & Aggression Pain & Aggression (Ulrich & Azrin, 1962) Pairing neutral stimulus with pain = Aggression Instrumental Conditioning & Aggression Reinforcing or rewarding aggressive behavior Modelled aggression https://www.youtube.com/watch?v=Pr0OTCVtHbU Vicarious reinforcement Observing rewards and punishments of a particular behavior will alter the probability of performing the modeled behavior Act that is punished is less likely to be performed! Sexual Motivation & Learning Classical conditioning shows a role in sexual learning in animals and humans! Mate preferences are learned early in life! Previous sexual experience influences copulation! Role of Culture: Sexual values Who is selected as mates What age is appropriate Sexual Motivation & Learning