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Behavioral Learning Theory Aws Khasawneh, MD. Learning is: The acquisition of new behavior patterns. A persisting change in human performance or performance potential . (brought) about as a result of the learner’s interaction with the environment. the relatively permanent change in a person’s knowledge or behavior due to experience. Behaviorists say that a person’s behavior is determined by adaptive and maladaptive learning. Learning methods are the basis of behavioral treatment techniques. Learning Mechanisms: A) Simple forms: - Habituation: Repeated stimulation results in a decreased response(a child who receives weekly allergy injections cries less and less with each injection) - Sensitization: Repeated stimulation results in an increased response(a child who is afraid of spiders feels more anxiety each time he encounters spider) B) Complex forms: - Classical Conditioning. - Operant Conditioning. Classical Conditioning CLASSICAL CONDITIONING A. Principles In classical conditioning, a natural or reflexive response (behavior) is elicited by a learned stimulus (a cue from an internal or external event). This type of learning is called associative learning. Key Definitions Unconditioned Stimulus (US) - stimulus naturally triggers a response Unconditioned Response (UR) - unlearned (natural), reflexive response (behavior) to the UCS Conditioned Stimulus (CS) – stimulus that produce a response following learning ( initially neutral) Conditioned Response (CR) – is a behavior (response) that is learned by an association between a conditioned stimulus and unconditioned stimulus. Ivan Pavlov Russian physiologist studying the digestive system Focusing on what substance helped to break food down One notable substance studied was saliva Developed method to measure saliva production Salivary Conditioning Apparatus Process of Pavlov’s Saliva Research Dog given food and salivation was recorded while the dog ate Key finding: Experienced dogs salivated before the food was presented Pavlov’s Theory: Some stimulus (e.g. experimenter; apparatus) that proceeded food presentation had acquired capacity to elicit the response of salivation What was happening? Dogs were exhibiting a type of learning This type of learning is the foundation of Classical Conditioning Paradigm of Classical Conditioning 1st: Select a stimulus that reliably elicits a characteristic response Stimulus – Unconditioned stimulus (US) Response -- Unconditioned response (UR) Unconditioned - Signifies the US - UR connection is unlearned (innate) 2nd: Select a Stimulus for Conditioning (CS) CS – Can be any reasonable stimulus that does not initially evoke the UR Conditioned – Signifies that CS will only elicit desired response after conditioning take place Pavlov’s Dogs Before Conditioning US (Food) UR (Salivation) CS (Bell) No CR; Dog may turn head (orienting response) During Conditioning CS paired/presented consistently before US Time CS (Bell) US (Food) UR (Salivation) As presentations continue: CS (Bell) CR (Salivation) US (Food) UR (Salivation) After Conditioning US (Food) UR (Salivation) CS (Bell) CR (Salivation) Extinction The CR decreases if the CS is never again paired with the US. Passage of time does not cause animals to “forget” to produce the CR in presence of CS Repeatedly present CS without the US, will eventually lose CR Spontaneous Recovery Even though no CRs present after one day of extinction trials, CR is present the following day Time is key factor More time between 1st and 2nd extinction session, more spontaneous recovery observed Rapid Reacquisition Acquisition phase extinction phase acquisition phase (i.e. reacquisition phase) Rate of learning is faster Repeated Cycles continues to get faster Generalization and Discrimination Generalization: Transfer of effects of conditioning to similar stimuli In general, the more similar a stimulus is to training stimulus, the greater its capacity to elicit a CR Discrimination: Subject learns to respond to one stimulus, but not to a similar stimulus J.B. Watson: “suggested…that human emotions might profitably be thought of as glandular and muscular reflexes which, like salivation, easily become conditioned” With Little Albert, Watson was able to demonstrate that the acquisition of a phobia (an exaggerated, seemingly illogical fear of a particular object or class of objects) could be explained by classical conditioning Little Albert [Little] Albert, eleven months of age, was an infant, afraid of nothing “under the sun” except a loud sound made by striking a steel bar. This made him cry. By striking the bar at the same time that Albert touched a white rat, the fear transferred to the white rat. After seven combined stimulations, rat and sound, Albert not only became greatly disturbed at the sight of a rat, but this fear had spread to include a white rabbit, cotton, wool, a fur coat, [a dog, a Santa Claus mask, and the experimenter’s hair. It did not transfer to his wooden blocks and other objects very dissimilar to the rat. Applications in Behavioral Therapy 1- Systematic Desensitization for Phobia is a treatment for phobias in which the individual is trained to relax while being exposed to progressively more anxiety-provoking stimuli. Phobia: Excessive and irrational fear of an object, place, or situation,Example: Spiders, Closed-Spaces, and Crowds 2- Aversion therapy: is a type of behavior therapy designed to encourage individuals to give up undesirable habits by causing them to associate the habit with an unpleasant effect. 3- Flooding: is a form of desensitization that uses repeated exposure to highly distressing stimuli until the lack of reinforcement of the anxiety response causes its extinction. A grade school principal has 1 week to try out a new fire-alarm system for the school. He decides to test the system three times during the week. The first time the alarm is sounded, all of the students leave the school within 5 minutes. The second time, it takes the students 15 minutes to leave the school. The third time the alarm is sounded, the students ignore it. The students' response to the fire alarm the third time it is sounded is most likely to have been learned by A. sensitization B. habituation C. classical conditioning Operant Conditioning OPERANT CONDITIONING A. Principles For an individual, behavior is determined by its consequences. The consequence (re-enforcement or punishment) occurs immediately following a behavior. The Skinner experiment Operant Conditioning Theorist B. F. Skinner Original research Rats in Skinner boxes Skinner Box Differences between Classical Conditioning and Operant Conditioning Classical Conditioning Simple/Reflex Behavior Operant Conditioning Complex/Voluntary Behavior Focuses on ANTECEDENTS: Focuses On Events which take place BEFORE the target response Learning takes place when CONSEQUENCES: Events which take place AFTER the target response there is an association made Learning takes place when a between two unrelated stimuli desired (target) response is affected by its consequences (before the desired / target (after the desired/target response) response) Operant Conditioning Concepts Positive reinforcement (reward) Strengthening (increasing) a behavior by presenting a positive stimulus immediately after the behavior has occurred Negative reinforcement ( escape, avoidance) Strengthening (increasing) a behavior by removing a negative stimulus immediately after the behavior has occurred Operant Conditioning Concepts punishment: the introduction of aversive stimulus after behavior aimed at reduced the rate of that behavior. Operant Conditioning Concepts Extinction When a previously reinforced behavior decreases in frequency and eventually ceases altogether because reinforcement is withheld Spontaneous recovery When an extinguished behavior reappears without having been reinforced Example: A mother would like her 8-year-old son to stop hitting his 6-year-old brother. She can achieve this goal by using one of the following features of operant conditioning: Feature Effect on behavior Example Comment Positive reinforcement Behavior is increased by reward Child increases his kind behavior toward his younger brother to get a praise from his mother Reward or reinforcement (praise) increases desired behavior (kindness toward brother) A reward can be praise or attention as well as a tangible reward like money Negative reinforcement Behavior is increased by avoidance or escape Child increases his kind behavior toward his younger brother to avoid being scolded Active avoidance of an aversive stimulus (being scolded) increases desired behavior (kindness toward brother) Punishment Behavior is decreased by suppression Child decreases his hitting behavior after mother scolds him Delivery of an aversive stimulus (scolding) decreases unwanted behavior (hitting brother) rapidly but not permanently Extinction Behavior is eliminated by non reinforcement Child stops his hitting behavior when the behavior is ignored by his mother Extinction is more effective than punishment for long-term reduction in unwanted behavior There may be an initial increase in hitting behavior before it disappears Operant Conditioning Concepts Shaping Reducing complex behaviors into several more simple behaviors Reinforcing successive approximations to the complex behavior Modeling: type of observational learning in which individual behaves in a manner similar to that of someone she/he admires Schedules of Reinforcement Continuous: Reinforcement presented after every response.( rapidly learned but has little resistance to extinction/ disappears rapidly.) E.g. A teenager receives a candy bar each time she puts a dollar into a vending machine. One time she puts a dollar in and nothing comes out. She never buys candy from the machine again. Fixed interval schedule Reinforcement occurs after a specific amount of time.( the response rate increases toward the end of each interval) . E.g. A student has an anatomy quiz every Friday. He studies for 10 minutes on Wednesday nights, and for 2 hours on Thursday nights. Fixed ratio schedule Reinforcement occurs after a specific number of responses.( fast response rate) E.g. - A man is paid $10 for every five hats he makes. He makes as many hats as he can during his shift. Variable interval schedule Reinforcement occurs after a random amount of time.( it is highly resistant to extinction.) . E.g. After 5 minutes of fishing in a lake a man catches a large fish. He then spends 4 hours waiting for another bite. Variable ratio schedule Reinforcement occurs after a random number of responses. (highly resistant to extinction) . E.g. - After a slot machine pays off $5 for a single quarter, a woman plays $50 in quarters despite the fact that she receives no further payoffs. Of all the reinforcement schedules, variable schedules are the most resistant to extinction. Applications of Operant Principles Behavior modification Shaping Token economies Contingency contracts Extinction, time-out, and response cost Punishment