Dr. Aws khasawneh. #8 : behavioral learning Hadeel alothman

Transcription

1 Dr. Aws khasawneh #8 : behavioral learning Hadeel alothman

2 - We study the concept of the behavioral learning because it helps us to demonstrate the mechanism of psychological diseases and to understand why does it happen - The behaviorist Said the we learn behavior by two ways : adaptive and maladaptive.. - The mal - adaptive way of learning will lead to abnormal behavior and the result will be a disease 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: the more important in behavioral therapy techniques 1 - Classical Conditioning. 2 - Operant Conditioning. 1-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.

3 We will come to explain this concept of classical conditioning but first we need to know some key definitions : Unconditioned Stimulus (US) - stimulus naturally triggers a response ( like when see or smell the food, this stimulates the natural or the reflex response ; the salivation) Unconditioned Response (UR) - unlearned (natural) or reflexive response (behavior) to the UCS Like the salivation Conditioned Stimulus (CS) stimulus that produce a response following learning ( initially neutral) : like when the ring sound of a bell or whatever stimulus doesn't initially cause salivation of a dog for example (it is neutral at first ) but after learning experience it may has the ability of salivation when it hears the sound Conditioned Response (CR) is a behavior (response) that is learned by an association between a conditioned stimulus and unconditioned stimulus. now let's come to an experience of a Ivan Pavlov explaining an example of person called Classical conditioning : - Firstly he was Russian physiologist studying the digestive system; he has nothing to do with psychology but his experiences helped in demonstrating or developing some psychological principles - Focused on what substance helped to break food down and One notable substance studied was saliva -Developed method (a machine or an apparatus) to measure saliva production B-The Processes of Pavlov s Saliva Research Dog given food and salivation was recorded while the dog ate C-The results :

4 Key finding: Experienced dogs salivated before the food was presented Pavlov s Theory: Some stimulus (e.g. when the dog see the experimenter or the 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 : models of ways for learning classical conditioning 1 st : 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) 2 nd : Select a Stimulus for Conditioning (CS) Conditioned stimulus 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 SO in pavlov's dogs we can demonstrates many concepts : Before Conditioning : US (Food) UR (Salivation) CS (Bell) No CR because it is initially neutral but the Dog may turn its head to the source of the sound (an orienting response) During Conditioning : which means that the CS is paired or presented consistently before presenting the unconditioned stimulus ( the bell with the sight of food ) with time After many times of pairing CS (Bell) US (Food) UR (Salivation) As presentations continue (more pairing tries ) : CS (Bell) CR (Salivation) US (Food) UR (Salivation)

5 After Conditioning : US (Food) UR (Salivation) CS (Bell) CR (Salivation) so the CS eventually elicit the CS :)الخمىداوانتهاءالشيء Extinction( -The conditioned response(cr) decreases if the conditioned stimulus(cs) is never again paired with the unconditioned stimulus (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 For example : in case of pavlov's dogs ; after learning ( the first pairing process ) if we just ring the bells without presenting the food the dogs will salivate only at first but after many times we will reach a state where dogs don t have salivation ( extinction ) after ringing the bells because we stop the pairing process If we do the pairing process again dogs will return to the first state again ( they salivate when they hear the bells ) also we have something called Spontaneous Recovery - Even though no CRs present after one day of extinction trials, CR is present the following day : after extinction we ring the bells and the dogs salivate because we have a spontaneous recovery -Time is key factor in explaining this spontaneous recovery - More time between 1 st and 2 nd extinction session, more spontaneous recovery observed : if we have more time between extinctions sessions, the pairing period will increase and the more spontaneous recovery we will have Rapid Reacquisition : - Acquisition phase (learning) extinction phase acquisition phase (i.e. reacquisition phase) - we may use this method when we want a rapid learning where we have : - Faster Rate of learning -Repeated Cycles continues to get faster

6 Generalization and Discrimination : -Generalization: Transfer of effects of conditioning to similar stimuli In general, the more similar a stimulus is to a training stimulus, the greater its capacity to elicit a CR ( in the previous experience in pavlove dogs ; we may use any another similar sound which would may elicit the salivation) - Discrimination: Subject learns to respond to one stimulus, but not to a similar stimulus : the dog will respond only to the ring sound not to any other sound of any other bell Some clinical applications Of generalization : J.B. Watson: suggested that human emotions might profitably be thought of as glandular and muscular reflexes which, like salivation, easily become conditioned : the emotions may be learned, get paired with places or times and conditioned to a certain stimulus and depending on that he explained the concept of phobia He did an experience with a Little child called Albert which was then considered unethical but it is important for you to know.. in this experience 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, 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.. this infant was only afraid of the sound of steel bar but when Watson did pairing between this sound and touching a white rat ( which is initially neutral ; doesn't scare him ), and after 7 times of pairing, little Albert had a fear from white hair, fur and wool etc ( he learned this fear response to these things and he experienced generalization by being scared of anything look like the white rat ) Applications in Behavioral Therapy 1- Systematic Desensitization for Phobia*** : It is a gradual treatment for phobias in which the individual is trained to relax while being exposed to progressively more anxiety-provoking stimuli : we may expose

7 these fears at first using imagination not necessarily by real and at the same we reduce the anxiety by drugs or relaxation techniques and breathing exercise. 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 It Means that we expose the person to an aversive and unpleasant stimulus if he shows anxietic phobia. 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. : *** Phobia isn t specific ; everything in the world may cause phobia Practical example : 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 The answer is b now we will come to the second type of complex form of learning 2 ) OPERANT CONDITIONING : more developed than classical conditioning - Principle For an individual, behavior is determined by its consequences. The consequences (reenforcement or punishment) occurs immediately following a behavior in classical conditioning ; the desired condition stimulus happen before the behavior ( we learn it ) while in operant condition; the behavior depends on the consequences ( if we do re-enforcement, the behavior will probably continue and if we do punishment, it will stop ) The Skinner experiment : It is a box with a lever عتلة and rats moving randomly in it and the rat learned that when it pushes the lever, a food will drop down into the box so it continously goes to

8 push the lever to get food as the food re enforces the rat, it will keep pushing the lever at the same time there was a place in the box where there Is an electrical current and in order for the rat to get away from this area it has to go and push the lever ( this is called negative re-enforcement : it is like people when escape from things that hurt them but at the same time we enforce desired behaviors ) Differences between Classical Conditioning and Operant Conditioning Classical Conditioning -Simple/Reflex Behavior - Focuses on ANTECEDENTS: Events which take place BEFORE the target response - Learning takes place when there is an association made between two unrelated stimuli (before the desired or target response) Operant Conditioning -Complex/Voluntary Behavior -Focuses On CONSEQUENCES: Events which take place AFTER the target response - Learning takes place when a desired (target) response is affected by its consequences (after the desired/target response) Operant Conditioning Concepts Always when we say re- enforcement we mean increasing any specific target or behavior even though it is positive or negative re-enforcement 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 punishment: the introduction of aversive stimulus after behavior aimed at reduced the rate of that behavior by giving aversive stimulus 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

9 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 ( she can achieve her goal by different mechanism ) : Feature Positive reinforcement Effect on behavior Behavior is increased by reward Example Child increases his kind behavior toward his younger brother to get a praise from his mother Comment 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 Punishment Extinction Behavior is increased by avoidance or escape Behavior is decreased by suppression ( child decreases his hitting behavior after the mother scolded him ) Behavior is eliminated by non reinforcement(ignorance) Child increases his kind behavior toward his younger brother to avoid being scolded( the mother tell his child that she will scold him if he hits his brother) Behavior is decreased by suppression Child stops his hitting behavior when the behavior is ignored by his mother(she doesn t do anything to him nor positive or negative) Active avoidance of an aversive stimulus (being scolded) increases desired behavior (kindness toward brother) Delivery of an aversive stimulus (scolding) decreases unwanted behavior (hitting brother) rapidly but not permanently 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 Remember : in reinforcement we increase particular behavior by reward or escape while in punishment we reduce a behavior.

10 Shaping - Reducing complex behaviors into several more simple behaviors - Reinforcing successive approximations to the complex behavior (for instance when the child wants to learn reading and writing, this process is long and consists of many steps so every time he learns something new, the letters for example, we give him a reward and so on.. same applies when we want o teach kids to use the bathroom -Modeling: type of observational learning in which individual behaves in a manner similar to that of someone she/he admires ;is it one of the techniques used in behavioral therapy specially in OCD ( obsessive compulsive disorder ) patients who are repeating actions over and over like washing hand or ( الوضوء ) So we tell these patients to follow a person whom are considered a model to them Schedules of Reinforcement 1 Continuous : Reinforcement presented after every response.( rapidly learned but has little resistance to extinction/ disappears rapidly if we stop the reinforcement ) 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. 2- 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... they have the habit to study more in the day before the exam in order to pass 3- 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 ( he tries to work more and more 4- Variable interval schedule Reinforcement occurs after a random amount of time.( it is highly resistant to extinction.)

11 . 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. 5-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 : used in many aspects of life : in our homes, with children, in schools, by people who works in and even with adults in behavioral therapy : Behavior modification -Shaping ( may apply in toilet training and learning reading and writing ) - Token economies ( for instance the child is reinforced to collect things with no value like stickers and may be asked to collect a particular number of it so the child can get money instead ) - Contingency contracts ( a contract between parents and their children so if they do a particular positive thing, their parents will allow them to go out, to use their car or any rewards things ) - Extinction, time-out, and response cost and punishment (more used with kids and teenagers) this lecture is specially dedicated to my special friends Aseel, hadeel and roaa