Preview Question 2: How does classical conditioning demonstrate learning by association?
Preview Question 3: How does a neutral stimulus become a CS, and what are the processes of acquisition, extinction, spontaneous recovery, generalization, and discrimination in classical conditioning?
Unconditioned Stimulus (UCS): A stimulus that automatically and naturally triggers a response. Unconditioned Response (UCR): A unlearned, naturally occurring response to the unconditioned stimulus, like salivation in the dog when food is in the mouth. Conditioned Stimulus (CS): Originally a neutral stimulus that, after association with an unconditioned stimulus, comes to trigger a conditioned response. Conditioned Response (CR): A learned response to a previously neutral conditioned stimulus.
Preview Question 4: Do cognitive processes and biological constraints affect classical conditioning?
Preview Question 5: Why is Pavlov’s work important?
Mod 17 Classical Conditioning
Learning How Do We Learn?http://www.youtube.com/watch?v=nKHxT7fDwN4
Definition Learning is a relatively permanent change in an organism’s behavior due to experience.Learning helps us adapt to our environment. Nature’s most importantgift to us may be our adaptability—our capacity to learn newbehaviors that enable us to cope with ever-changing experiences.Learning also breeds hope. What we learn we can also teach toothers.
How Do We Learn?The key to learning is experience. We learn by association. Ourminds naturally connect events that occur in sequence.2000 years ago, Aristotle suggested this law of association. Then200 years ago Locke and Hume reiterated this law.The events linked in associative learning may be two stimuli (asin classical conditioning) or a response and its consequences (asin operant conditioning). In observational learning, we learn byviewing others’ experiences and examples.
Associative Learning Learning to associate one stimulus with another. (classical conditioning)This sea snail withdraws its gills when squirted with water. In its naturalhabitat (i.e. choppy water) this response diminishes. However, if the squirtis followed by an electric shock, the response becomes stronger. The snailrelates/associates the squirt of water to the impending shock.
Associative Learning Learning to associate one stimuluswith another. (classical conditioning)
Associative Learning Learning to associate a responsewith a consequence. (operant conditioning)
Associative Learning Learning to associate a responsewith a consequence. (operant conditioning)
Associative Learning• Ex: 11 Mexican Grey Wolves (which has been extinct in the US since 1977) were bred and raised in captivity.• They were released in the Arizona Apache National Forest in 1988.• After 8 months there was only one surviving wolf. They had learned to hunt and move away from people but they had not learned to be afraid of them and hence did not run away from those with guns.• This supports that successful adaptation requires both nature (genetic predispositions) and nurture (history of appropriate learning).
• Conditioning is the process of learning associations. In this module (18/7ed or 17/8thed) we will cover classical conditioning which is when we learn to associate two stimuli and anticipate the events.• In the next module (19/7ed or 18/8ed), we look at operant conditioning where we learn to associate a response (our behavior) and its consequences. We usually repeat those acts that are followed by good rewards and avoid those acts that are followed by bad results.
Classical ConditioningIdeas of classical conditioning originate from old philosophicaltheories. However, it was the Russian physiologist Ivan Pavlov whoelucidated classical conditioning. His work provided a basis for laterbehaviorists like John Watson. Watson and Pavlov shared: (1) adisdain for mentalistic concepts such as consciousness and (2) abelief that the basic laws of learning were the same for all animals –whether dogs or humans. Today classical conditioning is seen as a basic form of learning by which all organisms adapt to their environment. However, it isagreeable that the conscious and mental processes should not be ignored either.Sovfoto Ivan Pavlov (1849-1936)
Pavlov’s Experiments Before conditioning, food (Unconditioned Stimulus, US) produces salivation(Unconditioned Response, UR). However, the tone (neutral stimulus) does not.
Pavlov’s ExperimentsPavlov would repeatedly present a neutral stimulus (such as a tone) just before an unconditioned stimulus (US), such as food, which triggered the unconditioned response (UR) of salivation. After several repetitions, the tone alone (now the conditioned stimulus [CS]) began triggering a conditioned response (CR), salivation. Unconditioned means “unlearned”; conditioned means “learned.” Thus, a UR is an event that occurs naturally in response to some stimulus. A US is something that naturally and automatically triggers the unlearned response. A CS is an originally neutral stimulus that, through learning, comes to be associated with some unlearned response. A CR is the learned response to the originally neutral but now conditioned stimulus.
Pavlov’s ExperimentsDuring conditioning, the neutral stimulus (tone) and the US (food) are paired, resulting in salivation (UR). After conditioning, the neutralstimulus (now Conditioned Stimulus, CS) elicits salivation (now Conditioned Response, CR)
ConditioningThe bigger picture (in regards to conditioning):Conditioning helps an animal survive and reproduce—by responding to cues that help it gain food, avoid danger, locate mates, and produce offspring.http://www.youtube.com/watch?v=hhqumfpxuzI
Acquisition Acquisition is the initial learning stage in classical conditioning in which an association between a neutral stimulus and an unconditioned stimulus takes place.1. In most cases, for conditioning to occur, the neutral stimulus needs to come before the unconditioned stimulus.2. The time in between the two stimuli should be about half a second.3. Responses acquired like this demonstrate how classical conditioning is biologically adaptive because it helps organisms prepare for good or bad events.
AcquisitionThe CS needs to come half a second before the US for acquisition to occur.
ExtinctionExtinction refers to the diminishing of a conditioned response whenthe conditioned stimulus occurs repeatedly without theunconditioned stimulus.When the US (food) does not follow the CS (tone), CR (salivation)begins to decrease and eventually causes extinction.
Spontaneous RecoverySpontaneous recovery is the reappearance, after a pause, of anextinguished conditioned response.After a rest period, an extinguished CR (salivation) spontaneouslyrecovers, but if the CS (tone) persists alone, the CR becomesextinct again.
Stimulus GeneralizationTendency to respond to stimulisimilar to the CS is calledgeneralization. Pavlov conditionedthe dog’s salivation (CR) by usingminiature vibrators (CS) on thethigh. When he subsequentlystimulated other parts of the dog’sbody, salivation dropped.Generalization has survival valuebecause it extends a learned response toother stimuli in a given category, forexample, fleeing from all dangerousanimals.
Stimulus DiscriminationDiscrimination is the learned ability to distinguish between aconditioned stimulus and other stimuli that do not signal anunconditioned stimulus.Discrimination has survival value because it limits our learned responsesto appropriate stimuli, for example, fleeing from a rampaging lion butnot from a playful kitten.
Taste AversionsTaste aversions are particularly good for illustrating classical conditioning. Perhaps you can share one of your own and explain it in terms of conditioning principles. Example: Some years ago my instructor stored a dinner in the freezer compartment of our department’s refrigerator. When he went to retrieve it, he found it in the company of a frozen laboratory rat. He learned that a student assistant, not knowing how to dispose of the deceased animal, had carefully packaged it in plastic and temporarily placed it in the freezer. Not only was he unable to eat the dinner in the freezer, but now he finds all such dinners repulsive. Do you have any experiences of your own?Psychologist Paul Rozin states, “Many people find slimy foods upsetting or anything with mucoid texture.” This is an example of what he calls “secondary disgust,” disgust for something that looks or feels similar to something disgusting in its own right. Rozin notes how subjects in one of his experiments were presented with two pieces of chocolate fudge, one shaped to look like a muffin, the other a replica of dog droppings. Guess which one subjects avoided.
Taste AversionIn the following exercise, react to the following tasteful situations described by Rozin. Then, we will compare your responses to those of Rozin’s 143 subjects. You should respond on a 9-point scale from 1 = dislike extremely through 5 = neutral to 9 = like extremely.For the first four questions, dream up a bowl of your favorite soup, one that would score an unqualified 9.1. Now imagine that the soup was served to you in an ordinary bowl, but had been stirred by a thoroughly washed, used flyswatter. How much would you like to eat that soup?2. If that flyswatter were brand new, how much would you like to eat the soup?3. If the soup was first stirred with a thoroughly washed but used comb, how much would you like to eat it?6. If the soup was served in a thoroughly washed, used dog bowl, how much would you like to eat it?Now fantasize about your favorite cookie, again one that would rate a 9.5. How much would you like to eat this cookie if you’d dropped it on the grass first?6. How much would you like to eat it if a waiter had taken a bite first? an acquaintance? a good friend?
Taste AversionClearly, the association principle is everything when it comes to food. The idea that something disgusting has been near a favorite dish puts most people off, even when the food is germ-free. Here are Rozin’s results.1. Eighty-two percent of Rozin’s subjects rated the “clean-flyswatter soup” a 4 or less; they would dislike eating it.2. Fifty-eight percent disliked this bowl of soup. Since the flyswatter is brand new, it has less of an association with insects. However, the idea that the soup had been stirred by an object that might meet a fly in the future was enough to make some people pass it up.3. Seventy-six percent disliked this soup. Presumably, the thought of human hair is slightly less disgusting than insect contamination.4. Seventy-one percent disliked soup served in a dog bowl.5. Only 34 percent would want to pass up this cookie. There’s no assurance of perfect cleanliness, but grass itself has few negative associations for most of us.6. Eighty-four percent would reject this cookie after a waiter had taken a bite. Only 31 percent would refuse it after an acquaintance had taken a bite, and just 16 percent, if a friend had taken a bite.
Extending Pavlov’s UnderstandingPavlov and Watson considered consciousness, ormind, unfit for the scientific study of psychology.However, they underestimated the importance of cognitive processes and biological constraints. Recap:http://www.youtube.com/watch?v=DUa_F2OJT0k&feature=related
Cognitive Processes Early behaviorists believed that learnedbehaviors of various animals could be reduced to mindless mechanisms. However, later behaviorists suggested thatanimals learn the predictability of a stimulus,meaning they learn expectancy or awareness of a stimulus (Rescorla & Wagner, 1972).
Biological Predispositions Pavlov and Watson believed that laws of learning were similar for all animals.Therefore, a pigeon and a person do not differ in their learning. However, behaviorists later suggested thatlearning is constrained by an animal’s biology.
The Importance of Cognitive Processes and Biological Predispositions in Classical ConditioningResearch indicates that, for many animals, cognitive appraisals are important for learning. That is, thoughts and perceptions are important to the conditioning process. For example, animals appear capable of learning when to expect an unconditioned stimulus. The more predictable the association between the CS and the US, the stronger the CR.The early behaviorists’ view that any natural response could be conditioned to any neutral stimulus has given way to the understanding that each species is biologically prepared to learn associations that enhance its survival. Thus, humans are likely to develop an aversion to the taste of a contaminated food but not to the sight of an associated restaurant, its plates, or the music they heard there. Similarly, rats develop aversions to tastes but not to sights or sounds. Conditioning occurs best when the CS and the US have just the sort of relationship that would lead a scientist to conclude that the CS causes the US.
Biological Predispositions Courtesy of John Garcia Garcia showed that the duration between the CS and the US may be long (hours), but yet result inconditioning. A biologically adaptive John Garcia CS (taste) led to conditioning but other stimuli (sight or sound) did not.
Biological PredispositionsEven humans can develop classically to conditioned nausea.
Pavlov’s LegacyPavlov’s greatest contribution to psychology is isolating elementary behaviors from more complex ones through objective scientific procedures. Ivan Pavlov (1849-1936)
Pavlov’s LegacyPavlov taught us that principles of learning apply across species and that classical conditioning is one way that virtually all organisms learn to adapt to their environment. Pavlov also demonstrated that significant psychological phenomena can be studied objectively. Finally, Pavlov taught us that conditioning principles have important applications such as how to treat fear.Classical conditioning principles provide important insights into drug abuse and how it may be overcome. Classical conditioning works on the body’s disease-fighting immune system. For example, when a particular taste accompanies a drug that influences immune responses, the taste by itself may come to produce those immune responses. Watson’s “Little Albert” study demonstrated how classical conditioning may underlie specific fears. Today, psychologists use extinction procedures to control our less adaptive emotions and condition new responses to emotion-arousing stimuli.
Applications of Classical Conditioning1. Former drug users often feel a craving when they are again in the drug-using context—with people or in places they associate with previous highs. This, drug counselors advise addicts to steer clear of people and settings that may trigger theses cravings.2. Classical conditioning even works on the body’s disease-fighting immune system. When a particular taste accompanies a drug that influences immune responses, the taste by itself may come to produce an immune response.
Applications of Classical Conditioning Watson used classicalconditioning procedures to develop advertisingcampaigns for a number of organizations, includingMaxwell House, making the“coffee break” an American Brown Brothers custom. John B. Watson
Little AlbertHuman behaviors and emotions are biologically influenced, however they are also greatly learned and are hence a bundle of conditioned responses.Case: Little Albert—he feared loud noises like most infants, but he did not fear rats. He was conditioned to fear rats and then generalized that fear to other things as well.http://www.youtube.com/watch?v=Xt0ucxOrPQE&feature=related