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Active vocabulary
conditioning [kqn'dIS(q)nIN] кондиціонування, установлення необхідного складу або стану; психологічна обробка, особ. з використанням умовних рефлексів
reveal [rI'vi:l] показувати, виявляти
predisposition ["pri:dIspq'zIS(q)n] нахил; схильність
verify ['verIfai] перевіряти, контролювати
digestive [d(a)I'dZestIv] засіб, що сприяє травленню
seize [si:z] вистачати, схопити
salivary [sq'laIv(q)r] слинний
salivary gland - слинна залоза
invariably [In've(q)rIqbli] незмінно, постійно
annoyance [q'nOIqns] джерело подразнення
stimulus ['stImjVlqs] стимул, спонукальна причина; стимулюючий, збудливий вплив
spontaneous [spPn'teInIqs] мимовільний, стихійний; спонтанний
generalization ["dZen(q)rqlaI'zeIS(q)n] узагальнення
Text.
The Outstanding Scientist Pavlov and His Great Discovery of Conditioned Reflex
Russian physiologist Ivan Pavlov explored one important form of learning in his classic experiments on conditioning dogs. Pavlov showed how scientific research can reveal learning principles that apply across species. Others have modified Pavlov's understandings by demonstrating the importance of cognition and of biological predispositions to learn certain associations.
Although the idea of learning associations had long generated philosophical discussion, it was not until this century that psychology's most famous research verified it. For many people, the name Ivan Pavlov rings a bell. His experiments are classics, and the phenomenon he explored we justly call classical conditioning
Pavlov's Experiments
Pavlov was driven by a lifelong passion for research. After receiving a medical degree at age 33, he spent the next 2 decades studying the digestive system, work that earned him Russia's first Nobel Prize in 1904. But it was his novel experiments on learning, to which he devoted the last 3 decades of his life that earned this feisty scientist his place in history.
Pavlov's new direction came when his creative mind seized on an incidental finding. After studying salivary secretion in dogs, he knew that when he put food in a dog's mouth the animal would invariably salivate. He also noticed that when he worked with the same dog repeatedly, the dog began salivating to stimuli associated with food-to the mere sight of the food, to the food dish, to the presence of the person who regularly brought the food, or even to the sound of that person's approaching footsteps. Because these "psychic secretions" interfered with his experiments on digestion, Pavlov considered them an annoyance-until he realized they pointed to a simple but important form of learning. From that time on, Pavlov studied learning, which he hoped might enable him to understand better the workings of the brain.
At first, Pavlov and his assistants tried to imagine what the dog was thinking and feeling as it drooled in anticipation of the food. This only led them into fruitless debates. So to attack the phenomenon more objectively, they experimented. They paired various neutral stimuli with food in the mouth to see if the dog would begin salivating to the neutral stimuli alone. To eliminate the possible influence of extraneous stimuli, they isolated the dog in a small room, secured it in a harness, and attached a device that diverted its saliva to a measuring instrument. From an adjacent room they could present food-at first by sliding in a food bowl, later by blowing meat powder into the dog's mouth at a precise moment. If a neutral stimulus-something the dog could see or hear-now regularly signaled the arrival of food, would the dog associate the two stimuli? If so, would it begin salivating to the neutral stimulus in anticipation of the food?
The answers proved to be yes. Just before placing food in the dog's mouth to produce salivation, Pavlov would sound a tone. After several pairings of tone and food, the dog began salivating to the tone alone in anticipation of the meat powder. Using this procedure, Pavlov conditioned dogs to salivate to other stimuli-a buzzer, a light, a touch on the leg, evens the sight of a circle.
Now for some necessary terminology: Because salivation in response to food in the mouth was unlearned, Pavlov called it an unconditioned response (UCR). Food in the mouth automatically, unconditionally, triggers a dog's salivary reflex. Thus, Pavlov called the food stimulus an unconditioned stimulus (UCS).
Salivation in response to the tone was conditional upon the dog's learning the association between the tone and the food. This learned response we therefore call the conditioned response (CR). The previously neutral tone stimulus that now triggered the conditional salivation we call the conditioned stimulus (CS). It's easy to distinguish these two kinds of stimuli and responses. Just remember: conditioned = learned; unconditioned = unlearned.
If this demonstration of associative learning was so simple, what did Pavlov do for the next 3 decades? He and his associates explored the causes and effects of classical conditioning. Their experiments identified five major conditioning processes: acquisition, extinction, spontaneous recovery, generalization, and discrimination.
Extinction and Spontaneous Recovery
After conditioning, what happens if the CS occurs repeatedly without the UCS? Will the CS continue to elicit the CR? Pavlov found that when he sounded the tone again and again without presenting food, the dogs salivated less and less. Their declining salivation illustrates extinction, which occurs when the CS (tone) no longer signals an impending UCS (food).
Pavlov found, however, that if he allowed several hours to elapse before sounding the tone again, the salivation to the tone would reappear spontaneously. This spontaneous recovery-the reappearance of a (weakened) CR after a rest pause-suggested to Pavlov that extinction was suppressing the CR rather than eliminating it.
After breaking up with his fire-breathing heartthrob, Tirrell also experienced extinction and spontaneous recovery. He recalls that "the smell of onion breath (CS), no longer paired with the kissing (UCS), lost its ability to shiver my timbers. Occasionally, though, after not sensing the aroma for a long while, smelling onion breath awakens a small version of the emotional response I once felt."
Generalization
Pavlov and his students noticed that a dog conditioned to the sound of one tone also responded somewhat to the sound of a different tone or even to a buzzer never paired with food. Likewise; a dog conditioned to salivate when rubbed would also salivate some when scratched (Windholz, 1989) or when stimulated on a different body part. This tendency to respond to stimuli similar to the CS is called generalization. Generalization can be adaptive, as when toddlers taught to fear moving cars in the street respond similarly to trucks and motorcycles.
Because of generalization, stimuli that are similar to naturally disgusting or appealing objects will, by association, evoke some disgust or liking. Normally desirable foods, such as fudge, are unappealing when presented in a disgusting form, as when shaped to resemble dog feces (Rozin & others, 1986). We perceive adults with childlike facial features (round face, large forehead, small chin, large eyes) as having childlike warmth, submissive-ness, and naivete (Berry & Me Arthur, 1986). In both cases, people's emotional reactions to one stimulus generalize to similar stimuli.
Discrimination
Pavlov's dogs also learned to respond to the sound of a particular tone and not to other tones. This learned ability to distinguish between a conditioned stimulus and similar but irrelevant stimuli is discrimination. Like generalization, discrimination has survival value. Slightly different stimuli are at times followed by vastly different consequences. Being able to recognize these differences is adaptive. Confronted by a pit bull, your heart may race; confronted by a cocker spaniel, it does not. Facing an approaching group of skinheads, you may cross the street; approaching some bald gentlemen, you don't.
Updating Pavlov's Understanding
Pavlov and Watson's disdain for "mentalistic" concepts such as consciousness has given way to a growing realization that they underestimated the importance of cognitive processes (thoughts, perceptions, expectations) and of biological constraints on an organism's capacity for learning.
Cognitive Processes
The early behaviorists believed that the learned behaviors of various organisms could be reduced to mindless stimulus-response mechanisms. The idea that rats and dogs exhibit cognition therefore struck many psychologists as silly No longer. Classical conditioning experiments by Robert Rescorla and Allan Wagner (1972) revealed that when two significant events occur close together in time, an animal learns the predictability of the second event, given the first. What matters is not how often an electric shock, say, follows a tone, but how predictably. The more predictable the association, the stronger the conditioned response.
It's as if the animal learns expectancy, awareness of how likely it is that the UCS will follow the CS. Rescorla (1988) surmises that classical conditioning "is not a stupid process by which the organism willy-nilly forms associations between any two stimuli that happen to occur." Rather, the organism is an information seeker, using relations among events to form its own adaptive representation of the world. Indeed, says Rescorla, a simple rule of thumb summarizes a host of facts about classical conditioning: Conditioning occurs best when the CS and UCS have just the sort of relationship that would lead a scientist to conclude that the CS causes the UCS.
This analysis helps to explain why classical conditioning treatments that ignore cognitive appraisals often have limited success. For example, therapy for alcoholics sometimes includes giving them alcohol spiked with a nauseating drug. Will they then associate alcohol with sickness? If classical conditioning were merely a matter of "stamping in" stimulus-response associations, we might hope so, and-to some extent-this does occur. However, alcoholics are aware that they can blame their nausea on the drug, not on the alcohol. This cognition often weakens the association between alcohol and sickness. So, even in classical conditioning, it is not only the simple stimulus-response association but also the thought that counts.
Answer the following questions
1. What did Ivan Pavlov explore and show?
2. What experiments earned the scientist his place in history?
3. What did Pavlov call an uncorditioned response? Why?
4. What did Pavlov and his associates explore for 3 decades/
5. What did their experiments identify?
6. What is spontaneous recovery?
7. Who else explored extinction and spontaneous recovery?
8. What did Pavlov and his students notice of a dogconditionedto the sound?
9. What tendency is called generalization?
10. What is discrimination?
11. What cognitive processes did Pavlov underestimate?
12. What did R. Rescola and A. Wagner’ experiments reveal?
13. Why do often classical conditioning treatments have limited succes?
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