PSYC 387 Unit 2 Pavolovian Conditioning PDF

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PSYC 387 Unit 2 Pavolovian Conditioning .......................................................................................................................................................................................................................................................................

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PSYC 387 Unit 2 Pavovlian Conditioning

1.

Describe Pavlov’s early life, career path, and other factors that led him to study the digestive processes and the salivary reflex in the dog. When did Pavlov become interested in psychic reflexes? (pp. 57–60) -

Pavlov spent years researching the physiology of digestion and research on the circulatory system. He developed surgical procedures that allowed him to study digestive processes in animals, with specific focus on the salivary glands and salivary reflex. One of his goals was to understand how food could be broken down into its chemical components to be absorded into the body. He discovered that the amount of saliva produced what dependent on the amount required to either begin digestion of a certain type of food, or to eject an inedible substance from its mouth.

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The discovery that after a number of feedings in the lab, the animals started salivating before the food was even presented led to his curiosity about psychic secretions and 'psychic reflexes'. He wanted to ensure he remained working in the physiology field, not psychology, but in order to determine this, he was compelled to continue his research.

2. What were the psychic secretions that became a focus of Pavlov’s work? Why did Pavlov shift the focus of his work from digestive processes to psychic secretions? (p. 59) -

These would be the conditioned reflexes that developed after prior feeding/testing.

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He wanted to ensure he remained working in the physiology field, not psychology, but in order to determine this, he was compelled to continue his research and determine the potential source for these secretions.

3.

Describe Pavlov’s work with dogs that illustrates Pavlovian conditioning. Define unconditional reflexes, conditional reflexes, unconditional stimulus, unconditional response, conditional stimulus, and conditional response. What terms are used in place of these? (pp. 60–62) Comment: In describing Pavlovian conditioning, it is customary to also speak of another type of stimulus, a neutral stimulus. Chance de-emphasizes the neutral stimulus in his treatment of the topic. (He does mention it on page 61 but does not include it in his diagrams of classical conditioning and does not include it as a critical term.) The neutral stimulus is simply a way of describing the conditional stimulus before it is able to elicit the conditional response. For example, the author describes the use of a hand clap as a conditional stimulus (p. 61). We would refer to the hand clap as a neutral stimulus before it could elicit the conditional response,

salivation. In this unit’s conceptual exercise, you will be asked to identify the neutral stimulus in examples of Pavlovian conditioning. -

There are, Pavlov concluded, two distinct kinds of reflexes. One kind is the largely inborn and usually permanent reflex found in virtually all members of a species and that varies little from individual to individual. The dog that salivates when food is put into its mouth manifests this type of reflex. Pavlov called these unconditional reflexes because they occur more or less unconditionally.

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The second type of reflex is not present at birth; it must be acquired through experience and is, compared to innate reflexes, relatively impermanent. Because these psychic reflexes depend on experience, they vary considerably from individual to individual. The dog that salivates at the sound of a particular person’s footsteps is an example of this type of reflex. Pavlov called these conditional reflexes because they “depend on very many conditions”

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An unconditional reflex consists of an unconditional stimulus (US) and the behavior it evokes, the unconditional response (UR). Unconditional stimuli are typically events that are important to survival. Example: Meat powder is an unconditional stimulus that reliably evokes the unconditional response of salivation: An unconditional reflex consists of an US

UR

meat powder

salivation

A conditional reflex consists of a conditional stimulus (CS) and the be- havior it reliably evokes, the conditional response (CR). When the sight of a food dish regularly evokes salivation, the food dish is a CS and salivating is a CR:

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CS

CR

food dish

salivation

Pavlov admitted that other terms would have served as well: Unconditional reflexes might have been referred to as inborn, unlearned, or species reflexes; conditional reflexes could have been called acquired, learned, or individual reflexes. But the terms conditional and unconditional caught on and are still used today.

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For our purposes, we will consider a stimulus to be neutral if it does not elicit a particular conditioned or unconditioned response. For example, a bright light does not elicit eye blinks, so it is a neutral stimulus with respect to the eye-blink response. However, bright light does elicit pupil contraction, so bright light would be an unconditioned stimulus (not a neutral stimulus) for the pupil-contraction response.

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An example will illustrate the point. If you were to clap your hands near a dog, it might respond in a number of ways, but salivating is not likely to be one of them. As far as the salivary reflex is concerned, clapping is a neutral stimulus. Now suppose you clap your hands and then immediately give the dog a bit of food:

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CS

US

UR

clap

meat

salivate

If you were to repeat this procedure several times, the dog might begin salivating when you clap your hands:

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CS

CR

clap

salivate

Pavlov showed that there are two kinds of reflexes, unconditional and conditional. An unconditional reflex consists of an unconditional stimulus and an un- conditional response; a conditional reflex consists of a conditional stimulus and a conditional response. Unconditional reflexes are largely innate; conditional reflexes are products of experience. The procedure that establishes a conditional response is called Pavlovian or classical conditioning. There are two critical features of Pavlovian conditioning: First, the behavior involved is a reflex response; second, the CS–US pairing occurs regardless of what the individual does.

5.

Describe Wallace and Rosen’s demonstration (2000) that rats show a strong response to an odorous chemical derived from fox feces. How does this assist in survival? (pp. 60–61) The rat that has an innate tendency to freeze or run away when it detects odors associated with its enemies has a better chance of avoiding those enemies.

6. Is the presentation of the two stimuli (i.e., the neutral stimulus and the unconditional stimulus) independent of the behaviour of the animal? Explain. Provide an original example illustrating that an organism whose behaviour is subject to Pavlovian conditioning is more likely to survive than an organism whose behaviour is not subject to such conditioning. (p. 63)

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Yes, the presentation of the two stimuli is independent of the behaviour of the organism; the CS and the US are presented regardless of what the organism does. Second, the behaviour involved is a reflex response

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Humans are subject to Pavlovian conditioning and it consistently improves our chances of survival, as experience increases survival chances. For instance when navigating busy streets or reacting to vehicular traffic. The ability to develop conditional reflexes would give any organism a much improved chance of surviving in a changing world.

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Example: an individual who reacts with fear to the sounds of an impending earthquake and learns to protect themselves is more likely to survive.

7.

Define higher-order Pavlovian conditioning. Describe Frolov’s demonstration of higher-order conditioning. Why does higher-order conditioning increase the importance of Pavlovian conditioning? (pp. 63–64) Describe Graham and Desjardins’ (1980) study in which the experimenters used Pavlovian conditioning to influence the mating behaviour of male rats. (pp. 63–64) -

The procedure of pairing a neutral stimulus with a well-established CS is called higherorder conditioning. In most conditioning experiments, a neutral stimulus is paired with a US, such as food. In higher-order conditioning, a neutral stimulus is paired with a well-established CS. This procedure may be less effective in establishing a CR than CS– US pairings, but it is very important in the lives of humans. Many of our emotional reactions (our likes, dislikes, fears, and loves, for example) appear to be acquired at least partly through higher-order conditioning.

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It means that many more stimuli can come to elicit conditional responses

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For example, physiologists J. M. Graham and Claude Desjardins (1980) demonstrated that a male rat that responds to a sexually receptive female by increasing the level of certain hormones will respond in a similar manner to an odor that has been paired with a receptive female. Thanks to higher-order conditioning, a neutral stimulus became a CS by being paired with the odor, without its ever having been paired with a receptive female. This might give the rat a reproductive ad- vantage in the wild: The rat that responds to a stimulus associated with the female’s scent has an advantage over the rat that responds only to her scent.

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Comment: Chance uses higher-order conditioning to refer to the use of a previously established conditional stimulus to function as an unconditional stimulus in Pavlovian conditioning. In this unit’s conceptual exercise, we refer to one form of higher-order conditioning as second-order conditioning. In second-order conditioning, the CS (CS-0) predicts another previously established CS (CS-1). The CS-1 obtained its ability to elicit a CR because it was paired with a US for a UR.

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In third-order conditioning, a CS-0 is paired with a CS-1 that gained its ability to elicit a response by being paired with a previously established CS (CS-2), whereas CS-2 gained its eliciting function by being paired with a US. As such, when we refer to second-order or third-order conditioning, we are referring to the number of steps that the CS is removed from a US. Although second-order conditioning can be quite effective, third-order conditioning (and further removed orders) have not generally been demonstrated to be very potent forms of conditioning. Fifth-order conditioning has been noted if the US is a shock, but generally the further away you get from the pairing with the US, the weaker the CR is likely to be.

8. Describe Staats and Staats’ (1957) classic experiment of verbal higher-order conditioning. (pp. 63– 64) Carolyn and Arthur Staats (1957) asked college students to look at nonsense syllables such as YOF, LAJ, and QUG as they were flashed on a screen. At the same time, the students repeated words spoken by the experimenters. For some students, the experimenters paired the syllable YOF with positive words such as beauty, gift, and win, and the syllable XEH with negative words such as thief, sad, and enemy. For other students, the associations were reversed: XEH was paired with positive words, YOF with negative ones. (Notice that no US was ever presented.) After this, the students rated each nonsense syllable on a seven-point scale ranging from unpleasant to pleasant. The results indicated that the nonsense syllables came to elicit emotional responses similar to the emotional value of the words with which they had been paired. When a nonsense syllable was regularly associated with pleasant words, it became pleasant; when it was paired with unpleasant words, it became unpleasant. In other words, YOF came to elicit good feelings in some students and bad feelings in oth- ers, depending on the words with which it had been associated. Higherorder conditioning, then, appears to play an important role in the emotional meaning of words. 9. How can response latency be used to measure Pavlovian conditioning? How is the use of latency as a measure of Pavlovian conditioning problematic? (pp. 65–66) -

the interval between the onset of the CS and the first appearance of saliva. As the number of CS–US pairings increases, the response latency diminishes; the dog may begin salivating even before the tone stops sounding.

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In some conditioning studies, the interval between CS onset and the appearance of the US is so short that using response latency as a measure of learning is difficult

10. Describe the use of test trials to measure Pavlovian conditioning. Provide an original example of this use of test trials. (p. 65) -

(also called probe trials). This involves presenting the CS alone (i.e., without the US) periodically, perhaps on every fifth trial. If the dog salivates even when it gets no food, the salivation is clearly a conditional response to the tone. Sometimes, test trials are

presented at random intervals, with the conditional stimulus presented alone, perhaps on the third trial, then on the seventh, the twelfth, the thirteenth, the twentieth, and so on (Rescorla, 1967; but see Gormezano, 2000). When test trials are used, the number of CRs in a block of, say, ten test trials is plotted on a curve. Learning is thus represented as an increase in the frequency of the conditional response 11. Describe the method of measuring Pavlovian conditioning by means of intensity or amplitude of the CR. Provide an original example. (p. 65) -

(sometimes called amplitude). Pavlov found that the first CRs are apt to be very weak (a drop or two of saliva), but with repeated trials, the saliva flow in response to the CS increases rapidly. The increase in the number of drops of saliva is a measure of learning.

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A person may blink when presented with a bright light and a clap very weekly at first, but after a few trials person blinks very hard when presented with a bright light

12. Define pseudoconditioning, and explain why it poses a problem in measuring Pavlovian conditioning. How can researchers overcome this problem? (pp. 65–66) -

A strong stimulus can sensitize you to other stimuli so that you react to them more or less as you would react to the strong stimulus

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Poses a problem in measuring Pavlovian conditioning when a stimulus has been paired with a strong US because you don't know if the behaviour that occurs is a conditional response or is the result of the earlier exposure to a strong stimulus

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Researchers can overcome this problem by presenting the CS and US to control group subjects in a random manner so that the stimuli sometimes appear alone and sometimes appear together. The performance of these control subjects is then compared with experimental subjects for which the CS and US always or at least usually appear together

13. Describe the following four ways of pairing the CS and the US in Pavlovian conditioning: trace conditioning, delayed conditioning, simultaneous conditioning, and backward conditioning. Specify the relative effectiveness of each of these procedures. Be able to provide and recognize original examples of each. (pp. 66–69)

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In trace conditioning, the CS begins and ends before the US appears. There is, then, a gap between the two stimuli. Trace conditioning gets its name from the assumption that the CS leaves some sort of neural trace. In the laboratory, trace conditioning is used to study eyelid conditioning in people. Typically, a buzzer sounds for, say, 5 seconds, and then, perhaps a half second later, a puff of air is blown into the person’s eye, causing him to blink. After sev- eral such pairings of the buzzer and air, the person blinks at the sound of the buzzer. The trace procedure has been used with a variety of reflex responses in a variety of species, including the honeybee. Trace conditioning often occurs outside the laboratory: We see the flash of lightning and a moment later we hear the crash of thunder; we hear the dog growl and then feel its teeth; the mother sings to her baby and then offers her nipple.

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In delay conditioning, the CS and US overlap. That is, the US appears before the CS disappears. To apply the delay procedure to eyelid conditioning, we might sound a buzzer for 5 seconds and sometime during this period, we might send a puff of air into the person’s eye. Like trace conditioning, delay conditioning often occurs outside the laboratory: We often hear the thunder before the lightning has faded from view; the dog may continue to growl even as it bites; the mother may continue to sing softly as she nurses her baby. As in trace conditioning, the CS appears before the US; the difference is that in the delay procedure the CS and US overlap.

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In simultaneous conditioning, the CS and US coincide exactly. We might, for instance, ring a bell and blow a puff of air into a person’s eye at the same moment. Both stimuli begin and end at the same time. The simultaneous ap- pearance of CS and US is probably rare in the natural environment, but some- thing approximating it may occur: Thunder and lightning sometimes occur together if the storm is nearby; the dog may snarl and bite at the same instant and stop snarling the moment it releases your leg; the mother may provide the nipple at the very same time she sings to her baby, and she may stop singing the instant she withdraws the nipple. Simultaneous conditioning is a weak procedure for establishing a conditional response (Bitterman, 1964; Heth, 1976). In fact,

if lightning always accompanied thunder but never preceded it, a sudden flash of lightning might not make us flinch in the least. -

In backward conditioning, the CS follows the US. For instance, a puff of air directed at a person’s eye could be followed by the sound of a buzzer. This US–CS sequence can occur outside the laboratory, as when a person sits on a splinter and then (having jumped up from the uncomfortable resting spot) sees the offending object. It is very difficult to produce a CR with the backward procedure. Pavlov described some attempts made at backward conditioning in his laboratory. In one experiment, one of his assistants exposed a dog to the odor of vanilla af- ter putting a mild acid into the dog’s mouth. (The acid, possibly vinegar, was a US for salivation.) The assistant presented acid and vanilla, in that order, 427 times, yet the odor of vanilla did not become a CS for salivating. How- ever, when another odor preceded the acid, it became a CS after only 20 pair- ings. These results are typical of those obtained by others who have attempted backward conditioning (Gormezano & Moore, 1969). There is evidence that backward conditioning is sometimes effective.

14. What is a contingency? Describe Rescorla’s (1968) experiment that demonstrated the importance of the CS-US contingency in the effectiveness of Pavlovian conditioning. In everyday life, do we generally encounter high or medium-low degrees of contingency between the CS and the US? Explain. (p. 69) -

A contingency is an if–then statement. One event, X, is contingent on another event, Y, to the extent that X occurs if and only if Y occurs.

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Various experiments have suggested that the effectiveness of Pavlovian procedures varies with the degree of contingency between CS and US. In one study, Robert Rescorla (1968) exposed rats to a tone followed by a mild shock. Although all the rats received the same number of CS–US pairings, in additional trials the US sometimes appeared alone. In one group, the shock...