Deck 6: Psychophysics

Question 1

A threshold based upon relative judgments where a constant comparison stimulus is judged relative to a series of changing stimuli is called the

A) mean threshold.
B) absolute threshold.
C) difference threshold.
D) median threshold.

Answer 1

difference threshold.

Question 2

Who formalized the psychophysical methods?

A) Edward Boring
B) Gustav Fechner
C) Hermann Ebbinghaus
D) S.S. Stevens

Answer 2

Gustav Fechner

Question 3

Which of the following is not an example of an operational definition?

A) great grandpa's recipe for moonshine
B) an actor has memorized his lines when he can repeat all of his lines twice without an error
C) reaction time is the interval between the presentation of a stimulus and the participant's response
D) a rat is hungry when the rat craves food

Answer 3

a rat is hungry when the rat craves food

Question 4

The most important control variable in a psychophysics experiment is

A) the stimulus magnitude.
B) the stimulus duration.
C) the participant's criterion.
D) the participant's ability.

Question 5

Which of the following is not a property of measurement scales?

A) difference
B) magnitude of attributes
C) subjective equality
D) equal intervals

Question 6

An ideal threshold would be a value of stimulus intensity such that stimulus intensities

A) above this threshold would always be detected.
B) below this threshold would always be detected.
C) equal to this threshold would never be detected.
D) above this threshold would never be detected.

Question 7

In a Receiver Operating Characteristic (ROC) function, chance performance is represented by

A) the bell-shaped curve.
B) Steven's function.
C) .
D) the diagonal.

Question 8

Fechner's law probably yields a __________ scaling, whereas Steven's law yields a __________ scale.

A) ordinal; ratio
B) nominal; interval
C) interval; interval
D) interval; ratio

Question 9

If a rock band turned up its amplifiers to produce twice as much energy as it produced before, the listener would experience a sound

A) twice as loud as before.
B) four times as loud as before.
C) one-half as loud as before.
D) ten time as loud as before.

Question 10

In general, the magnitude of the difference threshold ________with ________ in the magnitude of the standard stimulus.

A) increases; decreases
B) decreases; increases
C) increases; increases
D) remains constant; increases or decreases

Question 11

In signal-detection theory, the position of the criterion is determined by

A) the decision process.
B) the sensory process.
C) the stimulus intensity.
D) the mean of the signal distribution.

Question 12

In signal detection theory, moving the criterion to the left will

A) increase the hit rate.
B) decrease the false alarm rate.
C) increase d΄.
D) have no effect on the false alarm rate.

Question 13

In a task where the observer compares the weight of a constant comparison stimulus with the weights of a changing stimulus using the method of limits, the interval of uncertainty is operationally defined as

A) the mean of the upper and lower thresholds.
B) the difference between the upper and lower thresholds.
C) the distance between the means of the signal and noise distributions.
D) the mean of the stimulus values corresponding to the last "heavier" response and the first "equal," response.

Question 14

The method of limits can be used to determine

A) an absolute threshold.
B) a difference decision.
C) a response threshold.
D) a decision threshold.

Question 15

In signal detection theory, a liberal decision policy means the criterion will be set to the ________, and a conservative decision policy means the criterion will be set to the ___________.

A) left; right
B) right; left
C) right; right
D) left; left

Question 16

You are asked to decide if sugar is present in a cup of coffee. This is an example of a(n)

A) relative judgment.
B) absolute judgment.
C) response judgment.
D) uncertainty judgment.

Question 17

Psychophysical methods would NOT be used to measure judgments about

A) loudness.
B) brightness.
C) heaviness.
D) Happiness

Question 18

In a cold-pressor test,

A) participant must immerse his or her dominant hand and forearm into very cold water.
B) the amount of pressure a participant can tolerate is measured.
C) the amount of pressure a participant can exert using his or her dominant arm is measured.
D) the participant's tolerance for cold climates is measured.

Question 19

In actual practice, the threshold is operationally defined as the _________ of the points in each trial block where the observer switches from Yes to No (or No to Yes).

A) mean
B) standard deviation
C) mode
D) range

Question 20

In order of increasing informativeness, the measurement scales are

A) ratio, ordinal, nominal, and interval.
B) interval, ordinal, ratio, and nominal.
C) nominal, ordinal, interval, and ratio.
D) ordinal, interval, nominal, and ratio.

Question 21

A radiologist is using an MRI to determine whether a tumor detected in a patient is malignant, but the results are ambiguous. Deciding that the danger of missing a true malignancy is greater than the upset caused by what might be a false positive diagnosis, the radiologist reports that the tumor is probably malignant and refers the patient to a specialist for further evaluation and treatment. In this example,

A) the radiologist has adopted a neutral decision criterion.
B) the radiologist has adopted a conservative decision criterion.
C) the radiologist has adopted a liberal decision criterion.
D) the radiologist's decision criterion will depend on whether the tumor is later found to be malignant.

Question 22

An experimenter presents a subject with a standard weight of 100 grams followed by a comparison weight of 20 grams; the subject is asked if the two weights are the same or different. The standard is repeated followed by a comparison weight of 30 grams; the subject is again asked if the two are the same or different. This procedure continues with a comparison weight 10 grams heavier on each presentation until the subject says that both weights are the same. These steps are repeated starting with a comparison weight of 190 grams and decreasing it by 10 grams on each trial until the subject says the two weights are the same. What is the experimenter trying to measure?

A) absolute threshold
B) perceptual defense
C) method of limits
D) difference threshold

Question 23

In signal detection theory, the decision criterion of a cautious responder

A) will be lower than the decision criterion of an impulsive responder.
B) will be higher than the decision criterion of an impulsive responder.
C) will be the same as the decision criterion of an impulsive responder.
D) will be equal to d΄.

Question 24

Both d' and beta can be computed from ROC (receiver-operating characteristic) functions that plot hits against false alarms.

Question 25

In signal detection theory, the criterion determines

A) the hit rate.
B) the false alarm rate.
C) the miss rate.
D) all of these.

Question 26

In the experiment by Prescott and Wilkie (2007), tolerance for pain

A) decreased in the presence of a sweet-smelling odor.
B) increased in the presence of a sweet-smelling odor.
C) remained the same whether or not a sweet-smelling order was present.
D) decreased in the presence of a bad odor.

Question 27

The scale of measurement that has the least stringent requirements is the __________ scale.

A) interval
B) ratio
C) ordinal
D) nominal

Question 28

In signal detection theory, which of the following would be affected by increasing the strength of the target relative to the noise?

A) β
B) α
C) d΄
D) r

Question 29

An experimenter presents a subject with a series of tones. During each trial of the experiment, the experimenter signals the start of the trial by saying "ready," plays the tone, and then asks whether the subject heard it. The experiment begins with a fairly loud, clearly audible tone; on each subsequent trial, the loudness of the tone is reduced at a constant rate of 10 decibels until the subject does not hear the tone. The experimenter then starts a second series of trials with a tone too low to be heard and increases the volume gradually until the subject reports hearing the tone. What is the experimenter trying to measure?

A) absolute threshold
B) perceptual defense
C) method of limits
D) difference threshold

Question 30

Measurement scales provide information to the extent that they measure differences, magnitudes, equal intervals, and have a true zero.

Question 31

In psychophysical experiments, it is possible to generate the ROC function by changing the participant's decision criterion from conservative to liberal. The experimenter can change the decision criterion by

A) changing the probability that a stimulus rather than noise only will be presented.
B) changing the payoffs for hits and false alarms.
C) changing the proportion of trials on which a target is presented
D) all of these.

Question 32

Psychophysical experiments usually use largen designs.

Question 33

The labeled magnitude scale is numbered from

A) 0-100.
B) 0-50.
C) 10-100.
D) 50-100.

Question 34

You decide that sugar is present in a cup of coffee in which there is no sugar. This is a

A) miss.
B) hit.
C) false alarm.
D) correct rejection.

Question 35

The "psycho" in psychophysics refers to

A) unpredictable stimulus characteristics.
B) the external environment.
C) internal impressions.
D) the mental status of the researcher.

Question 36

According to the theory of signal detection, perceptual judgments involve

A) decision processes only.
B) an absolute threshold.
C) sensory processes only.
D) both sensory and decision processes.

Question 37

Clark and colleagues (Clark, 1969; Clark & Yang, 1972) found that participants reported less pain when treated with acupuncture even though there was no difference in d΄ between the treatment (acupuncture) and control (no acupuncture) conditions. This suggests that

A) acupuncture has no effect on reports of pain.
B) with acupuncture, the participant's decision criterion for reporting pain increased.
C) with acupuncture, the participant's decision criterion for reporting pain decreased.
D) participants had reduced sensitivity to pain when treated with acupuncture.

Question 38

Which of the following is an acceptable operational definition for an auditory threshold?

A) The lowest intensity of a sound, as measured in decibels, at which a participant always reports hearing the sound
B) The lowest intensity of a sound, as measured in decibels, at which every participant in an experiment reports hearing the sound
C) The lowest intensity of a sound, as measured in decibels, at which a participant reports hearing the sound 50% of the time
D) The lowest intensity of a sound, as measured in decibels, at which 50% of the participants report hearing the sound.

Question 39

At a horse race, the finishing positions are determined by how fast each horse ran the race. Thus, the first finishing horse ran the fastest, the second finishing horse ran the second fastest, and so on. These finishing position numbers form a(n) __________ scale.

A) interval
B) ratio
C) ordinal
D) nominal

Question 40

Classical psychophysicists placed a great deal of emphasis on determining the absolute threshold for a particular type of sensory stimulation. This proved to be difficult because

A) the point at which an observer detects a stimulus varies from trial to trial.
B) adequate technical equipment for measuring intensity was not available until recently.
C) subjects must be carefully trained to make these judgments accurately.
D) researchers used samples too small to give reliable results.

Question 41

Measurement scales refer to the degree of precision with which we can assign numbers to objects.

Question 42

Psychophysics involves the determination of the psychological reaction to events that lie along a physical dimension.

Question 43

Incorrectly responding that a signal is present is called a false alarm.

Question 44

Scientists using psychophysical techniques were able to formulate the first mathematical laws of psychological phenomena.

Question 45

The psychophysical relation between stimulus and judgment depends on the particular sensory modality that is stimulated.

Question 46

The use of operational definitions allows other scientists to replicate your measurements.

Question 47

Operational definitions were used in the early work on psychophysics, but they are rarely used today.

Question 48

Nominal scales of measurement are more informative than ordinal scales.

Question 49

A receiver-operating characteristic is often used to determine the scale of measurement to use.

Question 50

Steven's Power Law uses a direct scaling technique in which the observer responds in psychological units.

Question 51

In signal-detection theory, the criterion determines the hit rate, but not the false alarm rate.

Question 52

There is rarely a perfect relationship between stimulus intensity and perceptual measures.

Question 53

The main thing that is controlled in a psychophysical experiment is the observer's strategy or frame of mind about his or her judgment.

Question 54

Decision processes are measured by $\beta$ in signal detection theory.

Question 55

Signal-detection theory assumes that noise is always present when a human attempts to detect signals.

Question 56

Small-n designs usually involve a small number of observations per participant.

Question 57

The relationship between changes in an external stimulus and internal sensation is perfectly linear.

Question 58

If a liberal response criterion is applied, both hits and false alarms will increase.

Question 59

The version of the method of limits called the staircase method is efficient because it concentrates responses around the threshold.

Question 60

An absolute threshold can be determined by using the method of limits.

Question 61

Describe the classical psychophysicists' idea of threshold. Outline the methods used by classical psychophysicists to measure the value for the threshold.

Question 62

Meteorologists are sometimes blamed for the bad weather they predict, even though they are not responsible for the weather. If a TV meteorologist is very concerned about the negative reaction of his audience to predictions of bad weather, what effect do you think this might have on his decision-making criterion? Explain your answer in terms of signal detection analysis.

Question 63

Ratio scales do not have a true zero.

Question 64

Compare and contrast the small-n designs used in psychophysical research with the largen design used in most other areas of psychology. Why are inferential statistics needed in research using large-n designs but generally not needed in small-n designs?

Question 65

Describe how signal-detection theory alters the concept of a threshold held by classical psychophysicists.

Question 66

Imagine that you are designing an experiment to test the performance of your participants on detection of a difference in intensity of a stimulus near threshold under different conditions. You know that the detection threshold for each participant may be different. Describe the procedure you would use to determine the threshold for each participant.

Question 67

Describe briefly the key concepts concerning signal detection theory. How does signal detection theory approach the notion of a threshold?

Question 68

What is meant by the term operational definition? What is the value of using operational definitions? Provide an example of an operational definition.

Question 69

According to signal-detection theory, response bias factors can include the payoff for being accurate.

Question 70

Elaborate on the following statement, providing specific examples that support the statement: Psychophysics involves the determination of the psychological reaction to events that lie along a physical dimension.

Question 71

Give two examples for each of the four types of measurement scales. Explain why each is an example of that type of measurement scale.

Question 72

Briefly describe the method of limits, and discuss the concept of absolute and relative threshold.

Question 73

Draw hypothetical distributions of the sensory impression resulting from noise and signal-plus-noise. Establish a low criterion and indicate which areas correspond to hits, misses, false alarms, and correct rejections. On a second figure, do the same with a high criterion.