UIUC PSYC 230 TEST UPDATED
ACTUAL Questions and CORRECT
Answers
Sensation - CORRECT ANSWER -The ability to detect a stimulus and, perhaps, to turn
that detection into a private experience.
Perception - CORRECT ANSWER -The act of giving meaning to a detected sensation.
psychophysics - CORRECT ANSWER -The science of defining quantitative relationships
between physical and psychological (subjective) events
two-point threshold - CORRECT ANSWER -The minimum distance at which two stimuli
(e.g. 2 simultaneous touches) are just perceptible as separate
just noticeable difference (JND) - CORRECT ANSWER -Also known as the difference
threshold
The smallest detectable difference between two stimuli, or the minimum change in a stimulus
that enables it to be correctly judged as different from a reference stimulus.
Weber fraction - CORRECT ANSWER -The constant (K) of proportionality in Weber's
Law.
For weight: 1:40
Line length: 1:100
Weber's Law - CORRECT ANSWER -The principle describing the relationship between
stimulus and resulting sensation that says the JND is a constant fraction (K) of the comparison
stimulus.
,Fechner's Law - CORRECT ANSWER -A principle describing the relationship between
stimulus and resulting sensation that says the magnitude of subjective sensation increases
proportionally to the logarithm of the stimulus intensity
- S = k log (R)
S= psychological sensation R= physical stimulus
k= constant
Gustav Fechner - CORRECT ANSWER -- invented psychophysics
- thought by some to be the true founder of experimental psychology
absolute threshold - CORRECT ANSWER -The minimum amount of stimulation
necessary for a person to detect a stimulus 50% of the time
Method of constant stimuli - CORRECT ANSWER -A psychophysical method in which
many stimuli, ranging from rarely to almost always perceivable (or rarely to almost always
perceivably different from a reference stimulus), are presented one at a time. Participants
respond to each presentation: "yes/no," "same/different," and so on.
Methods of limits - CORRECT ANSWER -The magnitude of a single stimulus or the
difference between two stimuli is varied incrementally until the participant responds differently
- The experimenter begins with the same set of stimuli-- in this case, tones that vary in intensity.
Instead of random presentations, tones are presented in order of increasing or decreasing
intensity.
- ascending: asked to report when tone is first detected
- descending : report when tone is no longer audible
Method of adjustment - CORRECT ANSWER -Similar to the method of limits, but the
participant controls the stimulus directly
- subject is the one who steadily increases or decreases the intensity of the stimulus
,Magnitude estimation - CORRECT ANSWER -The participant assigns values according to
perceived magnitudes of the stimuli
- EX: give observers series of sugar solutions and ask them to assign numbers to each sample.
- i.e. Solution 2 is 2x as sweet as Solution 1
Stevens' power law - CORRECT ANSWER -Magnitude estimates are well described by
________________ .
- S = aI^(b)
(S) is related to stimulus intensity
(I) by an exponent (b)
- A principle describing the relationship between the stimulus and resulting sensation that says
the magnitude of subjective sensation is proportional to the stimulus magnitude raised to an
exponent.
- exponent for brightness is 0.3, so change from 1 candle to 11 is quite dramatic,
but adding 10 to 100 results in only a modest change
Adding 10 to 10,000 wouldn't even be noticeable
VS.
Apparent length = 1.0
- exponent for electric shock is quite large (3.5), meaning that the pain grows with I^(3.5), so a
4-fold increase in the electrical current is experienced as a 128-fold increase in pain
, Weber's law vs. Fechner's law vs. Stevens' power law - CORRECT ANSWER -Weber's
law: involves a clear objective measurement . We know how much we varied the stimulus, and
either the observers can tell that the stimulus changed or they cannot.
Fechner's law: begins with same objective measurements as Weber's, but the law is actually a
calculation based on some assumptions about how sensation works.
- assumes that all JNDs are perceptually equivalent
(they are not)
Stevens' power law: describes rating data well BUT the rating data are qualitatively different
from the data that supported Weber's law.
- no way to know whether subjects' ratings are objectively right or wrong
Cross-modality matching - CORRECT ANSWER -The participant matches the intensity of
a sensation in one sensory modality with the intensity of a sensation in another
Ex: Ask participant to adjust the brightness of a light so it matches the perceived loudness of a
particular tone
Signal detection theory - CORRECT ANSWER -A psychophysical theory that quantifies
the response of an observer to the presentation of a signal in the presence of noise
- internal noise (when close your eyes still see grey with occasional brighter flashes)
- external noise (when looking at a mammogram there are similar regions that look like the
signal (cancer) but aren't
- makes a distinction between an observers' ability to perceive a signal and their willingness to
report it
Hit - CORRECT ANSWER -(Signal detection theory)
Stimulus is present and observer responds "Yes"
Miss - CORRECT ANSWER -Stimulus is present and observer responds "No"
ACTUAL Questions and CORRECT
Answers
Sensation - CORRECT ANSWER -The ability to detect a stimulus and, perhaps, to turn
that detection into a private experience.
Perception - CORRECT ANSWER -The act of giving meaning to a detected sensation.
psychophysics - CORRECT ANSWER -The science of defining quantitative relationships
between physical and psychological (subjective) events
two-point threshold - CORRECT ANSWER -The minimum distance at which two stimuli
(e.g. 2 simultaneous touches) are just perceptible as separate
just noticeable difference (JND) - CORRECT ANSWER -Also known as the difference
threshold
The smallest detectable difference between two stimuli, or the minimum change in a stimulus
that enables it to be correctly judged as different from a reference stimulus.
Weber fraction - CORRECT ANSWER -The constant (K) of proportionality in Weber's
Law.
For weight: 1:40
Line length: 1:100
Weber's Law - CORRECT ANSWER -The principle describing the relationship between
stimulus and resulting sensation that says the JND is a constant fraction (K) of the comparison
stimulus.
,Fechner's Law - CORRECT ANSWER -A principle describing the relationship between
stimulus and resulting sensation that says the magnitude of subjective sensation increases
proportionally to the logarithm of the stimulus intensity
- S = k log (R)
S= psychological sensation R= physical stimulus
k= constant
Gustav Fechner - CORRECT ANSWER -- invented psychophysics
- thought by some to be the true founder of experimental psychology
absolute threshold - CORRECT ANSWER -The minimum amount of stimulation
necessary for a person to detect a stimulus 50% of the time
Method of constant stimuli - CORRECT ANSWER -A psychophysical method in which
many stimuli, ranging from rarely to almost always perceivable (or rarely to almost always
perceivably different from a reference stimulus), are presented one at a time. Participants
respond to each presentation: "yes/no," "same/different," and so on.
Methods of limits - CORRECT ANSWER -The magnitude of a single stimulus or the
difference between two stimuli is varied incrementally until the participant responds differently
- The experimenter begins with the same set of stimuli-- in this case, tones that vary in intensity.
Instead of random presentations, tones are presented in order of increasing or decreasing
intensity.
- ascending: asked to report when tone is first detected
- descending : report when tone is no longer audible
Method of adjustment - CORRECT ANSWER -Similar to the method of limits, but the
participant controls the stimulus directly
- subject is the one who steadily increases or decreases the intensity of the stimulus
,Magnitude estimation - CORRECT ANSWER -The participant assigns values according to
perceived magnitudes of the stimuli
- EX: give observers series of sugar solutions and ask them to assign numbers to each sample.
- i.e. Solution 2 is 2x as sweet as Solution 1
Stevens' power law - CORRECT ANSWER -Magnitude estimates are well described by
________________ .
- S = aI^(b)
(S) is related to stimulus intensity
(I) by an exponent (b)
- A principle describing the relationship between the stimulus and resulting sensation that says
the magnitude of subjective sensation is proportional to the stimulus magnitude raised to an
exponent.
- exponent for brightness is 0.3, so change from 1 candle to 11 is quite dramatic,
but adding 10 to 100 results in only a modest change
Adding 10 to 10,000 wouldn't even be noticeable
VS.
Apparent length = 1.0
- exponent for electric shock is quite large (3.5), meaning that the pain grows with I^(3.5), so a
4-fold increase in the electrical current is experienced as a 128-fold increase in pain
, Weber's law vs. Fechner's law vs. Stevens' power law - CORRECT ANSWER -Weber's
law: involves a clear objective measurement . We know how much we varied the stimulus, and
either the observers can tell that the stimulus changed or they cannot.
Fechner's law: begins with same objective measurements as Weber's, but the law is actually a
calculation based on some assumptions about how sensation works.
- assumes that all JNDs are perceptually equivalent
(they are not)
Stevens' power law: describes rating data well BUT the rating data are qualitatively different
from the data that supported Weber's law.
- no way to know whether subjects' ratings are objectively right or wrong
Cross-modality matching - CORRECT ANSWER -The participant matches the intensity of
a sensation in one sensory modality with the intensity of a sensation in another
Ex: Ask participant to adjust the brightness of a light so it matches the perceived loudness of a
particular tone
Signal detection theory - CORRECT ANSWER -A psychophysical theory that quantifies
the response of an observer to the presentation of a signal in the presence of noise
- internal noise (when close your eyes still see grey with occasional brighter flashes)
- external noise (when looking at a mammogram there are similar regions that look like the
signal (cancer) but aren't
- makes a distinction between an observers' ability to perceive a signal and their willingness to
report it
Hit - CORRECT ANSWER -(Signal detection theory)
Stimulus is present and observer responds "Yes"
Miss - CORRECT ANSWER -Stimulus is present and observer responds "No"
