UIUC PSYC 230 Test - Questions With Thorough
Solutions
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
Solutions
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
