Summary
Chapters 1 - 15
Sensation and Perception - 7th Edition
Jeremy M. Wolfe
0197663818
For: Maastricht University 2025
+ 76 test questions with answers
+ 55 important core concepts explained
,
,Chapter 1: Introduction
Sensation and perception
- Sensation: the ability to detect a stimulus and, perhaps, to turn that detection into a
private experience
- Perception: the act of giving meaning to a detected sensation
- Condillac: mental life relies on information from our senses
Methods used in the study of the senses
- Thresholds
- Scaling: measuring private experience
o Quale: in philosophy, a private conscious experience of sensation or perception
- Signal detection theory – measuring difficult decisions
- Sensory neuroscience
- Neuroimaging – an image of the mind
Thresholds and the dawn of psychophysics
- Dualism: the idea that the mind has an existence separate from the material world of
the body
- Materialism: the idea that the only thing that exists is matter, and that all things,
including the mind and consciousness, are the results of interactions between bits of
matter
- Panpsychism: the idea that the mind exist as a property of all matter, that is, that all
matter has consciousness (Fechner)
- Psychophysics: the science of defining quantitative relationships between physical
and psychological (subjective) events (Fechner)
- Two-point touch threshold: the minimum distance at which two stimuli are just
perceptible as separate (Weber)
- Just noticeable difference/ 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)
- Weber’s law: the principle describing the relationship between stimulus and resulting
sensation that says the JND is a constant fraction of the comparison stimulus (e.g. 1:100
for length, 1:40 for weight)
o Clear objective measurement, we know how much the stimulus varied and
the observer can either tell that it changed or not
- Fechner’s law: a principle describing the relationship between stimulus and resulting
sensation that says the magnitude of subjective sensation(S) increases proportionally to
the logarithm of the stimulus intensity(R) (S = k log R)
o Describes the relationship between mind and matter
o The smallest detectable change in a stimulus can be considered as a unit of the
mind, because this is the smallest bit of change that is perceived
o Assumes that all JNDs are perceptually equivalent, which turns out to be incorrect
- Absolute threshold: the min amount of a stimulation necessary for a person to detect
a stimulus 50% of the time
, o Detected 50% of the time due to the variability in the nervous system, stimuli near
the threshold will be detected sometimes and missed other times there is no
hard boundary
Psychophysical methods
- Method of constant stimuli: a psychophysical method in which many stimuli ranging from
rarely to almost always perceivable, are presented one at a time and participants respond
to each presentation: yes/no or same/different
- Method of limits: a psychophysical method in which the particular dimension of a stimulus,
or the difference between two stimuli, is varied incrementally until the participant
responds differently
o Tones are presented in increasing or decreasing intensity; increasing: report
when you first hear the tone; decreasing: report when the tone is no longer
heard. The threshold is set at the average of the crossover points
- Method of adjustment: a method of limits in which the participant controls the change in
the stimulus
Scaling methods and supertasters
- Magnitude estimation: a psychophysical method in which the participant assigns
values according to perceived magnitudes of the stimuli
o Steven’s power law: a principle describing the relationship between stimulus and
resulting sensation that says the magnitude of subjective sensation(S) is
proportional to the stimulus magnitude(I) raised to an exponent(b) ( S = aIb )
Measures subjective ratings, and we can check whether these are
reasonable and consistent but there is no way of knowing whether they are
objectively right or wrong
- Cross-modality matching: the ability to match the intensities of sensations that come
from different sensory modalities. This ability enables insight into sensory differences.
For example, a listener might adjust the brightness of a light until it matches the
loudness of a tone, the relationship between modalities appears to be similar across
individuals
Signal detection theory
- Signal detection theory: a psychophysical theory that quantifies the response of an
observer to the presentation of a signal in the presence of noise (internal noise, the static
in your nervous system). Measures obtained from a series of presentations are sensitivity
(d’) and criterion of the observer
o Criterion: an internal threshold set by the observer. If the internal response is
above the criterion, the observer gives one response (yes) and below the criterion
the observer gives another response (no)
Correct rejection, hit, false alarm, miss
o Sensitivity: a value that defines the ease with which an observer can tell the
difference between the presence and absence of a stimulus or the
difference between stimulus 1 and stimulus 2 (d’ or d-prime)
Chapters 1 - 15
Sensation and Perception - 7th Edition
Jeremy M. Wolfe
0197663818
For: Maastricht University 2025
+ 76 test questions with answers
+ 55 important core concepts explained
,
,Chapter 1: Introduction
Sensation and perception
- Sensation: the ability to detect a stimulus and, perhaps, to turn that detection into a
private experience
- Perception: the act of giving meaning to a detected sensation
- Condillac: mental life relies on information from our senses
Methods used in the study of the senses
- Thresholds
- Scaling: measuring private experience
o Quale: in philosophy, a private conscious experience of sensation or perception
- Signal detection theory – measuring difficult decisions
- Sensory neuroscience
- Neuroimaging – an image of the mind
Thresholds and the dawn of psychophysics
- Dualism: the idea that the mind has an existence separate from the material world of
the body
- Materialism: the idea that the only thing that exists is matter, and that all things,
including the mind and consciousness, are the results of interactions between bits of
matter
- Panpsychism: the idea that the mind exist as a property of all matter, that is, that all
matter has consciousness (Fechner)
- Psychophysics: the science of defining quantitative relationships between physical
and psychological (subjective) events (Fechner)
- Two-point touch threshold: the minimum distance at which two stimuli are just
perceptible as separate (Weber)
- Just noticeable difference/ 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)
- Weber’s law: the principle describing the relationship between stimulus and resulting
sensation that says the JND is a constant fraction of the comparison stimulus (e.g. 1:100
for length, 1:40 for weight)
o Clear objective measurement, we know how much the stimulus varied and
the observer can either tell that it changed or not
- Fechner’s law: a principle describing the relationship between stimulus and resulting
sensation that says the magnitude of subjective sensation(S) increases proportionally to
the logarithm of the stimulus intensity(R) (S = k log R)
o Describes the relationship between mind and matter
o The smallest detectable change in a stimulus can be considered as a unit of the
mind, because this is the smallest bit of change that is perceived
o Assumes that all JNDs are perceptually equivalent, which turns out to be incorrect
- Absolute threshold: the min amount of a stimulation necessary for a person to detect
a stimulus 50% of the time
, o Detected 50% of the time due to the variability in the nervous system, stimuli near
the threshold will be detected sometimes and missed other times there is no
hard boundary
Psychophysical methods
- Method of constant stimuli: a psychophysical method in which many stimuli ranging from
rarely to almost always perceivable, are presented one at a time and participants respond
to each presentation: yes/no or same/different
- Method of limits: a psychophysical method in which the particular dimension of a stimulus,
or the difference between two stimuli, is varied incrementally until the participant
responds differently
o Tones are presented in increasing or decreasing intensity; increasing: report
when you first hear the tone; decreasing: report when the tone is no longer
heard. The threshold is set at the average of the crossover points
- Method of adjustment: a method of limits in which the participant controls the change in
the stimulus
Scaling methods and supertasters
- Magnitude estimation: a psychophysical method in which the participant assigns
values according to perceived magnitudes of the stimuli
o Steven’s power law: a principle describing the relationship between stimulus and
resulting sensation that says the magnitude of subjective sensation(S) is
proportional to the stimulus magnitude(I) raised to an exponent(b) ( S = aIb )
Measures subjective ratings, and we can check whether these are
reasonable and consistent but there is no way of knowing whether they are
objectively right or wrong
- Cross-modality matching: the ability to match the intensities of sensations that come
from different sensory modalities. This ability enables insight into sensory differences.
For example, a listener might adjust the brightness of a light until it matches the
loudness of a tone, the relationship between modalities appears to be similar across
individuals
Signal detection theory
- Signal detection theory: a psychophysical theory that quantifies the response of an
observer to the presentation of a signal in the presence of noise (internal noise, the static
in your nervous system). Measures obtained from a series of presentations are sensitivity
(d’) and criterion of the observer
o Criterion: an internal threshold set by the observer. If the internal response is
above the criterion, the observer gives one response (yes) and below the criterion
the observer gives another response (no)
Correct rejection, hit, false alarm, miss
o Sensitivity: a value that defines the ease with which an observer can tell the
difference between the presence and absence of a stimulus or the
difference between stimulus 1 and stimulus 2 (d’ or d-prime)
