PS 262 Introduction to Perception Final Exam
Comprehensive Class Notes and Key Concepts
2026 update Wilfrid Laurier University
FULL PS 262 Final Exam Class Notes
Ablation
Removal of an area of the brain. This is usually done in experiments on animals to determine
the function of a particular area. Also called lesioning.
Absorption spectrum
A plot of the amount of light absorbed by a visual pigment versus the wavelength of light.
Accommodation, In vision bringing objects located at different distances into focus by
changing the shape of the lens.
Accretion
A cue that provides information about the relative depth of two surfaces. Occurs when the
farther object is uncovered by the nearer object due to sideways movement of an observer
relative to the objects. See also Deletion.
Achromatic color
Color without hue. White, black, and all the grays between these two extremes are
achromatic colors.
Acoustic shadow
The shadow created by the head that decreases the level of high-frequency sounds on the
opposite side of the head. The acoustic shadow is the basis of the localization cue of
interaural level difference.
Acoustic signal
The pattern of frequencies and intensities of the sound stimulus.
,Action potential
Rapid increase in positive charge in a nerve fiber that travels down the fiber. Also called the
nerve impulse.
Action-specific perception hypothesis
Hypothesis that people perceive their environment in terms of their ability to act on it.
Active touch
Touch in which the observer plays an active role in touching and exploring an object, usually
with his or her hands.
Method of Adjustment
A psychophysical method in which the experimenter or the observer adjusts the stimulus
intensity in a continuous manner until the observer detects the stimulus.
Affective (emotional) component of pain
The emotional experience associated with pain—for example, pain described as torturing,
annoying, frightful, or sickening. See also Sensory component of pain.
,Affordance
The information specified by a stimulus pattern that indicates how the stimulus can be used.
An example of an affordance would be seeing a chair as something to sit on or a flight of
stairs as something to climb.
Akinetopsia
A condition in which damage to an area of the cortex involved in motion perception causes
blindness to motion.
Amacrine cell
A neuron that transmits signals laterally in the retina. Amacrine cells synapse with bipolar
cells and ganglion cells.
Ames room
A distorted room, first built by Adelbert Ames, that creates an erroneous perception of the
sizes of people in the room. The room is constructed so that two people at the far wall of the
room appear to stand at the same distance from an observer. In actuality, one of the people is
much farther away than the other.
Amplitude
In the case of a repeating sound wave, such as the sinewave of a pure tone, amplitude
represents the pressure difference between atmospheric pressure and the maximum pressure
of the wave.
Amplitude modulation
Adjusting the level (or intensity) of a sound stimulus so it fluctuates up and down.
Amplitude-modulated noise
A noise sound stimulus that is amplitude modulated.
Amygdala
A subcortical structure that is involved in emotional responding and in processing olfactory
signals.
Angle of disparity
The visual angle between the images of an object on the two retinas. When images of an
object fall on corresponding points, the angle of disparity is zero. When images fall on non
corresponding points, the angle of disparity indicates the degree of non correspondence.
Angular size contrast theory
An explanation of the moon illusion that states that the perceived size of the moon is
determined by the sizes of the objects that surround it. According to this idea, the moon
appears small when it is surrounded by large objects, such as the expanse of the sky when the
moon is overhead.
Anomalous trichromat
A person who needs to mix a minimum of three wavelengths to match any other wavelength
in the spectrum but mixes these wavelengths in different proportions than a trichromat.
Anterior belt area
, The front of the posterior belt in the temporal lobe, which is involved in perceiving sound.
Aperiodic sound, Sound waves that do not repeat. See Periodic sound.
Aperture problem
Occurs when only a portion of a moving stimulus can be seen, as when the stimulus is viewed
through a narrow aperture or through the "field of view" of a neuron's' receptive field. This
can result in misleading information about the direction in which the stimulus is moving.
Apex (of the cochlea)
The end of the cochlea farthest from the middle ear.
Aphasia
Difficulties in speaking or understanding speech due to brain damage.
Apparent distance theory
An explanation of the moon illusion that is based on the idea that the horizon moon, which is
viewed across the filled space of the terrain, should appear farther away than the zenith
moon, which is viewed through the empty space of the sky. This theory states that because
the horizon and zenith moons have the same visual angle but are perceived to be at different
distances, the farther appearing horizon moon should appear larger.
Apparent movement
An illusion of movement that occurs when two objects separated in space are presented
rapidly, one after another, separated by a brief time interval. Architectural acoustics The
study of how sounds are reflected in rooms. An important concern of architectural acoustics
is how these reflected sounds change the quality of the sounds we hear.
Area V1
The visual receiving area of the brain, called area V1 to indicate that it is the first visual area
in the cortex. Also called the striate cortex.
Articulator
Structure involved in speech production, such as the tongue, lips, teeth, jaw, and soft palate.
Atmospheric perspective
A depth cue. Objects that are farther away look more blurred and bluer than objects that are
closer because we look through more air and particles to see them.
Attack
The buildup of sound energy that occurs at the beginning of a tone.
Attention
The process of focusing on some objects while ignoring others. Attention can enhance the
processing of the attended object.
Attentional capture
Occurs when stimulus salience causes an involuntary shift of attention. For example,
attention can be captured by movement.
Audibility curve
Comprehensive Class Notes and Key Concepts
2026 update Wilfrid Laurier University
FULL PS 262 Final Exam Class Notes
Ablation
Removal of an area of the brain. This is usually done in experiments on animals to determine
the function of a particular area. Also called lesioning.
Absorption spectrum
A plot of the amount of light absorbed by a visual pigment versus the wavelength of light.
Accommodation, In vision bringing objects located at different distances into focus by
changing the shape of the lens.
Accretion
A cue that provides information about the relative depth of two surfaces. Occurs when the
farther object is uncovered by the nearer object due to sideways movement of an observer
relative to the objects. See also Deletion.
Achromatic color
Color without hue. White, black, and all the grays between these two extremes are
achromatic colors.
Acoustic shadow
The shadow created by the head that decreases the level of high-frequency sounds on the
opposite side of the head. The acoustic shadow is the basis of the localization cue of
interaural level difference.
Acoustic signal
The pattern of frequencies and intensities of the sound stimulus.
,Action potential
Rapid increase in positive charge in a nerve fiber that travels down the fiber. Also called the
nerve impulse.
Action-specific perception hypothesis
Hypothesis that people perceive their environment in terms of their ability to act on it.
Active touch
Touch in which the observer plays an active role in touching and exploring an object, usually
with his or her hands.
Method of Adjustment
A psychophysical method in which the experimenter or the observer adjusts the stimulus
intensity in a continuous manner until the observer detects the stimulus.
Affective (emotional) component of pain
The emotional experience associated with pain—for example, pain described as torturing,
annoying, frightful, or sickening. See also Sensory component of pain.
,Affordance
The information specified by a stimulus pattern that indicates how the stimulus can be used.
An example of an affordance would be seeing a chair as something to sit on or a flight of
stairs as something to climb.
Akinetopsia
A condition in which damage to an area of the cortex involved in motion perception causes
blindness to motion.
Amacrine cell
A neuron that transmits signals laterally in the retina. Amacrine cells synapse with bipolar
cells and ganglion cells.
Ames room
A distorted room, first built by Adelbert Ames, that creates an erroneous perception of the
sizes of people in the room. The room is constructed so that two people at the far wall of the
room appear to stand at the same distance from an observer. In actuality, one of the people is
much farther away than the other.
Amplitude
In the case of a repeating sound wave, such as the sinewave of a pure tone, amplitude
represents the pressure difference between atmospheric pressure and the maximum pressure
of the wave.
Amplitude modulation
Adjusting the level (or intensity) of a sound stimulus so it fluctuates up and down.
Amplitude-modulated noise
A noise sound stimulus that is amplitude modulated.
Amygdala
A subcortical structure that is involved in emotional responding and in processing olfactory
signals.
Angle of disparity
The visual angle between the images of an object on the two retinas. When images of an
object fall on corresponding points, the angle of disparity is zero. When images fall on non
corresponding points, the angle of disparity indicates the degree of non correspondence.
Angular size contrast theory
An explanation of the moon illusion that states that the perceived size of the moon is
determined by the sizes of the objects that surround it. According to this idea, the moon
appears small when it is surrounded by large objects, such as the expanse of the sky when the
moon is overhead.
Anomalous trichromat
A person who needs to mix a minimum of three wavelengths to match any other wavelength
in the spectrum but mixes these wavelengths in different proportions than a trichromat.
Anterior belt area
, The front of the posterior belt in the temporal lobe, which is involved in perceiving sound.
Aperiodic sound, Sound waves that do not repeat. See Periodic sound.
Aperture problem
Occurs when only a portion of a moving stimulus can be seen, as when the stimulus is viewed
through a narrow aperture or through the "field of view" of a neuron's' receptive field. This
can result in misleading information about the direction in which the stimulus is moving.
Apex (of the cochlea)
The end of the cochlea farthest from the middle ear.
Aphasia
Difficulties in speaking or understanding speech due to brain damage.
Apparent distance theory
An explanation of the moon illusion that is based on the idea that the horizon moon, which is
viewed across the filled space of the terrain, should appear farther away than the zenith
moon, which is viewed through the empty space of the sky. This theory states that because
the horizon and zenith moons have the same visual angle but are perceived to be at different
distances, the farther appearing horizon moon should appear larger.
Apparent movement
An illusion of movement that occurs when two objects separated in space are presented
rapidly, one after another, separated by a brief time interval. Architectural acoustics The
study of how sounds are reflected in rooms. An important concern of architectural acoustics
is how these reflected sounds change the quality of the sounds we hear.
Area V1
The visual receiving area of the brain, called area V1 to indicate that it is the first visual area
in the cortex. Also called the striate cortex.
Articulator
Structure involved in speech production, such as the tongue, lips, teeth, jaw, and soft palate.
Atmospheric perspective
A depth cue. Objects that are farther away look more blurred and bluer than objects that are
closer because we look through more air and particles to see them.
Attack
The buildup of sound energy that occurs at the beginning of a tone.
Attention
The process of focusing on some objects while ignoring others. Attention can enhance the
processing of the attended object.
Attentional capture
Occurs when stimulus salience causes an involuntary shift of attention. For example,
attention can be captured by movement.
Audibility curve
