EXPLORING
PSYCHOLOGY
EIGHTH EDITION IN MODULES
David Myers
PowerPoint Slides
Aneeq Ahmad
Henderson State University
Worth Publishers, © 2011
Sensation and Perception
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Perceptual Organization and
Interpretation
Module 16
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Perceptual Organization
 Form Perception
 Depth Perception
 Perceptual Constancy
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Perceptual Interpretation
 Sensory Deprivation and Restored
Vision
 Perceptual Adaptation
 Perceptual Set
 THINKING CRITICALLY
ABOUT: Extrasensory Perception
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Perceptual Organization
How do we form meaningful perceptions
from sensory information?
We organize it. Gestalt psychologists
showed that a figure formed a gestalt, a
“whole” different than its surroundings.
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Form Perception
Figure-ground is the organization of the visual
field into objects (figures) that stand out from their
surroundings (ground). In this image, the figureground relationship is constantly changing.
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Grouping
After distinguishing the figure from the ground,
our perception needs to organize the figure into
a meaningful form using grouping rules.
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Grouping Principles
Although grouping principles usually help us construct
reality, they may occasionally lead us astray.
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Depth Perception
Depth perception enables us to judge distances. Gibson and
Walk (1960) suggested that human infants (crawling age)
have depth perception. Even newborn animals show depth
perception.
Visual Cliff
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Binocular Cues
Binocular cues are depth cues that depend on the use of two
eyes. One binocular cue is retinal disparity: Images from the
two eyes differ. Try looking at both index fingers pointing
them towards each other half an inch apart and 5 inches in
front of your eyes. You will see a “finger sausage”.
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Monocular Cues
Monocular cues are depth
cues available to either eye
alone.
This figure illustrates
interposition, when one object
partially blocks our view of
another we perceive it as
closer.
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Monocular Cues
For examples of these other monocular cues see Fig.
16.8 on page 221.
Relative Height: We perceive objects that are higher in
our field of vision to be farther away than those that are
lower.
Relative motion: Objects closer to a fixation point move
faster and in opposing direction to those objects that are
farther away from a fixation point, moving slower and
in the same direction.
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Monocular Cues
Linear Perspective: Parallel lines, such as railroad tracks,
appear to converge in the distance. The more the lines
converge, the greater their perceived distance.
Light and Shadow: Nearby objects reflect more light into
our eyes than more distant objects. Given two identical
objects, the dimmer one appears to be farther away.
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Perceptual Constancy
Perceiving objects as unchanging even as
illumination and retinal images change.
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Shape Constancy
Shape constancy is our tendency to perceive the form
of familiar objects as constant, even when while our
retinal image of it changes, like the door below.
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Size-Distance Relationship
The distant monster (below, left) and the top red
bar (below, right) appear bigger because of
distance cues.
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Size-Distance Relationship
Both girls in the room are of similar height.
However, we perceive them to be of different
heights as they stand in the two corners of the
room.
Ames Illusion
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Lightness Constancy
Light constancy: we
perceive an object as
having a constant
lightness even while
its illumination varies.
This depends on
relative luminance – the
amount of light an
object reflects relative
to it’s surroundings.
The color and brightness of
square A and B are the same.
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Color Constancy
Color constancy is perceiving familiar objects as having
consistent color even when changing illumination filters
the light reflected by the object.
Color depends on context. These 3 blue dots are all the same color.
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Perceptual Interpretation
Immanuel Kant (1724-1804) maintained that
knowledge comes from our inborn ways of
organizing sensory experiences.
John Locke (1632-1704) argued that we learn to
perceive the world through our experiences.
How important is experience in shaping our
perceptual interpretation?
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Sensory Deprivation & Restored
Vision
After cataract surgery, blind adults were
able to regain sight. These individuals
could differentiate figure and ground
relationships proving that this is innate,
yet they could not visually recognize
objects that were familiar by touch.
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Facial Recognition
Courtesy of Richard LeGrand
After blind adults
regained sight, they were
able to recognize distinct
features, but were unable
to recognize faces.
Normal observers also
show difficulty in facial
recognition when the
lower half of the pictures
are changed.
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Perceptual Adaptation
Perceptual adaptation is
the visual ability to
adjust to an artificially
displaced visual field,
e.g., prism glasses.
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Perceptual Set
A perceptual set is a mental predisposition to
perceive one thing and not another. What you
see in the center picture is influenced by
flanking pictures.
From Shepard, 1990.
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Perceptual Set
Other examples of perceptual set.
(a) Loch ness monster or a tree trunk;
(b) Flying saucers or clouds?
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Context Effects
Context can radically alter perception.
Is the “magician cabinet” on the floor or hanging from the
ceiling?
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Cultural Context
Context instilled by culture also alters
perception.
To an East African, the woman sitting is balancing a metal
box on her head, while the family is sitting under a tree.28
Perception is a Biopsychosocial
Phenomenon
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Is perception innate or learned? The answer is both.
Extrasensory Perception
Perception without sensory input is called
extrasensory perception (ESP). This includes,
telepathy, clairvoyance, and precognition. A large
percentage of scientists do not believe in ESP.
Parapsychology is the study of paranormal
phenomena, including ESP.
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