Chapter 6
Perception
The process of selecting, organizing, and
interpreting sensory information, which enables us
to recognize meaningful objects and events.
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Selective Attention
Perceptions about objects change from moment to
moment. We can perceive different forms of the
Necker cube; however, we can only pay attention
to one aspect of the object at a time.
Ex: Cocktail Party Phenomenon
Experiment - Video
Necker Cube
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Inattentional Blindness
Daniel Simons, University of Illinois
Inattentional blindness refers to the inability
to see an object or a person in our midst.
Simmons & Chabris (1999) showed that half
of the observers failed to see the gorillasuited assistant in a ball passing game.
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Change Blindness
Change blindness is a form of inattentional
blindness in which a majority of individuals giving
directions failed to notice a change in the
individual asking for directions.
Experiment - Video
© 1998 Psychonomic Society Inc. Image provided courtesy of Daniel J. Simmons.
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Perceptual Illusions
Illusions provide good examples in
understanding how perception is organized.
Studying faulty perception is as important as
studying other perceptual phenomena.
Line AB is longer than line BC.
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Illusions
• Physical
• Paradoxical/Perceptual
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Perceptual Organization
Visual Capture
Vision vs. other senses? Vision usually wins
GESTALT PSYCHOLOGY
-A movement formed in Germany in the 1920s
and ’30s
-The study of how people organize the world
visually into meaningful units and patterns.
- “The whole is more important than the sum of the parts”
- In other words, when we perceive something, properties
emerge from the object that are not found in any
particular component.
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Gestalt: Form Perception
• People ALWAYS organize the visual field
into 2 parts
– ___________: stands out from the rest of the
environment
– ___________: the background
SOMETIMES…
Your eyes have trouble
distinguishing FIGURE and
GROUND
GESTALT PRINCIPLES
• 1. _______________
– Things that are near each other, tend to
be grouped together
• For Example…
GESTALT PRINCIPLES
• 2. Connectedness
– In order to complete forms, the brain
FILLS IN THE GAPS
• For Example…
GESTALT PRINCIPLES
• 3. _______________
– Things that are alike in some way (e.g.
color, shape, size) tend to be perceived
as belonging together
• For example…
GESTALT PRINCIPLES
• 4. _________________
– Lines and patterns tend to be perceived
as continuing in time or space
• For Example…
Depth Perception
Innervisions
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
Retinal disparity: Images from the two eyes differ. Try
looking at your two index fingers when pointing them
towards each other half an inch apart and about 5 inches
directly in front of your eyes. You will see a “finger
sausage” as shown in the inset.
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Binocular Cues
Convergence: Neuromuscular cues. When two
eyes move inward (towards the nose) to see near
objects and outward (away from the nose) to see
faraway objects.
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Monocular Cues
See Characteristics of Perception assignment we
did in library and/or homework.
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Apparent Motion
Phi Phenomenon: When lights flash at a certain
speed they tend to present illusions of motion.
Neon signs use this principle to create motion
perception.
Two lights
one
after the Illusion
other. of motion.
One light jumping
from flashing
one point
to another:
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Perceptual Constancy
Perceiving objects as unchanging even as
illumination and retinal images change. Perceptual
constancies include constancies of shape and size.
Shape Constancy
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Size Constancy
Stable size perception amid changing size of the
stimuli.
Size Constancy
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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.
Alan Choisnet/ The Image Bank
From Shepard, 1990
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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.
Both photos from S. Schwartzenberg/ The Exploratorium
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Ames Room
The Ames room is designed to demonstrate the sizedistance illusion.
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What is your perception of…
What is your perception of…
What is your perception of…
What is your perception of…
What is your perception of…
What is your perception of…
What is your perception of…
What is your perception of…
What is your perception of…
What is your perception of…
What is your perception of…
What is your perception of…
What is your perception of…
Perception: Nature or Nurture?
Perceptual Interpretation: Restored Vision
Blind adults w/ restored vision:
could differentiate figure and
ground relationships, but had
difficulty distinguishing a circle
and a triangle (Von Senden, 1932).
Others struggled w/ facial
recognition & expressions.
Perceptual Interpretation: Sensory Deprivation
Kittens raised without
exposure to horizontal
lines later had difficulty
perceiving horizontal
bars.
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Perception: Nature or Nurture?
Perceptual Adaptation
Courtesy of Hubert Dolezal
Visual ability to adjust
to an artificially
displaced visual field,
e.g., prism glasses.
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Perception: Nature or Nurture?
Perceptual Set
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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Perception: Nature or Nurture?
Perceptual Set
Other examples of perceptual set.
Dick Ruhl
Frank Searle, photo Adams/ Corbis-Sygma
(a) Loch ness monster or a tree trunk;
(b) Flying saucers or clouds?
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FILL IN THE FOLLOWING
WORDS?
1. Goose
Swan
D_ck
4. Wager
Gamble
B_t
7. Bonnet
Derby
_at
2. Bear
Wolf
_ox
5. Sinful
Evil
B_d
8. Shoot
Kill
H_nt
3. Artist
Brush
P_int
6. Courage
Brave
_old
9. Tractor
Crops
_arm
FILL IN THE FOLLOWING
WORDS
1. Sam
Pete
M_ke
4. Base
Ball
B_t
7. Cat
Mouse
_at
2. Package
Carton
_ox
5. Pillow
Sheet
B_d
8. Help
Suggest
H_nt
3. Needle
Sharp
P_int
6. Bend
Crease
_old
9. Hurt
Punish
_arm
Perception: Nature or Nurture?
Schemas
Schemas are concepts that organize and
interpret unfamiliar information.
Courtesy of Anna Elizabeth Voskuil
Children's schemas represent reality as well as their
abilities to represent what they see.
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Schemas: Recognizing a Face
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Features on a Face
Face schemas are accentuated by specific
features on the face.
Kieran Lee/ FaceLab, Department of Psychology,
University of Western Australia
Students recognized a caricature of Arnold
Schwarzenegger faster than his actual photo.
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Eye & Mouth
Eyes and mouth play a dominant role in face
recognition.
Courtesy of Christopher Tyler
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Perception: Nature or Nurture?
Cultural & Context Effects
Context instilled by culture alters perception.
What do you see in this picture?
To an East African, the woman sitting is balancing a metal
box on her head, while the family is sitting under a tree. 59
Perception: Nature or Nurture?
Perception = Biopsychosocial
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Perception & Human Factors
Human Factor Psychologists design machines that
assist our natural perceptions.
Courtesy of General Electric
Photodisc/ Punchstock
The knobs for the stove burners on the right are easier to
understand than those on the left.
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Is There Extrasensory Perception?
Perception without sensory input is called extrasensory
perception (ESP). A large percentage of scientists do
not believe in ESP.
1. Telepathy: Mind-to-mind communication. One
person sending thoughts and the other
receiving them.
2. Clairvoyance: Perception of remote events,
such as sensing a friend’s house on fire.
3. Precognition: Perceiving future events, such as
a political leader’s death.
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Putting ESP to Experimental Test
In an experiment with 28,000 individuals,
Wiseman attempted to prove whether or not one
can psychically influence or predict a coin toss.
People were able to correctly influence or predict a
coin toss 49.8% of the time.
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Premonitions or Pretensions?
Can psychics see the future? Can psychics aid
police in identifying locations of dead bodies?
What about psychic predictions of the famous
Nostradamus?
The answers to these questions are NO!
Nostradamus’ predictions are “retrofitted” to
events that took place after his predictions.
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