Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Chapter 3: Perception
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Perception Is…
• The process of recognizing, organizing
and interpreting information
• How do you recognize these items?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Perceptual Illusions
• http://www.michaelbach.de/ot/#history
• Examine some of the illusions on this
page
– Some illusions cause you to perceive
what is not there
– Others lead you to perceive what cannot
be
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Perceptual Basics
• Sensory Adaptation
– Occurs when sensory receptors change
their sensitivity to the stimulus
– Constant stimulation leads to lower
sensitivity
• Our senses respond to change
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Perceptual Basics
• Perceptual Constancy
– Object remains the
same even though our
sensation of the object
changes
• Example:
– Shape constancy
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Depth Perception
• The ability to see the world in 3
dimensions and detect distance
– Vision only has a 2-dimensional view
– We must interpret the information given to
perceive depth
– We take flat images and create a three
dimensional view
– Optical illusions demonstrate that this
interpretation does not always have to be
correct
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Monocular Depth Cues
• Texture Gradients
– Grain of item
• Relative Size
– Bigger is closer
• Interposition
– Closer are in front of other objects
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Monocular Depth Cues
• Linear Perspective
– Parallel lines converge in distance
• Aerial Perspective
– Images seem blurry, the farther away
• Motion Parallax
– Objects get smaller at decreasing speed in
distance
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Binocular Depth Cues
• Binocular Convergence
– Eyes turn inward as object moves
towards you, brain uses this information
to judge distance
• Binocular Disparity
– Each eye views a slightly different angle
of an object; Brain uses this to create a
3-d image
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Object Perception
• Viewer-centered representation
– Object is stored in the perspective seen
– Store multiple views of object as seen under
various conditions
– Viewpoint dependent process
• Object-centered representation
– Object is stored in a way that best represents
the object
– Viewpoint invariant process
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Object Perception
• Evidence supports both
• How to reconcile?
– Maybe both contribute to object
recognition
– Two ends of a continuum that contribute
to object recognition
– Burgund & Tarr researched this issue
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Landmark-centered Orientation
• Information is coded by its relation to a
well known or prominent item
• Consider your college campus
– What is a prominent item you use to
orient yourself on campus?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Gestalt’s View of Perception
• Basic Tenet
– “The whole is more than a sum of its parts.”
• Law of Prägnanz
– Individuals organize their experience in as
simple, concise, symmetrical and complete
manner as possible
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Gestalt’s Principles of Visual Perception
• Figure-Ground
– Organize perceptions by
distinguishing between a figure and a
background
• Proximity
– Elements tend to be grouped together
according to their nearness
• Similarity
– Items similar in some respect tend to
be grouped together
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Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Gestalt’s Principles of Visual Perception
• Continuity
– Based on smooth continuity
which is preferred to abrupt
changes of direction
• Closure
– Items are grouped together if
they tend to complete a figure
• Symmetry
– Prefer to perceive objects as
mirror images
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Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Pattern Recognition Systems
• One system
– Recognize parts
– Assemble into wholes
• Second system
– See wholes
– Then analyze parts
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Evidence for Two Pattern
Recognition Systems
• Farah’s Research
• Face recognition and Object
recognition use different systems
– Functional independence
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Functional Independence Evidence
• Prosopagnosia
– Inability to recognize faces after brain
damage
– Ability to recognize objects is intact
• Associative Agnosia
– Difficulty with recognizing objects
– Can recognize faces
• Demonstrates two different systems
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
“Special” nature of Facial Recognition
• Tanaka & Farah (1993)
• Participants studied
– Faces and names
– Pictures of homes and home owner’s names
– At test, given only a piece of face (eg. Nose),
whole face, whole home or a piece of the
home (e.g., window)
• Asked to recall names
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Farah & Tanaka (1993) Results
• What pattern would you expect if
processing of homes (object) and faces
were the same?
• Which condition do you think had the
highest memory for the names?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Fusiform gyrus in Temporal lobe
• Implicated in pattern recognition
• Studies illustrate it is active in facial
recognition
• However, also active if high expertise
in any item (birds, cars) recognition
– Expert individuation hypothesis
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Theories of Perception
• Direct Perception theories
– Perception comes from the stimuli in the
environment
– Bottom-up processing
– Parts are identified, put together, and then
recognition occurs
• Constructive Perception theories
– People actively construct perceptions using
information based on expectations
– Top-down processing
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
•
•
•
•
•
Gibson’s Direct Perception
(Ecological model)
All the information needed to form a
perception is available in the environment
Perception is immediate and spontaneous
No top-down processing is necessary
Perception and action cannot be separated
Perception guides action and action
generates more new perceptual
information
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Bottom-Up Processing Theories
• Template theories
• Prototype theories
• Feature theories
• Structural description theories
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Template Theory
• Basics of template theory
– Multiple templates are held in memory
– To recognize the incoming stimuli, you
compare to templates in memory until a
match is found
Search memory for a match
See stimuli
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Template Theory
• Weakness of theory
– Problem of imperfect matches
– Cannot account for the flexibility of
pattern recognition system
Search for match in memory
See stimuli
No perfect match in memory
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Prototype Theories
• Modification of template matching
(flexible templates)
• Takes various instances of an object
and abstracts out the common
characteristics
• No match is perfect; a criterion for
matching is needed
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Prototype Evidence
• Franks & Bransford (1971)
– Presented objects based on prototypes
– Prototype not shown
– Yet participants are confident they had
seen prototype
– Suggests existence of prototypes
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Prototype Evidence
• Solso & McCarthy (1981)
– Participants were shown a
series of faces
– Later, a recognition test
was given with some old
faces, a prototype face,
and some new faces that
differed in degree from
prototype
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Solso & McCarthy (1981) Results
• Participants
were more
confident they
had seen the
prototype than
actual items they
had seen.
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Research on Prototypes
• Researchers have found that prototypical
faces are found to be more attractive to
participants
• Halberstadt & Rhodes (2000)
– Examined the impact of prototypes of dogs,
wristwatches, and birds on attractiveness of
the stimuli
– Results indicate a strong relationship
between averageness and attractiveness of
the dogs, birds, and wristwatches
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Feature Theories
• Recognize objects on the basis of a small
number of characteristics (features)
– Detect specific elements and assemble them
into more complex forms
– Brain cells that respond to specific features,
such as lines and angles are referred to as
“feature detectors”
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Feature Evidence
• Hubel & Wiesel (1979) using single cell
technique
– Simple cells detect bars or edges of particular
orientation in particular location
– Complex cells detect bars or edges of particular
orientation, exact location abstracted
– Hypercomplex cells detect particular colors
(simple and complex cells), bars, or edges of
particular length or moving in a particular
direction
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Navon (1977)
Participants asked
what they saw on the
–Global level
–Local Level
Results depended on whether letters are more widely
spaced. Local –precedence effect stimuli depicted
here. Participants were faster at identifying local
features of the letters.
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Structural-Description Theories
• Biederman (1987)
– Describes how 3D
images are identified
– Breaks objects down
into geons
– Objects are identified
by geons and
relationship between
them
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Evidence for Geons
• Biederman & Cooper (1991)
– Used visual priming to demonstrate the
existence of geons in a picture naming
task
– Subjects were shown a series of
fragmented pictures and were asked to
identify the objects
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Top-down Processing
(Constructive Perspective)
• Perception is not automatic from raw
stimuli
• Processing is needed to build
perception
• Top-down processing occurs quickly
and involves making inferences,
guessing from experience, and basing
one perception on another
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Top-down Processing Evidence
•Context effects
Context helps us to be able to recognize letters in many different
styles.
Context helps us to be able to recognize letters in many different styles.
Context helps us to be able to recognize letters in many different styles.
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Configural-Superiority Effect
• Objects presented in context are easier
to recognize than objects presented
alone
• Task: Spot the different stimuli, press
button
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Configural Superiority Effect
Target
Composite
Measure Reaction time
Target alone = 1884
Composite = 749
Target spotted faster in a context!
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Which approach is right?
• Top-down or Bottom-up
– Perhaps a bit of both
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Visual Pathways in the Brain
• What / Where Hypothesis
– One path for identifying
• Temporal lobe lesions in monkeys
– Can indicate where but not what
– Another for spatially locating
• Parietal lobe lesions in monkeys
– Can indicate what but not where
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Visual Pathways : Alternative
• What/How hypothesis
– Where something is located in space
– How do we reach for it?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Deficits in Perception
• Agnosia
– Inability to recognize and identify objects
or persons despite having knowledge of
the characteristics of the objects or
persons
– Shows the specialization of our
perceptual systems
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Prosopagnosia
• Inability to recognize faces, including
one's own
• Cannot recognize person from face
• Knows a face is a face
• Can recognize individuals from voice
• Can recognize objects
• Can discriminate whether two faces are
same or different
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
More Agnosias
• Simultagnosic
– Normal visual fields, yet act blind
– Perceives only one stimulus at a time—single
word or object
• Spatial Agnosia
– Cannot navigate in even familiar enviroment
– Gets lost
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
More Agnosias
• Auditory Agnosia
– Cannot recognize certain sounds
– Can not tell if two melodies are the same
or different
• Color Agnosia
– Can see two colors are different, but
cannot name the colors
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Ataxia
• Disruption of the “how” pathway
• Optic ataxia
– Cannot use vision to guide movement
– Unable to reach for items
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 3
Agnosias, Ataxias & Cognition
• Demonstrate the modularity of
cognition
• Help us to understand what brain
locations are associated with different
types of higher level processing
• Provide us with a model of how
normal processing must work