Transcript Matlin, Cognition, 7e, Chapter 2: Perceptual Processes I: Visual and

Cognition
Chapter 2
Perceptual Processes I:
Visual and Auditory
Recognition
Cognition 7e, Margaret Matlin
Chapter 2
Introduction
visual stimuli
previous knowledge
perception – pattern recognition
– object recognition
(1/10 sec)
interpretation
Cognition 7e, Margaret Matlin
Chapter 2
Background on Visual
Object Recognition
The Visual System
distal stimulus = what is “out there”
proximal stimulus = active retina cells
iconic memory = visual sensory memory
occipital lobe - - primary visual cortex
inferotemporal cortex
Cognition 7e, Margaret Matlin
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Cerebral Cortex
Cognition 7e, Margaret Matlin
Chapter 2
Background on Visual
Object Recognition
Organization in Visual Perception
Gestalt Psychology
figure
ground
ambiguous figure-ground relationship
Explanation for figure-ground reversal
1) adaptation of neurons in visual cortex
2) people try to solve the visual paradox
Cognition 7e, Margaret Matlin
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Figure-Ground
Relationship
Cognition 7e, Margaret Matlin
Chapter 2
Background on Visual
Object Recognition
Organization in Visual Perception
Illusory Contours (subjective contours)
1) early stages of processing - interpretation
2) later stages of processing - understanding
Cognition 7e, Margaret Matlin
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Illusory Contours
Cognition 7e, Margaret Matlin
Chapter 2
Background on Visual
Object Recognition
Theories of Visual Object Recognition
Template-Matching Theory
templates
compare stimulus to templates until a match is found
Problems
inflexible
only works for isolated letters, numbers, objects
Cognition 7e, Margaret Matlin
Chapter 2
Background on Visual
Object Recognition
Theories of Visual Object Recognition
Feature-Analysis Theory
distinctive features
Eleanor Gibson's research
time to decide if two letters are different (p. 40)
recognizing letters and numbers on envelopes
Cognition 7e, Margaret Matlin
Chapter 2
Background on Visual
Object Recognition
Feature Analysis Theory of Visual Object
Recognition
Hubel and Wiesel's research
single-cell recording technique
feature detector “cells” in primary visual cortex – respond to
orientation of a visual stimulus
Cognition 7e, Margaret Matlin
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Feature-Analysis Theory
Problems with Feature-Analysis approach
doesn't account for the relationship between
features
doesn't explain recognition of more complex objects
Cognition 7e, Margaret Matlin
Chapter 2
Background on Visual
Object Recognition
Theories of Visual Object Recognition
The Recognition-by-Components Theory
Irving Biederman
structural theory
Geons = 3-D shapes
combine geons to form objects
Problem
standard viewpoint vs. different viewpoint
Viewer-centered approach
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Geons
Cognition 7e, Margaret Matlin
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Top-Down Processing and
Visual Object Recognition
The Distinction Between Bottom-Up
Processing and Top-Down Processing
bottom-up processing
top-down processing
Top-down processing is especially strong when
stimuli are incomplete or ambiguous.
Top-down processing is also strong when a
stimulus is registered for just a fraction of a
second.
Combining bottom-up and top-down processing
Cognition 7e, Margaret Matlin
Chapter 2
Top-Down Processing and
Visual Object Recognition
Top-Down Processing and Reading
We don't read letter-by-letter
Analyzing all the individual features in the letters
of words would be too much work for the
perceptual processes
We can still manage to read a sentence, even if
some of the middle letters in a word have been
rearranged or …
twlv mr ppl @ prty. Brng2 6pks br.
Cognition 7e, Margaret Matlin
Chapter 2
Top-Down Processing and
Visual Object Recognition
Top-Down Processing and Reading
Word superiority effect
Say the letter
O
R
C
Cognition 7e, Margaret Matlin
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Word superiority effect
Say the RED letter
COW
OAR
BACK
MRD
SEDT
Cognition 7e, Margaret Matlin
Chapter 2
Top-Down Processing and
Visual Object Recognition
Top-Down Processing and Reading
The context of a sentence facilitates the
recognition of a word in a sentence
Rueckl and Oden's “bears/beans” study
both bottom-up and top-down processing operate in
a coordinated fashion
Cognition 7e, Margaret Matlin
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Rueckl & Oden’s
“Bears/Beans” study
Cognition 7e, Margaret Matlin
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Top-Down Processing and
Visual Object Recognition
In Depth: Overactive Top-Down
Processing and Occasional Errors in
Object Recognition
Change Blindness
fail to detect a change in an object or a scene
Simons and Levin's stranger-and-the-door study
Detecting the difference between two scenes
identify important changes more quickly
more likely to notice an improbable change
do not store a detailed representation of a scene
individual differences
Cognition 7e, Margaret Matlin
Chapter 2
Top-Down Processing and
Visual Object Recognition
In Depth: Overactive Top-Down
Processing and Occasional Errors in
Object Recognition
Inattentional Blindness
fail to notice when an unexpected but completely
visible object suddenly appears
Simons and Chabris' basketball study
Cognition 7e, Margaret Matlin
Chapter 2
Top-Down Processing and
Visual Object Recognition
In Depth: Overactive Top-Down
Processing and Occasional Errors in
Object Recognition
Similarities between change blindness and
inattentional blindness
 both involve top-down processing
 when an object appears that is not consistent with their
concepts, expectations, and memory, people often fail to
recognize this changed object (change blindness) or this new
object (inattentional blindness)
Cognition 7e, Margaret Matlin
Chapter 2
Top-Down Processing and
Visual Object Recognition
In Depth: Overactive Top-Down
Processing and Occasional Errors in
Object Recognition
ecological validity
visual system is accurate in integrating the gist or
general interpretation of a scene
focus on what is important
Theme 2: Our cognitive errors can often be
traced to the use of a rational strategy
Cognition 7e, Margaret Matlin
Chapter 2
Top-Down Processing and
Visual Object Recognition
Ecological validity
Why Seeing Is Often Not
Believing
Boston police officer Kenneth
Conley was convicted of perjury
and obstruction of justice because
he claimed not to have seen a
brutal police beating as he chased
a murder suspect. The conviction
was later overturned, but a new
study re-examines his claim.
(Handout)
Cognition 7e, Margaret Matlin
Chapter 2
Face Perception
Should be a challenging task
Recognizing faces from different angles, in
different settings, with different expressions
Recognizing Faces Versus Recognizing
Other Objects
Face perception as "special"
Tanaka and Farah--facial features in context vs.
isolation
feature identification vs. holistic approach
(Gestalt)
Cognition 7e, Margaret Matlin
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Face Perception
Neuroscience Research on Face
Recognition
Prosopagnosia – non-Gestalt
inferotemporal cortex
single-cell recording technique in monkeys
fMRI studies
brain's response to faces in upright and upside-down
positions
Cognition 7e, Margaret Matlin
Chapter 2
Face Perception
Applied Research on Face Recognition
cashiers' judgments about ID photos (Kemp and
colleagues 1997)
security surveillance systems (Burton and
colleagues 1999)
familiarity and expertise
Cognition 7e, Margaret Matlin
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Face Perception
Individual Differences: Face Identification
in People with Schizophrenia
schizophrenia
use of top-down processing in visual perception
difficulty perceiving faces
same/different person
same/different emotion
Cognition 7e, Margaret Matlin
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Speech Perception
Record sound vibrations of someone talking
 Translate vibrations into a sequence of sounds
that you perceive to be speech

 English: 15 sounds/sec = 900 sounds/min
Distinguish the sound pattern of one word from
all other irrelevant words
 Separate voice of speaker from background
noise, including other conversations

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Speech Perception
 What is a speech sound? A “phone” is the
smallest identifiable unit found in a stream of
speech. (e.g., “k” in Kit vs. Skill)
 What is a phoneme? The smallest unit of
sound that enable meaning contrasts (e.g.,
“p” and “t” in Spill vs. Still)
 How many sounds are there?
Cognition 7e, Margaret Matlin
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Speech Perception
 According to UCLA Phonetic Segment Inventory
Database (UPSID), there are 770 sounds in the world’s
languages
 47% are unique (i.e., occur in only one language)
 Languages average 20 to 27 sounds
 Approximately 44 phonemes in English
 “Smallest” languages: Rotokas (New Guinea) and Mura
(Brazil) with 11 phonemes each.
 “Largest” language: !Xu‚) with 141 phonemes.
 (a.k.a. !Kung – in parts of Namibia & Botswana)
Cognition 7e, Margaret Matlin
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Speech Perception
Characteristics of Speech Perception
Word Boundaries
Listeners can impose boundaries between words,
even when these words are not separated by silence.
Example 
Cognition 7e, Margaret Matlin
Chapter 2
Speech Perception
Characteristics of Speech Perception
Word Boundaries
Cognition 7e, Margaret Matlin
Chapter 2
Speech Perception
Characteristics of Speech Perception
Variability in Phoneme Pronunciation
Phoneme pronunciation varies tremendously
pitch, tone, and rate
lack of precision,
sloppy pronunciation
coarticulation
Cognition 7e, Margaret Matlin
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Speech Perception
Characteristics of Speech Perception
Context and Speech Perception
Context allows listeners to fill in missing sounds.
Phonemic restoration
Warren & Warren's wheel/heel/peel study
Fail to notice mispronunciations
Role of top-down processing
Cognition 7e, Margaret Matlin
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Speech Perception
Characteristics of Speech Perception
Visual Cues as an Aid to Speech Perception
Visual cues from the speaker’s mouth help us
interpret ambiguous sounds.
McGurk effect
Cognition 7e, Margaret Matlin
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Speech Perception
Theories of Speech Perception
The Special Mechanism Approach
speech-is-special approach
1) humans are born with a specialized device that
allows us to decode speech stimuli (phonetic
module or speech module)
2) we process speech sounds more quickly and
accurately than other auditory stimuli
categorical perception
Cognition 7e, Margaret Matlin
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Speech Perception
Theories of Speech Perception
The General Mechanism Approaches
1) humans use the same neural mechanisms to
process both speech sounds and nonspeech
sounds
2) speech as learned ability
event-related potential studies
phoneme judgment and visual cues
Cognition 7e, Margaret Matlin
Chapter 2