Cognition 7e, Margaret MatlinChapter 2 Cognition Perceptual Processes I: Visual and Auditory Recognition Chapter 2

Cognition 7e, Margaret Matlin Chapter 2

CognitionCognition

Perceptual Processes I: Perceptual Processes I: Visual and Auditory Visual and Auditory

RecognitionRecognition

Chapter 2Chapter 2


IntroductionIntroduction

visual stimuli previous knowledge

perception – pattern recognition

– object recognition

(1/10 sec)

interpretation


Background on Visual Background on Visual Object RecognitionObject Recognition

The Visual SystemThe Visual Systemdistal stimulus = what is “out there”proximal stimulus = active retina cellsiconic memory = visual sensory memoryoccipital lobe - - primary visual cortexinferotemporal cortex


Cerebral CortexCerebral Cortex



Organization in Visual PerceptionOrganization in Visual PerceptionGestalt Psychology

figure

ground

ambiguous figure-ground relationshipExplanation for figure-ground reversal

1) adaptation of neurons in visual cortex

2) people try to solve the visual paradox


Figure-Ground Figure-Ground RelationshipRelationship



Organization in Visual PerceptionOrganization in Visual PerceptionIllusory Contours (subjective contours)

1) early stages of processing - interpretation

2) later stages of processing - understanding


Illusory ContoursIllusory Contours



Theories of Visual Object RecognitionTheories of Visual Object RecognitionTemplate-Matching Theory

templates

compare stimulus to templates until a match is found

Problemsinflexible

only works for isolated letters, numbers, objects



Theories of Visual Object RecognitionTheories of Visual Object RecognitionFeature-Analysis Theory

distinctive features

Eleanor Gibson's researchtime to decide if two letters are different (p. 40)

recognizing letters and numbers on envelopes



Feature Analysis Theory of Visual Object Feature Analysis Theory of Visual Object RecognitionRecognition

Hubel and Wiesel's researchsingle-cell recording technique

feature detector “cells” in primary visual cortex – respond to orientation of a visual stimulus

Feature-Analysis TheoryFeature-Analysis Theory

Problems with Feature-Analysis approach

doesn't account for the relationship between features

doesn't explain recognition of more complex objects




Theories of Visual Object RecognitionTheories of Visual Object RecognitionThe Recognition-by-Components Theory

Irving Biederman

structural theory

Geons = 3-D shapes

combine geons to form objects

Problemstandard viewpoint vs. different viewpoint

Viewer-centered approach


GeonsGeons


Top-Down Processing and Top-Down Processing and Visual Object RecognitionVisual Object Recognition

The Distinction Between Bottom-Up The Distinction Between Bottom-Up Processing and Top-Down ProcessingProcessing and Top-Down Processing

bottom-up processingtop-down processingTop-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



Top-Down Processing and ReadingTop-Down Processing and ReadingWe don't read letter-by-letterAnalyzing 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.



Top-Down Processing and ReadingTop-Down Processing and ReadingWord superiority effect

Say the letterSay the letter

OO

RR

CC

Word superiority effectWord superiority effect

Say the RED letterSay the RED letter

CCOOWW

OAOARR

BABACCKK

MRMRDD

SSEEDTDT




Top-Down Processing and ReadingTop-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


Rueckl & OdenRueckl & Oden’’s s ““Bears/BeansBears/Beans”” study study



In Depth: Overactive Top-Down Processing In Depth: Overactive Top-Down Processing and Occasional Errors in Object Recognitionand Occasional Errors in Object Recognition

Change Blindnessfail to detect a change in an object or a sceneSimons and Levin's stranger-and-the-door studyDetecting the difference between two scenes

identify important changes more quicklymore likely to notice an improbable changedo not store a detailed representation of a sceneindividual differences



In Depth: Overactive Top-Down In Depth: Overactive Top-Down Processing and Occasional Errors in Processing and Occasional Errors in Object RecognitionObject Recognition

Inattentional Blindnessfail to notice when an unexpected but

completely visible object suddenly appears

Simons and Chabris' basketball study




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)




ecological validityvisual system is accurate in integrating the gist or

general interpretation of a scenefocus on what is importantTheme 2: Our cognitive errors can often be

traced to the use of a rational strategy



Ecological validityEcological validityWhy 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)


Face PerceptionFace Perception

Should be a challenging taskRecognizing faces from different angles, in different settings, with different expressions

Recognizing Faces Versus Recognizing Recognizing Faces Versus Recognizing Other ObjectsOther Objects

Face perception as "special"Tanaka and Farah--facial features in context vs. isolation

feature identification vs. holistic approach(Gestalt)



Neuroscience Research on Face Neuroscience Research on Face RecognitionRecognition

Prosopagnosia – non-Gestaltinferotemporal cortexsingle-cell recording technique in monkeysfMRI studies

brain's response to faces in upright and upside-down positions



Applied Research on Face RecognitionApplied Research on Face Recognitioncashiers' judgments about ID photos (Kemp and colleagues 1997)security surveillance systems (Burton and colleagues 1999)

familiarity and expertise



Individual Differences: Face Identification Individual Differences: Face Identification in People with Schizophreniain People with Schizophrenia

schizophreniause of top-down processing in visual perceptiondifficulty perceiving faces

same/different person

same/different emotion


Speech PerceptionSpeech 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



What is a speech sound?What is a speech sound? A “phone” is the A “phone” is the smallest identifiable unit found in a stream of smallest identifiable unit found in a stream of speech. (e.g., “k” in Kit vs. Skill)speech. (e.g., “k” in Kit vs. Skill)

What is a phoneme?What is a phoneme? The smallest unit of The smallest unit of sound that enable meaning contrasts (e.g., sound that enable meaning contrasts (e.g., “p” and “t” in Spill vs. Still)“p” and “t” in Spill vs. Still)

How many sounds are there?How many sounds are there?


According to UCLA Phonetic Segment Inventory According to UCLA Phonetic Segment Inventory Database (UPSID), there are 770 sounds in the world’s Database (UPSID), there are 770 sounds in the world’s languageslanguages

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 Smallest” languages: Rotokas (New Guinea) and Mura (Brazil) with 11 phonemes each. (Brazil) with 11 phonemes each.

““Largest” language: !Xu‚) with 141 phonemes. Largest” language: !Xu‚) with 141 phonemes. (a.k.a. !Kung – in parts of Namibia & Botswana)




Characteristics of Speech PerceptionCharacteristics of Speech PerceptionWord Boundaries

Listeners can impose boundaries between words, even when these words are not separated by silence.

Example



Characteristics of Speech PerceptionCharacteristics of Speech PerceptionWord Boundaries



Characteristics of Speech PerceptionCharacteristics of Speech PerceptionVariability in Phoneme Pronunciation

Phoneme pronunciation varies tremendously

pitch, tone, and rate

lack of precision,

sloppy pronunciation

coarticulation



Characteristics of Speech PerceptionCharacteristics of Speech PerceptionContext and Speech Perception

Context allows listeners to fill in missing sounds.

Phonemic restorationWarren & Warren's wheel/heel/peel study

Fail to notice mispronunciations

Role of top-down processing



Characteristics of Speech PerceptionCharacteristics of Speech PerceptionVisual Cues as an Aid to Speech Perception

Visual cues from the speaker’s mouth help us interpret ambiguous sounds.

McGurk effect



Theories of Speech PerceptionTheories of Speech PerceptionThe 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



Theories of Speech PerceptionTheories of Speech PerceptionThe 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

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Cognition 7e, Margaret MatlinChapter 2 Cognition Perceptual Processes I: Visual and Auditory Recognition Chapter 2