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

Cognition Chapter 2

Perceptual Processes I: Visual and Auditory Recognition Cognition 7e, Margaret Matlin

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Introduction visual stimuli

previous knowledge perception – pattern recognition – object recognition (1/10 sec)

interpretation

Cognition 7e, Margaret Matlin

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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

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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

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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

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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

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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

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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

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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 Cognition 7e, Margaret Matlin

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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 

Cognition 7e, Margaret Matlin

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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

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Speech Perception Characteristics of Speech Perception Word Boundaries

Cognition 7e, Margaret Matlin

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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

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