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Cognition: Lecture 2
Modern Cognitive Psychology and techniques (Ch 1)
Perceptual Processes I (Ch 2)
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Plan for today’s class
 Registering
 Finish
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your iclicker
Ch 1
Rise of and current status of cognitive psychology
Cognitive Neuroscience
 Techniques
Related disciples: Artificial intelligence
 Start
Section I: Perceptual Processes
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Registering Your Clicker
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To register i>clicker:
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Log in to MyConcordia Portal at http://www.myconcordia.ca
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In the left-side menu, select Student Services.
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Select i>clicker registration.
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Enter their i>clicker remote ID and click Enter
You only have to register your i>clicker once unless they
have changed your remote.
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Summary/Review of Last class
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Course syllabus and contact information
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Does everyone have the textbook?
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Does everyone have the iClicker and/or REEF?
Origins of cognitive psychology
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Philosophy, Early psychologist and cognitive psychologists
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Early memory researchers
Behaviorism and Gestalt Approach
 Ready
for review questions?
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Chapter 1 cont.
An Introduction to Cognitive Psychology
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Rise of Cognitive Psychology
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The cognitive psychology revolution began in 1956
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Factors driving revolution:
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Disappointment in behaviorism
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Difficulty explaining complex human behavior
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I.e., Advancements in linguists (Reinforcement ≠ Language
complexity and ease)
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Human behavior can’t be entirely explained by learning
principles from lab animals
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Rise of Cognitive Psychology
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Factors driving revolution (cont.):
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Research in human memory began to blossom
 Awareness of memory altered by previous knowledge
 ‘Discovery’ of Frederic Bartlett’s work
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Developmental psychology research
 Jean Piaget
 Children actively explore their world in order to understand
important concepts
 Cognitive strategies change throughout development
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Enthusiasm surrounding Information-Processing Approach
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Rise of Cognitive Psychology
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Information processing approach
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Theoretical approach to human memory originating in the 1960’s
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Asserts that:
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Mental processes are similar to the operations of a computer
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Information is processed in a series of stages
Example: The Atkinson-Shiffrin model (1968)
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Memory involves a a sequence of separate steps
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Information is transferred from one storage ‘area’ to another at
each step
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Rise of Cognitive Psychology
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Current Status of Cognitive
Psychology
 Widespread
influence of cognitive psychology
Pure behaviorism is extremely rare
 Importance of mental representations
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 Concern
and focus on designing studies with
ecological validity
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the extent to which the findings of a research study
are able to be generalized to real-life settings
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Cognitive Neuroscience
 Cognitive
Neuroscience combines research from
cognitive psychology with neuroscience theory
and techniques for assessing brain structure and
function
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Related social cognitive neuroscience uses neuroscience to
explore cognitive processes involved in social interactions
 Cognitive
neuroscience pop psychology findings
must be treated with caution
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Extremely complex system; multiple processes and active
regions
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Cognitive Neuroscience:
Techniques
 Study
of brain lesions
 Destruction
of a region of the brain often due to
stroke or accident
 Assumption: Relationship between damaged
region and cognitive deficit
 Example
 Aphasia: Loss of ability to understand or
produce speech following brain damage
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Cognitive Neuroscience: Lesions
 Broca’s
aphasia
 Expressive
aphasia
 Sentence formation
 Wernicke’s
aphasia
 Receptive
 Comprehension
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Cognitive Neuroscience: TMS
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Transcranial Magnetic Stimulation (TMS)
technique for temporary disrupting the function
of specific cortical regions
 non-invasive and no residual effects
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Cognitive Neuroscience:
Techniques
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Imagery Techniques:
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Positron emission tomography (PET) v. Functional magnetic
resonance Imaging (fMRI)
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Both measure brain activity indirectly
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Increased blood flow in active brain regions
PET measures blood flow using radioactively labeled compounds
named radiotracers
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Benefit use of different chemicals ie., glucose, raclopride etc
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Cognitive Neuroscience:
Techniques
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Imagery Techniques:
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fMRI measures relies on paramagnetic properties of
oxygenated and deoxygenated hemoglobin
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Blood-oxygen-level dependent contrast (BOLD signal)
events)
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Cognitive Neuroscience:
Techniques
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Event-related potential technique (ERP)
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Able to assess timing of neural events through
electrodes places on scalp
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Each electrode records from a group of neurons
located directly under skull
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Cannot penetrate the cortex
Stereotypic electrophysiological response to
stimulus
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Raw electroencephalogram (EEG) recordings
averaged to eliminate random brain activity
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Artificial Intelligence
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Artificial Intelligence
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A branch of computer science concerned with making
computers behave like humans
Theory and development of computers able to complete
complex human tasks
 Ie., visual perception, speech recognition and decisionmaking
Pure AI v Computer Simulation
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Pure AI
 Computer programs designed to as efficiently as
possible
Computer simulation (or computer modeling)
 Program computer to preform task in the same way as a
human
 Produces human errors
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Artificial Intelligence
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Connectionist Approach:
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Emerged due to advances in neuroscience and AI
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Cognitive processes can be understood in terms of networks
(network approach)
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McClelland et al., 1986
Simultaneous (parallel distributed processing) operations
rather than serial processing (information-processing
approach)
Like the brain model focuses on ‘neuron-like’ units with numerous
interconnections and distributed neural activity
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Textbook Themes
 Recurring
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themes throughout the text
Review these and note when you see these themes
reemerging
 Theme
1: Cognitive processes are active rather
than passive
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Examples?
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Section I: Perceptual Processes
and Mental Imagery
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Section I: Perceptual Processes &
Mental Imagery
 Section
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I: Perceptual Processes
Chapter 2: Perceptual Processes I: Visual and Auditory
Recognition
Chapter 7: Mental Imagery and Cognitive Maps
Chapter 3: Perceptual Processes II: Attention and
Consciousness
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Perception v Sensation
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Perception and sensation are related but not the same
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Sensation: the process allowing our brains to take in information
via our senses, which can then be experienced and interpreted
by the brain
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Perception: Uses previous knowledge to gather and interpret
stimuli registered from the senses.
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Perception = experience and interpretation by the brain
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Combines external world (stimuli) and internal world (previous
knowledge)
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Perception is Complex
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Perception is complex
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Object are recognized even with less than perfect visible
information
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Ie., Missing components (Gestalt), 2-D representation, Inverted
image, changing visual scene, short presentation
Shape constancy: Refers to the ability to perceive objects as
having a constant shape despite receiving different sensory
images
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Perception: Iconic Memory
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Visual sensory memory (iconic memory)
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Large capacity storage system that records information for each
of the senses with reasonable accuracy
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Preserves an image of a visual stimulus for a brief period after the
stimulus has disappeared
Can identify visual stimuli presented for less than a 1/10s
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Gestalt and Visual Perception
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Visual system is designed to impose organization
on a richly complicated visual world
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Gestalt Psychology principle: Humans have basic
tendencies to organize what they see; without any effort
we patterns rather than random unrelated
arrangements
Gestalt Principles of Perception
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Figure-Ground
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Element are perceived as either figures (distinct
elements of focus) or ground (the background or
landscape the figure(s) rest on)
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Figures seem closer and more dominant
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Gestalt and Visual Perception
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Gestalt Principles of Perception: Figureground relationships
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Stable: Figure and ground are clear and distinct
Ambiguous-figure ground relationship: The
figure and ground can reverse
 In ambiguous situations our perceptual
system imposes organization
Accustomed to the certainty of figure ground
relationships; it is surprising when figure and
ground reverse
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Adaptation of neurons in visual cortex
Reversal related to solving visual paradox
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Gestalt and Visual Perception
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Why to these images have the quality of Gestalt?
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Prägnanz Principle/Law
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German word loosely translated into of good figure
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Most general Gestalt principle states that the simplest
organization, requiring the least cognitive effort, will emerge as
the figure
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Gestalt and Visual Perception
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Why to these images have the quality of Gestalt?
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Proximity Principle: Elements tend to be perceived as aggregated
if they are near each other
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Common Fate or Continuity Principle Continuity: Elements tend
to be perceived as aggregated if they move together
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https://www.youtube.com/watch?v=nuH6dIcgaoU
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Gestalt and Visual Perception
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Why to these images have the quality of Gestalt?
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Similarity Principle: Elements tend to be perceived as aggregated
if they are similar to each other
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Closure Principle: Objects grouped together are seen as a whole
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We ignore groups and create contour lines
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Illusory contours (Subjective Contours)
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Rational perceptual error (fill-in the blanks)
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Visual System
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The Visual System: Stimuli
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Perceptual Stimuli
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Distal Stimuli
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The actual object that is “out there” in the environment
Proximal Stimuli
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The information registered on your sensory receptors
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Image created on retina
Retina convers images to electrical signals sent via the optic
nerve to the primary visual cortex
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The Visual System
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Primary visual cortex
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Located in the occipital lobe
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Basic processing of visual stimuli
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First place visual information from both eyes is combined
First stop in cortex before further processing
At least 30 additional areas of the cortex have been
shown to be involved in visual perception
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Ie., Parietal lobe: involved in recognition of tools
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Visual Object Recognition
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Visual Object Recognition:
Introduction
 Object
Recognition (Pattern Recognition)
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Involves identifying a complex arrangement of sensory
stimuli into distinct objects or patterns separate from the
background and separate from each other
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Transformation of raw sensory information into perceptual
units based on information in memory
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Theories of Visual Object
Recognition
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Three theories of visual object recognition
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Matching to Templates
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Feature-Analysis Approach (F-A)
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Recognition-by-components (RC)
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Theories of Visual Object
Recognition
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Matching to Templates
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Earliest of the theories
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Stimuli compared with a set of stored templates
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Similar to the idea of prototypes
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Problems with more complex stimuli and deviations
from template
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Theories of Visual Object
Recognition
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Feature-Analysis Theory
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Visual stimuli composed of a small number of distinct
characteristics or components called distinct features
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Features are extracted and compared to memory
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Ie., For letters we store a set of distinct features:
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For R we have
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1 straight component
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1 curved component
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1 diagonal component
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Theories of Visual Object
Recognition
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Feature-Analysis Theory: Eleanor Gibson (1969)
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More time needed to distinguish between
letters with more similar features
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Theories of Visual Object
Recognition
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Lets have a look at the Feature Analysis Theory
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iClicker
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Press 1 if the letters are the same
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Press 2 if the letters are different
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E and F
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I and Z
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G and C
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Theories of Visual Object
Recognition
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Support for Feature-Analysis Theory
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Longer time to recognize differences b/t letters sharing features
(Reaction Time Studies)
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Using F-A structure AI models can recognize 95% of envelope
addresses
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Hubel & Wiesel (1960’s-1980’s): Neurobiological evidence of
feature detector neurons in the primary visual cortex
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Theories of Visual Object
Recognition
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Hubel & Wiesel (1960’s-1980’s)
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Additional Info
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https://www.youtube.com/watch?v=y_l4kQ5wjiw
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Theories of Visual Object
Recognition
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Problems with Feature-Analysis Theory
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Theory constructed to explain relatively recognition of letters
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Does not address complex shapes
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Ie., what are the features of a dog
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Distortion of features with movement (moving dog)
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Relationship between features can be different
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Theories of Visual Object
Recognition
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Recognition-by-components (RC) theory: Irving Biederman
(1987)
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Deal with recognition of complex shapes
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Objects are represented as an arrangement of geometric icons
called Geons
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Geons are like 3D features
Biederman listed 36 geons that can be used to form 3D objects
Recognition-by-components theory is essentially a 3-D
Feature-Analysis Theory
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Theories of Visual Object
Recognition
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What are Geons?
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Theories of Visual Object
Recognition
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Support of Recognition-by-components theory
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fMRI and neuronal responses to Geons
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Young children may perceive undifferentiated object but older
children represent objects as geons
Modification to Recognition-by-components theory
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Viewer-centered approach: Proposes we store a small number of
views of 3-D objects
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Storage or ‘regular’ viewing angles
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Quicker recognition at standard viewing angles
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Viewing from unusual angle requires mental (slower reaction
times)
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Bottom-Up and Top-Down
Processing
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Bottom-Up and Top-Down
Processing
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Thus far we have focused on the nature of visual stimuli
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Bottom-Up Processing
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Data driven (sensory input)
Observable patterns inform higher order cognitive processes
Stimulus characteristics influences cognition (behavior)
Top-Down Processing
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Ie., features, geons
Behavior is influenced by conceptual data Higher order conceptual processes
construct our experiences and expectations
Perception and behavior directed by expectations
Syn: Conceptually driven perception or construct perception
https://www.youtube.com/watch?v=TLHlfPTRekA
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Bottom-Up and Top-Down
Processing
Object recognition requires both bottom-up
and top-down processing.
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Top-Down Processing: Context
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What is this object(s)?
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Based on what we have learn how
might our brain this out?
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Feature Analysis
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1 straight line component
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2 connected curved components
Gestalt perspective? (Top downImposed organization)
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Is this two objects or one
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Top-Down Processing: Context
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Let’s put this in context
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What about now?
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Top-Down Processing: Context
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A new context
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What about now?
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Top-Down Processing & Reading
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Read this aloud (Rayner et al., 2006)
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“Aoccdring to a rscheeaech at Cmabrigde Uinervtisy, it deosn’t
mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt
tihng is taht the frist and the lsat ltteer be at the rghit pclae. The
rset can be a tatol mses and you can sitll raed it wouthit porbelm.
Tihs is bcuseae the huamn mnid deos not raed ervey lteter by
istlef, but the wrod as a wlohe.”
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Top-Down Processing & Reading
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Word Superiority Effect: Letter more rapidly and more
accurately identified when appearing in a meaningful word
then when alone or in non-sense word
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Richer, 1969
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Brief presentations of four letter words, same letter nonwords and single letters
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WORD
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OWRD
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D
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Each followed by masking
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Forced letter choice
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Top-Down Processing & Reading
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Word Superiority Effect
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Top-Down Processing & Reading
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Word-in-a-sentence effect (Ruecki & Oden, 1986)
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Bottom-up processing: Varied the shape (features) of a stimulus
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Top-down processing: Varied the context of the sentence
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Example: “The ________ raised
to
supplement his income”
lion tamer
zookeeper
botanist
dairy farmer
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Top-Down Processing & Reading