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Camillo Golgi
- - brain tissue staining (Golgi staining)
- - 1 of 4 fathers of psych
- -Used silver nitrate to stimulate (potassium chloride mix)
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Santiago Ramon and Cajal
- - Used Golgi stain on newborn brains
- -Neuron Doctrine: signal transmits from the first neuron, continually down each neuron
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Neuron Characteristics
- - A neuron not firing is at a constant rate of -70 mV
- - Threshold is at -55mV
- - Reaches action potential once it depolarizes beyond threshold
- - Action potential maxes out at 40mV
- - Re polarizes to refractory period (below -70mV), then back to resting state
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Basics of Neurons
- - Transduction
- -Sensory receptors (afferent)
- 1. Sensory receptors
- 2. Signal transduction
- 3. Physiological response
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Visual Transduction
- Environmental energy in retina and electrical energy when entering optic chiasm
- -Signals meet, converge, and are directed
- -Brain works contralaterally
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Corpus Callosum & Split Brain
- Connects the left and right hemispheres, communication
- - seizure occur when there is too much activity between the left and right hemispheres
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Gazzanigas Split Brain Studies
- - Screen and imaging
- - Visual cue: reach with left and reach with right
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Representations
- 2 types of info:
- 1. Linguistic: language based info
- 2. Visuo-spatial: mental imagery
Goal: good mapping of the world
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Method of Loci
Mnemonic Device: using visual objects to represent parts of a story
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Wundt's Introspectionsim
- Verbalizing a mental image
- -how many windows do you have in your house?
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Behaviorism
Mental images are unproven and mythological - Watson
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Early Measurement of Mental Imagery
- -Performance scores: mentally rotating objects
- - Mental rotation test
- -Problems: visual imagery cannot be directly observed
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Memory
- Mental imagery = elaboration
- -Shepard: memory for pictures is high with 87% accuracy after 1 week
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Proposal
Visual imagery = perception without originality stimulus
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Dual Code Theory (Paivio's Theory)
- 2 independent codes to help elaboration
- 1. Verbal: make verbal associations
- 2. Visual: form mental images
- Concrete v. Abstract words: abstract words are difficult to represent visually
- *Association is a better predictor of learning
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Recall Study of Dual Code Theory
Studied word pairs with high or low imagery potential, not told to use imagery
Results: imagery used most for 2 high high words and least for low low pairs
Implications: imagery potential = strong predictor of learning
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Early Attempt to Measure Imagery
- - "F" task
- - quickly view block letter on screen
- - participants mentally trace outline of letter
- - extreme top or bottom = "yes"
- - not extreme top or bottom = "no"
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Brooks Measurement of Mental Imagery
- 3 methods of responding:
- 1. say yes or no
- 2. tap left or right finger
- 3. point to irregularly placed Ys and Ns on a page
- Results: verbal responses greater than pointing to responses
- Implications:
- - Using 2 different systems = no selective interference
- - Using the same system = selective interference
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Pylyshyn's Arguement on Mental Imagery v. Visual Perception
Propositional Theory: all knowledge based on description, not sensory characteristics. No "pictures" in memory
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Kosslyn & Pomerantz's Counterarguement to Mental Imagery v. Visual Perception
- Analog: processing visual images is analogous to perceptual processing
- -Had 5 types of evidence
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1. Map Scanning
- -Participants study map, focus on one landmark and quickly switch focus to another
- -Hypothesis: mental scanning time = time to visually scan picture
- -Results: RT = linear function of distance between landmarks; same RTs for visual scans
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2. Sequential v. Parallel Processing
- -Phase 1: participants view pictures of faces or descriptions of faces
- -Phase 2: participants view face; decide "same" or "different"
- Hypothesis: fast match RT (parallel processing) for pictures of faces
- Results: RT: Pictures of faces is less that description of faces
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3a. Mental Transformations
- -Participants view pairs of 3D objects and decide "same" or "different"
- -Hypothesis: degree of orientation should affect RT to decide same or different
- -Results: RT increased linearly with increases in degree of rotation
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3b. Mental Transformations
Participants view image of pulley system
Hypothesis: if mental imagery is like visual perception, RT should increase as number of pulleys increases
Results: RT increases linearly with number of pulleys
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4. Interference
- "F" Task
- Hypothesis: imagery and perception simultaneously = selective interference
Results: poor performance for visually based responses
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5a. Visual Perception and Visual Imagery Activate the Same Brain Regions
- Normal subjects in fMRI
- - Shown patterns on a screen: occipital lobe activation
- Imagine same pattern
- - almost as much visual cortex activation
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5b.Visual Neglect Patients
- Right parietal damage
- - contralateral effect
- - Not aware of anything in left visual field
- - Attention problem that results in visual deficits
- -Perception is in retina, mental image is in LTM
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Evidentiary Task 1
Imagine animal, then view animal part, decide if part belongs to animal
- Results: faster RT for larger animals
- -easy to isolate features
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Evidentiary Task 2
Imagine 2 animals at the same time
- Results: faster RT for elephant parts
- - elephant is bigger in 'visual' field (easier to imagine features)
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Evidentiary Task 3
Imagine giant fly and tiny elephant
- Results: reverse effect
- RT: fly less than the elephant
- - relative and imagined size matter
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Evidentiary Task 4
- Imagine animals with high and low association values and big and small features
- Imagine group = form images
- control group = not told to form mental image
Results: faster RT for image group
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Limitations of Mental Imagery
- 1. Mental image details are selective
- 2. Reality monitoring
- 3. Breakdown of Reality Monitoring
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Mental Image Details Are Selective
Reinterpreting perceived figure better than reinterpreting imagined figure
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Reality Monitoring: distinguishing between internal and external sources
- Cues help us make the distinction
- -Perceptual Info:
- Spacial details
- Uses context
- Processed automatically
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Breakdown of Reality Monitoring: judgements of reality v. imagination can be poor
- False/Illusory Memory
- -Causes:
- long delays
- repeated suggestions
- mental rehearsal
- guided imagery
- -Example:
- eye witness testimony
- 9/11 flashbulb memory
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Breakdown of Reality Monitoring: judgements of reality v. imagination can be poor (continued)
- Hallucinations
- Causes:
- -Impaired discrimination btwn reality and imagination
- -hallucination content relates to personality and present stressors
- Example: Sz patients have enhanced imagery vividness
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Semantic Organization
- -Organization = efficiency
- -Meaning based
- -Ex: Listing US states and how we do it (alphabetize, location)
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Semantic Networks
- 1. Organization
- 2. Activation
- 3. Priming
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Organization
- Linking semantically related concepts
- -Concepts = NODES (provide complexity)
- -Types of relationships = LINKS (provide info)
- *types, characteristics, leads to etc.
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Activation
how concepts are assessed
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Priming
Decreased RT and increased accuracy based on prior exposure to related information
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Hierarchical Network Model
- Categorization
- -Superordinate (vehicles)
- -Basic (SUV, truck, motorcycle)
- -Subordinate (envoy, trailblazer, CRV)
- Categorical info stored through associations
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Feature Comparison Model
- Categorization = matching features
- -Defining features are required
- -Characteristic features are common
- Stage 1: feature comparison
- Stage 2: focus on defining features
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Spreading Activation Model
- Ease of activation = degree of relatedness
- - length of links: shorter lengths = stronger relationships
- Priming : "giving" activation to related items
- - activation lessens with distance
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Research on Testing
- Some with semantic training, some with no training
- Did better trained
- Implications: Semantic networks organize knowledge efficiently
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Why are we good at semantic organization?
Extracting meaning: semantic organization is helpful
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Why are be bad at semantic organization?
Cant remember verbatim because it's rarely important to do so
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Ant Passage
- We false alarm to the fact that info is consistent with expectations
- We fill gaps with plausible information
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Schema
- General knowledge structure/framework for organizing clusters of info
- Ex: worldviews, occupations, social roles, scripts
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Bartlett and War of the Ghosts Story
- When recalling ghost story, participants:
- Omitted irrelevant info
- Rationalized unacceptable issues
- Changed details, content, and style to fit own culture/expectations
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4 General Characteristics of Schemata
- 1. Knowledge - our model of the world
- 2. General - not specific to 1 situation
- 3. Structured - include relationships about facts
- 4. Comprehension - fill in incomplete info
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Balloon Passage
- Results:
- No context - 3.6 out of 14 ideas
- Context before - 8 out of 14
- Context after - 3.6
- Implications:
- Context improves comprehension
- Schemata/context needed before new info is given
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What do schemata help us do?
- Generate expectations
- Make inferences
- Comprehend written/spoken material
- Schema = skeletal structure
- Default knowledge
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Scripts
- Sequences of events for routine activities
- Components:
- Standard roles
- Props/objects
- Conditions
- Results
- Script organization possibilities:
- Temporal ordering
- Centrality/importance of events
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Studies on scripts show...
- Retrieval results: temporal order >order of importance
- Implications: temporal order accesses all events
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Perceptual Symbols Model
- Barsalou:
- General semantic representations are amodal (without sensory input)
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Modal Representations
- Incorporate perceptual information:
- audition
- gustation
- vision
- olfaction
- mechanoreception
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Autobiographical Representations
- Special case of perceptual symbols model (Rubin)
- Representations of personal experiences:
- Perceptual experiences
- Language
- Emotion
- Implications: autobiographical memories are constructed
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Neurological Evidence on Autobiographical Representations (Cabeza & St. Jacques fMRI)
- Retrieve personal memories for target word
- >press button when memory is retrieved
- >rate emotional intensity
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Categorization
- Importance:
- Decreased complexity
- Increased object identification
- Decreased need for constant learning
- Increased good decisions on how to act
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Hierarchical Organization
- Hierarchies = levels of abstraction
- Superordinate: members share few attributes
- Basic: Most informative, many shared attributes, good differentiation between categories
- Subordinate: poor differentiation from other categories
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3 Levels of Abstraction
- 1. Classification in the basic categories
- Fastest verification RTs
- Exception - experts
- 2. Prototype Theories
- "Average" category shape acts as representative
- 3. Superordinate v. Basic-Level
- Fast verification RT for basic and subordinate forms
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