Cognitive Processes PSY 334

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Cognitive ProcessesPSY 334

• Chapter 4 Perception-Based Knowledge
  Representation

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Dual-Code Theory

• The mind operates upon internal representations
  of knowledge.
• How is visual information (imagery) represented
  in memory?
• Paivios Dual-Code Theory memory is better if
  we encode information visually and verbally.
• Separate representations are maintained for
  verbal and visual information.

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Behavioral Evidence for Dual Codes

• Santa compared linear and spatial arrays of
• Three geometric objects
• Three names of geometric objects
• Subjects were asked whether the arrays contained
  the same objects or names.
• Subjects were faster when shapes were in the same
  spatial arrangement but faster when words were
  linear.

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Santas Results
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Evidence From Brain Imaging

• Subjects were asked to mentally rehearse
• A word jingle
• Navigating their neighborhood
• Increased blood flow occurred in different areas
  of the brain, depending upon the task.
• The same brain areas were active as when actually
  speaking or seeing.

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Brain Evidence for Dual Codes
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No Homunculus

• Homunculus -- the idea that there are pictures
  in the head implies someone to look at those
  pictures.
• Both images and percepts are represented
  topographically in the brain, but there is no
  homunculus to view them.
• Kosslyn -- the same cognitive processes are used
  to view mental images and external percepts.

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Mental Rotation

• Shepard two-dimensional and three-dimensional
  mental images are rotated in the same way as
  actual objects.
• The more an object is rotated, the longer it
  takes to respond in a same/different task.
• Georgopoulos et al. measured neurons firing in
  monkey brains when moving a handle.
• Intermediate cells fire showing rotation.

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Shepard Metzlers Results
2D
3D
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Image Scanning

• Brooks subjects scanned imagined diagrams (like
  letter F) and noted outside corners, or sentences
  noting nouns.
• Respond by saying yes or no
• Tap left hand for yes, right hand for no
• Point to Y or N on a sheet
• Scanning a sheet for Ys Ns conflicted with
  scanning the mental image.
• Conflict is spatial not visual.

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Mentally imagine the F and scan the outline
beginning at the .
Point to Y if an outside corner is present or N
if not.
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Pointing Was Slowest
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Comparing Visual Quantities

• Time to make a judgment decreases as the
  difference in size between objects increases.
• The smaller the difference the longer it takes to
  make a judgment.
• Which is larger
• moose or roach, wolf or lion?
• The same pattern emerges when asked to judge
  actual differences, line lengths.

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Which is bigger?
The closer in size, two animals are, the longer
it takes to decide which is bigger.
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Two Types of Imagery

• Images involving visual properties (what) --
  impaired with temporal damage.
• Images involving spatial properties (where)
  impaired with parietal damage.
• Bilateral temporal lobe damage
• Difficulty judging color, size, shape.
• No deficit in mental rotation, image or letter
  scanning, judgment of relative positions.

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Are Images Like Perception?

• A series of experiments to compare perception and
  imagery
• Imagining transformations of mental images vs
  perceived stimuli.
• Ponzo illusions occur with imagery.
• Difficulty with reversible figures depends on
  instructions, harder.
• MRI plots show same brain activity.

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Similar Brain Activity
Fusiform face area
Parahippocampal place area
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Cognitive Maps

• Two kinds of maps
• Route map indicates places and turns, but not
  all landmarks.
• Survey map shows all relevant portions of
  space, not just route.
• Adults produce survey maps, kids produce route
  maps.
• Survey maps more versatile.

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Examples

• Disneyland to Cal Poly Pomona via Yahoo Maps
• http//maps.yahoo.com/mvtmlat33.932385lon-11
  7.85789zoom12q1disneyland2C20anaheimq23801
  20W20Temple20Ave2C20Pomona2C20CA2C2091768

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Navigation

• Navigation is complicated by the need to tie
  together different kinds of mental
  representations.
• Egocentric representation space as we see it
• Allocentric representation not specific to a
  particular viewpoint
• Most maps are allocentric

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Types of Representations
Egocentric
Allocentric
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Thinking About Maps

• People rotate physical maps to fit their
  egocentric perspective.
• When the map itself cannot be rotated, extra
  processing time shows that people rotate an image
  of the map in their heads.
• Cognitive maps show no orientation effects.
• Allocentric representations are maintained by the
  hippocampus.

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Map Distortions

• Which is farther east San Diego or Reno?
• People make wrong guesses because they reason
  from the positions of the states, not cities.
• Relative positions of larger areas are compared,
  not details hierarchical chunking.

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Which is farther East San Diego or Reno?
Which is farther North Seattle or Montreal?
Which is farther West the Atlantic or the
Pacific entrance to the Panama Canal?
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Atlantic
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Translating Verbal Descriptions

• Subjects were asked to read passages, rotate
  themselves and make judgments
• Fastest when making above-below judgments, slower
  with right-left.
• Verbal directions (survey or route) are as good
  as using actual maps.

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Remembering Serial Position

• Serial position what comes first and what comes
  later in a list.
• Anchoring first items are better remembered in
  sequences.
• Hierarchical encoding helps serial recall
• Alphabet song

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Serial Position in Lists
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Hierarchical Encoding of Serial Order Information

• Long sequences are remembered using hierarchical
  chunks, just as maps are
• Alphabet song
• Spacing of letters separates them into
  subsequences (chunks).

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Alphabet Song
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Position Aids Recall
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Baddeleys Working Memory

• Imagery is accomplished in working memory.
• Two parts correspond to dual-codes
• Visuospatial sketchpad visual info
• Phonological loop verbal info
• Central executive coordinates the slave systems
  (sketchpad loop)

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Verbal Working Memory
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Parts of the Phonological Loop

• Articulatory loop inner voice that rehearses
  verbal information
• Activates Brocas area of the brain
• Phonological store an inner ear that stores the
  inner voice and stores it in phonological form.
• Activates parietal-temporal areas of brain