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PATTERN RECOGNITION:Template Matching Models, Human flexibility

<< AUTOMATICITY (continued):Predicting flight performance, Thought suppression
PATTERN RECOGNITION:Implications, Phonemes, Voicing, Place of articulation >>
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CognitivePsychology ­ PSY 504
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Lesson 14
PATTERNRECOGNITION
We know how information is first recorded by senses andselected for processing by attentional
mechanisms.The most criical questionfor a theory of perception is how is thisinformation
recognizedfor what it is?
Mostresearch has focused on letter recognition or recognition of letters identity: forexample how
do we recognize
A
as an instance of
A
TemplateMatching Models
Thetemplate-matching theory of perceptionassumes that a retinal image of an object is faithfully
transmitted to the brain. An attempt is made to compare it directly to various storedpatterns.
Thesepatterns are calledtemplates. So, the basic is that the perceptual systemtries to compare
theletter to templates it hasfor each letter andreports the template thatgives the bestmatch.
Figureillustrates various attempts to make template matching work. In each case, an attempt is
made to achieve a correspondence betweenthe retinal cells stimulated by the A and theretinal
cellsspecified for a templatepattern.
Inputrepresents retinalcells.
Templatematching
Thepattern is stored for eachretinal cell activated; if different retinal cells areactivated there
won't be a match. As the figure is shown:
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CognitivePsychology ­ PSY 504
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a
successfulmatching
b
wrongmatching
c
successfulmatching
d
wrongpart of retina
e
wrongsize
f
wrongorientation
g
and h non-standard images
Examples in machines
Sometemplate matching machinesare;
Finger-printmatching machines. Fingerprints machine are templatematching machines.These
machinesmatch finger prints withcriminal fingerprints.
Barcode reading machines in shopping stores are alsoexample of template matchingmachines.
ATM/ Credit card readingmachines. These machinesmatch the numbers of ATM card with
passwords.
Butthese are machines thatrecognize exact matches. Any minor change means there is no
match.
Humanflexibility
In Humanswe canrecognize LARGE letters andsmall characters, Characters in the wrong place
and in strange.
It means if you meet youruncle after many yearseven he is in different appearanceyou can
recognizehim. This is humanflexibility to recognize things,people or places.
Problemswith templates
Humanperceptual system is muchmore flexible.
Mostpatterns we encounter undergo at least some minor changes.Like,
Lettersare different font sizesand styles
Shapeschange slightly
Orientationsare different
Butstill we can recognizethings.
FeatureAnalysis model
In this model, Stimuli arethought of as combination of elemental or primitive features.
Thefeatures for alphabets mayconsist of horizontallines
_
verticallines
I
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CognitivePsychology ­ PSY 504
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Lines at approx 45 degree angle/
And curves (
Likealphabet  T  hastwo line one verticaland other is horizontal lineboth make alphabet
T. Allletters are consisted on these four patterns. Ourmind analyzes lettersaccording to
thesefeatures.
How is it better than templatemodel?
Featuresare mini-templates butfeatures are simpler.
Onecan identify criticalfeatures for a letter
For A, 2 45 degree angles (/ \) intersect at the top and a horizontalline _ intersects
both of these near the middle.the pattern of A consists of these lines plus a specification
as to how they should be combined.
Thesefeatures are very muchlike the output of edgeand bar detectors in thevisual cortex.
Example
Many other details areunimportant
So,
A A A A A A AAA
All of the above can be recognized as the sameletter. Even they are in different shapes and
differentstyles.
In the feature model we do notneed a template for eachletter but only forevery feature, this
would be a great saving. We have 26 letters small and capital. If letters have manyfeatures in
common,subjects are prone to confuse them.
By these four features we canstore all 26 letters.English model is alsoapplicable in Urduletters
withthe addition of Dot (nukta).Urdu writing is much morecomplex than English. Urdureading is
alsodifficult as well.
Thefeature model has a number of advantages over thetemplate models.
First,since the features aresimpler, it is easier to seehow the system mighttry to correct forthe
kinds of difficulties caused by templatesmodel.
A second advantage of thefeature combination scheme is that it is possible to specifythose
relationshipsamong features that aremost critical to thepattern.
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Table of Contents:
  1. INTRODUCTION:Historical Background
  2. THE INFORMATION PROCESSING APPROACH
  3. COGNITIVE NEUROPSYCHOLOGY:Brains of Dead People, The Neuron
  4. COGNITIVE NEUROPSYCHOLOGY (CONTINUED):The Eye, The visual pathway
  5. COGNITIVE PSYCHOLOGY (CONTINUED):Hubel & Wiesel, Sensory Memory
  6. VISUAL SENSORY MEMORY EXPERIMENTS (CONTINUED):Psychological Time
  7. ATTENTION:Single-mindedness, In Shadowing Paradigm, Attention and meaning
  8. ATTENTION (continued):Implications, Treisman’s Model, Norman’s Model
  9. ATTENTION (continued):Capacity Models, Arousal, Multimode Theory
  10. ATTENTION:Subsidiary Task, Capacity Theory, Reaction Time & Accuracy, Implications
  11. RECAP OF LAST LESSONS:AUTOMATICITY, Automatic Processing
  12. AUTOMATICITY (continued):Experiment, Implications, Task interference
  13. AUTOMATICITY (continued):Predicting flight performance, Thought suppression
  14. PATTERN RECOGNITION:Template Matching Models, Human flexibility
  15. PATTERN RECOGNITION:Implications, Phonemes, Voicing, Place of articulation
  16. PATTERN RECOGNITION (continued):Adaptation paradigm
  17. PATTERN RECOGNITION (continued):Gestalt Theory of Perception
  18. PATTERN RECOGNITION (continued):Queen Elizabeth’s vase, Palmer (1977)
  19. OBJECT PERCEPTION (continued):Segmentation, Recognition of object
  20. ATTENTION & PATTERN RECOGNITION:Word Superiority Effect
  21. PATTERN RECOGNITION (CONTINUED):Neural Networks, Patterns of connections
  22. PATTERN RECOGNITION (CONTINUED):Effects of Sentence Context
  23. MEMORY:Short Term Working Memory, Atkinson & Shiffrin Model
  24. MEMORY:Rate of forgetting, Size of memory set
  25. Memory:Activation in a network, Magic number 7, Chunking
  26. Memory:Chunking, Individual differences in chunking
  27. MEMORY:THE NATURE OF FORGETTING, Release from PI, Central Executive
  28. Memory:Atkinson & Shiffrin Model, Long Term Memory, Different kinds of LTM
  29. Memory:Spread of Activation, Associative Priming, Implications, More Priming
  30. Memory:Interference, The Critical Assumption, Limited capacity
  31. Memory:Interference, Historical Memories, Recall versus Recognition
  32. Memory:Are forgotten memories lost forever?
  33. Memory:Recognition of lost memories, Representation of knowledge
  34. Memory:Benefits of Categorization, Levels of Categories
  35. Memory:Prototype, Rosch and Colleagues, Experiments of Stephen Read
  36. Memory:Schema Theory, A European Solution, Generalization hierarchies
  37. Memory:Superset Schemas, Part hierarchy, Slots Have More Schemas
  38. MEMORY:Representation of knowledge (continued), Memory for stories
  39. Memory:Representation of knowledge, PQ4R Method, Elaboration
  40. Memory:Study Methods, Analyze Story Structure, Use Multiple Modalities
  41. Memory:Mental Imagery, More evidence, Kosslyn yet again, Image Comparison
  42. Mental Imagery:Eidetic Imagery, Eidetic Psychotherapy, Hot and cold imagery
  43. Language and thought:Productivity & Regularity, Linguistic Intuition
  44. Cognitive development:Assimilation, Accommodation, Stage Theory
  45. Cognitive Development:Gender Identity, Learning Mathematics, Sensory Memory