perceptual processes: visual & auditory recognition dr. claudia j. stanny exp 4507 memory &...
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Perceptual Processes:Visual & Auditory Recognition
Dr. Claudia J. StannyEXP 4507
Memory & Cognition
Spring 2009
Perception
• Distal stimulus• Proximal stimulus• Sensory memory
• Iconic memory• Echoic memory
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Iconic Memory
• Perceptually detailed visual memory
• Duration is very short ( .5 sec - 1 sec)
• Information stored has not been analyzed yet for meaning
• Precategorical sensory information• Content can be cued effectively based on sensory
qualities, not meaning
Echoic Memory Auditory analog to iconic memory
Precategorical auditory (sensory) information• Can cue recall of selected items based on
sensory qualities but not based on meaning
Very short duration (approximately 2 sec)
Sensory Processes & the Brain
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Gestalt Psychology: Organizing Principles in Perception
Form perceptionFigure-ground resolutionDetection of contours (subjective contours)Principles of organization
• Proximity• Similarity• Good continuation• Closure• Common fate
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Object Recognition
• Template-matching models• Feature analysis models• Recognition-by-components models
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Template-Matching Models
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Effective for pattern recognition for small sets of well-defined patterns
Template matching used today for pattern recognition of bank codes on checks
Feature Analysis Models
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Selfridge (1958) Pandemonium
Feature Analysis ModelsRelies on simpler features for
template matching
Includes a system of rules for how features are combined to create specific patterns
Draws on single-unit data for neurons responding to sensory input (e.g., work by Hubel & Wiesel, 1965, 1979, 2005)
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Recognition-by-Components Models
Similar to feature analysis models
Developed for perception of 3-dimensional objects
Biederman (1990)
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Top-Down & Bottom-Up Processing
• Bottom-up processing• Emphasis on sensory input• Raw sensory input → pattern recognition
• Top-down processing• Emphasis on concepts and expectations• Expectations and context create biases to extract
certain patterns from sensory input
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Errors in Perception
• Levin & Simons (1997, 2000)• Change blindness• Inattention blindness
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Change Blindness Demonstration
Links to VideosMagic Trickhttp://www.youtube.com/watch?v=voAntzB7EwE
Harvard: Participants signing up for an experiment
http://www.youtube.com/watch?v=mAnKvo-fPs0
Original Door Study (Levin & Simon, 1997)http://viscog.beckman.uiuc.edu/flashmovie/12.php
Recreation of Simon’s Door Experimenthttp://www.youtube.com/watch?v=p1aEqBaK3aM
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Face Recognition
Perception of faces Prosopagnosia
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Thatcher Illusion
Based on tendency to process faces holistically
When faces are viewed upside down, we might not detect alterations in component parts
When faces are viewed right side up, these changes are easily detected
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Speech Perception
• Phoneme recognition• Detection of word boundaries• Constructive nature of speech perception• Context effects on speech recognition
• Phonemic restoration• McGurck effect
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Theories of Speech Perception
• Speech perception as a special mechanism of the brain
• Speech perception as characteristic of general perceptual mechanisms
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