Perceptual Processes: Visual & Auditory Recognition Dr. Claudia J. Stanny EXP 4507 Memory & Cognition Spring 2009

Perception Distal stimulus Proximal stimulus Sensory memory Iconic memory Echoic memory Claudia J. Stanny2

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 Claudia J. Stanny5

Gestalt Psychology: Organizing Principles in Perception Form perception Figure-ground resolution Detection of contours (subjective contours) Principles of organization Proximity Similarity Good continuation Closure Common fate Claudia J. Stanny6

Object Recognition Template-matching models Feature analysis models Recognition-by-components models Claudia J. Stanny7

Template-Matching Models Claudia J. Stanny8 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 Claudia J. Stanny9 Selfridge (1958) Pandemonium

Feature Analysis Models Relies 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) Claudia J. Stanny10

Recognition-by-Components Models Similar to feature analysis models Developed for perception of 3-dimensional objects Biederman (1990) Claudia J. Stanny11

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 Claudia J. Stanny12

Errors in Perception Levin & Simons (1997, 2000) Change blindness Inattention blindness Claudia J. Stanny13

Change Blindness Demonstration

Links to Videos Magic Trick Harvard: Participants signing up for an experiment Original Door Study (Levin & Simon, 1997) Recreation of Simon’s Door Experiment Claudia J. Stanny15

Face Recognition Perception of facesProsopagnosia Claudia J. Stanny16

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 17

Speech Perception Phoneme recognition Detection of word boundaries Constructive nature of speech perception Context effects on speech recognition Phonemic restoration McGurck effect Claudia J. Stanny18

Theories of Speech Perception Speech perception as a special mechanism of the brain Speech perception as characteristic of general perceptual mechanisms Claudia J. Stanny19