Presentation on theme: "Perception and Pattern Recognition What types of information do we use to perceive the world correctly? What are the major theories about how we recognize."— Presentation transcript:
Perception and Pattern Recognition What types of information do we use to perceive the world correctly? What are the major theories about how we recognize patterns? What are the strengths and weaknesses of these theories?
Types of Perceptual Processes Bottom-up - work up from sensory info. Top-down - apply knowledge and experience
Top-Down Effects Chess masters remember chess board patterns better than novices (Chase & Simon,1973) Easier to recognize objects in context (Palmer,1975) C
Template Matching Theory Recognize patterns by matching stimulus to template Works in price scanners
Problems with Template Matching Differences in orientation R R Differences in size R R Differences in form R R R R
Feature Analysis Identify simple features of patterns Combine features into complex patterns Hubel & Wiesel (1965) found feature detector neurons in cats Visual search: easier to find target when it doesn’t share features with the background (Neisser,1964)
Find the Z
Treisman’s Feature Analysis Theory Preattentive Stage: detect visual features Pop-Out Illusory Conjunctions Focused Attention Stage: combine features into objects
Problems with Feature Analysis Two different patterns can have the same features Patterns may not have any features that are required H
Gestalt Approach Law of Pragnanz Similarity Good Continuation Proximity Common Fate Familiarity
Prototype Matching Theory Prototype - “best” or “typical” representation of a pattern Stimulus is compared to prototypes Uncertainty in pattern recognition Pseudomemory (Solso & McCarthy,1981)
Study These Faces...
Which Did You See? A is the prototype; it was not seen. B was not seen. C was one of the original faces. A B C
Evolutionary Psychology What problems must the brain solve to perceive accurately? Figure-ground separation Inverse projection problem Occlusion Edge perception
Evolutionary Psychology How does the brain solve these problems? Top-down and bottom-up Heuristics Built-in brain organization Plasticity