Lecture 5: Pattern Recognition; Bottom-Up Flashcards
Bottom-Up Processing
Incoming stimulus initiates and determines higher level processes needed for recognition, interpretation, and categorization
Pattern Recognition
The ability to recognize and identify a stimulus, happens after perception
Shape Constancy
The percept of the shape of a given object remains constant despite changes in the shape of the object’s retinal image
Template Theory
○ We make a template for every object we see or interact with
○ Compare an incoming stimulus to mental image or representation
○ Once an exact match is found, you can identify the stimulus
Problems with Template Theory
- Transformations: once the object is transformed, it will not line up with the template
- Ex. Differences in handwritten letters
○ Obstructions: We sometimes do not get the full view of an object but can still identify it
- Ex. Differences in handwritten letters
Feature Theory
We can recognize an object when the features we perceive match the features of a particular object representation stored in memory
Problems with Feature Theory
Some objects cannot be recognized by features alone, and different objects can share the same features in different orientations
4 Types of Demons
-Image- Receives sensory input
-Feature: Decodes specific features
- Cognitive: Activates when they receive a certain combination of features
- Decision: Decides what is being most stimulating and makes a decision about the identity of the object
- There is competition between cognitive demons
Evidence for Feature Theory
○ Feature detecting neurons in the brain
○ Retinal stabilization: Features of an image begin to disappear when the image is constant on the retina
○ Faster to recognize caricatures than normal faces
○ Feature distinctiveness affects the speed of visual search
Pandemonium Model
Metaphorical demons with specific duties that receive and analyze the features of a stimulus, is a bottom-up process
Geons
Shapes that form simple parts of objects
Recognition by Components Theory
Recognition is achieved due to the arrangement of an object’s component genes
Problems with RBC
Many objects are made of the same arrangement of geons but we can still distinguish between them, ex. Faces
RBC Evidence
Partial or degraded objects, object complexity, and unusual orientations
Non-Accidental Properties
Visual characteristics of an object that are unaffected by the viewpoint of an observer, geons have these properties
