Exam 1 - L4

Question 1

Bottom-up processing

Answer 1

Incoming stimulus initiates and determines higher level processes needed for recognition, interpretation, and categorization
Processing originates in sensory areas and proceeds up to higher levels of cognition

Question 2

Pattern recognition

Answer 2

The ability to recognize and identify a stimulus
-Happens after perception
3 theories: template, feature, and structural description theories

Question 3

Template theory

Answer 3

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
Limitations:
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
Why would we need a template for every possible obstruction?

Question 4

Feature theory

Answer 4

We can recognize an object when the features we perceive match the features of a particular object representation stored in memory
Ex: to recognize a tree, we first identify the features (branches, trunk, leaves) which are matched to the representation of a tree stored in memory
More flexible than template theory

Limitations:
Some objects cannot be recognized by features alone
Different arrangements of the same features create different objects

Evidence:
Physiology: feature detecting neurons in the brain
Ex: simple cells in visual cortex
Retinal stabilization: when we stare at an image without moving our eyes (stabilized retinal image), the features of the image begin to disappear one by one
Caricatures: faster to recognize caricatures
(exaggerated features)
Visual search: feature distinctiveness affects the speed of visual search

Question 5

Pandemonium model

Answer 5

Metaphorical demons with specific duties
Receive and analyze the features of a stimulus
Start at a low level and proceed up to recognition (bottom-up)
4 types of demons
Image demon: receives sensory input
Feature demon: decodes specific features
Cognitive demon: “shout” when they receive a certain combination of features
Decision demon: “listen” for the loudest shout and make a decision about the identity of the stimulus

Competition between cognitive demons

Question 6

Recognition by Components (RBC) theory

Answer 6

Recognition is achieved due to the arrangement of an object’s components (geons)
Use geons to perceive and recognize objects based on their spatial relationships
Geons: simple 3D shapes that form objects
Viewpoint invariant and non-accidental

How do we match objects?
Detect elementary features and edges
Find non-accidental properties
Non-accidental properties: visual characteristics of an object that are unaffected by the viewpoint of an observer; provide useful clues to an object’s identity; geons have them
Determine component geons
Match to memory

Evidence for RBC
Partial or degraded objects
Deleting non-accidental properties
Makes something much less recognizable
We can still recognize objects as long as we have some non-accidental properties
Object complexity
We are faster to identify more complex objects (more geons)
Unusual orientations
Objects are harder to identify from unusual angles (may not be able to see non-accidental properties)
Ex: blender from the top

Limitations:
Many objects are made of the same arrangement of geons, but we can still distinguish between them
Ex: individual faces