Perception Flashcards
Bottom-up processing
Receptor stimulation (raw sensory data)
Top-down processing
Applying knowledge to sensory data
Feature detectors
Neurons that break sensory info up into features
Located in visual cortex
Visual search experiments
Evidence for feature analysis
Items that stand out are easier to identify than items that don’t
More distraction with items that don’t: greater variance in time to identify
Feature integration theory
Attention is needed for some perception, but not for others
2 stages to object recognition: preattentive stage (object is broken down into features), focused attention stage (features are combined in proper order to identify object)
Limitation to feature integration theory
Works well for 2-D features (color, shape), but not for 3-D objects
Geons
Shapes that when combined, make up 3-D objects (cylinder, cone, rectangle, triangle, “elbow noodle”)
Allow for recognition of objects by components
Features of geons
View invariance (can be seen from any direction)
Discriminability (can be distinguished from each other)
Resistance to visual noise (can be distinguished from background stimuli)
Easiest to recognize when corners are seen
Problem with recognition by components
Additional processing is needed to identify complex objects
Ex- blob test (blobs all look the same, but when put into context, make up totally different objects)
How we recognize faces
Features (feature detectors, recognition by components) Holistic approach (Gestalt heuristics)
What eye tracking studies tell us
More eye movement is used when learning a face than when recognizing a face
Important features used to recognize a face: eyes, then nose, then mouth (eyes far and away the greatest)
Evidence for holistic processing
We expect certain patterns (nose sticking out, eyes on top, mouth on bottom)
If the overall feature is right and the key features are right, we see a more or less normal face (even when the face is far from normal)
Fusiform face area
Area of brain that recognizes faces
Expert recognition of anything requires this part of the brain
Located in temporal lobe
