Template models
- Match stimuli to template in memory
- Computers and scantrons support the idea
- Inefficient, irregular world, strict match
Feature models
- Features more regular than patterns
- Complex objects composed of simple features
Support for feature model
Neisser (1964) - Extract features - Makes note of features - Compared to something we have stored Lettvin et al. (1959) - Microelectrodes into cells of frog retina - Recorded activity
Simple cells
- Simple patterns of light
- Location specific
- Edge, slit, line
Complex cells
- Simple patterns of light
- Not location specific
- Edge, slit, line
Hypercomplex cells
Moving lines
Beyond features: top-down pattern recognition
- Gestalt grouping principles
- Neuroimaging evidence shows specialized brain areas for processing whole visual objects
- Pattern recognition influenced by knowledge
Interval required to mask patterns
Shorter interval required to mask known patterns rather than unknown patterns (BOY vs YOB)
Reading
- Top-down
- Patterns because of knowing words
Word superiority effect (WSE)
- Show letter, mask
- Is letter this or this
- Show word, mask
- Is word this or this
- Did better with word
RSVP paradigm
- Rapid serial visual presentation
- When present stimulus once then presented shortly after
- If shown second time in specific time it won’t be seen
“When she spilled the ink there was ink all over”
Wouldn’t see ink second time
Recognition by components (RBC) theory
- Objects made up of combinations of geons
Recognition involves: - Parse objects into component geons
- Note where geons join (find edges)
- Match geon combinations to representations in memory
- Very bottom-up model
Recognition by components (RBC) problems
- Expertise and experience affects early perception of object
- Overall can be perceived as fast as components
Agnosia
- Failure or deficit in recognizing objects
- Patterns or features cannot be synthesized into a whole
- A person cannot connect the whole pattern to a meaning
- Caused by specific brain damage
Prosopagnosia
- Disruption of face recognition
- Patients typically able to recognize other objects
Apperceptive agnosia
- Disruption in perceiving whole patterns
- Cannot process basic features
- Cannot integrate into a whole object
- Located in right hemisphere parietal lobe
Associative agnosia
- Can combine features into a whole, can copy and describe a drawing
- Cannot associate with a meaning
- Involves temporal lobes of both hemispheres
Agnosia studies tell us
- Perception of features
- Integration of features into larger whole pattern (Gestalt)
- Association of the pattern to a meaning
Space-based attention
- Attention placed in location
- Direction of visual attention can be separated by direction of gaze
- Direction of attention can influence our perceptions
Exogenous cues
Draw attention to potentially important events in space
Endogenous cues
Place attention according to expectancy
Object-based attention
Attention is placed on objects
