Exam 3 Deck Flashcards
Our last exam before the final ! (146 cards)
What does RSVP stand for?
Rapid Serial Visual Presentation (RSVP)
What is Modified RSVP?
When you have two targets instead of one in a steady stream of items
What is the attentional blink?
it is the tendency not to perceive or respond to the second target stimuli that has been presented 200-500 miliseconds after the first target stimuli
Explain the ‘Fishing’ Metaphor of the Attentional Blink
The things you perceive are like things flowing by in a (dirty) river
Fishing metaphor: What happens when we Catch a Fish?
After we catch the fish our ‘net is out of the water’, and we’ll miss any other fish (targets) that come along, can explain attentional blink
Perceiving and Understanding ‘Scenes’
we perceive objects at locations within the
environmental context as part of some larger whole
– Collections of objects in the proper spatial relations to each other create “scenes”
Do we have a good picture memory?
YES! We’re very good at remembering complex scenes
– In original version, people correctly recognized 98% of 612 pictures as ‘old’
– Still 90% correct a week later
– Can be in the 80 - 90% range with sets as large as 10,000
images
What is change blindness?
The failure to notice differences between two images of a scene
A Problem: Saccade Speed
• We only make about 3–4 saccades per second
– This is too slow to account for our scene recognition abilities • We can observe more items in a scene than 3 - 4 per
second
What are Covert Attention Shifts?
we can move our attention independent of eye movements
– Attention shift without eye movement = covert attention shift
Describe the Scene Mosaic theory
• Perhaps attention shifts around a scene faster than eye movements building a collage of objects at locations that make up the scene
What are some problems with the Mosaic Idea?
• Requires a larger working memory load than we have
– Larger than the 7±2 working memory capacity
• Experimental results indicate that we can identify a scene in less than an eighth of a second (125 ms)
– Too fast for putting together a bunch of collage pieces
Define: Schema
A rough outline of a scene or situation with placeholders for details
– e.g. farm, classroom, mall
– Perhaps identified by a rough spatial frequency analysis
Are we good at recognizing a scene after we see it?
Yes, We’re really good at recognizing scenes but we’re really bad at noticing details in a scene. We have ‘placeholders’ for things that ought to be in a scene but don’t fill in those blanks unless needed
Physiology of Object Perception
• Some kinds of objects appear to be represented in specific parts of the brain
– e.g. faces appear to be represented in a special part of inferior temporal cortex
• If we’re attending to that kind of object, then that part of the brain should be more active
Define: Change Blindness
The failure to notice differences between two images of a scene
How do we extract meaning from scenes?
To extract a scene quickly from perceptual elements, we appear attend to the ‘gist’ of the scene and ignore detail
• The ‘gist’ of a scene is its core meaning, what the overall scene is
• Change perception depends on the meaning of the change – If scene meaning stays the same, we don’t notice the
change
• A market is a market, independent of the color of some
guy’s pants
The primary visual cortex is _______ and ______
retinotopic (locations close is space are close on the brain) and contralateral (right visual field processed in left hemisphere, LVG in right hemisphere)
What is the physiology of object perception?
Some kinds of objects appear to be represented in specific parts of the brain
– e.g. faces appear to be represented in a special part of inferior temporal cortex
• If we’re attending to that kind of object, then that part of the brain should be more active
How do we test the theory of object perception?
-Show pictures of faces, places, and control stimuli
• Sometimes ask subject to respond to faces
• Sometimes as to respond to places
• Measure brain activity
• Different parts of the brain light up to faces and places
How do we know it’s Attention not Perception?
• The fusiform face area likes faces
– It lights up to a face whether we’re attending to it or not – Could just be face perception
• Solution
– Show combined face/place stimulus
– Have participant attend to face or place but not both
• Same results
What could the individual neurons be doing to create these attention responses?
– Response enhancement
– Sharper tuning
– Altered tuning
all of which have been seen and studied
What does the inability to attend to contralesional space result from?
posterior parietal lobe damage (usually right
side)
Describe the waterfall illusion:
– Stare at a waterfall for a while, then stare at the still rocks beside it
• Rocks will appear to ‘crawl’ upward • After-image of downward motion is up
