Attention
Any of the very large set of selective processes in the brain- To deal with the impossibilities
Selective Attention
The form of attention involved when processing is restricted to a subset of the possible stimuli
Varieties of Attention
External vs internal
- External- attending to stimuli in the world
- Internal- attending to one line of thought over another line of thought or selecting one response over another
cue
Stimulus that might indicate where or what a subsequent stimulus will be
-they can be calid invalid or neutral
Exogenous cues
“hey look right here”
Endogenous
Ok here is the code “red means look to the right..”
Stimulus onset Asynchrony (SOA)
The time between the onset of one stimulus, the target, and the onset of another, the cue
Inhibition of return (IOR)
The relative difficulty in getting attention (or the eyes) to move back to a recently attended (or fixated ) location
Visual Search
Looking for a target in a display containing distracting elements
Target
The goal of the visual search
Distractor
In visual search any stimulus other than the target
Set size
The number of items in a visual search display
Feature search
-chose red bar among the blue –easy
Conjunction search
Find red vertical bar among red/blue horizontal/vertical bar -medium hard
Spatial configuration search
Find blue shape T among blue L- hard
Feature searches are efficient
feature search: search for a target defined by a single attribute such as a salient color or orientation
Salience
The vividness of a stimulus relative to its neighbor
Parallel
in a visual attention, referring to the processing of multiple stimuli at the same time
Real world searches
- picture on wall
- coffee mug on table
The binding problem
-the challenge of tying different attributes of visual stimuli( color, orientation, motion) which are handling by different brain circuits to the appropriate object so that we perceive a unified object
Feature integration theory
Anne treismans theory of visual attention which holds that a limited set of basic features can be processed in parallel preventively but that other properties including that correct binding of features to objects require attention
Preattentive Stage
the processing of a stimulus that occurs before selective attention is deployed to that stimulus
Illusionary conjuction
-saying you saw red X, which is plausible, but it was blue
Rapid serial visual representation RSVP
is used to study the temporal dynamics of visual attention think of it as visual search in time
Attentional Blink
-The difficulty in perceiving and responding to the second of two target stimuli amid a RSVP stream of distracting stimuli
3 ways responses of a cell could be changed by attention:
1) response enhancement -graph grows vertically
2) Sharper tuning -graph decreases horizontally
3) Altered tuning- graph moves over
Fusiform Face area (FFA)
identifies face/facial expressions
Parahippocampal place area
A region of cortex that responds to stimuli that indicates specific locations
Visual-Field defect:
A portion of the visual field with no vision or with abnormal vision, typically resulting from damage to the visual nervous system
Damage to parietal lobe
-visual field defect such that one of the world is not attended
Neglect
in visual attention, the inability to attend to or respond to stimuli in the contralesional visual field
Contralesional field
The visual field on the side opposite a brain lesion
ipsilesional field
the visual field on the same side as a brain lesion
Attention can be object based
evidence from neglect patients indicates that they sometimes neglect one side of an object rather than one side of the visual field
Extinction
The visual attention the inability to perceive a stimulus to one side of the point of fixation (eg to the right) in the presence of another stimulus typically in a comparable position in the other visual field
ADHD
one of the most common disorders of attention
- impulsivity
- hyperactivity
- don’t follow direction
- -only a little worse than normal kids on tests
The two pathways to scene perception are?
Selective pathway: Permits the recognition of one or another very few objects at a time. this pathway passes through the bottleneck of selective attention
Nonselective Pathway
Contributes information about the distribution of features across a scene as well as information about the gist of the scene . This pathway does not pass through the bottleneck of attention
Ensemble statistics
The average and distribution of properties like orientation of color over a set of objects or over a region in a scene
Change blindness
the failure to notice a change between two scenes. if the gist or meaning of the scene is not altered quite large changes can pass unnoticed
inattentional blindness
a failure to notice– or at least to report a stimulus that would be easily reportable if it were attended