unit 2 chpt 7 attention and scene perception

attention

any of the very large set of selective processes in the brain

– To deal with the impossibility of handling all inputs at once,

the nervous system has evolved mechanisms that are able to

restrict processing to a subset of things, places, ideas, or

moments in time.

selective attention

The form of attention involved when processing

is restricted to a subset of the possible stimuli.

external attention

attending to stimuli in the world ex looking at slides in class

internal attention

attending to one line of thought over another or selecting one response over another. ex your thoughts and feeling

overt attention

directing a sense organ toward a stimulus, like turning your eyes or your head

covert attention

attending without giving an outward sign you are doing so

divided attention

splitting attention btw two diff stimuli

sustained attention

continuously monitoring some stimulus ex a lifeguard monitoring the pool to make sure no one drowns

inattentional blindness

a failure to notice- or at least to report- a stimulus that would be easily reportable if it were attended ex the gorilla crossing the screen while ppl throwing ball

change blindness

the failure to notice a change btw two scenes

bottom-up processing

automatic, stimulus-driven

top-down processing

controlled, goal-driven

interaction

working together in complementary roles

reaction time

a measure of the time from the onset of a stimulus to a response

cue

a stimulus that might indicate where (or what) a subsequent stimulus will be

stimulus onset asynchrony

the time btw the onset of one stimulus and the onset of another

“spotlight” model theory of attention

attention is restricted in space and moves from one point to the next. areas within the spotlight receive extra processing

“zoom lens” model theory of attention

the attended region can grow or shrink depending on the size of the area to be processed

visual search

looking for a target in a display containing distracting elements ex wheres waldo

guided search

attention is restricted to a subset of possible items based on info abt the items basic features (type of visual search) ex i knew what waldo looked like so i look for the striped shirt

inhibition of return

the relative difficulty in getting eyes to move back to a recently attended location ex during hide and seek i would hide in the place the seeker just looked bc they think they alr searched so they dont need to look again

serial self terminating search

a search from item to item, ending when a target is found. least efficient way of searching. ex looking at every single person in picture until you find waldo

feature search

efficient. 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 neighbors

parallel

in visual attention, referring to the processing of multiple stimuli at the same time

conjunction search

search for a target defined by the presence of two or more attributes

scene-based guidance

info in our understanding of scenes that helps us find specific objects in scenes ex. asked to find plate and you look on table bc thats where it would normally be

the binding problem

the challenge of tying diff attributes of visual stimuli, which are handled by diff brain circuits, to the appropriate objects so we perceive a unified object

feature integration theory

– a limited set of basic features can be processed in parallel

preattentively (automatically), but that other properties, including the correct

binding of features to objects, requires attention.

preattentive stage

the processing of a stimulus that occurs before selective attention is deployed to that stimulus

illusory conjunction

an erroneous combination of 2 features in a visual scene ex you remember there was a blue F in a picture but there was actually a blue A and an orange F

rapid serial visual presentation

an experimental procedure in which stimuli appear in a stream at one location at a rapid rate

attentional blink

the difficulty in perceiving and responding to the second of two target stimuli amid a rapid serial visual presentation stream of distracting stimuli

– The second target is often missed if it appears within 200 to 500 ms of the first target.

– Reflects the limitations of the brain's processing capacity and the time needed to reset attention.

miss the second fish bc u caught the first

*three ways responses of a cell could be changed by attention*

1. response enhancement

2. sharper turning

3. altered tuning

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 the parietal lobe can cause a visual field defect such that one side of the world is not attended to

neglect

in visual attention, the inability to attend to or respond to stimuli in the contralesional visual field

-typically, neglect of the left visual field after damage to the right parietal lobe

selective pathway

permits the recognition of one or of very few objects at a time. this pathway passes through the bottleneck of selective attention

nonselective pathway

contributes info abt the distribution of features across a scene as well as info abt te “gist” of the scene. this pathway does not pass through the bottleneck of attention

ensemble statistics

the nonselective pathway computes _ _

ensemble statistics

the avg distribution of properties, such as orientation or color, over a set of objects or a region in a scene

fish look horizontal overall

the nonselective pathway computes _ and _ very quickly

scene gist and layout

spatial layout

The description of the structure of a scene (e.g.,

enclosed, open, rough, smooth) without reference to the identity of

specific objects in the scene.