Topic 7: Visual Attention Flashcards
overt attention
over shifts of attention require eye movements
saccades
fixations
smooth pursuit
- rapid, ballistic movements from one place to another
- short pauses at points of interest
- slower movements tracking a moving object
Yarbus eye tracker
bottom up and top down
-varying instructions changed where p’s looked on the same painting
instructions influenced learning
visual salience
cognitive factors
bottom up, exogenous, in environment, reflexive and automatic
- distinct subjective perceptual quality which makes some items stand out and grab attention
- top down, endogenous, in mind, voluntary and intentional
saliency maps
scene schema
areas that stand out in a particular scene based on basic features (bottom up), shows where eyes are fixated
- knowledge about what is contained in a typical scene
- helps guide fixations from one area to another
task and action plans
intentions and goals
eye movements precede motor actions by fraction of a second
-purpose for which an observer views a scene influences where they look
spatial cueing task
P’s focus on fixation point with valid and invalid trials where stim will/wont follow cue direction
-faster reaction times on valid cue trials as attention was already primed in that direction
longer to separate and go to invalid side
Egly cueing task
used two rectangles with invalid on same object or other object
- fastest rxn time when stimulus is in exact spot as cue, faster when its on same object
- attention spreads to entire object
Apparent contrast
cue for L/R then p’s had to judge orientation of higher contrast grating
manipulation of attention influences judgement
attention causes weaker contrast to appear as if it were stronger
if cue was opposite to stim p’s viewed contrast as identical
illusory conjunction study
rapidly flashed display followed by a mask
task 1 report numbers
task 2 report object
p’s reported combos of features from different stim
IC- occurred because features are free floating since attention was focused on numbers
when reporting just objects less IC because of focused attention
feature integration theory
attention is required to bind different features into consciously experienced wholes
preattentive stage
focused attention stage
automatic, no effort/attention, unaware of process, object analyzed into features
-attention is key, features are combined/bound
inattentional blindness
we can be unaware of clearly visible stimuli if attention isnt focused
-p’s missed square doing simple line judgement task
change blindness
load theory of attention
changes in picture/scene between viewing can go unnoticed if not attended to, immediate changes will capture attention
-low load tasks dont use all resources and there is remaining perceptual capacity, high load dont have any resources left over
flanker task
higher reaction time for non-compatible trial as there are resources left over
CAC = non compatible
BAB= compatible
flanker compatibility task
low load task only uses ‘O’ distractors
flanker effect show since its low load task
high load uses confusing distractors
no effect between compatible/incompatible since first task is hard and uses resources
retinotopic map of V1
p’s fixate in center of checkerboard and attend to 1/18 locations
observe neural changes based on attention
could see which area of brain respond to near/far center of board
attention in VF moves activation in visual cortex
O craven face/house
attend to face or house that are ontop of each other and transparent
-shifting focus is only processing change
detectd changes by fmri in FFA ad PPA
attention to an object increases neural activity in areas representing that object
colby light and monkey
monkey trained to fixated eyes on fixation light while peripheral light flashed
-single cell recording in neuron with receptive field location of peripheral light
fixation only - release when fixation dims
fixation and attention - release bar when peripheral light dimmed
single neuron activity increased when monkey payed attention to spatial location
bosman local field potentials
recording local field potentials in v1 and v4
fixation and will change to determine which stimulus to attend (blue or yellow), respond when changes
receptive fields in v4 record both object but v1 is distinct
synchronization switched based on activation in v1 and v4
attention will bind visual features
womelsdorf
eyes at fixation and cue will say to attend to s1 s2 or s3
record area mt neuron with indicated receptive field
2/3 stims are within receptive field
change in visual field based on attention - dynamic
s1 small rf
s2 shifting rf
s3 normal rf
appearance vanish transportation restoration penetration
object appears by magic object disappears by magic object changes position in space object is damaged then restored object moves through matter
extraordinary feats
telekinesis
transformation
extrasensory perception
mental or physical
levitation animation of object
object changes form - size colour
telepathy, mind reading etc.
