Lecture 3- Visual selective attention Flashcards
what is Space-based attention and object based attentin?
Space-based attention: Selection from regions of space
Object-based attention: Selection of objects.
what is attention
- acts as a means of focusing limited mental resources on the info and cognitive processes that are most salient at a given moment
what is selective attention for vision
attention is limited in capacity
vision; we can typically see more than one thing in our visual world at once- how do we select what is most important and disregard the rest
- posner 1980= spotlight or torch beam model
- necessary to process info of interest
why do we need to select visual attention
alot of info- need to reduce cognitive overload
what is being argued about the 2 schools of thought about how we select visual attention
2 schools of thought -
selects from space based view: visual attention directed towards and selects based on regions of space within our visual fields
selects from object based view - visual attention directed towards objects rather than a potentially empty region of space
argued about which view provides the best characterisation
describe the space based view and analogies proposed that go with it
Visual attention is directed to and selects on the basis of regions of space in a visual scene
eg spotlight (posner 1980) zoom lens (erikson and st james 1986) multiple spotlights (awh and pashler 2000)
all share idea that objects that fall withi a beam of attention are subject to further processing with priority (for things we are interested in)
describe object based view - including Duncan 1984s theory
wew select attention form objects themselves rather than empty regions of space.
Duncan said objects are processed in according to gestalt laws - then subject to further processing.
What is covert and overt attention- space based view
overt- looking at what attending to
covert- mental shift, shifts interdependently of eyes, not necessarily looking at what attending to
in posner 1980’s spatial cueing paradigm- what type of attention is used
covert attention - as draws attention away from stimulus of interest
who created / investigated the spatial cueing paradigm
Posner 1980
what was the method in posners spatial cueing paradigm
pps had to fixate on a cross in the middle of the screen
shown an arrow (directional cue - left/right/up/down)
and then a target (eg a square)
had to press a button when saw the target
3 types of trials
valid trial (80%) - arrow pointed towards target invalid (20%)- pointing away from target neutral- double headed arrow with no directional cue
What were the 3 trial conditions in posners spatial cueing paradigm
3 types of trials
valid trial (80%) - arrow pointed towards target invalid (20%)- pointing away from target neutral- double headed arrow with no directional cue
what is the DV in in posners spatial cueing paradigm
reaction times
what were the results of in posners spatial cueing paradigm
pps reacted quicker when the arrow was pointing towards the target (valid)
and slower on invalid and neutral trials
what is the three part process which was attributed form the trials in in posners spatial cueing paradigm
The slowing of responses on invalid trials was attributed to a three part process
1) disengaging attention
2) moving attention to the true location
3) engaging attention at the new location
iNTERPRETATION :
attention can be likened to a spotlight that enhances the efficiency of detection of events within a beam
how do results from posners spatial cueing paradigm relate to a spotlight
attention can be likened to a spotlight that enhances the efficiency of detection of events within a beam
who created the space based selection zoom lens model ?
erikson and st James 1986
what is argued in the zoom lens model ?
argue that a window of attention can be increaseed/ decrease with task demand
Example:
when driving a car attend to as much as possible- but when someone walks out in front of your car - your attention focusses and (zooms) into that one event
what was laberge 1983 trying to investigate?
Spotlight vs zoom lens modelling
describe the method of laberge 1983 test on spotlight vs zoom lens modelling -
pps shown a series of 5 letter words
occasionally a probe requiring rapid response presented instead of or after a word
probe could appear in any location of the 5 letters
reaction times measured
2 conditions:
focussed condition: pps asked to categorise the middle letter of the word- (to focus on a narrow space)
unfocussed condition: pps asked to categorise the whole word (wide spread attention)
what were the 2 conditions in laberge 1983 test on spotlight vs zoom lens modelling -
2 conditions:
focussed condition: pps asked to categorise the middle letter of the word- (to focus on a narrow space)
unfocussed condition: pps asked to categorise the whole word (wide spread attention)
what were the findings of laberge 1983 test on spotlight vs zoom lens modelling -
in focused conditions- detecting probe was fastest when happened in central letter - which pps were told to focus on
in unfocussed - detecting probe was equal for all 5 letter locations
shows that attentional spotlight does appear to zoom in and out
who proposed the multiple spotlights model in spatial modelling
Awh and Pashler 2000
describe the multiple spotlights model in spatial modelling in relation to conserving cognitive resources
allows us to conserve cognitive resources by avoiding attending to irrelevant regions of visual space that fall between relevant areas
helps us in terms of limited attention resources
Describe Awh and Pashler 2000 multiple spotlights model study
2 dots/ probes (spatial cues) were presented to pps
this was followed by a 5x5 grid of 23 letters and 2 numbers
task was to find the 2 numbers
80%of trials predicted the locations of numbers- i.e in the same place as the numbers on the grid
20% trials didnt predict the location (invalid)
reaction time measured
what were the finding of Awh and Pashler 2000 multiple spotlights model study
supported multiple spotlights model
- no difference in detection speed at digits a or b in invalid task (A between the probes- B 2 below )
therefore attention can select the cued locations at the same time and not the space between it
If zoomed lens was true then:
attention should cover both cued locations- also taking in number at location a - therefore easier to detect a than b (BUT THIS WAS NOT THE CASE)
describe the typical manipulation looking at object VS space based manipulation
if object based true- can select two objects which are overlapping- but find it hard to attend to the 2 at the same time in the same location
If space based is true- then fall under the beam of spotlight and can process the two simultaneously
describe the method in O’craven , downing and Kanwisher (1999) study
Fmri study
used 2 stimuli - face and a house overlapping at the same location- with one object moving slightly
had to attend to direction of motion or one stimuli or to position of stationary target stimuli
what werre the object and space based predictions for O’craven , downing and Kanwisher (1999) study
if attention is space based : should select both stimuli (both at same location)
if object based : one or the other stimuli shold be selected
What are the findings of O’craven , downing and Kanwisher (199) study
- found selective activation - object based
- when the face moved, it was selected resulting in more activation in the fusiform face brain area
when the house moved, there was more activity in the parahipocampal place brain area
Compelling evidence
