visual selective attention Flashcards
what are the 3 analogies of the space based view
Spotlight (Posner, 1980)
Zoom-lens (Eriksen & St. James, 1986)
Multiple spotlights (Awh & Pashler, 2000)
The idea is the same for all of them: objects that fall w/in the “beam” of attention are subject to further processing w/ priority.
define the space based view
Visual attention is directed to and selects on the basis of regions of space in a visual scene
whats the difference between covert and overt attention
Overt attention: you look at what you are attending to
Covert attention: attention moves independently of eyes (a mental shift)
define the object based view
Attention selects from objects themselves, rather than potentially empty regions of space
spatial cueing paradigm (posner 1980)
Makes use of covert attention
P’s fixate a central cross, then shown directional cue (arrow)
& then target (square in this example)
Ps’ task is to respond (usually by pressing a key on the computer keyboard) as soon as they see the target
80% of trials arrow pointed to direction where target appears (valid trials) (as opposite)
20% of trials, cue = invalid – arrow pointed away from where the target (square) appears
Neutral trials presented a double-headed arrow w/ no direction cue
spatial cueing paradigm (posner 1980) results
When attention was shifted to the correct area (valid 80% of trials) response times to target faster
When the cue was invalid (20% of trials) responses were slower (than valid and neutral conditions)
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
spatial cueing paradigm (posner 1980) interpretation
moving attention = cog phenomenon not tied to physical eye movements, but due instead to an internal mechanism
“Attention can be likened to a spotlight that enhances the efficiency of detection of events within its beam”
what is the Zoom Lens Model
Eriksen and St. James (1986)
the argument that the window of attention can be increased or decreased w/ task demands
Spotlight vs. Zoom Lens Models Study (LaBerge, 1983)
Ps saw series of 5 letter words
Occasionally, a probe requiring a rapid response was presented instead of, or after, the word.
The probe could appear in any of the locations of the 5 letters.
Reaction times measured
There were two conditions:
Focused condition: Ps asked to categorize the middle letter of the word (to focus attention on a narrow space)
Unfocussed condition: Ps asked to categorize the whole word (spreading attention wider).
Spotlight vs. Zoom Lens Models Study (LaBerge, 1983)
results
In the focused condition, detecting the probe was fastest when it appeared at the central letter (the one Ps were told to focus on)
In the unfocussed condition, detecting the probe was equal for all 5 letter locations
This shows that the attentional ‘spotlight’ does appear to be able to zoom in and out.
what are the 3 models of selective visual attention
Multiple spotlights model
zoom lens model
spotlight model
Awh and Pashler (2000)
multiple spotlights model
Could conserve cognitive resources by avoiding attending to irrelevant regions of visual space that fall between relevant areas
Zoom Lens vs. Multiple Spotlights Models (Awh & Pashler, 2000)
5x5 grid containing 23 letters and two numbers
Task: Find the two digits
Two spatial cues presented before the display
80% trials: Predicted locations of numbers (valid trials)
20% trials: Not predictive locations of numbers (invalid trials)
awh and pashler findings
Attention should cover both cued locations, also taking in the number at location A
Therefore, it should be easier to detect the target at A than B
Attention can select the cued locations at the same time (and not the space in between)
No difference in detection speed of digits at A and B
typical manipulation of object based view
If attention can select objects, then overlapping objects should be selected independently of one another
That is, there should be difficulty in attending to two objects at the same location
If attention selects space, then both objects should be processed at the same time, as both fall with the ‘beam’ of the spotlight
