attention: selectivity and resource allocation selectivity –what events “capture” attention?...
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ATTENTION: SELECTIVITY AND RESOURCE ALLOCATION
• SELECTIVITY– what events “capture” attention?– how complete is selectivity?
• AROUSAL AND ALERTNESS– does capacity change over time?– how is it affected by arousal,task
demands or intention?
• DIVIDED ATTENTION– how well can we do two things at once?– can we improve our skill in dividing
attention?
MEASURING WHERE ATTENTION IS FOCUSSED
tracking eye fixations
tracking ear fixations (“shadowing”)
this is thefirst day of therest of yourlife in the.
“when in thecourse of …..”
“and anotherscore for theGators ……”
“.. another score, uh …”
Seven records of eye movements by the same subject. Each record lasted 3 minutes. 1) Free examination. Before subsequent recordings, the subject was asked to: 2) estimate the material circumstances of the family; 3) give the ages of the people; 4) surmise what the family had been doing before the arrival of the "unexpected visitor;" 5) remember the clothes worn by the people; 6) remember the position of the people and objects in the room; 7) estimate how long the "unexpected visitor" had been away from the family (from Yarbus (1967).
“COVERT” SHIFTS OFSPATIAL ATTENTION
(Posner & Cohen, 1984)
fixate centerthroughout trial:
@
respond totarget figure:
X @
cue for likelyside of test:(p. = .8)
100 to1000msec
300
350
400
450
500
550
600
De
cis
ion
Tim
e
100 300 500 700 900
Cue-Target Delay
valid
invalid
UNILATERAL NEGLECT:Impaired shifting of
spatial attention
Left hemisphere: focus on right sideof space
Right Hemisphere: focus on left and right side
Damage to Right Hemisphere:
• Evidence for “early” selection:– poor detection and memory for
unattended input channel(s)– tendency to report concurrent inputs
“by channel”
SELECTIVE ATTENTION AS A SENSORY FILTER(Broadbent, 1958)
input“channels”
sensoryanalysis
patternrecogn
“early” filter
left ear: 2 . .4 . .9right ear: 6 . .1 . .8
report:2,4 ,9 . .6, 1
•Evidence against “early” selection:–shadowing disrupted by S’s name–context can force switch to ignored ear–meaning of “ignored” words can affect behavior
EFFECTS OF AN “UNATTENDED” WORD
(MacKay, 1972)
“ . . the boy threw a rock at the bank and..”
“ . .scissor . . ladder . . money . . finger . .”
“Ignored” words not remembered, but still bias interpretation of sentence
• Evidence for “activation without awareness”
• Such “automatic” effects are small, and depend on special conditions
AROUSAL, ATTENTION AND PERFORMANCE
For many tasks, performance suffers if arousal is too low or too high (Yerkes & Dodson, 1903)
+
-Arousallow high
Per
form
ance
capacity too low
focus toonarrow
Easterbrook, ‘59: Cue Utilization Theory
task: decide if two successive letters are the same or different
+ R J ?presskey
200
300
400
500
600
RT
to
TO
NE
(m
se
c)
-1 -0.5 0 0.5 1 1.5 2 2.5
MEASURING ATTENTIONAL ALLOCATION
(Posner & Boies, 1971)
• decision and response selection as attentional “bottlenecks”
THE ATTENTIONAL DEMANDS OF SHADOWING
(Johnston & Heinz, 1978)
ShadowedList:
deskcouchchairsofaetc...
ignoredList:
NONE
voice classDIFF DIFF
SAME DIFF
DIFF SAME
or
RT toTONE
RT to tone alone: 320 msec
PRACTICE AND EXPERTISEStaszewski, 1988
task: mental multiplication
300 hours (!) of practice on simple (1 by 1) and complex (2 by 5) problems using left-to-right procedures
e.g. 267 x 97: “. . nine times two is eighteen hundred; nine time six is 540, that’s 2340 . .”
0
20
40
60
80
100
120
So
lutio
n t
ime
(se
c)
1x1 1x3 1x5 2x3 2x5Problem Size
first block
last bock
PRACTICE AND DIVIDED ATTENTION
• Practice in shadowing (Underwood, 1976)– Task: shadow prose in left ear– and detect occasional digits in right ear
• Oxford Undergrads: 13% hits• Neville Moray: 71% hits
• Practice in dictation (Spelke, Hirst & Neisser, 1976)– Task: read text for meaning, and
write down spoken words– after months of practice, no “cost” of
dictation on reading speed or comprehension
Is attention skill domain-specific?
ATTENTION AND CELL PHONESStrayer, Drew & Johnston, 2003
• About 150 million cell phones• 85% use them while driving• Inattention a leading cause of
crashes• So: simulated driving task (track
pace car), with/out hands-free chat
Drive Drive & ChatAccidents 0 3Brake onset 933 ms 1112 msFollowing distance 25.8 ft 29.3 ftBillboard recognition 6.9 3.9Billboard fixation 0.66 0.62
Date: 2003-03-27New Study Shows Drivers Using Cell Phones Twice As Likely To Cause Rear-end Collisions
CHAPEL HILL -- Drivers talking on cell phones are nearly twice as likely as other drivers involved in crashes to have rear-end collisions, according to a new University of North Carolina at Chapel Hill study. Crashes involving cell phone use, however, are less likely to result in fatalities or serious injuries than crashes not involving the devices.
LAPSES OF ATTENTION:THE “COGNITIVE FAILURES
QUESTIONNAIRE (CFQ)• How often do you . . .
– read something and realize you haven’t been thinking about it?
– forget why you went from one room to another?
– bump into people?– forget if you’ve locked the door?– forget to keep appointments?– drop things?– fail to hear people speaking when
you’re doing something else?
• Ratings correlate with performance in tasks of selective and divided attention (e.g., stroop interference; Tipper & Baylis, 1987)