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
this is the
first day of the
rest of your
life in the.
tracking ear fixations (“shadowing”)
“when in the
course of …..”
“and another
score for the
Gators ……”
“.. another score, uh …”
EYE TRACKING TECHNOLOGY
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).
DYNAMICS OF
VISUAL ATTENTION
Fig. 4-18, p. 122
“COVERT” SHIFTS OF
SPATIAL ATTENTION
(Posner & Cohen, 1984)
fixate center
throughout trial:
cue for likely
side of test:
(p. = .8)
@
100 to
1000
msec
D e c is io n T im e
respond to
target figure:
X
@
700
900
600
550
500
450
400
valid
350
300
invalid
100
300
500
Cue-Target Delay
ATTENTION TO OBJECTS
vs. LOCATIONS (Egly 1994)
Fig. 4-22, p. 126
UNILATERAL NEGLECT:
Impaired shifting of
spatial attention
Damage to Right Hemisphere:
Left hemisphere: focus on right side
of space
Right Hemisphere: focus on left and
right side
SELECTIVE ATTENTION AS A
SENSORY FILTER
(Broadbent, 1958)
input
“channels”
sensory
analysis
pattern
recogn
“early” filter
• Evidence for “early” selection:
– poor detection and memory for
unattended input channel(s)
– tendency to report concurrent inputs
“by channel”
left ear: 2 . .4 . .9
right 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
ATTENTION AS ALLOCATION
OF LIMITED CAPACITY
(Kahneman, 1972)
AROUSAL, ATTENTION AND
PERFORMANCE
Performance
For many tasks, performance suffers
if arousal is too low or too high
(Yerkes & Dodson, 1903)
+
- low
capacity
too low
Arousal
high
focus too
narrow
Easterbrook, ‘59: Cue Utilization Theory
R T to T O N E ( m s e c )
MEASURING ATTENTIONAL
ALLOCATION
(Posner & Boies, 1971)
task: decide if two successive letters
are the same or different
600
500
400
300
200
-1
-0.5
0
+
0.5
R
1
1.5
2
J
2.5
?
press
key
• decision and response selection as
attentional “bottlenecks”
THE ATTENTIONAL DEMANDS
OF SHADOWING
(Johnston & Heinz, 1978)
Shadowed
List:
ignored
List:
desk
couch
chair
sofa
etc...
NONE
or
voice class
DIFF
DIFF
SAME DIFF
DIFF
SAME
RT to tone alone: 320 msec
RT to
TONE
PRACTICE AND EXPERTISE
Staszewski, 1988
task: mental multiplication
S o lu tio n tim e ( s e c )
300 hours (!) of practice on simple (1 by 1)
and complex (2 by 5) problems using leftto-right procedures
e.g. 267 x 97: “. . nine times two is
eighteen hundred; nine time six is 540, that’s 2340 . .”
120
100
80
first block
60
last bock
40
20
0
1x1
1x3
1x5
2x3
Problem Size
2x5
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 PHONES
Strayer, 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
Accidents
0
Brake onset
933 ms
Following distance
25.8 ft
Billboard recognition 6.9
Billboard fixation
0.66
Drive & Chat
3
1112 ms
29.3 ft
3.9
0.62
Date: 2003-03-27
New 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)