Psych 435
Attention
Issues
• Capacity
– We can’t respond to everything in the environment
– Too many pieces of information
– we can only actively respond to a subset of these
• Attention
– The selection of relevant cues to respond to
– Cues may be externally or internally generated
Attention
• What is attention?
– “The concentration of mental effort on sensory or mental
events”
• Phenomena
–
–
–
–
Switching vs. sharing attention
Attention Capture
Visual Search
Selective attention- Stroop
Examples of Controlled vs.
Automatic Processes
• Show 3 pairs of search demos
• Each member of each pair will have a few or a
lot of items
• Search for a single target
Find the T:
L
L
L
L
T
L
L
L
• This was an automatic process: fast
Find the T:
L
L
L
L
L
L
L
L
T
L
L
L
L L
L L
L
L L L
L L
L
L
L
L L
L
L
L
L
L
L
L
• This was an automatic process: still fast even
with more distractors
Find the T:
L
T
L
L
L
L
L
• Slower without color
Find the T:
L
L
L
L
L
L
L
L
L
L
L
L L
L L
L
L L L
L L
L
L T
L
L L
L
L
L
L
L
L
L
• This was a controlled search- slower, look at
each letter
• Much slower than with colored T
Find the Red L
T
T
L
L
T
T
L
L
T
L
• Slow: searching for a conjunction
Find the Red L
T L
T L T
L
L
L L
LL TL
L T L
L
T
T T
T
L
L
T
T L
L L T L
T L L
T
T
L L L
L L T L
L
T L T
L
T
L
L
L
L
L T
T
• Even slower- searching for a conjunction
Data from Display Set-Size
Experiment
Fast search done with automatic (preattentive) mechanisms
Done in parallel
Slow search done with controlled (attentive) mechanisms
Done in serial
Applications of Attentional
Seach
• List search situations and decide if fall into
preattentive or attentive search requiring
focal attention
• E.g.
–
–
–
–
Search computer screen for icon
scan crowd for people
scan crowd for americans
look for airplane in sky
• What makes things preattentive?
–
–
–
–
probably the amount of difference between the objects
L’s and T’s are similar
Red and blue are quite different
Looking for small differences requires focal attention
Models of attention
• Filter Models
– Recognition after Filtering
» Broadbent
-or-
– Recognition before Filtering
» Broadbent’s critics
• Attentuation Models
– Treisman
• Automatic vs. Controlled Processes
– Also called Preattentive vs. Attentive Processes.
– Neisser
– Schneider and Shiffrin
Filter Models
• What is a Filter?
• A description of the response properties of
the system
• Describes what a system responds to, and
what it doesn’t respond to.
Types of Filter Models
Input
Detection
Recognition
Recognition After Filtering (Broadbent):
Filter
Input
Detection
Recognition
Recognition Before Filtering:
Input
Detection
Recognition
Filter
Broadbent’s Filter Model
• Channels carry different types of information
• E.g. color, spatial frequency, pitch, hot, etc.
• Apply mental effort: selectively process info
coming from a small set of channels
• We must do this: limited capacity processing
and memory system
– We just can’t deal with all the information at once
• However, can switch between channels
Broadbent’s Filter Model cont.
• On the basis of some aspect of the stimulus
or our memories, we can switch between
channels
• This switching may be voluntary or
involuntary
• Switching takes effort, reduces performance
– Broadbent’s dichotic listening techinque- present two
digits at once, one to each ear
– 8, 3, 2 in left ear
– 9, 1, 5 in right ear
– recall by ear (left or right): subjects respond “8 3 2 9 1 5”
– or in order: subjects respond “8 9 3 1 2 5”
– performance for latter task is reduced (65% to 20%)
– In second task subjects had to switch more often- hurts.
Broadbent’s Filter Model cont.
• Problems: Gray and Wedderburn (1960)
– Easy to switch if information in the to-be-switched-to ear
is relevant
– e.g.: Story continues in alternating ears
• Problems: GSR experiments
– Associate word with shock- hearing word elicits a GSR
response.
– When that word is presented in unattended channel,
produces GSR response.
– Semantically similar words also elicit response- some
semantic processing takes place in unattended channel.
Attenuation Models-Treisman
• Info in unattended channels is still processed
– but at a reduced rate
– info in unattended channels is attenuated.
Treisman’s Attention Model
Attention Capture
Failures of Selective Attention
• Attention is supposed to focus in on what you
want to attend to
• Exclude irrelevant information
Stroop Task
Blue
Yellow
Red
Green
Green
Yellow
Green
Yellow
Yellow
Green
Blue
Blue
Red
Blue
Red
Green
Stroop Task
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
Stroop Task
Blue
Yellow Red
Green
Green Yellow Green Yellow
Yellow Green Blue
Blue
Red
Green
Blue
Red
Stroop Task
Yellow Green Blue
Yellow
Blue
Blue
Red
Green
Red
Red
Yellow Red
Blue
Yellow Blue
Blue
Stroop
• Failure of selective attention
• Race model
– Word name is processed automatically
– Color is not so automatic
– Both arrive at the same time, we have a hard time
attending to the relevant stimulus attribute
– Doesn’t happen upside down
e ul B woll e Y
de R neer G
neer G woll e Y neer G woll e Y
woll e Y neer G
de R
e ul B
e ul B
e ul B
de R neer G
.
Stroop Task
Failure of Attention: Failure to
Disengage
• Mind Develops Brain clip
– infant- failure to disengage
Spatial Attention: Posner Task
Fixation
Point
T
i
m
e
Cue
75%
accurate
Attention switches
to here
(but eyes don’t
move)
or here:
Target might
appear here:
A
A
Sharing Attention: Dual Tasks
• Do two things at once: can they be
performed at the same time?
• Do they interfere?
• Experiment has 3 conditions
• Task A alone
• Task B alone
• Task A and B together at the same time
Sharing Attention: Dual Tasks
•
•
•
•
Example:
Pat head and rub belly
Now speed up just your belly
If you can’t do it, it suggest that they share
the same processing capacity
• Same brain area?
Sharing Attention: Dual Tasks
Example:
Task A: Driving without an accident
Task B: Talking on cell phone
Can you talk on your cell phone at the normal rate while still driving
without getting into an accident?
Normal Save Driving Speed: 30 mph
Normal speaking rate: 80 wpm
40
c
30
Safe Driving
Speed
a
b
20
10
0
0
50
100
words per minute
Central Executive Interactions
Pet Evidence-Right Parietal
Lesion Data- Attending to
Different Spatial Scales