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Models of Attention and PRP
Attention 3
Dichotic Listening Task
Big question is where and or when does attention
operate in the information-processing stream
Listen to two auditory messages
Different message played in each ear
Shadow one message
Failure to notice changes in unattended ear
Early Selection Models
Filter Model of Attention
Donald Broadbent
Selection occurs by attending to low-level properties of stimuli
and/or location
5
I 3 2
N
P
U
T
4
1
“2, 3, 5”
7
Sensory
register
Selective
filter
Detection
device
R
E
S
P
O
N
S
E
Short-term
memory
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Early Selection Models
Filter model of attention assumes a bottleneck
4
Filter
Left Ear
W
Right Ear
H
7
2
D
F
Early Selection Models
Problems with early selection?
Gray & Wedderburn (1961)
Subjects switched attention with changes in meaning
Left ear: mice ...
three ...
cheese
Right ear: two
...
eat
...
four
Cocktail Party Effect
Moray (1959)
65% of subjects recognized their name in unattended ear
Unattended information is processed to recognition
Early Selection Models
Attenuation Model of Attention
Anne Treisman
Filter is in same location as in Broadbent’s model, but it has
different function
Attenuator or “leaky” filter
R
E
S
P
O
N
S
E
I
N
P
U
T
Sensory
register
Attenuation
control
Detection
device
Short-term
memory
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Early Selection Models
Attention is directed toward
All attended stimuli (shadowed message)
Unattended stimuli that reach a threshold of recognition
“Dictionary”
High
Word thresholds
Subjective
thresholds
Low
Own name
Attenuator (selective filter)
Discrimination of channels based
on basic features (e.g., location,
pitch, intensity, etc.)
Attended, “shadowed” channel
Unattended, “ignored” channel
Late Selection Models
Maybe attention operates after meaning is assessed
Donald MacKay (1973)
Biasing information in unattended ear influenced reporting:
Attended:
Unattended:
“They were throwing stones at the bank.”
“money” or “river”
These unattended stimuli had high subjective thresholds
Selection
Sensory
register
Detection
device
Short-term
memory
Sensory
Store
Filter
Filter vs. Attenuation vs. Late Selection
Attended
Channel
Unattended
Channel
Pattern
Recognition
Memory
Pattern
Recognition
Memory
Sensory
Store
Selection
Attended
Channel
Unattended
Channel
Attenuator
(a)
Sensory
Store
Pattern
Recognition
Selection
Attended
Channel
Unattended
Channel
Sensory Filter
(b)
Memory
(c)
Critical Stages for Model
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Capacity Model of Attention
Load Model of Attention
Nilli Lavie
A “blend” of early-selection and late-selection
Passive stage
Sensory input and pattern recognition
Selects information until capacity used up
Active stage
Controls passive stage
Limited in resources
Capacity Models of Attention
Load Model of Attention
High Load
Passive Stage
Active Stage
Environmental Input
Irrelevant
Stimuli
High Load
“Cognitive
Load”
Relevant
Stimuli
“Attentional
Control”
Low Load
Low Load
Capacity Models of Attention
Load model is tested by manipulating “load” on each stage
Perceptual load
Influences passive stage
Modified flanker task
Cognitive (working memory) load
Z
Z
OONOOO
HKNXME
Low Load
High Load
Influences active stage
Easy or difficult secondary task performed during flanker task
Z
+
92865
OONOOO
6?
Fixation
Cog. Load
Flanker Task
Probe
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Capacity Models of Attention
Load model supportive data
Lavie (1995, JEP:HPP)
1100
650
1050
600
1000
550
950
RT (ms)
RT (ms)
700
500
450
400
Lavie et al. (2004, JEP:G)
900
850
800
350
750
300
700
Low Load
High Load
Perceptual Load
Incompatible
Low Load
High Load
Cognitive Load
Compatible
Incompatible
Compatible
Capacity Models of Attention
Psychological Refractory Period (PRP) Paradigm
Respond to two stimuli (S1 and S2)
S1 = tone (high / low)
S2 = letter (identify)
Vary SOA between S1 and S2
Examine RT1 and RT2 as function of SOA
R1
Task 1
S1
R2
Task 2
S1
RT1
SOA
RT2
Capacity Models of Attention
Typical PRP Results
Psychological refractory period
Cognitive “slack”
900
850
800
RT (ms)
750
700
RT1
650
RT2
600
550
500
0
50 100 150 200 250 300 350 400 450
SOA (ms)
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Capacity Models of Attention
Psychological refractory period...what’s going on?
Tone (S1)
P1
Letter (S2)
P2
0
Response
Selection 1
Motor
Response 1
PRP
(‘wait’)
Response
Selection 2
RT1 (tone)
Motor
Response 2
RT2 (letter)
Time [ms]
6