Psychology 100:12
Chapter 5
Sensation &
Perception
Part V
Outline• Pattern recognition• Attention
> Bottleneck theories
> Capacity theories
> Cells phones and driving
Study Question:
• Why might a proponent of Kahneman’s attention theory feel that driving a car while talking on a cell phone is a bad idea?
PerceptionFeature
detectors Perception
– Visual Illusions, attempt II.>Fraser Illusion>Lines>Perspective>Stereokinetic object
– Auditory Illusions> Never ending auditory staircase
Shepard Illusion
Perception• Other evidence for feature theory:
Stabilized retinal images.• Physiological nystagmus
PerceptionFeature
detectors Perception
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a
b
c
Perception• Problems with Feature theory
– How features go together are as important as the features themselves.
PerceptionPerceptionFeature
detectors Perception
Perception• Structural Theories
– Like feature theories, except that they also consider the structure of the features (i.e., How they go together.
– Biederman’s Theory of 3-d object recognition.>Geons: 3-D ‘volume’ features
PerceptionPerceptionFeature
detectors Perception
-> Eliminating information about the relationship between geons should be detrimental to pattern recognition.
E.g.,
PerceptionPerceptionFeature
detectors Perception
-> What are these objects?
Recognition accuracy
70 %50 % 100 %
PerceptionPerceptionFeature
detectors Perception
Perception• The word superiority effect
PerceptionPerceptionFeature
detectors Perception
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Perception• The word superiority effect
D
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_ _ _ D
W O R D
XX X X
_ _ _ D
R U E D
XX X X
_ _ _ D
-> It is easier to identify a letter in the context of a word than by itself.
PerceptionPerceptionFeature
detectors Perception
• The interactive - activation model: Bottom-up
PerceptionPerceptionFeature
detectors Perception
PerceptionPerceptionFeature
detectors Perception
• The interactive - activation model: Top-down
Pattern Recognition
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Perception Perception
• Dichotic listening § Shadowing
Doughnuts TV
Pork rindsFootball
Cheap meatBeer
WorkDieting
Romantic moviesLiterature
OperaBallet
Doughnuts ,TV, Pork rinds, Football, Cheap meat, Beer ...
PerceptionPerceptionFeature
detectors Attention
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Attention• Bottleneck theories: Early selection
– The bottleneck metaphor>Cherry (1953): What do we perceive in
the unattended ear? Physical characteristics Not meaning Where’s the unattended message?
>Broadbent’s all-or-nothing filter
TableHorseChairDeskPaperHouse
TreeRock
HomerBarnStreet
Table, horse, chair, ..Homer...
• Problems with the all-or-nothing filter
– Moray’s (1959) experiment
Attention
• Treisman’s experiment
I saw the girl song was wishing
Hand me that bird jumping in the street
I saw the girl jumping inthe...
Attention
Capacity theories of attention
• Different tasks require different amounts of mental effort
§ i.e., Automatic vs. Controlled processing
e.g.1, Attentional resources and Driving
e.g.2, Automaticity and word recognition
The Stroop Effect
Attention
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Capacity theories of attention
• Kahneman’s Model
§ Limited resources to allocate to different tasks
§ Spreading attention out over multiple tasks results in performance decrements
e.g., Mowbray’s (1953) experiment
- Trying to copy notes and listening to a lecture
Attention
Resolving the locus of the bottleneck
• Johnston & Heinz’s (1978) multimode theory- Measured the amount of resources required to shadow using a dual task
procedure.
- Participants shadowed on either the basis of pitch (early) or semantic category (late)
- Viewed a computer monitor and had to hit a button quickly whenever a dot appeared on the screen (detection).
• Results
Attention
No list 1 list 2 lists 2 lists (pitch) (semantic)
Detection time 310 ms 370 ms 433 ms 482 msShadowing errors n/a 1.4% 5.3% 20.5%
• Johnston & Heinz’s (1978) multimode theory- Measured the amount of resources required to shadow using a dual task
procedure.
- Participants shadowed on either the basis of pitch (early) or semantic category (late)
- Viewed a computer monitor and had to hit a button quickly whenever a dot appeared on the screen (detection).
• Results
Attention
No list 1 list 2 lists 2 lists (pitch) (semantic)
Detection time 310 ms 370 ms 433 ms 482 msShadowing errors n/a 1.4% 5.3% 20.5%
Attention• The cell phone diversion
– Strayer’s Research> Used a driving simulator
Single vs. dual task Hands free vs. hand held
• No difference
> Can drivers recognize objects that they have fixated on? Recognition accuracy for fixated objects about half when
conversing• Even when fixation duration is equated performance was far
worse
> The inattentional blindness hypothesis Cell-phone conversation disrupts performance by diverting
attention from the external environment associated with the driving task to the cellphone converstation.
Demo
Attention
Attention• The cell phone diversion
– Strayer’s Research> What about strategic reallocation?
There are important and unimportant objects
> Two-Alternative forced choice recognition Drivers rated the importance of the items.
> Performance was significantly poorer in the dual task. even when fixation duration is controlled. Absolutely no effect of the importance of the object on the
inattentional blindness effect.
Attention
Attention• The cell phone diversion
– Strayer’s Research>Conversing on the phone vs. with a passenger
>Instructed to drive 8 miles down a freeway and exit at a truck stop.
Only 12% of drivers with a passenger missed the exit. About 50% talking on a cell phone missed the exit
• The passengers assisted the drivers
Attention
Attention• The cell phone diversion
– Strayer’s Research>Conversing and driving vs. drinking and driving
Car-tailing paradigm Compared .08% alcohol intoxication with hands held
and hands free.• No differences were observed between the cell
phone conditions• Both Alcohol and phone groups showed impaired
driving• 4 of the cell phones talkers rear-ended the pace
car (none of the drinkers had a collision)
Attention