Cog5 lecppt chapter04
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Transcript of Cog5 lecppt chapter04
© 2010 by W. W. Norton & Co., Inc.
Paying Attention
Chapter 4Lecture Outline
Chapter 4: Paying Attention
Lecture OutlineSelective AttentionDivided AttentionPractice
Selective Attention
Selective attention refers to the skill through which one focuses on one input or one task while ignoring other stimuli
Selective Attention
Shadowing (repeating an audio track)Dichotic listening—Different messages to
each ear Attended channel—Listen to this one Unattended channel—Ignore this one
Selective Attention
Count passes from players with white shirts
Participants ignore those with black shirts
People do not notice the gorilla
DEMO 1DEMO 2
Selective Attention
Cocktail party effect Other conversations tuned out Unattended channel can be noticed
The participant’s own name Words of high personal significance
Boost attended items and dampen unattended items
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Selective Attention
Sometimes effects of attention are so strong that we fail to see stimuli that are directly in front of our eyes
Selective Attention
Look at a fixation target
Attend to another part of the screen
No warning leads to failure to detect change
Selective Attention
Selective Attention
Inattentional blindness: “no perception without attention”
Unconscious perception can still occur in the absence of attention
Selective Attention
People asked
to judge bars
Do not perceive
fins but still see illusion Typical
illusion
Selective Attention
Change blindness: inability to detect changes in scenes DEMO 1 DEMO 2DEMO 3Other DEMos
Selective Attention
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Selective Attention
Selective Attention
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Selective Attention
改變盲的意涵
The absence of visual representationGrand illusion (Noe, 2002) “…seeing constitutes an active process of
probing the external environment as though it were a continuously available external memory.” (O’Regan, 1992)
Do people not preserve any visual representation in their brain?
Multiple stages in CD
Retrieval and ComparisonEncoding Retention
Encoding
Time
Change or No change?
Is there any change?
Five possible hypotheses
Simons (2000)
Selective Attention
Early-selection hypothesis
Late-selection hypothesis
Attended input
Unattended input
Attended input
Unattended input
Consciousness
Consciousness
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Selective Attention
Early- and late-selection hypotheses are both trueStimuli that are not attended to have effects
on perception, which indicates late selectionElectrical brain activity for attended inputs
differs within 70 ms from unattended inputs, which indicates early selection
Selective Attention
Selection depends on resourcesPerceptual load theory (Lavie, 1994)Complex stimuli involve more effort, leading to
early selection (high perceptual load)Easy stimuli involve less effort, leading to late
selection (low perceptual load)
Perceptual load vs cognitive load?
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Selective Attention
Selection as a form of priming Lower threshold leads to easier recognition
Attended channel has lower threshold Your name is frequent and is primed even when
unattended
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Selective Attention
Posner and Snyder (1975) found two kinds of priming related to attentionStimulus-based priming does not involve effortExpectation-based priming does involve effort
Selective Attention
Selective Attention
Low-validity conditionMany misled trialsPrimed condition faster than neutralMisled same as neutralFacilitation only
Selective Attention
High-validity condition Primed condition much faster than neutralExpectation augments repetition priming
Misled slower than neutral conditionExpectation limited in capacityWrong expectation interferes with correct
detectors
Selective Attention
Stimulus-based primingFastFew costs
Expectation-based primingSlowMore costly
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Selective Attention
Spatial attention the ability to focus on a particular
position in space
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Selective Attention
Costs and benefits
Selective Attention
What do you see when you adjust the size of the beam?
Selective Attention
Eye movementsAround 180 ms
Shifts in attentionAs early as 150 ms
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Selective Attention
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Parietal and frontal cortexare involved in attention
Selective Attention
Do we attend to positions in space or to objects? Object-based attentionSpace-based attention: unilateral neglect
syndromeFeature-based attention?
Selective Attention
Unilateral neglect syndromeDamage to the right parietal lobeCannot attend to the left side of space
Unable to attend to left half of clock
Selective Attention
However, some experiments suggest that the deficit is also object-based
Selective Attention
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Patients see targets in red
Item rotates
Patients continue seeing targets in red
Intact side
Selective Attention
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Larger cost when the misled trial is on the uncued triangle
Selective Attention
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Narrow attention allows you to bind things together
Broad attention allows you to detect features but not bind them
Selective Attention
Summary of selective attentionBoth facilitating desired input and inhibiting
unwanted inputAttention directed both to an object and to
spaceFlexibility of early and late attentionAttention is not a single process or a
particular mechanism
Divided Attention
Julius Cesar was praised for multitasking (dividing his attention) cognitive budget
Controlled vs. Automatic Processing
Automatic processingRequires no conscious control
Controlled processing Requires conscious control
Divided Attention
Some cognitive resources are specialized For instance, verbal and spatial tasks can sometimes
be performed spatially because each draws upon different resources
Divided Attention
Other cognitive resources are general
Gauging Your Distraction During Driving
http://www.nytimes.com/interactive/2009/07/19/technology/20090719-driving-game.html
Divided Attention
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Success drops when talking on a cell phone
Passenger adjusts to driving conditions
Divided Attention
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Most similar
Least similar
Somewhat similar
Divided Attention
Several task-general cognitive resources have been proposed, such as:Response selectorCentral executive
Divided Attention
Executive control is strongly connected with working memory Necessary for overcoming habitual responses
Moving eyes away from a cue
Divided Attention
Executive control Works to keep the desired goal in mind Serves to inhibit automatic responses
Divided Attention
The prefrontal cortex is particularly important to executive control
Goal neglectBad planning
PerseverationRigid planningNo damage
Practice
Practiced skills require less executive control
Practice
Why does practice improve performance?Complex tasks get broken into partsWith practice, these parts go from being
controlled to being automatic
Practice
Controlled tasks Automatic tasks
Flexibility Yes No
Attention Yes No
Novel Yes No
Practice
Name the color ink
Easy Hard
Practice
Automaticity of number makes counting and saying the number harder
Practice
Summary of divided attention and practiceTasks require resources, and you cannot
“spend” more resources than you haveSome resources are task-specific and others
are task-general If two tasks make demands upon the same
resources, the result will be interferencePractice increases the automaticity of a task,
resulting in the need for fewer cognitive resources
Chapter 4 Questions
1. Which of the following is a failure of selective attention?
a) You are in the basement washing clothes and you hear the dog bark unexpectedly upstairs.
b) You are able to change the radio station while driving.
c) While you are working on your problem set in the living room, you are thrown off track when your sister changes your favorite radio station.
d) While upstairs talking to your best friend, you pretend not to hear your brother asking you to help clean the kitchen.
2. Which statement about visual attention is LEAST accurate?
a) Stimuli that are expected are very likely to catch our attention.
b) The only way to point attention to a place is to point our eyes in the direction.
c) By priming our detectors, we make expected stimuli more likely to be noticed and remembered.
d) Attention can be directed toward specific areas of space but not specific objects.
3. You are at a cocktail party conversing with a friend. In this situation, you are MOST likely to hear
a) whether the person behind you is speaking intelligently or foolishly.
b) whether it is a man or a woman standing behind you talking.
c) that the couple beside you are talking about a movie you just saw and loved.
d) that your name is being called out by the person next to you.
4. Which of the following statements applies to stimulus-based priming but not to expectation-based priming?
a) It has an immediate effect on attention.
b) It has a cost attached.
c) It leads to faster recognition of subsequent related stimuli.
d) It is bottom-up.
5. In the absence of attention:
a) there is no perception.
b) participants still consciously perceive stimuli if the stimuli are simple enough.
c) participants can perceive most aspects of the world but are not influenced by what they perceive.
d) stimuli may not be consciously perceived but can still have an influence on the perceiver.
6. In a study of spatial attention, participants were given a neutral, correct, or misleading cue about where on the screen a stimulus would appear. What is an explanation for what happened on trials with misleading cues?
a) There were costs because spatial attention is a limited-capacity system.
b) There were costs because the spotlight of attention had moved to the misled location and had to move back.
c) both a and bd) neither a nor b
7. According to most current thinking, what process is impaired (in the affected half of space) in patients with unilateral neglect syndrome?
a) disengaging attention from its current focus
b) moving attention to a new focus
c) locking attention on to a new focus
d) holding attention on its current focus