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