Cognition – 2/e
Dr. Daniel B. Willingham
Chapter 3:
Attention
PowerPoint by Glenn E. Meyer, Trinity University
©2004 Prentice Hall
Attention
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Definition: The mechanism for continued
cognitive processing. All sensory information
receives some cognitive processing; attention
ensures continued cognitive processing.
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Two Properties of Attention
• Attention is limited in some fashion. Cognitive
processing cannot occur for all stimuli
simultaneously
• Attention is selective - you can expend your
mental energy on a cognitive process as you see
fit
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In What Way Is Attention Limited?
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Parallel Performance
• Consistent Attention Requirements
• Allocation of Attention
• Reduction in Attentional Demands
with Practice: Automaticity
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Parallel Performance
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Attention can be distributed to more that one task at a time multiple tasks can be done in parallel
 Tested with the Dual Task Paradigm using continuous tasks
rather than discrete tasks to avoid switching from task to task
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Dual task: A method of examining attentional demands. The target
task is performed alone and in the presence of a secondary task; if
the target task requires little or no attention, performance should
not deteriorate when the secondary task is added.
Continuous task: A task in which there is no obvious beginning and
ending to each trial; there is a continuous stream of stimuli and
responses (e.g., a pursuit tracking task). Ex. - touch typing
Discrete task: Each trial has a discrete beginning and ending (e.g.,
a simple response time task). Ex. - simple reaction time to a light
However, it is difficult even with dual task paradigms to guarantee
parallel performance as compared with task switching - Broadbent
(1982), Welford (1980), Salthouse (1984)
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Consistent Attention Requirements
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When performing multiple tasks, does the amount of attention
assigned to each task remain constant? Probably not.
Multiple Resource Theories: Attention is thought to be
composed of number attentional pools, dedicated to a different
type of task (Navon & Gopher, 1979; Norman & Bobrow, 1975)
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One suggestion - pools separated on basis of sense modality - Navon and
Gopher (1979)’s analysis of Brooks (1968) simultaneous spatial and vocal
tasks. Same modality task interfere more than cross modality.
Not supported by Driver and Spence (1994) as seen in Fig. 3.4 Audition
and vision not completely separate
Wickens (1984, 1992) - pools of attention based on dimensions of task
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Perceiving the stimulus/ selecting the response
Verbal or spatial processing used
Modalities of input/output
While appealing multiple resource pools have been difficult to specify in a
usual predictive manner. It is not clear how many pools exist or how they
are related to tasks - Allport, 1989; Luck and Vecrea, 2002.
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Allocation of Attention
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Psychologist assume people can allocate more or less
attention to a task according to their goals - Example:
when driving becomes difficulty you stop talking to your
friend.
Experimental test - Sperling and Melchner (1978)
 Subjects view inner set of four letters surrounded by 16 letters
 Arrays flashed on computer screen, containing two digits that have
to be reported as to identity and location
 Subjects told to allocate 90% of attention to one array or the other
 As seen in Figure 3.3, when subjects attend to an array, they get
most of the digits correct
 Attention allocation seems to be demonstrated
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Reduction in Attentional Demands
with Practice: Automaticity
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Automatic process: A process that takes few or no attentional resources
and that happens without intention, given the right set of stimuli in the
environment. For ex.: Some aspects of driving a car.
Two characteristics of automaticity:
 Requires little or no attention
 Happens without intention
Automaticity and Attention
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Schneider and Shiffrin (1977)
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Search for targets with consistent or inconsistent distractors
• Consistent distractors led to pop-out of targets. Indicates search is automatic.
• When targets was selected from same set on each trial, automaticity developed
over many trials as seen in Fig. 3.6
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Exact mechanism of the development of automaticity is under debate Anderson, 1983; Newell and Rosenbaum, 1981; Willingham, 1998.
Logan (1988, 2000) suggests automaticity related to increase in use of
memory in task.
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Automaticity - Continued
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Automaticity and Inattention
 Automatic processes can happen beyond our control but one must be
cautious in interpretation
 Two Examples:
• Stroop test -- Try to say the color of each word - not the word itself.
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Interfering
RED
GREEN
YELLOW
BLUE
Noninterfering
GREEN
RED
BLUE
YELLOW
• Suggests reading is automatic
• Flanker Effect (task) - Stimuli (usually words) that appear to the sides
of a target and that participants are to ignore, affect behavior.
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Dallas and Merikle (1976) - reading a target word faster when flankers
semantically related
Shaffer & Laberge (1979) - categorization faster with related flankers
 We still must consider what elicits automatic response. When walking and
you see a red light - you don’t make a braking movement with your foot.
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What is the Fate of Sensory Stimuli
that Are Not Selected to Receive
Attention?
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Early Filter Theories
Later Filter Theories
Movable Filter
What is Selected?
How Does Selection Operate?
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Early Filter Theories
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First studies - Cherry (1953) using dichotic listening and shadowing tasks
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Participants listen to material on headphones, and each earpiece plays a different
message (dichotic listening). They attend to one message and must shadow that
message. Shadowing means repeating the attended message aloud as they hear it.
Task used to study how much the unattended material is processed
Participants didn’t notice:
• If the unattended message switched languages
• If the unattended message was played backwards
Participants did notice:
• If the unattended message became a pure tone
• If the unattended message switched gender
• If the unattended message was repeated 35 times (Moray, 1959)
Cherry concluded that the unattended message was not analyzed for meaning, only
for physical characteristics.
Broadbent (1958) - One of the first Early Attentional Filter Models
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Information first enters very brief sensory store
Filter occurs after this store
Small portion of information sent to the next stage of primary memory
Primary memory: awareness and assignment of meaning
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Late Filter Theories

Problem with Broadbent and Cherry’s Proposals - Meaning has been found to
be processed in the unattended message
 Moray (1959) and Wood and Cowan (1995) found subjects detected their
own names in the unattended ear.
 Treisman (1960) found that shadowing switched ears if the semantic
context of the attended message switched to the unattended ear
 Treisman proposed the filter is sensitive to context and certain important
words (like FIRE!) will always be considered contextually relevant and
pass through the filter.
 Led to the development of Late Filter Theories (Deutsch & Deutsch, 1963;
Norman, 1968)
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Late Filter Theories: Attention acts as a filter late in the processing stream. All sensory
stimuli are analyzed for their physical characteristics and meaning, but only those that
are attended to enter awareness.
 Theories supported by experiments using indirect measures such as seeing if
performance on a task is influenced by unattended messages.
 Example: Corten & Wood (1972) conditioned GSR to an electrical shock paired
with a specific word. Subjects demonstrated the GSR responses to the word even
when presented in the unattended ear and the subjects had little conscious
knowledge of having heard it.
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Late Filter Theories - Continued
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Example 1: Corten & Wood (1972) conditioned GSR to an electrical shock
paired with a specific word. Subjects demonstrated the GSR responses to
the word even when presented in the unattended ear and the subjects had
little conscious knowledge of having heard it. Some failures to replicate
(Wardlaw & Kroll, 1976) but was replicated by Dawson and Schell (1982)
but effect was not as robust.
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Example 2: Eich (1984) – words in the unattended ear disambiguated the
meaning of word homophones in the attended ear (ex. attend to fair/fare
and taxi is in the unattended ear). On testing, subjects write fare. Wood, et
al (1997) suggests result might be due to switching of attention from
channel to channel rather than a late filter.
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Movable Filter Theories
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Movable filter model:
 An attentional model where the filter can be chosen to
be early or late in the processing stream depending on
needs (Posner & Snyder, 1975)
• Unattended stimuli analyzed for physical characteristics
• Choose to allocate attention to some material or allocate
attention mostly to the material and switch periodically to the
other
 Supporting Experiments
• Johnston & Heinz (1978) – shadowing on a semantic level
interferes more than shadowing on a physical level with a
secondary task. Indicates differential allocation of attentional
resources
• Koelsch and Tervaniemi (1999) – amount of processing may be
affected by training, trained musicians demonstrated specific
ERPs to unattended musical stimuli that were technically
discordant.
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What Is Selected?
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Attention seen as a spotlight before early ’80s (Norman, 1968; Posner
et al, 1980) – Attention selected spatial locations
Today – attention thought to select objects and not locations
Experimental Evidence for Object Selection
 If attention was spotlight, then it should take a longer time to move
attention over a greater distance NOT confirmed by Kwak et al. (1991) as seen in Fig. 3.8 in a
same/different task with targets at varying distances
 If attention was a beam, then as it swept from location to location it might
be caught by an intervening object –
NOT confirmed by Sperling & Weichselgartner (1995) in task with stimuli
appearing between fixated items and attended items. The in-between
stimuli did not draw attention as they would if caught in a passing
attentional beam
 Neisser & Becklen (1975) – attention can be successfully allocated to one of
two visually superimposed video streams (two different games). Difficult to
explain if attentional allocation is spatial in nature.
 Baylis and Driver (1993) – more difficult to judge distances between points
when they are from different objects rather than the same object (as seen
in Fig 3.9). Argues for object based attention.
Which vertex is higher? Examine the
white parts or black parts of each illustration.
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What Is Selected? - Continued
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Neural Evidence – O’Craven et al. (1999)
 FMRI used
 Subjects viewed semitransparent face superimposed over a house, with one
stimulus moving
 Subjects had to attend to house, face or motion
 Activation was studied for specific cortical regions for separate stimulus
attributes (face, place, motion)
 Only the attended characteristic had its locus activated – arguing against
“spotlight” or area view of attention
How Does Selection
Operate?
Treisman & Gelade (1980)
Stimulus Arrays and Search
Examples
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How Does Selection Operate? - Continued
• Object Selection most studies by visual search – please see
the illustration on slide #16 - Treisman & Gelade (1980)
• Two types of searches
 Disjunctive: In a visual search task, the target differs from
distractors on just 1 feature (e.g., target is larger than distractors
or target is only stimulus that has a horizontal line in it).
 Conjunctive: In a visual search task, target differs from distractors
on two features, for example, the target is large and red and
although some of the distractors are large and some are red, none
of the distractors are both large and red. It requires a conjunction
of two features (largeness and redness) to identify the target.
 On the illustration on slide #16, the left and middle are disjunctive,
the right is conjunctive
 Disjunctive searches are parallel in nature – all items at one time
 Conjunctive searches are serial – one item at a time
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How Does Selection Operate? - Continued
• Treisman and Gelade (1980)
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Perceptual system organized into feature maps
Map contains location info for one feature (e.g. color, texture, etc.)
Contents of maps loaded preattentively
Conjunctive searches need to access two or more maps
Attention conjoins the contents of maps together
• Shih and Sperling (1966)
• Attention drawn to correct stimulus rather than filtering out others
• Subjects had to find digit among letters. Telling them that the
target would be in a slide with all large letters didn’t help.
• Telling them that it would be the only small target among large
characters did
• Conclusion: Critical feature can draw attention but it cannot filter
out incorrect stimuli.
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Why Does Selection Fail?
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Assumed Order of Sensory Processing
1. Processing Physical Characteristics
2. Processing Semantics
3. Awareness
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Early Filters – located right after
sensory processing
Late Filters – located right after
semantic processing
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Properties of Attention that Cause Selection Failure
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Inhibition of Return:
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If attention focuses on an object and then moves to
another object, it is difficult to return attention to that
object for several seconds.
First described by Posner (1978; Posner and Cohen,
1984) – warning signal interferes with response to
target at same location
Tipper, et al. (1991) – Inhibition of Return based on
objects and not location
Theorized that IOR makes search more efficient as
there would be a bias not to return to an already
inspected item
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Properties of Attention that Cause Selection Failure Continued
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Ironic Processes of Mental Control:
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Attending to something you don’t want to (Wegner, et
al. 1987)
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Two processes of mental control
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Operating process – seeks mental contents consistent with
what you want to think about
Monitoring process – searches for processes that are
inconsistent
Operating process demands attention, Monitoring
does not
o If resources are scare, the Operating process cannot
bring consistent contents to awareness and the
Monitoring processes brings inconsistent thoughts to
alert the system that they are present.
o
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Properties of Attention that Cause Selection Failure Continued
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Maintaining Attention: Vigilance
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The ability to maintain attention to a task in which
stimuli appear infrequently
Can be analyzed in terms of Signal Detection Theory’s
two factors
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Sensitivity – absolute ability to detect
Bias – whether you use a liberal or conservative criterion for
reporting a detection
Sensitivity decreases can be due to boredom, habituation,
decline in motivation
Sensitivity declines also depend on task – Parasuraman and
Davies suggest sensitivity drops only for tasks with high event
rates
Koelega, et al. (1989) suggests sensitivity drops for sensory task
but is stable for cognitive tasks
See, et al. (1995) – with sensory tasks, sensitivity gets worse for
simultaneous tasks and better for successive task, vice versa for
cognitive tasks
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Interaction of Attention with other Components of
Cognition
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Structural Explanation – Interference between two task is
caused by competition for mental structures, not
attentional resources
Two effects of interest
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Psychological Refractory Period (Welford, 1952; Pasher, 1998):
A period of time after one response is executed during which a
second response cannot be selected. Reflects a bottleneck in
response selection as seen in Figure 3.12
Attentional Blink: In a rapid serial visual presentation (RSVP) as
seen in Fig. 3.13, observers have trouble identifying the second
target if it appears anywhere between 100 to 600 ms after the first
target. Seems to represent a central bottleneck but not one of
attention
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Automaticity and the Brain
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Do regions of the brain or processes differ when a task
becomes automatic?
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Jansma, et al. (2001) – with a working memory task found
no difference in dorsolateral prefrontal cortex, right
superior frontal cortex and supplementary motor cortex
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Jueptner et al. (1997) with a sequenced motor task found:
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Early learning associated with dorsal prefrontal cortex and
anterior cingulate cortex
Automatic performance with posterior parietal cortex
Thinking about movements activated dorsal prefrontal and
anterior cingulate cortices
There may be more than one brain mechanism for
automaticity.
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