Introduction to attention

Introduction to
Attention
Dr Mahdi Alizade
1
‫در‬ ‫شده‬ ‫ارائه‬:
‫توجه‬ ‫توانبخشی‬ ‫تخصصی‬ ‫کارگاه‬
‫شناختی‬ ‫های‬ ‫هفته‬ ‫آخر‬ ‫های‬ ‫کارگاه‬ ‫سری‬ ‫از‬
‫پاییز‬96

© 2001 Dr. Laura Snodgrass, Ph.D. 2
Attention
• Determines which codes get processing
• Often associated with conscious awareness
• A continuum that varies with the amount of
conscious awareness and effort
conscious decision processes unconscious monitoring
(require attention and effort) (effortless)

Theories of Attention
• All theories agree on limited capacity and selectivity
• Disagree on location of limits and how selection is
done
• All share the basic information processing premises
– disagree on order of information flow

Basic Information Processing
Stimulus
Sensory Register
STM (working Memory)
LTM
Response

Dichotic Listening
• Common research technique to investigate selective
attention
• One message is presented to one ear and a different
message is presented to the other ear
• Subjects are instructed to shadow one ear
– shadow = repeat out loud what they hear
• What happens to your memory for the information?

Early Selection Model
Sensory filter theory (Broadbent)
Stimulus
Sensory Register
Sensory FILTER
STM limited capacity LTM
Response

Early Selection
• All information enters the sensory register
• FILTER selects based on physical characteristics
– Only what passes through filter has access to LTM
– No selection based on meaning because meaning
is stored in LTM

Experiments that support early selection
• Cherry (53) - dichotic listening
– no memory for information in unattended ear
– not notice change from English to German
• Neisser & Becklen (75) - superimposed video images
– ballgame and handslap
– attend to one and not notice bizarre events in the other

Contradictory Results
• Cocktail Party Phenomenon
– own name is recognized in unattended ear
• Treisman
– subjects switch shadow to follow message when
message is switched to “unattended” ear
– only is message continues in other ear
• Both results indicate knowledge of meaning from the
unattended ear

Attenuator Model
• Treisman (64)
– How can subjects be influenced by the meaning in
the unattended ear?
– Unattended information is only dampened (attenuated)
not filtered completely
– Significant information gets through the filter

Late Selection Model
Norman (68)Stimulus
Sensory Register
LTM
Selection based on pertinence or
saliency mechanism
STM
Response

Late selection
• All incoming information activates LTM
• Saliency
– expectancy or constant monitor for some stimuli
• Pertinence
– important to you
• Information with highest activation is selected for
response

Comparison
• Differences
– location of filter (before or after LTM)
– basis for selection
• Similarity
– no permanent memory for unattended (not selected)
information

Experiments supporting late selection
• Lewis (73)
– unattended information increases RT to attended IF
semantically related
• e.g. RT to animal names
• Mackay (73)
– unattended disambiguate the meaning of attended
• “they threw money towards the bank” in one ear
• “money” or “river” in unattended influences interpretation
• GSR study
– reaction to words associated with shock even if presented in
unattended ear

Capacity Theory
• Selective attention as the allocation of capacity, NOT
a block or filter
• Attend to more than one thing at a time
– divide up attention
• Shiffrin and Schneider (77)
– finite capacity to be divided
– attention = process of allocating resources to various
inputs
– divide attention among automatic and controlled
processes

Automatic and Controlled Processes
• Automatic
– not use limited capacity
mechanism
– not use working memory
– not interfere with other auto or
control processes
– occur in parallel
– effortless
– not interruptible- once initiated
continue to completion without
control (e.g. Stroop effect)
– does NOT lead to learning (no
LTM)
• Controlled
– use limited capacity
mechanism
– limited # can operate at once
– usually sequential
– necessary for learning (LTM)
– two types
• conscious and
accessible
• veiled, unconscious, e.g.
a memory search

Research on the capacity theory
• Distinguishing automatic and controlled processes
– dual task - if performance decreases then both must
be controlled; if no decrease then one or both
automatic (or not exceed capacity)

• Overlearning - many controlled processes can
become automatic with “overlearning”
– motor skills
– components of reading (Stroop)
– letter search task
– practice to avoid panic
• emergency response becomes automatic
– concurrent tasks e.g. reading and taking dictation
– retrieval of test items

• Investigations of
– allocation
– vigilance
– switching
– selection
– flexibility
• focused vs. divided attention
• e.g. jet fighter pilots and bus drivers

• Performance under two types of constraints
– data limitations
• not enough data, no matter how much cognitive
resources are applied
• e.g. poor quality copies, asked to land a jet
– resource limitations
• can do better if pay more attention
• e.g. listen to lecture and take notes
• Performance is limited by the demands that the task
places on the cognitive system

• Measure capacity demands of a given task by amount
of interference
• Secondary Task technique and cognitive effort
– the harder the primary task the poorer the performance
on the secondary task
– star tracing experiment

Secondary Task Technique
• Ellis
– memory increases with increasing cognitive effort
– measure effort with secondary task
– primary task is hard or easy anagrams
• ootdcr vs. tordoc
– secondary task is tone detection (probe)
– found - memory and RT to probe increases for
harder anagrams
– measure difference in capacity demand

• Posner and Boies
– letter matching and tone
detection
– look at RT to tone during
different points in the task
shows that cognitive load varies
during the task
– notice RT during rehearsal and
during decision
0
100
200
300
400
500
600
warning first second
RT

• Keele - investigate cognitive effort of different tasks
• Assumption - each task has two stages
– receive sensory input and activate memory
– mental operations based on memory activation
• mental operations such as:
• recognition and search, compare and match,
rehearsal, response initiation, movement correction,
counting (beyond subitization)
• Stage one takes little (or no) attention (effort) but stage
two does

Other theories of attention
• Logogen model - levels of activation in memory
– as concept reaches a threshold of activation you
become consciously aware of it (pay attention)
– preset criterion level of activation
• ignore = set high
• expectation = set low
• redundancy and context = low
• spatial location and physical characteristics can be
used to set high or low

Other theories of attention
• Posner and Keele
– attention = mechanism that coordinates the different
codes
– optional filtering of input based on physical
characteristics
– cost and benefits of presetting attention
– individual differences in flexibility
• focused and divided attention
• Treisman and Gelade
– attention glues the codes back together

‫تخصصی‬ ‫کارگاه‬‫توجه‬ ‫توانبخشی‬
‫سپاسگزاریم‬
www.farvardin-group.com
@farvardin_group_channel
@neuroscience4family
@farvardin_group96

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