Post on 21-Dec-2015
© 2001 Dr. Laura Snodgrass, Ph.D. 1
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)
© 2001 Dr. Laura Snodgrass, Ph.D. 2
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
© 2001 Dr. Laura Snodgrass, Ph.D. 3
Basic Information Processing
Stimulus
Sensory Register
STM (working Memory)
LTM
Response
© 2001 Dr. Laura Snodgrass, Ph.D. 4
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?
© 2001 Dr. Laura Snodgrass, Ph.D. 5
Early Selection Model
Sensory filter theory (Broadbent)Stimulus
Sensory Register
Sensory FILTER
STM limited capacity LTM
Response
© 2001 Dr. Laura Snodgrass, Ph.D. 6
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
© 2001 Dr. Laura Snodgrass, Ph.D. 7
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
© 2001 Dr. Laura Snodgrass, Ph.D. 8
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
© 2001 Dr. Laura Snodgrass, Ph.D. 9
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
© 2001 Dr. Laura Snodgrass, Ph.D. 10
Late Selection Model
Norman (68)Stimulus
Sensory Register
LTM
Selection based on pertinence orsaliency mechanism
STM
Response
© 2001 Dr. Laura Snodgrass, Ph.D. 11
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
© 2001 Dr. Laura Snodgrass, Ph.D. 12
Comparison
• Differences– location of filter (before or after LTM)
– basis for selection
• Similarity– no permanent memory for unattended (not selected)
information
© 2001 Dr. Laura Snodgrass, Ph.D. 13
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
© 2001 Dr. Laura Snodgrass, Ph.D. 14
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
© 2001 Dr. Laura Snodgrass, Ph.D. 15
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
© 2001 Dr. Laura Snodgrass, Ph.D. 16
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)
© 2001 Dr. Laura Snodgrass, Ph.D. 17
Research on the capacity theory
• 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
© 2001 Dr. Laura Snodgrass, Ph.D. 18
Research on the capacity theory
• Investigations of– allocation– vigilance– switching– selection– flexibility
• focused vs. divided attention• e.g. jet fighter pilots and bus drivers
© 2001 Dr. Laura Snodgrass, Ph.D. 19
Research on the capacity theory
• 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
© 2001 Dr. Laura Snodgrass, Ph.D. 20
Research on the capacity theory
• 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
© 2001 Dr. Laura Snodgrass, Ph.D. 21
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
© 2001 Dr. Laura Snodgrass, Ph.D. 22
Secondary Task Technique
• 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
© 2001 Dr. Laura Snodgrass, Ph.D. 23
Secondary Task Technique
• 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
© 2001 Dr. Laura Snodgrass, Ph.D. 24
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
© 2001 Dr. Laura Snodgrass, Ph.D. 25
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