ATTENTION AND MENTAL RESOURCES

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ATTENTION AND MENTAL RESOURCES

• Nantida Wisawayodhin M Sc. M.Erg.S.

Module Cognition and Information
Processing Course Human Centered Design
(HCD) SOAD, KMUTT
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OVERVIEW

• Mental Resources
• Multiple Resources Theory
• Bottleneck Theory
• S-R Compatibility
• Design Guidelines
• Practical

• Attention
• Auditory and visual attention
• Selective
• Focused
• Divided
• Automatic vs. Controlled processing

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MODEL OF HUMAN INFORMATION PROCESSING
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ATTENTION

• A process dictates by the central executive in
  working memory
• Applies throughout the information processing
  stages
• Is closely related to intention and conscious
  awareness
• Is resource limited
• Three main types
• Focused attention
• Selective attention
• Divided attention

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ATTENTION AUDITORY vs. VISUAL
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SELECTIVE ATTENTION
Factors affecting your selective attention

• Salience
• the features of the environment that will attract
  or capture attention
• Expectancy
• the use of our knowledge to predict where to look
  for information and what changes to expect of
  product/system behaviour
• pay attention more intently and frequently to the
  area of the visual field in which changes are
  likely to appear

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SELECTIVE ATTENTION

• Value
• the value of information received
• what each task means to the person and the
  intended goal
• Expert users make use of their knowledge about
  values and expectancy to guide their attention
  much better than novices
• Effort
• information access effort
• the amount of effort requires to do something is
  considered in terms of the perceived expected
  value of the information received

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SELECTIVE ATTENTION

• Features of salience
• Auditory modality
• Non-directional
• More attention grabbing than visual events
• Used in alarms
• Visual modality
• Onsets (the commencement of stimuli) tend to be
  the most salient or attention-grabbing property
• Unique shape size and brightness
• Use of repeated onsets (flashing) as visual
  alerts

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SELECTIVE ATTENTION
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FOCUSED ATTENTION
Attentional resources are directed to one single
task and maintained until desired goal is
achieved

• Effort - the amount of resources being invested
  into a task
• Difficulty - the amount of resources a task
  demands
• Distraction - similarity and proximity of
  irrelevant stimuli to the target stimulus can
  cause distraction

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FOCUSED ATTENTION
Relationship between effort and difficulty

• Investing effort or resource into a task of
  constant difficulty will improve its performance
• Increasing the difficulty of a task will decrease
  performance unless more resources are supplied to
  compensate
• A ceiling of performance level will be met for a
  task of constant difficulty however much effort
  is being put into it

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DIVIDED ATTENTION

• The ability to respond simultaneously to multiple
  tasks or multiple task demands
• Sometimes referred to as dual-tasking,
  concurrent processing and time-sharing
• Efficient time-sharing
• driving while having a conversation
• cycling while navigating a mountainous route
• thinking and writing at the same time

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DIVIDED ATTENTION

• We can time share between two tasks if
• One is a manual and another is a verbal task
• At least one is a skilled or routine task
• One is a perceptual and the other is a response
  task

Psychologists have provided theories to
explain these phenomena
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AUTOMATIC vs. CONTROLLED PROCESSING

• Practice improves performance -
• Become automatic as a result of prolonged
  practice
• Automatic tasks can be readily and efficiently
  time-shared with other more demanding tasks

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AUTOMATIC vs. CONTROLLED PROCESSING

• Current model proposed by Norman Shallice in
  1986
• Fully automatic processes
• Partially automatic processes
• Controlled processes

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AUTOMATIC vs. CONTROLLED PROCESSING

• Fully automatic processes
• When the situation provides a set of retrieval
  cues that matched only one schema
• Controlled by schemas contained within our
  long-term memory
• Requires very little conscious awareness
• This process would frequently disrupt behaviour
  if left entirely to its own devices.

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AUTOMATIC vs. CONTROLLED PROCESSING

• Partially automatic processes
• When two or more schemata have been activated by
  incomplete or ambiguous retrieval cues or calling
  conditions
• Controlled by a process called contention
  scheduling
• An automatic conflict resolution process without
  deliberate direction or conscious control
• A process based on similarity-matching and
  frequency-gambling mechanisms

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AUTOMATIC vs. CONTROLLED PROCESSING

• Controlled processes
• A fully conscious process
• Controlled by a higher level control mechanism
  known as the supervisory attentional system (SAS)
• SAS will become active when an individual
  encounters danger, novelty and temptation, and
  where a response selection is required
• Permits flexible responding in novel situations

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MENTAL RESOURCES

• Current theories on the processes involved when
  we make use of attention
• The theories will be presented based on the
  information-processing framework with three main
  processes input (perception) processing
  (cognition) output (response) and processing
  modalities

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MENTAL RESOURCES
Two well accepted theories

• Multiple Resources Theory (MRT) (Wickens, 1984
  and 1987)
• Bottleneck Theory (Welford, 1952 Pashler, 1998)

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MULTIPLE RESOURCES STRUCTURE
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MULTIPLE RESOURCES THEORY

• Attentional resources are defined along three
  dichotomous dimensions
• Stage of processing perception and cognition and
  response selection and execution
• Perceptual modalities visual and auditory
• Processing code verbal and spatial
• Based on an expansive systematic review of the
  interference patterns in the dual-task data

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STAGE OF PROCESSING

• First dimension
• Distinct separate resources between response
  selection and execution AND perceptual and
  working memory (cognitive activities)
• Example Thinking and talking while stirring a
  pot of soup

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PERCEPTUAL MODALTY

• Second dimension
• Distinction between auditory AND visual
  modalities within the perception stage
• Cross-modal (between modals) time-sharing is
  better than intra-modal (within modal)
• Due to visual scanning and confusion cost rather
  than separate resources

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PROCESSING CODE

• Third dimension
• Distinct separate resources between verbal AND
  spatial processing codes
• The separation between verbal and spatial
  processing codes can be associated with the two
  cerebral hemispheres
• Left for verbal
• Right for spatial

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MULTIPLE RESOURCES THEORY

• Distinction between perceptual modalities and
  processing codes
• Reading is a visual input, but uses verbal
  processing code
• Describing the content of a room is a vocal
  output, but uses spatial processing code
• Therefore, manual and vocal outputs can be
  time-shared efficiently as long as manual
  response is spatial in nature (e.g. drawing) and
  vocal is a verbal one (e.g. making comments).

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APPLICATION OF MRT

• The three dichotomies must be considered together
  when designing a set of tasks.
• Exploiting the modality distinction (cross-modal)
  alone would not mean that perfect time-sharing is
  achieved.
• A written text, even though employs a visual
  modality, is likely to be processed by the verbal
  code at the processing stage.
• Writing would be a manual response exploiting a
  different resource to verbal code, but vocal
  response would be accessing the same processing
  code.

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USEFULLNESS OF MRT

• To make predictions of human performances on
  concurrent tasks and differing task patterns
  based on scientific evidence
• To assess whether an introduction of a particular
  task is likely to affect the performance of
  existing tasks

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IMPLICATIONS IN DESIGN

• Time-sharing between two tasks is optimal when
  they affect separate resources
• Time-sharing of tasks using the same resources
  are likely to lead to increase in errors and
  mental workload
• It is more difficult to reallocate resources
  among task components that make use of highly
  dissimilar resources
• Tasks to be carried out serially with a common
  goal should be designed to share the same
  resources
• Two tasks with different goals should be designed
  to access different resources

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BOTTLENECK THEORY

• Bottleneck narrowing of something
• Bottleneck theory states that resources available
  for response selection stage are allocated in an
  all or none fashion to one task or the other
• Two independent responses cannot be selected at
  the same time one or the other must be postponed
  
• It does not affect response execution or any
  other cognitive processes

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BREAK

• 15 MINUTES

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S- R COMPATIBILITY

• Grouping principles
• How displays and controls should be presented to
  aid mapping between them
• Location compatibility
• Where controls should be located to control their
  respective displays
• Reflects the humans intrinsic tendency to move
  or orient toward the source of stimulation
• Movement compatibility
• How controls should move to control the displays
• Refers to expectancies (mental models) that users
  have about how the display will respond to the
  control activity
• Modality compatibility
• What modalities should be used
• Population stereotype
• Mappings related to direct experience
• Consistency

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GROUPING PRINCIPLES

• Proximity Display elements that are located
  close together will tend t be grouped together
• Similarity Display elements that are similar in
  appearance will tend to be grouped together.
• Continuity Display elements which are presented
  in line will tend to be grouped together.
• Closure Display elements that make up a closed
  figure will tend to be grouped together.

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GROUPING PRINCIPLES
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GROUPING PRINCIPLES

• Common fate Elements with a common motion
  (direction or type of motion) will tend to be
  grouped together.
• Principle of connectedness Line drawn between
  some elements but not others will cause the
  connected elements to be grouped together.
• Principle of common region A contour drawn
  around display elements will cause those elements
  to be grouped together

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GROUPING PRINCIPLES
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GROUPING PRINCIPLES

• If a task requires that information be integrated
  mentally, that information should be presented in
  an integral or integrated display
• If a task requires that the information be kept
  distinct mentally, the information should be
  presented in a display with separable dimensions
• If unsure about whether the displays should form
  an integrated whole, err towards grouping
  displays.

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LOCATION COMPATIBILITY

• Controls should be located as close to the
  relevant displays as possible

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LOCATION COMPATIBILITY

• If this is not possible due to constraints such
  as physical or safety, the spatial layout of
  controls should be consistent with the spatial
  layout of displays

X
v
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LOCATION COMPATIBILITY

• If consistency mapping is not possible, simple
  rules should be available to map the set of
  stimuli to the set of responses
• To convey increase in quantity move from left
  to right, aft to forward, clockwise and from
  bottom to top

Scale display
Volume control
Light control
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LOCATION COMPATIBILITY

• Minimise information access cost as much as
  possible by placing displays and controls which
  are frequently used together close to each other
  to reduce visual search and avoid attention
  reallocation cost

Displays and controls for auto pilot are placed
close to each other
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MOVEMENT COMPATIBILITY

• The moving elements of any displays of dynamic
  information should move in a spatial pattern and
  direction that is compatible with the users
  mental model of how the represented element moves
• Linear (slide) controls should move in an axis
  and direction parallel to linear display movement.

Movement of altitude display in fighter cockpit
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MOVEMENT COMPATIBILITY

• A mismatch between users expectations of the
  result of an action and the actual result could
  trigger a further unnecessary and possibly
  disastrous control action and should be avoided

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MOVEMENT COMPATIBILITY

• The moving elements of any displays of dynamic
  information should move in a spatial pattern and
  direction that is compatible with the users
  mental model of how the represented element
  moves.
• Dial displays are more compatible or congruent
  with rotary controls.

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MOVEMENT COMPATIBILITY

• The closest part of the moving element of a
  control should move in the same direction as the
  closest part of the moving element of a display.

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MODALITY COMPATIBILITY

• Ideally a stimulus should match the sensory
  feedback produced by the response. For example
  
• A seen letter a written response
• A heard letter a spoken response

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MODALITY COMPATIBILITY

• Tasks that use verbal working memory are served
  best by auditory inputs and vocal outputs. Most
  suitable only when material is short and response
  is immediate. Long verbal inputs risks forgetting

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MODALITY COMPATIBILITY

• Tasks that use spatial working memory are served
  best by visual inputs and manual outputs. This
  should only be applied when the vocal response
  does not disrupt rehearsal of the retained
  information

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MODALITY COMPATIBILITY

• Many-one mapping of stimulus and response will be
  less compatible than a one-to-one mapping

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POPULATION STEREOTYPE

• Global designs should take into account mappings
  that are related to direct experience. For
  example
• Light switch Americans flick switch up to turn
  lights on Europe flicks switch down to turn
  lights on.
• Indicator controls in cars European cars
  indicator controls on left hand side, Japanese
  cars indicator controls tend to be on right hand
  side.
• Direction of screws clockwise for tightening and
  anti-clockwise for loosening (Universal)
• Colour coding red for danger, yellow/amber for
  caution and green for go (Universal). Other
  colour use, such as blue, white and brown on
  information design is not as universal.

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CONSISTENCY

• If consistency is being applied to a set of
  control-display design, it should be carried out
  for all of the S-R pairings. Violations of
  consistency across relations may result in users
  confusion as to which rule to apply.

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TRAINING

• Training can be used to formulate correct mental
  models or to enhance the agreement between mental
  models and the physical product dynamics
• Training should not be used to mitigate for bad
  designs. Extensive training of incompatible
  mapping will never catch up to a compatible one.
  Under stress, performance with an incompatible
  mapping deteriorates further than that of a
  compatible mapping

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Any Questions?
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BREAK

• 15 MINUTES

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PRACTICAL

• BTS ticketing machine interface and task design
• User types Novice, Occasional Expert
• Users Tourist, daily users, blind, deaf
• Objectives
• Buy a correct ticket for the right destination

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PRACTICAL

• BTS ticketing machine

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PRACTICAL

• Task
• Design a new interface for the ticketing machine
  based on knowledge and design guidelines learnt
  so far to make it easier to use.
• Make sure to include
• A drawing of the proposed design
• Design guidelines applied
• Justifications for the new design
• Duration 30 minutes
• 2 volunteers to give 5 minutes presentation of
  their proposed design

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PRACTICAL CONSIDER

• From searching for the machine to receiving the
  ticket
• Appearance
• Interface design
• Sequence of task
• Ease of tasks
• Efforts required vs. value achieved
• The application of memory aid

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PRACTICAL Issues

• Appearance
• Not attention catching no clear indication that
  it is a ticketing machine
• Design blends in with the environment
• Look like another advertisement board
• Task sequence
• Not clear where to start
• Too many sub tasks
• Does not fit user expectations (one-stop shop,
  take bank note)
• Design around system convenience than user
  convenience
• Memory Aid
• Step 1 is not the start point of the ticket
  buying process

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PRACTICAL Solutions

• Appearance
• Attention catching Clear information sign to
  indicate location of Ticket Machine
• Make it stand out
• Task sequence
• Reduce number of steps
• Make it a one-stop shop
• Design to take bank notes
• Design with user in mind
• Memory Aid
• Start step 1 where it should be at the map

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PRACTICAL

• Pedestrian crossing indicator

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PRACTICAL

• Pedestrian crossing indicator interface design
• Users Pedestrians and drivers
• Descriptions normal, blind, deaf, in wheelchair,
  Elderly
• Objectives
• Inform pedestrians of safe crossing time
• Inform pedestrians to prepare to stop
• Inform pedestrians of unsafe crossing time
• Informative to drivers

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PRACTICAL

• Task
• Design a new interface of the indicator based on
  knowledge and design guidelines learnt so far.
• Ensure to include
• A drawing of the proposed design
• Explanation of how it works
• Design guidelines applied
• Justifications for the new design
• Duration 30 minutes
• 2 volunteers to give 5 minutes presentation of
  their proposed design