Exam 3

• Three core elements of Norman's ch 4:

  1. Constraints
  2. Discoverability
  3. Feedback
• Four types of constraints:

  1. Physical - being physically unable to do something
  2. Cultural - societal constraints, ex. standing the "wrong" way in an elevator
  3. Semantic - the meaning of something; relies on our knowledge of the situation and the world; ex. a person must face forward on a motorcycle
  4. Logical - ruling out other options to decide where a part goes; ex. having a part leftover when building furniture
• Perception action cycle:

  1. Object (information available) modifies
  2. Schema, which directs
  3. Exploration, which samples from (repeat)
• Beliefs of Theory of Reasoned Action/Planned Behavior:

  1. Behavioral beliefs (evaluation of behavioral outcomes) -> attitude
  2. Normative beliefs (motivation to comply) -> subjective norm
  3. Control beliefs (perceived power) -> perceived control

  Attitude + Subjective norm + Perceived control = intention to perform behavior -> behavior
• Action Cycle Theory

  
• Two definitions of information displays:

  1. An element of the system intended “to support perception of relevant system variables and facilitate the further processing of that information.”
  2. ...to present information to the human operator at the time that it is needed (when), at a location that requires little effort to access (where), and in a format in which it can be understood correctly with little cognitive effort (how).”
• Characterizing displays:

  1. sensory modality
  2. physical display properties
  3. tasks supported
  4. characteristics of human user
• Physical display properties:

  • ex. color vs monochrome
  • size, shape, etc
• Characteristics of human user:

  • ex. visual angle
• Four broad categories of display principles:

  1. Perceptual
  2. Mental model support
  3. Attention
  4. Memory
• Perceptual display principles:

  1. legible/discernable
  2. avoid absolute judgement (support it only when necessary)
  3. consider top-down influences
  4. exploit redundancy gain
  5. similarity leads to confusion
• Mental model support display principles:

  1. pictorial realism
  2. principle of the moving part
• Attention display principles:

  1. minimize access/interaction costs
  2. proximity compatibility principle
  3. multiple resources
• Memory display principles:

  1. replace memory with knowledge in the world
  2. predictive aiding
  3. exploit consistency
• Top-down influences:

  • don't depend on them; do think about overriding them
  • When information counters a top-down process the displaymust take extra steps to ensure information transfer (ex. exit signs)
• Similarity can either be confusing (ex. having two different buttons that do two different things the same color) or exploited (ex. using multiple stimuli to hammer home the point to the user, like walk/don't walk signs)
• Pictorial displays:

  • provides more information and detail than icons
  • ex. telling you which specific door on a car is open
• Icons:

  • Icons are pseudo pictorial displays elements often requiring considerable top-down knowledge
  • Requires more knowledge in the head (ex. oil lamp for change oil on a car's display)
• Two types of principle of the moving part displays:

  1. showing the full spectrum - ex. spedometer on a car
  2. showing only a snippet or window of the gauge that moves
• Proximity compatibility principle:

  • Within a display or screen, items should be grouped together when they are related to a common task.
• quickened vs. predictive display:

  • prediction shows the current state of the system and what will be happening in the future.
  • quickening only shows a prediction of the future
• HF issues with multi-functional displays:

  • multiple information streams -> can overwhelm user or distract
  • limited display real estate -> have to make choices on what's important and needs to be included
• Display compatibility principles:

  1. proximity compatibility principle - similar controls are grouped together
  2. display movement compatibility - principle of the moving part
  3. frequency of use principle - the most frequently used information should be centered
  4. display task compatibility - ex. digital displays for exact values, others for rough estimates
  5. display control compatibility - ex. moving something clockwise and expecting the pointer to do the same
• Integral displays:

  • multiple variables are relevant to task
  • integration of information is necessary for optimal performance
• Separable displays:

  • Single variable information is necessary for performance
• Configural (object) display:

  • Objectness is used to create an emergent feature
  • Ex. bigger dots to represent areas with higher populations and vice versa
• Comformal display:

  • Display whose properties match that of the outside world
  • ex. green information overlaid on a pilot's screen
• Qualifying errors:

  1. Error as a Frequency (1- accuracy rate)
  2. Error as Deviation
  3. Absolute Error
  4. Root Mean Square Error (RMSE)
• Reason's Error Taxonomy:

  Unsafe actions

  1. Unintended Actions
  2. slip (attentional failures)
  3. lapse (memory failures)
  4. Intended Actions
  5. mistake
  6. rule based mistake
  7. knowledge based mistake
  8. violation
  9. routine violation
  10. exceptional violation
  11. sabotage
• Two approaches to errors:

  1. Person approach
  2. System approach
• Person approach:

  • people are usually the root cause of errors
  • strong link to psychology (bio/psycho/social elements)
  • psychologically satisfying
  • hinders error reduction
• Railroad error taxonomy interactions:

  1. interaction between men
  2. man machine interaction
  3. human environment interaction
• In automotive error taxonomy:

  • mode errors - erroneous classification of the situation (ex. wrong pedal)
  • description errors - ambiguous or incomplete specification of intention
• • Aviation safety reporting system - oldest taxonomy discussed (1976)
  • Railroad or healthcare - newest taxonomy (early 2000s)
• Aviation Reporting Safety System:

  • voluntary, confidential and non-punitive incident reporting system
  • designed because pilots were unaware of their immediate surroundings as well as what else was flying in the air
  • designed to help enable information sharing among other pilot operators and aviation community
  • helped identify and eliminate unsafe conditions and prevent accidents
• Three classes of error taxonomy for healthcare:

  1. Behavioral
  2. Contextual
  3. Conceptual
• Accidents:

  • Event with consequences resulting in loss or harm
  • Sometimes reserved for failures occurring from unknowable triggers (random events)
• Faults

  Adverse event/failure linked to elements of the system
• Incident

  • Event that COULD have resulted in loss or harm but may not have
  • Near misses
• Root Cause Analysis - process with a goal of finding the underlying (lowest level) trigger for an accident or incident.