Milestone 3 more.

  1. A good interface should have:
    • Effective affordances
    • Visibility
    • Natural mappings
    • Feedback to the user
  2. Natural mappings --> In the context of creating a good interface
    Understanding which control maps to what action....controls are in logical proximity to the thing they are controlling. Easy to tell which control controls what action/thing.
  3. Visibility
    • make relevant parts visible
    • make what has to be done obvious
  4. Affordance -> what is effective affordance?
    It should be obvious how a control is used. Does the user perceive that clicking on that object is a meaningful, useful action?
  5. Feedback --> In the context of creating a good interface.
    Let the user always know where they are in the process

    • Feedback about
    • where you can go
    • where you are (feedback and feed forward)
  6. Affordance vs. Visibility
    • Affordance: how do you interact with these controls?...what the heck are they?
    • Visibility: what do these controls do?...I know this is a button or hyperlink...what does this do?
  7. Mapping: example of bad mapping.
    1.5 to 2 million votes were "lost" in the controversial 2000 Presidential election due to ballot design.

    Image Upload 1
  8. Feedback: Unhelpful feedback example:
    Tells the user they have a problem but offers no direction in what to do about the problem.Image Upload 2
  9. Feedback: good feedback
    Good feeback: What did my action do?User susieQ has been added to the class roster.
  10. Execution-Evaluation cycle (Don Norman)

    Image Upload 3
    To get something done:

    • Start with some notion of what is wanted—the goal that is to be achieved. 
    • Then, you have to do something to the world, that is, take action to move yourself or manipulate someone or something.
    • Finally,you check to see that your goal was made.
  11. The Seven Stages of Action
    • 1    Forming the Goal
    • **Norman's Stages of Execution**
    • 2    Forming the Intention
    • 3    Specifying an Action Sequence        
    • 4    Executing an Action
    • **Norman's stages of evaluation**
    • 5    Perceiving the State of the World
    • 6    Interpreting the State of the World
    • 7    Evaluating the Outcome
  12. Norman's Stages of Execution:
    • 2    Forming the Intention
    • 3    Specifying an Action Sequence        
    • 4    Executing an Action
  13. Norman's stages of Evaluation
    • 5    Perceiving the State of the World
    • 6    Interpreting the State of the World
    • 7    Evaluating the Outcome
  14. Gulf of Execution:
    • What we do to the world.
    • Image Upload 4
  15. Gulf of Evaluation:
    • Comparing what happened to what we wanted to happen.
    • Image Upload 5
  16. Execution:
    • Goals
    • 1: What we want to happen   
    • 2: An intention to act so as to achieve the goal   
    • 3: The actual seq. of actions that we plan to do.   
    • 4: The physical execution of that action sequence.   
    • V
  17. Execution (chart/graph):
    Image Upload 6
  18. Evaluation:
    • Goals:   
    • 4: What we want to happen
    • 3: Evaluation of the interpretations with what we expected to happen   
    • 2: Interpreting the perception according to our expectations   
    • 1: Perceiving the state of the world
    • ^   
  19. Evaluation (chart/graph):
  20. Image Upload 7
  21. The Seven Stages: The whole chart:
    Image Upload 8
  22. The Psychopathology of computers (Britain 1976)
    • On December 10th, police failed to change the speed limit signs when fog descended
    • 34 vehicles crashed
    • 3 people killed11 people injured and trapped in their vehicles
    • motorway closed for 6.5 hours
  23. Britain 1976 (Famous Moterway Mishap); Example problems:
    cryptic input codes

    • XR300/1: change (X)  sign 300 on highway M5 (R) to code 1
    • i.e. change particular sign to indicate fog condition

    no feedback

    operator entered command, no visible effect of system response

    cryptic error messages

    “Error code 7”

    teletype machine was old text illegible

    people could not see what they typed or system’s reply

    operator overloaded with other chores

    also handled radio and telephone traffic
  24. Outcome of Britains Moterway Misshap of 1976:
    • People on the higher echelon denied responsibility
    • Ruled operator error
  25. What did Donald Norman say in regard to Mistakes and Design?
    We often blame users when we should blame designers.
  26. Tractor Problem and "Driver Error"
    Early tractor design suffered from:

    • high center of gravity
    • narrow front wheel base.


    • un-surfaced and
    • rough hilly


    • works long hours
    • works quickly

    Propensity for accidents: used to be called user error. designs have gotten better there have been less accidents:

    Modern Tractor:

    • wider wheel base
    • roll cage
    • low center of gravity
  27. Early tractor design suffered from:
    • high center of gravity
    • narrow wheel base
  28. Farmers worked on Terrain that was ____ & ___, ___
    un-surfaced & rough, hilly
  29. Conditions of farmers:

    • long hours
    • quickly
  30. In the past tractor mishaps and accidents were ruled out as:_____ _____.
    drivers errors.
  31. As tractor design has evolved progressed:
    Now have:

    • roll cages
    • lower center of gravity
    • wider wheel base
  32. Tractor design has progressed in such a way that:
    There are less accidents with the tractors -- who's to blame really; the farmer or the designer???
  33. The seven stages of action prompt the following design questions:
    How easily can one:

    • determine the function of the device?
    • tell what actions are possible?
    • determine mapping from intention to physical movement?
    • perform the action?
    • tell  what state the system is in?
    • tell if system is in desired state?
    • determine mapping from system state to interpretation?
  34. The significance of these questions can be summed up as the following principles of good design:
    Principals of good design...fallout of the seven questions as follows:

    • Visibility.  By looking, the user can tell the state of the device and the alternatives for action.
    • A good conceptual model.  The designer provides a good conceptual model for the user, with consistency in the presentation of operations and results and a coherent, consistent system image.
    • Good mappings.  It is possible to determine the relationship between actions and results, between the controls and their effects, and between the system state and what is visible.
    • Feedback.  The user receives full and continuous feedback about the results of actions.
Card Set
Milestone 3 more.
Chapter 2 of the Norman book: