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Human-Computer Interaction
Lecture 10
Examples Illustrating Stages in the Theory of Action.


The issue covered in this lecture is the PROBLEMS that may arise in each of the stages in the Theory of Action (ToA).
The following are some of the examples brought up during the lecture.

The ToA Stages (partial)
  1. Decision
  2. Planning
  3. Translation
  4. Execution
  5. Segmentation




Decision

Possible Problem:

  • User fail to perform an action which they would have wished to do.

    • Example:

  • Failing to save document before quiting.
  • Failing to adjust settings before printing.

    • Suggested Solutions:

  • Automatic saving - e.g. saving changes at specified time interval
  • Visual interfaces - e.g. positioning of icons in declared temporary or permanent area.





    • Planning

    Possible Problem:

  • Missing out on some steps during planning.
  • Inserting text to the bottom or right-side of the page.

    • Example:

  • Cut and paste procedure.
  • Printing dialogue box.

    • Suggested Solutions:

  • Executing a command which will lead to a string of steps to be performed.





    • Translation

    Possible Problem:

  • Not being able to identify the command name for the desire action - e.g. graphs vs chart
  • Not being able to remember the command itself, especially for command line driven applications.

    • Example:

  • Display menu vs command line - e.g. MacOS vs Unix.

    • Suggested Solutions:

  • On-line help to translate command names.
  • Distinction of command options by length and letters.





    • Execution

    Possible Problem:

  • Too much on screen movement for on-screen applications - e.g. MacOS

    • Example:

  • Dragging an icon to the Wastebasket, especially on a big screen.
  • Keyboard design.

    • Suggested Solutions:

  • Alternate command on the menu to place items in the Wastebasket.
  • Isolate dangerous keys from the frequently used ones.





    • Segmentation

    Possible Problem:

  • Colour appearing differently in different machine.
  • Dark font on dark background.
  • Font style and size used in the wrong occasion.

    • Example:

  • Programmers vs office clerks.
  • Radio buttons and their labels.

    • Suggested Solutions:

  • Dark fonts on light background.
  • Use standardise colour and use single shade.
  • Font style and size should be chosen with consideration of the ultimate users.





    • Links to related materials

    Previous Lecture: Lect 9
    Next Lecture: Lect 11
    Index Page
    Main Page





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