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Norman – design of everyday things

• Objects
  • affordances
    • “the perceived and actual properties of the thing, primarily those fundamental properties that determine just how the thing could possibly be used. “
    • “when affordances are taken advantage of, the user knows what ot do just by looking: no picture, label, or instruction is required. Complex things may require explanation, but simple things should not. When simple things need pictures, labels, or instructions, the design has failed.”
  • conceptual models
    • transparent design lets people create conceptual models of how things work. pushing on a bike pedal results in the wheel turning. however, a watch with many functions and only a few buttons creates a situation where there is no obivious mapping between the controls and the functions.
    • refrigerator/freezer example
  • visibility
    • phone example: hiding functions behind obscure key strokes.
  • mapping
    • natural mappings: make the relationship between control and results obvious by “taking advantage of physical and cultual standards”.
      • example car seat control that looks like a car seat shape makes controls easy.
      • example: twist nob for front/back sound mapping makes controls not natural.
  • feedback
    • old phone example. buttons makes tones when pressed, call progress was beeps and clicks before connecting, and user's voice was fed back into the earpiece to help the person talk at the appropriate volume.
    • new phones harder to use because of more features and less feedback.
• Users
  • falsely blaming yourself
    • happens when you run into problems and you assume that it was your own fault
    • goes against the human tendency to blame your environment for failures.
    • might be caused by poorly designed technology creating a situation where users have 'learned' they are not good at working with technology.
  • errors should be easy to detect by users, minimal consequences, and if possible reversible.
  • once people have a mental explanation for a situation they often can logically explain even details that should indicate their mental explanation is wrong.
• the seven stages of action
  • forming the goal
  • forming the intention specifying an action
  • executing the action
  • perceiving the state of the world
  • interpreting the state of the world
  • evaluating the outcome
• gulf of execution and evaluation
• “the seven stages of action as design aids
  • 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.”

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