Transcript Norman Ch1

Norman Chapter 1
Psychopathology
Jeff Offutt
http://www.cs.gmu.edu/~offutt/
SWE 205
Software Usability and Design
Psychopathology
• Huh ?
• Anybody know what that means?
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1.
the study of mental illness or mental distress
2.
the manifestation of behaviors and experiences
that may be indicative of mental illness or
psychological impairment
© Jeff Offutt
2
Basic Concepts
• Well designed objects are simple to interpret and
understand
– They match our expectations
• Visibility : The correct parts to any object must be
visible and must convey the correct message
• Mapping : How what you want to do maps to
what you can do
• Affordance : The properties of a thing—especially
the fundamental properties that determine how it
can be used
– A chair is for sitting, a classroom is for sleeping
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© Jeff Offutt
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Basic Concepts (2)
• Correlation : Two things happen at the same time
• Causality : One thing causes the other
– Humans naturally mix these
– No, cold weather does not give us colds !
• Conceptual model : A mental simulation of how
something works
A UI that requires a user manual has
already failed
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© Jeff Offutt
4
Basic Concepts (3)
• Mental model : How the user expects something to
behave
– If the UI does not match the mental model … fail
• Natural mapping : Using physical analogies and
cultural standards to map the UI to the
implementation
• Feedback : Telling the user that something
happened, and what
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© Jeff Offutt
5
Why is Designing UIs Hard ?
• Good UIs take time to design
– Many programmers are lazy
• Designing a good UI requires thinking like the user
instead of an engineer
– Engineers often think they are users
• Different users want different things
Engineers love features
They want to do everything the
technology allows!
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