HCI
User Interfaces
Human Factors
• Design for users who may (will) not be
programmers
• Goal – make the computer transparent to the
user; similar to a pencil when writing
Objectives for transparency
• Understand User’s own model of what each
task requires
• And, the environment in which they work
• http://www.sju.edu/~jhodgson/gui/cogn.html
Wrong Paths
• Forgetting the user – Do not design for what
you know
• Give users control – Do not control the user
• Too many features at the top level – think of
evolution of VCR (1985)
– But make sure frequently used features are readily
available
Successes
• Intuitive
– Use bitmaps of logos, such as Visa and
MasterCard, on payment buttons
• Speed and responsiveness
– Avoid repainting the screen unless absolutely
necessary
– Have all field validations occur on a whole-screen
basis instead of field-by-field basis
• Mnemonics, accelerator keys, toolbar buttons (icons)
Understand People
• Applications must reflect the perspectives and
behaviors of the users
• People learn more easily by recognition than
by recall
• Provide a list of data values to select from –
rather rely on user memory
Messages
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Information
Warning
Question
Error
Example of Reserved Words
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OK
Cancel
Close
Exit
Help
Save
Save As
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Undo
Copy
Cut
Paste
• Mnemonic keystrokes
• Shortcut keystrokes
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Design for consistency
Provide visual/audible feedback
Keep text clear
Provide traceable paths
Provide keyboard support
Look and feel consistency