1. Norman Chapter 4 Knowing What To Do
Jeff Offutt
SWE 205
Software Usability and Design

2. People Expect Simplicity
When a task is simple, people expect a simple UI
Making a phone call is simple
Devices that do a lot of things are harder
Multi-purpose devices
The most common action should be the easiest to find
It is okay for rare actions to be harder
When we encounter a new device, we either :
transfer knowledge of how to use a similar device or
seek instructions
11-Nov-18
© Jeff Offutt

3. Syntactic Signals
The UI design must explicitly indicate what should be done
Physical or syntactic constraints limit our actions
Affordances of controls—that is, the controls look familiar
Down arrows look like drop downs
“B” looks like bold face
If the UI design matches the user’s mental model and offers good controls, users will not need help
11-Nov-18
© Jeff Offutt

4. Doors & Switches Dozens of ways to open doors
A sign on a door that tells us how to open it is a very short instruction manual
If a simple device needs a manual, the UI is a failure
Doors on the Paris subway do not open automatically
Switches have two basic problems
Which switch controls which function (grouping) ?
Which switch controls which device (mapping) ?
11-Nov-18
© Jeff Offutt

5. Door Opening Confusion
A push bar for an emergency door …
This is much clearer
When under stress, people revert to stereotypes
But which side to push ?
11-Nov-18
© Jeff Offutt

6. My Very Own “Norman Door”
How do you open it?
11-Nov-18
© Jeff Offutt

7. Light Switch Device Confusion
My parents’ house,
Light arrangement on the ceiling
Light switch arrangement one
Light switch arrangement two
Kitchen
Porch
11-Nov-18
© Jeff Offutt

8. Summary: Visibility and Feedback
Make relevant parts visible
Feedback
Give each action an immediate and obvious effect
11-Nov-18
© Jeff Offutt