1. Norman Chapter 1 Psychopathology
Jeff Offutt,
edited by Paul Ammann
SWE 205
Software Usability and Design

2. Psychopathology Huh ? Anybody know what that means?
the study of mental illness or mental distress
the manifestation of behaviors and experiences that may be indicative of mental illness or psychological impairment
Translation: Everyday designs have pathologies
18-Apr-19
© Jeff Offutt

3. 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
Door handles should not be hidden
Mapping : How what you want to do maps to what you can do
Think about the mapping for the class seating chart
18-Apr-19
© Jeff Offutt

4. Basic Concepts (2)
Affordance : The properties of an object in relation to an agent (user)—especially the fundamental properties that determine how it can be used
What can the specific user do with the object?
Affordances vary by user!
A typical chair is for sitting, although perhaps not by very small children
We say, “This chair affords sitting (by adults)”
A chair is also for moving from place to place, but perhaps not by a frail person
Glass affords seeing through (for an agent with sight)
18-Apr-19
© Jeff Offutt

5. A UI that requires a user manual has already failed
Basic Concepts (3)
Signifier : Communicates what action should take place
The vertical bar on the door signifies an affordance: an agent can pull the door open.
“In design, signifiers are more important than affordances.” (page 19)
False signifiers abound (this is usually bad…)
A UI that requires a user manual has already failed
18-Apr-19
© Jeff Offutt

6. A UI that requires a user manual has already failed
Basic Concepts (4)
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
18-Apr-19
© Jeff Offutt

7. Basic Concepts (5)
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
18-Apr-19
© Jeff Offutt

8. 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!
18-Apr-19
© Jeff Offutt