1. More on Design of Everyday Things

2. Designer and user models
Goal: user model and design model should be identical
Design Model
User Model
Communication from designer to user is via the system image
So system image must lead user to acquire a user model equal to the design model
Designer
User
System
System Image

3. So how does a designer help users acquire the right model?
Visibility
Affordances
Mappings
Constraints
Feedback

4. So how does a designer help users acquire the right model?
Visibility - Don’t hide things. Make the status visible
Affordances
Mappings
Constraints
Feedback

5. So how does a designer help users acquire the right model?
Visibility - Don’t hide things. Make the status visible
Affordances - the design aspect of an object which suggests how the object should be used
Mappings
Constraints
Feedback

6. So how does a designer help users acquire the right model?
Visibility - Don’t hide things. Make the status visible
Affordances - the design aspect of an object which suggests how the object should be used
Mappings - Take advantage of physical analogies
Constraints
Feedback

7. Constraints Limit the range of possible actions Physical Constraints
Only some possibilities are physically possible (only one way the battery in my camera)
Semantic Constraints
Only some possibilities make sense
Cultural Constraints
Only some possibilities are acceptable
Logical Constraints
General principles: e.g., every part should be used

8. Feedback Remember that people will build models
And feedback leads to causal models: “if Y happened after X, then X caused Y”
So provide the proper feedback immediately: respond to user actions – don’t hide the results!
Did I press the button? (visual and/or audio feedback)
All actions should have effects
Promote exploration
Provide meaningful error messages

9. Wii I recently bought a used original Wii.
While trying to setup the device to use my wireless I received:
Wii Error Code 51330
What does that mean?

10. Wii It turns out that it means I had entered my password incorrectly.
BUT, I had to search the internet (see the catch 22 on this) to learn that.
Say what you mean and mean what you say

12. Dr. Diesburg’s TV Say what you mean and mean what you say.
Make sure that end users don’t see error messages that they can’t understand (and arguably shouldn’t see).

13. White House Form

14. Last resort - standardization
Fewer things to memorize
Quicker to learn
Clocks should run clockwise
But note that standards are culture-dependent!

15. “Standards” and cultures
What does the color red mean?
US – danger, warning, …
India – purity
What color should a wedding dress be?
US – white
India – red & yellow
How do you turn on a faucet?
US – counter-clockwise
UK – clockwise
Problems with icons – mailboxes, trashcans, …

16. Applying the principles

17. A usable design - scissors
Affordances
Holes for something to be inserted
Constraints
Big hole for several fingers, small hole for thumb
Mappings
Between holes and fingers suggested and constrained by appearance
A cultural standard
Conceptual model
Implications of actions clear – feedback is immediate

18. How do I pump the gas?

19. “Push To Start”

20. Design Principle Problems
Visibility
Affordances

21. When does the bottom light go on?

22. Design Principle Problems
Conceptual Model
Feedback

23. Setting Options in MS Word

26. Design Principle Problems
Conceptual model – “What happened?!?”

27. Which string turns on the fan, which turns on the light?

28. Design Principle Problems
Mappings

29. What’s that thing in the corner?

30. It’s a mop sink!

31. Design Principle Problems
Affordances
Conceptual Model
Standardization

32. How do you raise/lower this screen?

34. Design Principle Problems
Conceptual Model
Mappings

35. Next Steps For next time Upcoming Assignments DOET Chapters 5 and 6
Begin to talk with others about teams
Upcoming Assignments
Friday, September 8 – Team Formation