1. Design of Everyday Things
Don Norman on Design & HCI

2. Summary Darn these hooves! I hit the wrong switch again!
Who designs these instrument
Panels, raccoon?!

3. Don Norman
Professor at Northwestern and Principal of Nielsen Norman group
Previously Professor at UCSD, senior positions at Apple & HP
ACM/CHI Lifetime Achievement Award
Prolific author

4. Discussion
What did you take away from DOET book so far?

5. Here are some Affordances are important
Minimize the gulf of interpretation and gulf of execution
Use natural mappings
Make state visible
Use a conceptual model that makes sense
Provide feedback

6. Daily Challenges How many of you can use all the functionality in your
VCR
Digital watch
Copy machine
Stereo system
Plumbing fixtures

7. Hall of Shame Example Leitz slide projector
To move forward, short press
To move backward, long press
What happens when you get frustrated?

8. Fun Examples Phones How do you - transfer a call - change volume
- store a number
- ...

10. Changing Ringer Volume
Press “Program”
Press “6”
Set volume
Low - Press “1”
Medium - Press “2”
High - Press “3”

11. Much better…

12. Important Concepts Affordances Visibility Conceptual models Mapping
Feedback
Constraints

13. Affordances
Perceived and actual properties of an object that determine how it could be used
Chair is for sitting
Button is for pushing
Door handle is for ….
Scroll arrow is for …
Icon is for …

14. Door Opening Affordances1 2 3 4 5
Which doors are easy to open?
Which doors are hard to open?
Why? 6 7

15. Affordances in interfaces
Interfaces are virtual and do not have ‘real’ affordances like physical objects
Interfaces have ‘perceived’ affordances
Learned conventions of arbitrary mappings between action and effect at the interface
Some mappings are better than others

16. Mantra
Complex things may need explanation, but simple things should not
If a simple thing requires instructions, it is likely a failed design

17. Designing for People Norman’s 2 main principles
Provide a good conceptual model
Make things visible
Affordances is part of this

18. Conceptual Models People build their own systems of how things work
Example - thermostat
Designer can help user foster an appropriate conceptual model
Appearance, instructions, behavior...

19. Conceptual Models Mental models are not always right Two Classes:
Functional model
Stimulus - response
“Press the accelerator once, then turn the key”
At surface or superficial level
Structural model
Deeper sense of why it happens, not just what happens
“Press the accelerator to engage the automatic choke on a carburetor”

20. Visibility When functionality is hidden, problems in use occur
Occurs when number of functions is greater than number of controls
When capabilities are visible, it does not require memory of how to use
Recognition over Recall
in the world vs. in the head

21. Simple Example
Bathroom faucets
Two functions
Hot/cold
Flow

22. Bathroom Faucets 1 Can you figure out how to use it? Are two functions
clear and
independent?

23. Bathroom Faucets 2 Can you figure out how to use it? Are two functions
clear and
independent?

24. Bathroom Faucets 3 Can you figure out how to use it? Are two functions
clear and
independent?

25. My parent’s microwave
5:45

26. My microwave

27. About that VCR…
That old joke - “how many of you have a VCR that is blinking 12:00?” :-)
Still true today :-(

28. Which is Faster for Setting Time?

29. Two Important Principles
Mapping
Feedback

30. Mapping Relationship between control and action/result in the world
Take advantage of physical analogies or cultural understandings
Good:
Car, various driving controls
Mercedes Benz seat adjustment example
Bad
Car stereo - Knob for front/back speakers

31. Which is better? or

32. Mapping Example: Euros
Size::value

33. Mapping Example: Stove
Which controls which?

34. Why not this?

35. Yikes!

36. Why Not Design Better Stove Speakers Physical, monetary,
convenience, etc.,
constraints dictate
otherwise

37. Feedback Sending information back to the user about what has been done
Includes sound, highlighting, animation and combinations of these
e.g. when screen button clicked on provides sound or red highlight feedback:
“ccclichhk”

38. Example Scissors Affordances - Insert something into holes
Constraints - Bigger hole for
several fingers, small for thumb
Mapping - How to insert fingers
into holes suggested by visible
appearance
Conceptual model - Suggested by
how parts fit together and move
Scissors

39. Execution-Evaluation cycle
Norman (DOET, p. 46)
Gulf of
Execution
User
Goals
Physical
System
Gulf of
Evaluation

40. Goals, Execution, Evaluation
What we
want to happen
Execution
What we
do to the world
Evaluation
Comparing what happened
with what we wanted to happen
(Gulf of Execution)
(Gulf of Evaluation)
Physical System

41. Execution Physical System Goals What we want to happen
An intention to act
so as to achieve the goal
The actual sequence of actions
that we plan to do
The physical execution of that
action sequence
Physical System

42. Evaluation Physical System Goals What we want to happen
Evaluation of the interpretations
with what we expected to happen
Interpreting the perception according
to our expectations
Perceiving the state
of the world
Physical System

43. Seven Stages - All Together
Goals
What we
want to happen
An intention to act
so as to achieve the goal
Evaluation of the interpretations
with what we expected to happen
The actual sequence of actions
that we plan to do
Interpreting the perception according
to our expectations
The physical execution of that
action sequence
Perceiving the state
of the world
Physical System

44. Implications – Which Gulf does these Address?
Make current state and action alternatives visible
Need good conceptual model with consistent system image
Interface should include mappings that reveal relationships between stages
User should receive continuous feedback
Provide affordances

45. Goal: Minimize Gulfs Gulf of Execution Gulf of Evaluation
Conceptual model
Affordances
Natural mappings
Gulf of Evaluation
Make state visible
Feedback

46. Try and Try Again
Norman thinks that it often takes 5 or 6 tries to get something “right”
Simply may not have that luxury in a competitive business environment