Finishing Norman

1
Finishing Norman

• COMM/INFO 345
• http//www.infosci.cornell.edu/courses/info345/200
  7sp/
• http//commune.cit.cornell.edu/wikis/COMM345/

2
Last time

• Reflection on critical design
• Design lifecycles iteration evaluation
• Group assignments, and deliverable 1

3
Today

• Finishing Norman
• Normans high-level design principles
• With some HCI-specific bits
• Interface Hall of Fame/Shame
• The central role of error
• Next a bit of cognitive science

4
High level design values

• Affordances (a reminder)
• Mappings
• Visibility
• Feedback
• Remember, principles are like opinions
• DIS textbook
• Bruce Tognazzini http//www.asktog.com/basics/firs
  tPrinciples.html

5
Affordances are constraints

• Signs are warnings of design weakness!

6
Affordances in HCI

• Affordances are physical
• How to leverage the idea in virtual contexts?
• Greyed out boxes
• Cultural affordances?
• Coding Horror native vs. cross-platform GUI
• The world looked like Yahoo

7
Tradeoffs and mappings
8
Mappings and HCI

• Start with the numbers 1, 2, 3, ..., 9
• Alternate turns, take one number at a time
• A player wins with any 3 numbers that sum to 15
• e.g., 1, 3, 9, 5 wins because 195 equals 15
• If numbers are all used with no winner, the game
  is a draw

9
OK, now try it another way
3
4
8
1
5
9
2
6
7
10
Mappings in HCI

• Good mappings give value
• Indirect action requires good representations
• So does working with information
• How do we do mappings in HCI?
• Labels
• Metaphor
• Links

11
Labels
12
(No Transcript)
13
Metaphors are imperfect
14
which can give them power
15
Links (information scent")
16
Visibility

• A simple principle make people aware

17
Visibility (aha, things overlap)
18
Icons visibility meets mappings

• Icons make lots of commands visible
• But is this a good thing?
• Recognition vs. recall
• Tool tips knowledge in the world

19
Issues with icons

• Small size is a big constraint
• People different words, same thing
• Icons are small targets (Fitts law)
• Some solutions
• Consistency
• Mobility
• Customizability
• Good art (sorry, cant help you here!)

20
Why doesnt enter work?
21
Feedback in HCI

• People who feel no pain
• Designs that fail to provide feedback
• Did I save?
• Markup vs. WYSIWYG
• How to provide feedback?

22
Interface hall of f(sh)ame

• Our goal become attuned
• Find examples of good and bad design
• Artifacts are fine remember, design has many
  universal aspects
• Software and websites perhaps better
• Explain why, in terms of some set of desirable
  attributes or principles
• Suggest how to fix it.

23
Visibility and the alarm clock
24
What if its dark or Im ½ blind?
25
Suggestion improve visibility
PM
ALARMOFF
And lets not get started on time setting
controls see Normans brutal critique of the
digital watch
26
Now, you do it

• Find an example
• Critique it
• Suggest improvements
• Use a little more text than I did, because people
  will view these on the wiki
• Anyone want to do them in class?

27
Text editing in the bad old days
28
Seven stages of action
Goals
Evaluation of the interpretations
Intention to act
Interpreting the perception
Sequence of actions
Execution of the action sequence
Perceiving the state of the world
The World
29
Gulfs of Execution Evaluation
Goals
Evaluation of the interpretations
Intention to act
GULF OF EXECUTION
Interpreting the perception
GULF OF EVALUATION
Sequence of actions
Execution of the action sequence
Perceiving the state of the world
The World
30
The Gulf of Execution

• Does the system provide actions that correspond
  to the users intentions?
• The difference between intentions and allowable
  actions is the Gulf of Execution

31
The Gulf of Evaluation

• Does the system provide a representation that can
  be readily perceived and interpreted in terms of
  the users intentions and expectations?
• The Gulf of Evaluation reflects the amount of
  effort that the person must exert to interpret
  the system state and determine how well the
  intentions have been met.

32
Seven Stages as Design Aids
Determine the function of the system?

• Think about how affordances, feedback,
  visibility, and mappings fit in here

Tell if the system is in the desired state?
Tell what actions are possible?
Determine a mapping from system state to
interpretation
Determine a mapping from intention to physical
action?
Perform the action?
Tell what state the system is in?
33
When errors do happen

• notes to be added

34
Main ideas from these notes

• Normans principles of good product design do
  (mostly) translate to HCI
• Think like a designer! The Hall of Fame and Shame
  are everywhere in your life
• Use the force, or at least the principles
• To err is human, so we must plan ahead