This document summarizes a lecture on user interface principles. It covers topics like vision, cognition, memory, action, and emotion as they relate to designing interfaces. Specific principles discussed include proximity, similarity, continuity, symmetry, structure, prominence, sequence, clutter, minimalism, affordances, mental models, metaphors, and direct manipulation. The goal is to design intuitive interfaces that are easy for users to understand and interact with.

1. 3 — User Interface Principles
From Code to Product
gidgreen.com/course

2. Lecture 3
• Introduction
• Vision
• Cognition
• Memory
• Action
• Emotion
From Code to Product Lecture 3 — UI Principles — Slide 2 gidgreen.com/course

3. User Interface
“The aspects of a computer system or
program which can be seen (or heard or
otherwise perceived) by the human user,
and the commands and mechanisms the
user uses to control its operation and input
data.”
— Free On-Line Dictionary of Computing
From Code to Product Lecture 3 — UI Principles — Slide 3 gidgreen.com/course

4. Other terms
• Graphical user interface
• User experience
• Interaction design
• Human-computer interaction
• Usability
• Information architecture
From Code to Product Lecture 3 — UI Principles — Slide 4 gidgreen.com/course

5. Layers of a product
Core
From Code to Product Lecture 3 — UI Principles — Slide 5 gidgreen.com/course

6. The problem
I want to see MOV r0, #10
this guy’s face ADD r0, r0, r1
How do we bridge this gap?
From Code to Product Lecture 3 — UI Principles — Slide 6 gidgreen.com/course

7. The solution
I want to see MOV r0, #10
this guy’s face ADD r0, r0, r1
I can use Skype Function call in
on my mobile Skype app
I will press his Touch event
name in the app detected
From Code to Product Lecture 3 — UI Principles — Slide 7 gidgreen.com/course

8. Channels of communication
Pressing buttons
Flashing lights
Pointing on screen
Image on screen
Talking and singing
Playing sound
Being photographed
Vibration
Moving the device
From Code to Product Lecture 3 — UI Principles — Slide 8 gidgreen.com/course

9. Lecture 3
• Introduction
• Vision
• Cognition
• Memory
• Action
• Emotion
From Code to Product Lecture 3 — UI Principles — Slide 9 gidgreen.com/course

10. Vision
From Code to Product Lecture 3 — UI Principles — Slide 10 gidgreen.com/course

11. Proximity
From Code to Product Lecture 3 — UI Principles — Slide 11 gidgreen.com/course

12. Similarity
From Code to Product Lecture 3 — UI Principles — Slide 12 gidgreen.com/course

13. Similarity
From Code to Product Lecture 3 — UI Principles — Slide 13 gidgreen.com/course

14. Proximity
From Code to Product Lecture 3 — UI Principles — Slide 14 gidgreen.com/course

15. Similarity
From Code to Product Lecture 3 — UI Principles — Slide 15 gidgreen.com/course

16. Similarity
From Code to Product Lecture 3 — UI Principles — Slide 16 gidgreen.com/course

17. Continuity
From Code to Product Lecture 3 — UI Principles — Slide 17 gidgreen.com/course

18. Symmetry
From Code to Product Lecture 3 — UI Principles — Slide 18 gidgreen.com/course

19. Continuity and Symmetry
From Code to Product Lecture 3 — UI Principles — Slide 19 gidgreen.com/course

20. Ambiguity
From Code to Product Lecture 3 — UI Principles — Slide 20 gidgreen.com/course

21. Grids
From Code to Product Lecture 3 — UI Principles — Slide 21 gidgreen.com/course

22. Photo by Sha Sha Chu
Figure and Ground
From Code to Product Lecture 3 — UI Principles — Slide 22 gidgreen.com/course

23. Figure and Ground
From Code to Product Lecture 3 — UI Principles — Slide 23 gidgreen.com/course

24. Hierarchy
1
5
4
3
2
From Code to Product Lecture 3 — UI Principles — Slide 24 gidgreen.com/course

25. Movement
From Code to Product Lecture 3 — UI Principles — Slide 25 gidgreen.com/course

26. Tunnel Vision
Photo by Ali Khurshid
From Code to Product Lecture 3 — UI Principles — Slide 26 gidgreen.com/course

27. Tunnel Vision
From Code to Product Lecture 3 — UI Principles — Slide 27 gidgreen.com/course

28. Structure
Thank you for your reservation. Your indoor
table has been booked for four people at 8 in
the evening on Tuesday January 6th 2012 at
Sushi Samba. The address is 245 Park Avenue
South, between East 19th and 20th Street. You
must arrive by 8.15pm to maintain your
reservation. In the event of problems, please
call the restaurant on 2124759377. Note that
the minimum charge is $50 per person.
From Code to Product Lecture 3 — UI Principles — Slide 28 gidgreen.com/course

29. Structure
Thank you for your reservation.
Sushi Samba Date Tue 6 Jan
245 Park Avenue South
(212) 475–9377 Time 8.00pm
Latest 8.15pm
People 4
Table Indoors
Minimum $50/person
From Code to Product Lecture 3 — UI Principles — Slide 29 gidgreen.com/course

30. Structure
Thank you for your reservation.
Sushi Samba 245 Park Avenue South (212) 475–9377
Date Tue 6 Jan
Time 8.00pm
Latest 8.15pm
People 4
Table Indoors
Minimum $50/person
From Code to Product Lecture 3 — UI Principles — Slide 30 gidgreen.com/course

31. Prominence
From Code to Product Lecture 3 — UI Principles — Slide 31 gidgreen.com/course

32. Prominence
1
2
3
4
From Code to Product Lecture 3 — UI Principles — Slide 32 gidgreen.com/course

33. Sequence
Source: xkcd.com
From Code to Product Lecture 3 — UI Principles — Slide 33 gidgreen.com/course

34. Sequence
From Code to Product Lecture 3 — UI Principles — Slide 34 gidgreen.com/course

35. Sequence
From Code to Product Lecture 3 — UI Principles — Slide 35 gidgreen.com/course

36. Sequence
From Code to Product Lecture 3 — UI Principles — Slide 36 gidgreen.com/course

37. Sequence
From Code to Product Lecture 3 — UI Principles — Slide 37 gidgreen.com/course

38. Clutter
Photo by Metro Centric
From Code to Product Lecture 3 — UI Principles — Slide 38 gidgreen.com/course

39. Clutter
From Code to Product Lecture 3 — UI Principles — Slide 39 gidgreen.com/course

40. Minimalism
“Perfection is achieved, not
when there is nothing more to
add, but when there is nothing
left to take away.”
— Antoine de Saint-Exupéry
From Code to Product Lecture 3 — UI Principles — Slide 40 gidgreen.com/course

41. Minimalism
The face of a $200b company
From Code to Product Lecture 3 — UI Principles — Slide 41 gidgreen.com/course

42. Visual affordance
Source: ChrisElyea.com
From Code to Product Lecture 3 — UI Principles — Slide 42 gidgreen.com/course

43. Visual affordance
From Code to Product Lecture 3 — UI Principles — Slide 43 gidgreen.com/course

44. A few words about sound…
• Don’t do it, unless…
– Audio/video player
– Game or other experiential product
– Alert from desktop/mobile app
– Phone number entry
– Reassuring key clicks
– Accessibility
• Let users switch it off
From Code to Product Lecture 3 — UI Principles — Slide 44 gidgreen.com/course

45. Lecture 3
• Introduction
• Vision
• Cognition
• Memory
• Action
• Emotion
From Code to Product Lecture 3 — UI Principles — Slide 45 gidgreen.com/course

46. Cognition
Consider babies Ben and Sam.
They were born to the same woman,
on the same day, in the same month
and the same year.
Yet they're not twins.
How can this be?
From Code to Product Lecture 3 — UI Principles — Slide 46 gidgreen.com/course

47. The ideal interface
From Code to Product Lecture 3 — UI Principles — Slide 47 gidgreen.com/course

48. Implementation model
From Code to Product Lecture 3 — UI Principles — Slide 48 gidgreen.com/course

49. Mental model
From Code to Product Lecture 3 — UI Principles — Slide 49 gidgreen.com/course

50. Talk to people
From Code to Product Lecture 3 — UI Principles — Slide 50 gidgreen.com/course

51. Metaphors
From Code to Product Lecture 3 — UI Principles — Slide 51 gidgreen.com/course

52. Overly literal metaphors
From Code to Product Lecture 3 — UI Principles — Slide 52 gidgreen.com/course

53. Mapping
Source: UXHero.com
From Code to Product Lecture 3 — UI Principles — Slide 53 gidgreen.com/course

54. Mapping





From Code to Product Lecture 3 — UI Principles — Slide 54 gidgreen.com/course

55. Unnecessary burdens
From Code to Product Lecture 3 — UI Principles — Slide 55 gidgreen.com/course

56. Unnecessary burdens
adminapps.utep.edu/changepassword
From Code to Product Lecture 3 — UI Principles — Slide 56 gidgreen.com/course

57. Examples + Defaults
From Code to Product Lecture 3 — UI Principles — Slide 57 gidgreen.com/course

58. Interruptions
From Code to Product Lecture 3 — UI Principles — Slide 58 gidgreen.com/course

59. Interruptions
From Code to Product Lecture 3 — UI Principles — Slide 59 gidgreen.com/course

60. Lecture 3
• Introduction
• Vision
• Cognition
• Memory
• Action
• Emotion
From Code to Product Lecture 3 — UI Principles — Slide 60 gidgreen.com/course

61. Memory
From Code to Product Lecture 3 — UI Principles — Slide 61 gidgreen.com/course

62. Two types of memory
Short-term Long-term
Contents Current task Life history
Capacity Tiny (7 items?) Huge
Recall Instant Slow
Retention Short Eternal
Accuracy Perfect Poor
Just like… CPU cache Lots of floppy disks
From Code to Product Lecture 3 — UI Principles — Slide 62 gidgreen.com/course

63. Modes
From Code to Product Lecture 3 — UI Principles — Slide 63 gidgreen.com/course

64. Modes
From Code to Product Lecture 3 — UI Principles — Slide 64 gidgreen.com/course

65. Modes
Drawing Selection
From Code to Product Lecture 3 — UI Principles — Slide 65 gidgreen.com/course

66. Modes
From Code to Product Lecture 3 — UI Principles — Slide 66 gidgreen.com/course

67. Context
Photo by jima
From Code to Product Lecture 3 — UI Principles — Slide 67 gidgreen.com/course

68. Context
From Code to Product Lecture 3 — UI Principles — Slide 68 gidgreen.com/course

69. Instructions
Image by Zoagli
From Code to Product Lecture 3 — UI Principles — Slide 69 gidgreen.com/course

70. Instructions
From Code to Product Lecture 3 — UI Principles — Slide 70 gidgreen.com/course

71. Instructions
From Code to Product Lecture 3 — UI Principles — Slide 71 gidgreen.com/course

72. Comparisons
From Code to Product Lecture 3 — UI Principles — Slide 72 gidgreen.com/course

73. Offer, don’t ask
From Code to Product Lecture 3 — UI Principles — Slide 73 gidgreen.com/course

74. Offer, don’t ask
Car$ /bin/set-temperature 73f
Temperature set OK
Car$ /bin/rear-demister on
COMMAND NOT RECOGNIZED
From Code to Product Lecture 3 — UI Principles — Slide 74 gidgreen.com/course

75. Overviews
From Code to Product Lecture 3 — UI Principles — Slide 75 gidgreen.com/course

76. Autosuggest
From Code to Product Lecture 3 — UI Principles — Slide 76 gidgreen.com/course

77. Show what’s old
From Code to Product Lecture 3 — UI Principles — Slide 77 gidgreen.com/course

78. Show what’s new
From Code to Product Lecture 3 — UI Principles — Slide 78 gidgreen.com/course

79. Consistency
Source: bhc3.com
From Code to Product Lecture 3 — UI Principles — Slide 79 gidgreen.com/course

80. Learned mapping
From Code to Product Lecture 3 — UI Principles — Slide 80 gidgreen.com/course

81. Learned affordance
From Code to Product Lecture 3 — UI Principles — Slide 81 gidgreen.com/course

82. Learned idioms
From Code to Product Lecture 3 — UI Principles — Slide 82 gidgreen.com/course

83. Lecture 3
• Introduction
• Vision
• Cognition
• Memory
• Action
• Emotion
From Code to Product Lecture 3 — UI Principles — Slide 83 gidgreen.com/course

84. Action
http://www.85qm.de/up/BigRedButton.swf
From Code to Product Lecture 3 — UI Principles — Slide 84 gidgreen.com/course

85. Goals and subgoals
Make my friend feel better
Wait for flowers Call
Send flowers to friend online
to arrive friend up
Find a flowers website Order the flowers
Open web Go to Type in
Choose the best site
browser google.com “flowers”
f l o w e r s
From Code to Product Lecture 3 — UI Principles — Slide 85 gidgreen.com/course

86. Execute—Evaluate
Try Was the
Define Next
something subgoal YES!
subgoal NO subgoal…
sensible reached?
From Code to Product Lecture 3 — UI Principles — Slide 86 gidgreen.com/course

87. Execute—Evaluate
Choose the best site
Wikipedia
Looks OK, but
Seems to be UK
only first. Back!
only. Back!
Seems really Looks perfect.
pricey. Back! We’re done!
From Code to Product Lecture 3 — UI Principles — Slide 87 gidgreen.com/course

88. Enabling evaluation
• Every user action
– Key presses and mouse clicks
• Instant results, or…
– Waiting cursor (0.1s … 1s)
– Progress bar (>1s)
• If invisible…
– Confirmation message
– Activity logs
From Code to Product Lecture 3 — UI Principles — Slide 88 gidgreen.com/course

89. Evaluation
From Code to Product Lecture 3 — UI Principles — Slide 89 gidgreen.com/course

90. Information scent
• Information = food
– We follow a ‘scent’
• Links and category names
– Don’t make up words!
• Provide feedback
– Scent getting stronger
• Gain vs cost
– Good content, easy to find
From Code to Product Lecture 3 — UI Principles — Slide 90 gidgreen.com/course

91. Information scent
From Code to Product Lecture 3 — UI Principles — Slide 91 gidgreen.com/course

92. Information scent
From Code to Product Lecture 3 — UI Principles — Slide 92 gidgreen.com/course

93. Direct manipulation
Photo by garryknight
From Code to Product Lecture 3 — UI Principles — Slide 93 gidgreen.com/course

94. Direct manipulation
From Code to Product Lecture 3 — UI Principles — Slide 94 gidgreen.com/course

95. Reversibility
From Code to Product Lecture 3 — UI Principles — Slide 95 gidgreen.com/course

96. Dangerous actions
From Code to Product Lecture 3 — UI Principles — Slide 96 gidgreen.com/course

97. Dangerous actions
From Code to Product Lecture 3 — UI Principles — Slide 97 gidgreen.com/course

98. Common actions
From Code to Product Lecture 3 — UI Principles — Slide 98 gidgreen.com/course

99. Common actions
From Code to Product Lecture 3 — UI Principles — Slide 99 gidgreen.com/course

100. Lecture 3
• Introduction
• Vision
• Cognition
• Memory
• Action
• Emotion
From Code to Product Lecture 3 — UI Principles — Slide 100 gidgreen.com/course

101. Emotion
From Code to Product Lecture 3 — UI Principles — Slide 101 gidgreen.com/course

102. Waiting…
From Code to Product Lecture 3 — UI Principles — Slide 102 gidgreen.com/course

103. Time limits
Moment of perception
0.01 sec
Stylus input on screen
Hand–eye coordination
0.1 sec
Clicks, drags, keys
Gap in conversation
1 sec
Waiting without progress bar
Concentration on mini-task
10 sec
Wizard step, field entry
From Code to Product Lecture 3 — UI Principles — Slide 103 gidgreen.com/course

104. Avoid insults
From Code to Product Lecture 3 — UI Principles — Slide 104 gidgreen.com/course

105. Color
From Code to Product Lecture 3 — UI Principles — Slide 105 gidgreen.com/course

106. Color
From Code to Product Lecture 3 — UI Principles — Slide 106 gidgreen.com/course

107. Design
From Code to Product Lecture 3 — UI Principles — Slide 107 gidgreen.com/course

108. But…
From Code to Product Lecture 3 — UI Principles — Slide 108 gidgreen.com/course

109. Feeling served
• What you want
• When you want it
• How you like it
• No grunt work
• No criticism
• No “personality”
• Cleanly presented
From Code to Product Lecture 3 — UI Principles — Slide 109 gidgreen.com/course

110. Books
From Code to Product Lecture 3 — UI Principles — Slide 110 gidgreen.com/course

111. Memory
From Code to Product Lecture 3 — UI Principles — Slide 111 gidgreen.com/course