Performance Is Good for Brains [We Love Speed 2024]

Tammy Everts

September 18, 2024

Tweet Share

Transcript

1. 1 Performance is Good for Brains webperf.social/@tammy @tameverts

2. None

3. Alarm Vectors by Vecteezy

4. None
5. None

6. Made pages 1.9 seconds faster, increased conversion rate by 94%

   1-second improvement, 14% decrease in bounce rate and 13% increase in conversions Improved Largest Contentful Paint by 31%, increased sales by 8% WPOstats.com
7. None
8. None
9. None

10. Waiting is hard

11. Passive waiting is harder

12. Perception is more important than reality

13. Perception is more important than reality

14. How do we perceive time?

15. None
16. None

17. Our memory exaggerates wait times

18. 18

19. We remember endings more than beginnings and middles

20. None

21. Time feels slower when we are relaxed

22. When the span between heartbeats is longer, time feels slower*

    *by milliseconds

23. Women tend to underestimate prospective time estimations compared to men.

    This suggests they may perceive time to be passing by more slowly.

24. Women tend to underestimate prospective time estimations compared to men.

25. Women tend to underestimate prospective time estimations compared to men.

    This suggests they may perceive time to be passing by more slowly.

26. Have you ever thought time is speeding up as you

    get older?

27. Have you ever thought time is speeding up as you

    get older? It is.

28. Over time, the rate at which we process visual information

    slows down.

29. Over time, the rate at which we process visual information

    slows down. This is what makes time ‘speed up’ as we grow older.

30. Users aged 65+ are 43% slower at using websites than

    users aged 21-55 nngroup.com/articles/usability-for-senior-citizens/

31. Our perception is affected by how time is quantified

32. 86,400 seconds

33. 86,400 seconds 1,440 minutes

34. 86,400 seconds 1,440 minutes 24 hours

35. 86,400 seconds 1,440 minutes 24 hours 1 day

36. None
37. None

38. 38

39. 35 minutes 7 Sharonas

40. sex age pain heart rate boredom

41. None

42. How does memory work?

43. 43

44. None

45. 45

46. What is “flow”?

47. “…a state in which people are so involved in an

    activity that nothing else seems to matter; the experience is so enjoyable that people will continue to do it even at great cost, for the sheer sake of doing it” Mihály Csíkszentmihályi Flow: The Psychology of Optimal Experience (1990)

48. 48

49. 49

50. 50 Image by BalashMirzabey on Freepik It can take up

    to 23 minutes to regain focus after an interruption

51. 51 Productivity It can take up to 23 minutes to

    regain focus after an interruption

52. 52 Productivity Wellbeing It can take up to 23 minutes

    to regain focus after an interruption

53. Slow sites create extra friction in an already friction-filled world

54. The average web user believes they waste two days a

    year waiting for pages to load

55. What we say we want vs. what we need 1999

    • 8 seconds 2006 • 4 seconds Now • 2 seconds

56. A wait longer than 2 seconds breaks concentration and affects

    productivity Robert Miller Response Time in Man-Computer Conversational Transactions

57. A wait longer than 2 seconds breaks concentration and affects

    productivity Robert Miller Response Time in Man-Computer Conversational Transactions 1968

58. 58 “We want you to be able to flick from

    one page to another as quickly as you can flick a page on a book. So, we’re really aiming very, very high here… at something like 100 milliseconds.” Urs Hölzle SVP Engineering, Google
59. None

60. What do we know about how people perceive speed on

    the web?

61. 61 Jakob Nielsen, Website Response Times

62. 62 When do we start to interact with a page?

63. 63 Jakob Nielsen, Website Response Times

64. 64

65. “web stress” When apps or sites are slow, we concentrate

    up to 50% harder to stay on task
66. None

67. People experience slowness in the moment

68. Frustration peaks between 11.5 and 26% during browsing and checkout

69. Slowness affects perception of everything

70. fast slow

71. Content “boring” Visual design “tacky” “confusing” Usability “frustrating” “hard-to-navigate”

72. Slowness affects long-term behaviour

73. None

74. What we think we want does not always make us

    happy
75. None
76. None
77. None
78. None

79. “When, as with the Progressive JPEG method, image rendition is

    a two-stage process in which an initially coarse image snaps into sharp focus, cognitive fluency is inhibited and the brain has to work slightly harder to make sense of what is being displayed.” Dr. David Lewis Chair, Mindlab International
80. None
81. None

82. Slowness is a feeling, not a thought

83. “Phone rage”: How people react to slow mobile sites Tealeaf/Harris

    Interactive
84. None

85. nicj.net/measuring-continuity/

86. nicj.net/measuring-continuity/

87. Steve Souders Author, High Performance Web Sites “The real thing

    we are after is to create a user experience that people love and they feel is fast…

88. …and so we might be front-end engineers, we might be

    devs, we might be ops, but what we really are is perception brokers.” Steve Souders Author, High Performance Web Sites “The real thing we are after is to create a user experience that people love and they feel is fast…

89. How do you measure perception …at scale?

90. Biggest measurement mistakes 1. Not measuring at all You can’t

    fix what you don’t measure.

91. Biggest measurement mistakes 1. Not measuring at all You can’t

    fix what you don’t measure. 2. Assuming your experience is universal “It’s fast enough on my desktop/phone.”

92. Biggest measurement mistakes 1. Not measuring at all You can’t

    fix what you don’t measure. 2. Assuming your experience is universal “It’s fast enough on my desktop/phone.” 3. Not monitoring continuously Things can change suddenly (e.g., server issues, third parties).

93. Biggest measurement mistakes 1. Not measuring at all You can’t

    fix what you don’t measure. 2. Assuming your experience is universal “It’s fast enough on my desktop/phone.” 3. Not monitoring continuously Things can change suddenly (e.g., server issues, third parties). 4. Not monitoring real users Synthetic measurements are only snapshots. CrUX data is not comprehensive RUM.

94. Biggest measurement mistakes 1. Not measuring at all You can’t

    fix what you don’t measure. 2. Assuming your experience is universal “It’s fast enough on my desktop/phone.” 3. Not monitoring continuously Things can change suddenly (e.g., server issues, third parties). 4. Not monitoring real users Synthetic measurements are only snapshots. CrUX data is not comprehensive RUM.. 5. Not focusing on the right metrics e.g., “Load time” is dated; Core Web Vitals are only available in Chromium browsers.

95. Biggest measurement mistakes 1. Not measuring at all You can’t

    fix what you don’t measure. 2. Assuming your experience is universal “It’s fast enough on my desktop/phone.” 3. Not monitoring continuously Things can change suddenly (e.g., server issues, third parties). 4. Not monitoring real users Synthetic measurements are only snapshots. CrUX data is not comprehensive RUM. 5. Not focusing on the right metrics e.g., “Load time” is dated; Core Web Vitals are only available in Chromium browsers. 6. Looking only at averages or medians Measure at 75th and 95th percentiles to understand the breadth of user experiences.

96. Optimize the entire experience 1. Eliminate confusion whenever possible Don

    Norman, Cofounder/emeritus, Nielsen Norman Group

97. Optimize the entire experience 1. Eliminate confusion whenever possible 2.

    Make the wait appropriate to the results Don Norman, Cofounder/emeritus, Nielsen Norman Group

98. Optimize the entire experience 1. Eliminate confusion whenever possible 2.

    Make the wait appropriate to the results 3. Meet or exceed expectations Don Norman, Cofounder/emeritus, Nielsen Norman Group

99. Optimize the entire experience 1. Eliminate confusion whenever possible 2.

    Make the wait appropriate to the results 3. Meet or exceed expectations 4. End strong Don Norman, Cofounder/emeritus, Nielsen Norman Group

100. Made pages 1.9 seconds faster, increased conversion rate by 94%

     1-second improvement, 14% decrease in bounce rate and 13% increase in conversions Improved Largest Contentful Paint by 31%, increased sales by 8% WPOstats.com

101. 101 Create an experience that isn’t just tolerable...

102. 102 Create an experience that isn’t just tolerable... it’s delightful

103. Thank you! webperf.social/@tammy @tameverts

104. The Psychology of Site Speed and User Happiness speedcurve.com/web-performance-guide/the-psychology-of-web-performance/ Why

     Waiting Is Torture nytimes.com/2012/08/19/opinion/sunday/why-waiting-in-line-is-torture.html Wrinkles in Subsecond Time Perception Are Synchronized to the Heart onlinelibrary.wiley.com/doi/abs/10.1111/psyp.14270 Sex Differences in Time Perception During Self-paced Running ncbi.nlm.nih.gov/pmc/articles/PMC5065319/ Why the Days Seem Shorter as We Get Older cambridge.org/core/journals/european-review/article/why-the-days-seem-shorter-as-we-get-older/ Flow: The Psychology of Optimal Experience Mihaly Csikszentmihalyi The Cost of Interrupted Work: More Speed and Stress ics.uci.edu/~gmark/chi08-mark.pdf Response Time in Man-Computer Conversational Transactions dl.acm.org/doi/10.1145/1476589.1476628 Website Response Times nngroup.com/articles/website-response-times/ Progressive Image Rendering: Good or Evil? radware.com/blog/applicationdelivery/wpo/2014/09/progressive-image-rendering-good-evil/ The Psychology of Waiting Lines Don Norman – jnd.org/the-psychology-of-waiting-lines/ Sources