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Psychology of performance

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"Psychology of performance" slides from Velocity 2010.

http://en.oreilly.com/velocity2010/public/schedule/detail/13019

Running PageSpeed - all checks. YSlow - A. So what's next to do? Well, you can cheat! You know that time is relative - one hour with your mother-in-law feels much longer than one hour on the beach. The same way you can bend the perception of the page loading time and make the page feel faster, even though the RTT is the same.

Publié dans : Technologie
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Psychology of performance

  1. Psychology of performance Stoyan Stefanov, @stoyanstefanov June 23, 2010 Velocity
  2. Perception
  3. Perception
  4. Perception
  5. Perception
  6. Durations actual expected perceived rem’d time
  7. Time perception •  UCLA – 53s -> 67s -> 91s (dopamine) •  Age •  Geography - NY vs. LA •  Culture, climate •  Time of day, day the week •  Body temperature
  8. Time perception •  Clock is usually faster •  Long durations are harder to judge
  9. When the time stops •  Athletes •  Martial arts
  10. Remembered time •  Emotional state •  Pleasant vs. painful memories •  “hit vs. smash” speed – 34/40.5 mph
  11. Unpleasant memories •  34sec fake assault on campus -> 81 sec (~250% off) •  30 sec bank robbery video -> 2 day later.. -> 150 sec (500% off) -> - 50% diff
  12. Temporal illusions •  Kappa effect time 1 = time 2 Longer part of a journey feels slower
  13. It feels slower when… •  Unpleasant •  Unknown •  Boring •  Too much to keep track •  Never ever put too many •  Bullets points •  On a slide •  Never •  Harder to parse
  14. Study of frustrations •  University of Maryland •  Slow worse than pop ups •  1/3 to ½ the time lost in frustrations •  Frustrations affect all else
  15. Effect of waiting •  Irritation •  Stress •  High cholesterol •  ☠
  16. Feels faster when… •  Task is successful •  Responsive system •  Progress •  Informed
  17. Expectations Maister’s first law of service: Service = Perception - Expectation
  18. Expectations •  Brand name •  Pre-existing bias
  19. Managing expectations •  Provide feedback •  Wait with a warning is shorter
  20. Flow Mihaly Csikszentmihalyi: “Positive state of consciousness… We lose sense of self and time distorts”
  21. Flow •  Learning through failure •  Doing is the reward
  22. Some numbers
  23. PARC research •  0.1s – instantaneous •  1s – flow •  10s – attention
  24. A framework •  0.1 - 0.2s – instantaneous •  0.5 - 1s – immediate •  2 - 5s – flow •  7 - 10s – captivity - conversation
  25. RTT – response time test •  190ms college students •  Slower when go/no-go •  Correlation to IQ
  26. Blink of an eye •  0.3 - 0.4s
  27. Turning a page Two attempts 1 minute each: •  Kid A – 31, 27 •  Kid B – 39, 38 •  Dad – 44, 43 1.3 – 2.2 seconds a page
  28. Tips?
  29. Progressive rendering Chunk #1 Chunk #2 Chunk #3
  30. Worst enemy? CSS
  31. CSS
  32. CSS
  33. Progress indication •  We learn the hints •  Status bar, page title •  What we hate to see:
  34. Too many indicators
  35. Progress indication •  Progress is good, not ugly •  Flicker-free rendering?
  36. Progress indication •  Immediate responses don’t require indicator •  Lazy drop-downs? •  TMI: 4-5 words a second •  Wording: “Please wait”, “Stand by” vs. “Saving…”
  37. Prefetch •  Components •  DNS •  favicon
  38. Keep the flow •  “Idiot” box •  Back, undo •  No uncertainty •  Responsive to commands
  39. Intuitions lie •  Are you a user? •  Surprising expectations •  “Where’s the rest” •  Paging
  40. Colors and time •  White feels faster •  But higher expectations
  41. Help remembered durations •  Negate effects of waits •  Show benefits •  WIIFM
  42. Help remembered durations •  Reporting time?
  43. Long-running tasks •  WebWorkers, setTimeout •  After 10s let people stop or leave and come back •  Don’t report elapsed time
  44. First time experience •  Unfamiliar = slow •  Optimize empty cache or there will be no full cache
  45. Too fast •  Edit-in-place •  Yellow fades
  46. Distractimations
  47. Good/bad animations •  Short and sweet •  Transitions – nothing pops in life •  Easing animations
  48. Thank you! Stoyan Stefanov @stoyanstefanov http://www.phpied.com

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