Date post: | 27-Jan-2015 |
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Psychology of
performance
Stoyan Stefanov, @stoyanstefanov June 23, 2010 Velocity
Perception
Perception
Perception
Perception
Durations
actual expected
perceived rem’d
time
Time perception
• UCLA – 53s -> 67s -> 91s (dopamine)
• Age • Geography - NY vs. LA • Culture, climate • Time of day, day the week • Body temperature
Time perception
• Clock is usually faster • Long durations are harder
to judge
When the time stops
• Athletes • Martial arts
Remembered time
• Emotional state • Pleasant vs. painful
memories • “hit vs. smash” speed –
34/40.5 mph
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
Temporal illusions
• Kappa effect time 1 = time 2
Longer part of a journey feels slower
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
Study of frustrations
• University of Maryland • Slow worse than pop ups • 1/3 to ½ the time lost in
frustrations • Frustrations affect all else
Effect of waiting
• Irritation • Stress • High cholesterol
• ☠
Feels faster when…
• Task is successful • Responsive system • Progress • Informed
Expectations
Maister’s first law of service:
Service = Perception - Expectation
Expectations
• Brand name • Pre-existing bias
Managing expectations
• Provide feedback • Wait with a warning is
shorter
Flow
Mihaly Csikszentmihalyi: “Positive state of
consciousness… We lose sense of self and time distorts”
Flow
• Learning through failure • Doing is the reward
Some numbers
PARC research
• 0.1s – instantaneous • 1s – flow • 10s – attention
A framework
• 0.1 - 0.2s – instantaneous • 0.5 - 1s – immediate • 2 - 5s – flow • 7 - 10s – captivity
- conversation
RTT – response time test
• 190ms college students • Slower when go/no-go • Correlation to IQ
Blink of an eye
• 0.3 - 0.4s
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
Tips?
Progressive rendering Chunk #1
Chunk #2
Chunk #3
Worst enemy?
CSS
CSS
CSS
Progress indication
• We learn the hints • Status bar, page title • What we hate to see:
Too many indicators
Progress indication
• Progress is good, not ugly • Flicker-free rendering?
Progress indication
• Immediate responses don’t require indicator
• Lazy drop-downs? • TMI: 4-5 words a second • Wording: “Please wait”,
“Stand by” vs. “Saving…”
Prefetch
• Components • DNS • favicon
Keep the flow
• “Idiot” box • Back, undo • No uncertainty • Responsive to commands
Intuitions lie
• Are you a user? • Surprising expectations • “Where’s the rest” • Paging
Colors and time
• White feels faster • But higher expectations
Help remembered durations
• Negate effects of waits • Show benefits • WIIFM
Help remembered durations
• Reporting time?
Long-running tasks
• WebWorkers, setTimeout • After 10s let people stop or
leave and come back • Don’t report elapsed time
First time experience
• Unfamiliar = slow • Optimize empty cache or
there will be no full cache
Too fast
• Edit-in-place • Yellow fades
Distractimations
Good/bad animations
• Short and sweet • Transitions – nothing pops
in life • Easing animations
Thank you!
Stoyan Stefanov @stoyanstefanov http://www.phpied.com