Video: Giles Colborne’s #mexsession on illusions of efficiency in UX

Giles Colborne’s March 2014 talk at MEX challenges preconceived notions about time and efficiency. Drawing on years of experience leading cx partners, the UX agency he founded, Giles’ explores a broad and compelling array of references to show how users think about speed and latency. He goes on to explain the advantages of different methods for tracking these often illogical user reactions and turning them into delightful customer experiences, grounded in the research conducted for his highly regarded books on UX.

Giles Colborne (@gilescolborne | has spoken at MEX on several occasions over the last few years, as well as leading creative sessions where teams go in-depth on defining new thinking for specific areas of user experience.

Details and tickets for MEX:


  • User perception of time is unreliable. For instance, by making users walk 6 times further, an airport was able to ensure users’ bags were waiting on the carousel when they arrived in the baggage hall. The total time from leaving the plane to collecting bags was unchanged, but satisfaction levels improved.
  • Users create temporal illusions. For instance, under high pressure situations, like falling off a building, people create a high quantity of memories, so when they look back, it seems like time slowed down, when in fact they just did more with it.
  • Emotional engagement changes perception of efficiency. For instance, Coinstar machines deliberately slow the coin counting process and use mechanical sound effects to ensure the user trusts the counting process.
  • Users’ tolerance for lag rises on an exponential scale (0.1 to 1 to 10) across categories of interaction. Direct manipulation (e.g. moving objects on a touchscreen) must be responsive within 0.1 seconds and dialogue (e.g. a conversation) must respond with 1 second. 10 seconds is the limit of how long users will wait for a digital interface to respond before their attention is lost.
  • Manipulating perception of time is key to efficient user experience design. For instance, Canon’s CAT computer in the 1980s used an illusory screenshot to trick the user into thinking the computer was active to overcome the lag of loading floppy disks.
  • The International Standards Organisation (ISO) defines usability as a combination of efficiency, effectiveness and satisfaction. The relative importance of these elements depends on user context. In the mobile environment efficiency is most important, where desktop sites tend to focus more on overall effectiveness. However, an Amazon experiment found even a 0.1 second delay to its processing times led to a 1% drop in sales. Google found a 0.5 second delay led to a 20% drop in searches.
  • Focusing on convenience which delights users can lead to overall usability improvements. For instance, the Pocket app scans the users’ clipboard and, if it finds a web address, automatically asks whether the user wants to add it as an article, because research has shown this to be a common user flow.
  • Humans are naturally efficient in their use of conversational language and digital experiences can learn from this. For instance, City Mapper assigns human names like ‘Home’ and ‘Work’ to shortcut buttons instead of using technical geographical addresses.
  • The need for detailed tutorials or splash screens is usually a sign of inefficiency. Focus on delivering instant usability, where additional depth is suggested by visual and interaction clues, not explained by tutorial.
  • Tiny improvements in perceived efficiency can have a big impact. For instance, Wells Fargo remembers how much cash users withdraw from ATMs and makes this amount the default choice for the next withdrawal. The time saved is small, but leads to higher levels of customer advocacy.
  • Efficiency improvements can be achieved through many sensory channels – including sound and touch – and aren’t just limited to visual interactions.
  • Identify efficiency bottlenecks by splitting them into individual components and measuring each element in human, not computer terms. For instance, consider everything from the time it takes to place a hand on the control device, to thinking time to physically entering text on a keyboard. A way of doing this is KLM GOMs methodology.
  • Digital designers could learn efficiency lessons from sports science, where the marginal gains theory – achieving small percentage improvements in numerous areas to great overall effect – has been successfully used by British Cycling.

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