The real cost of “just checking”

“Just checking” takes two seconds. That’s the part you notice. The research on switching tasks says the expensive part is everything after: the way back, and the bit of your head that stays behind.

Numbers about this get passed around a lot, and some of the famous ones don’t come from a study. So here is what the papers measured, linked, and where two popular figures actually came from.

What a working day looks like, measured

In 2016, Gloria Mark and colleagues logged the computers of 40 office workers for two working weeks. Dividing each day’s computer time by the number of times people switched screens, attention on any one screen lasted 47 seconds on average, with a median of 40 (Mark, Iqbal, Czerwinski, Johns & Sano, CHI 2016).

Zoom out from screens to whole pieces of work and it’s not much calmer. Watching 24 information workers through their days, an earlier study found they spent about 11 minutes on a project before switching to another or being interrupted, and that 57% of those stretches of work were interrupted (Mark, González & Harris, CHI 2005).

Almost half of it is us

It’s tempting to blame the pings. But in a study that observed 36 people for 889 hours, 889 of the 2,030 interruptions they saw, about 44%, were people interrupting themselves; the authors sum up earlier work the same way: “almost half of the interruptions individuals experience are self-initiated” (Dabbish, Mark & González, CHI 2011).

That’s the “just checking” half. Nobody sent you to X. Your hand went there on its own.

The switch is cheap. Coming back isn’t.

In the lab, switching between two simple tasks costs time, and more when the rules are complicated: from a fraction of a second to about a second per switch (Rubinstein, Meyer & Evans, 2001). Tiny, per switch. The bigger costs are elsewhere.

The way back is long. In the 2005 study, most interrupted work was picked up again the same day (77%), but on average 25 minutes later, with more than two other things done in between. That isn’t time spent refocusing; people were doing other work. It’s how long the thing you were in the middle of sat waiting.

Part of you stays behind. Sophie Leroy’s experiments found that people find it hard to move their attention off a task they haven’t finished, and that their work on the next task suffers for it. She called it attention residue (Leroy, 2009).

You can keep up, at a price

One more finding, and it’s the one that matches how a bad afternoon feels. In a lab study of interrupted email work, people finished faster and just as well as without interruptions, but reported more stress, frustration, time pressure and effort, “after only 20 minutes of interrupted performance” (Mark, Gudith & Klocke, CHI 2008). You can keep up. It costs you something that doesn’t show up in the output.

Two numbers you’ll see everywhere

• “23 minutes and 15 seconds to get back on task.” Gloria Mark said this in a 2006 interview with Gallup, and even there it’s how long it took before interrupted work was picked up again, not how long it took to refocus. It isn’t a figure in the papers linked here; the 2005 paper’s own number for that gap is 25 minutes, above.
• “Multitasking costs up to 40% of your productive time.” This is an American Psychological Association web page reporting what a researcher “has said”. The 2001 paper it’s often pinned to measured switch costs in fractions of a second.

Neither is needed. The measured findings make the point on their own.

What SqwarkSelf does with this

It steps in at the switch. During a watch, when a window you ruled out comes to the front, it goes dark straight away, with your own words on it and ten seconds to go back. Changing a song is allowed: Spotify, Apple Music and YouTube Music get about 30 seconds in front before they count. And at the end of the day, the Today view shows where the time went, your top time sinks, and how much of the watch you actually kept.

It can’t make you finish the thing. It can make “just checking” a decision instead of a reflex.

Sources

• Mark, G., Iqbal, S. T., Czerwinski, M., Johns, P. & Sano, A. (2016). Neurotics can’t focus: An in situ study of online multitasking in the workplace. Proc. CHI 2016. doi.org/10.1145/2858036.2858202
• Mark, G., González, V. M. & Harris, J. (2005). No task left behind? Examining the nature of fragmented work. Proc. CHI 2005. doi.org/10.1145/1054972.1055017
• Dabbish, L., Mark, G. & González, V. M. (2011). Why do I keep interrupting myself? Environment, habit and self-interruption. Proc. CHI 2011. doi.org/10.1145/1978942.1979405
• Rubinstein, J. S., Meyer, D. E. & Evans, J. E. (2001). Executive control of cognitive processes in task switching. Journal of Experimental Psychology: Human Perception and Performance, 27(4). doi.org/10.1037/0096-1523.27.4.763
• Leroy, S. (2009). Why is it so hard to do my work? The challenge of attention residue when switching between work tasks. Organizational Behavior and Human Decision Processes, 109(2). doi.org/10.1016/j.obhdp.2009.04.002
• Mark, G., Gudith, D. & Klocke, U. (2008). The cost of interrupted work: More speed and stress. Proc. CHI 2008. doi.org/10.1145/1357054.1357072