Stuck on a puzzle? The science of stepping away

The most thorough summary is a 2009 meta-analysis by Ut Na Sio and Thomas Ormerod, who pooled experiments comparing people who kept working on a problem with people who set it aside for a while before trying again. Overall, they found a positive incubation effect. It was not uniform. Creative, open-ended tasks, such as thinking of new uses for a brick, benefited more than insight puzzles based on words or pictures.

Three details are especially useful. Longer preparation before the break gave a larger effect: incubation works on a problem you have properly engaged with, not one you glanced at. Filling the break with a demanding task shrank the effect. And for word-based insight problems, a light task during the break did better than rest.

It is worth being honest about the fit with puzzle games. The visual problems in these studies are not the same as a sliding-block board, and visual insight problems benefited less than open-ended ones. The effect is real, but nobody has measured it on colour sort puzzles, and it would be wrong to promise that a break will always crack a board.

Sources1Source 1Sio, U. N., & Ormerod, T. C. (2009). Does incubation enhance problem solving? A meta-analytic review. Psychological Bulletin, 135(1), 94–120.

One explanation is almost mechanical. Steven Smith and Steven Blankenship gave people word puzzles alongside misleading hints designed to send them down the wrong path. The hints worked: people became fixated and solved fewer problems. When the fixated problems were retried after a delay, people improved more than when they retried straight away. In their experiments, the incubation effect appeared only when fixation had been induced first.

That fits the experience of being stuck on a board. After a few minutes you are no longer looking at the puzzle; you are looking at your own plan for it. It is the lane you are sure must open first, the brick you are sure must leave last. A break lets that plan lose its grip, and when you return you see the board a little more as it is. It is also why a friend glancing at your board can sometimes spot the move at once: they never built your plan, so it cannot mislead them.

Other researchers argue that the mind also keeps working on the problem below awareness. Ken Gilhooly’s 2016 review sets out the case for this kind of unconscious work, drawing on studies in which the break begins immediately after a problem is presented. The two accounts are not exclusive, and for a puzzler the practical advice is the same.

Sources2Source 2Smith, S. M., & Blankenship, S. E. (1991). Incubation and the persistence of fixation in problem solving. The American Journal of Psychology, 104(1), 61–87.3Source 3Gilhooly, K. J. (2016). Incubation and intuition in creative problem solving. Frontiers in Psychology, 7, 1076.

What you do during the break seems to matter. Benjamin Baird, Jonathan Schooler and colleagues gave people a creative task, then a break of one of several kinds: a demanding task, an undemanding task that let the mind wander, rest, or no break at all. Only the undemanding task produced a substantial improvement on problems people had already seen, and the people in that group reported more mind wandering. It is a single study with a creative task, but it matches the meta-analysis.

Sleep may play a similar part on a longer timescale. Ullrich Wagner, Jan Born and colleagues trained people on a number task with a hidden shortcut. After a night’s sleep, more than twice as many people discovered the shortcut as after the same time awake. Sleep did not help people who had not first practised the task. That finding is about discovering a hidden rule rather than about puzzles in general, but it echoes the rest of the research: preparation first, then time away.

• Work the board properly before stepping away; incubation needs something to incubate.
• Choose something light, such as washing up or a short walk, rather than another demanding mental task.
• Before you leave, say what you think the board needs, so you know which plan you are letting go of.
• Come back and read the board fresh, with a reading routine rather than your old plan.

Sources4Source 4Baird, B., Smallwood, J., Mrazek, M. D., Kam, J. W. Y., Franklin, M. S., & Schooler, J. W. (2012). Inspired by distraction: Mind wandering facilitates creative incubation. Psychological Science, 23(10), 1117–1122.5Source 5Wagner, U., Gais, S., Haider, H., Verleger, R., & Born, J. (2004). Sleep inspires insight. Nature, 427(6972), 352–355.

The signs that you are fixated rather than making progress are easy to spot once you know them. You keep making the same opening move. You undo back to the same position. You can no longer say what your next few moves are for. That is the moment to stop, because pressing on usually deepens the rut.

Coming back is a skill too. The temptation on your return is to pick up exactly where you left off, replaying the same opening in your head. Resist it. Start from the goal as if the board were new, and deliberately try the move you were most sure was wrong. If fixation was the problem, the answer is often hiding in the part of the board you had stopped looking at.

Stepping away is easier when the game does not punish you for it. Nothing on an OutBrick board is timed; the limit on each board counts moves, not seconds, so you can put the phone down and think without anything counting down. The daily board stays the same all day, which makes it a natural candidate for a second look after lunch.

A break is also a good moment to notice whether you want to come back at all. Some evenings a puzzle is the right thing and some evenings it is not; our piece on when to play and when to put the phone down looks at that side of it. And when the answer does arrive suddenly after a break, it tends to feel like a flash of insight, a strange experience of its own that we explore in the aha moment.