At the Nijmegen Unconscious lab in The Netherlands, Ap Dijksterhuis and his colleagues have shown that participants who are distracted for a while from a main creative challenge end up generating better ideas, and more of them, than others who just work straight through.

Dijksterhuis's theory is that the period of "incubation" allows your creative unconscious to get working. Unconstrained by convention and deliberation, your unconscious makes novel links between concepts that you would have missed if you'd stayed focused on the task.

An obvious question for creatives is how best to help your unconscious work its magic. What should you do when you're taking a short incubation break from your main project? Rather than twiddling your thumbs or taking a nap, it makes sense to get on with some other task. But should you work on a similar type of problem or aim for something radically different?

A team of British psychologists led by Ken Gilhooly has looked into this question and they say it's best to work in the incubation period on a different kind of mental activity. The researchers gave over a hundred volunteers one of two main challenges. One was verbal in nature and involved spending five minutes coming up with as many new uses as possible for a brick (akin to brainstorming session in the office). The other was a spatial task, equivalent to a design-based project at work, and this involved arranging five simple shapes into recognizable objects - for example: a triangle, letter C and rectangle formed in such a way to resemble an ice cream cone.

Once the incubation period was over, the participants returned to their main challenge for an additional five minutes and the key test was whether they'd outperform a control group who'd just worked on either the brick task or the shape task for ten minutes straight through.

The take-home finding was that incubation breaks boosted creative performance, but only when the time was spent engaged in a different kind of mental activity. Participants who in the break switched from verbal to spatial, or from spatial to verbal, excelled when they returned to their main task – in terms of the number and quality of their solutions. The change in focus freed up their unconscious to spend the incubation period tackling the main challenge.

On the other hand, the participants who'd used the incubation period to perform the same kind of activity – verbal or spatial – were unable to capitalize on the break. Staying in the same mental domain appeared to tie up their unconscious, robbing its ability to work behind the scenes.

This study has clear implications for how to optimize your performance at work. The next occasion that you feel burnt out on a creative task and decide to take a time out, don't simply switch to a similar kind of project. Aim to work in a completely different way. If you were writing, try switching to numbers or design; and vice versa. While you're doing that, your unconscious will be free to work its magic.