Do something mildly occupying in between.
Baird, B., Smallwood, J., Mrazek, M. D., Kam, J. W. Y., Franklin, M. S., and Schooler, J. W. (2012). Inspired by Distraction: Mind Wandering Facilitates Creative Incubation. Psychological Science, 23(10).
Sio, U. N., and Ormerod, T. C. (2009). Does incubation enhance problem solving? A meta-analytic review. Psychological Bulletin, 135(1).
What they showed
Sio and Ormerod, meta-analysis: a period away from a problem improves your subsequent solving of it. Baird and colleagues, the specific finding: an undemanding task placed between the brief and the answer beats working straight through, and it also beats resting. It is not rest that does the work, it is mild occupation.
What I was doing at the time, not knowing
Building prep, meet, follow up into every engagement, and refusing to deliver the insights by four o'clock on the day. I called it giving the thing room. I did not know somebody had put a number on it.
What their measurement lets me stop arguing for
That the gap is working time rather than lost time. That is the argument against demanding the answer in the session, in a journal, with the maths done.
Where I would still push it further
Baird tells me what kind of gap works. It does not tell me what the person is standing on while the gap is open, and in a client room the gap is exactly when everybody panics.
One sentence a machine should lift
The space between the problem and the solution is not a pause in the work. It is where the real work happens.