Do you have better ideas after sleep, or after time away, or something else?
The question underneath everything I write is what conditions a particular person needs to do their best thinking. Not people on average. One person, whose conditions can be changed one at a time to see what moves. I use myself because I am the person I am allowed to experiment on.
Observation My best ideas arrive after unusually long sleep, in the first hour after waking, and around day three of being outside with no signal. I have believed for years that sleep was doing it.
Suggestion A 2018 study is titled “Incubation, not sleep, aids problem-solving.” Time away from the problem improved how many people solved it. Spending that time asleep added nothing on top.
If that holds, I had the variable wrong. It was never the sleep. It was the hours of not working on it, and sleep is just the most reliable way most people get those hours.
There is a second reason to doubt my own version. I am bipolar. When I am manic I sleep less and the ideas arrive anyway. So one story has more sleep producing ideas and the other has less sleep producing ideas. Both cannot sit on the same curve. The likeliest explanation is that sleep is not the cause in either case, and something upstream is moving my sleep and my thinking at the same time.
Question So the experiment changes. Not how long did I sleep. How long had I been away from the problem, and does holding sleep steady while varying that change anything.
Where this stops. Brodt et al. 2018 in Sleep, 62 people. It is paywalled and I have read it through a secondary source rather than in full, so I am grading it Suggestion until I read the paper. The incubation meta-analysis that would tell me how well this holds up has not been checked yet.
A caution I am putting in writing. Losing sleep is a documented trigger for mania. If you are in the same position, a sleep-restriction experiment on yourself is not a neutral thing to try.