<i>Some were then allowed to sleep while others were not. They repeated the same tasks the next day while having their brains scanned.</i><p>So are we talking about letting the test subjects nap or keeping the control group up all night?
I heard a sample of McCartney talking about the origins of Yesterday years ago on the radio and how he just woke up and there it was.<p>Then a while later I was given a Naxos album following a Baroque music theme in my stuff on another continent and there's a theme from one of the songs on it that's eerily similar to yesterday except several hundred years older. Not quite Eric Carmen similar, but close to.<p>But that's OK - all artists derive and there is no shame in it so long as you give credit where you can and from the sounds of things he wasn't even aware of the connection.<p>The Naxos article is one of the very early ones and the labelling on it is terrible so I could never identify which labels applied to which CDs.
Sometimes i have a very hard time going to sleep, and i am at what i call the middle ground. Some random thoughts go through my mind while i try to sleep and sometimes i think of problems and get to something like a solution. Usually its just a subconscious hint that i understand in the morning after thinking about it. But i don't remember my dreams, so i rarely get to solutions in my sleep, just some hints in my middle ground. But who knows, maybe i get some work done and don't know it.
Not sure that the "Yesterday" anecdote was appropriate; it's an example of creative thinking rather than learning.<p>It's also unclear as to whether the "same tasks" on subsequent days were exactly the same, or simply the same activity with different specifics. For instance, are people following the same path with a joystick, or a different path with a joystick? Are we talking about memory retention here, or learning skills?
I've got to the point where I plan for this now. I stuff my head with the problem before I go to sleep, the next morning I wake up and there's the solution, I even get schedules some times :-), some times I wake up at 3 or 4 with the solution, if it's a curly one sleep can be elusive or I sort of have this twilight sleep where I'm half asleep but working on the problem as well.
I'm reminded of the fascinating <i>Tetris Dreams</i> study:<p>[<a href="http://www.sciam.com/article.cfm?id=tetris-dreams" rel="nofollow">http://www.sciam.com/article.cfm?id=tetris-dreams</a>]