Norman Geras doesn't have a comments box on his site. If he did, I'd put this post in one.
Reading this post, Norm asks, if our cognitive abilities are supposed to be impaired for a while after we awake, why does he wake up and find it easy to solve problems that perplexed him the previous evening.
I'd suggest that what he really does is go to sleep pondering his problems, processes them as he sleeps, and awakes with the answers ready. It's what I do, anyway....
So, while he thinks that he's brighter first thing in the morning, the research is probably still wise to advise him against operating heavy machinery before eating his Sugar Puffs.