One of the most interesting discoveries of neuroscience of the last 20 years is that when you acquire memories, they’re stored in temporary, fragile form, like cement. When you pour it, initially it’s soft, but when it dries and hardens, it becomes strong and durable. Memories are like that. They become hardened through a process of consolidation, which happens largely during sleep.
Memory consolidation actually transforms the memory, as well. It brings out details, hidden relationships. That can be the stuff of creativity and insight.
That’s why there are so many stories of people waking up in the middle of the night with a new idea or solution to a problem. Like Paul McCartney. He was awakened one morning with this melody in his head. It was the song, “Yesterday.” It just appeared to him. Sleep supercharges creativity.
Brigid Schulte writing in The Washington Post