Have you ever tried to sell something big to someone, who tells you, “I’ll have to sleep on it.” There is validity to this technique. A person can enhance their decision making power while sleeping. This is done through dreams. It seems that while dreaming we are practicing our thinking skills, and more specifically, reprocessing our thoughts and activities of the previous day. We are able to see issues more clearly the next day, and therefore make better decisions, because we have new power. We have let our brain process the issue overnight. This is an essential trait to survival.
For proof, we look at the spiny anteater, a simple mammal who does not have periods of rapid eye movement (REM) during sleep. This indicates that the little guy does not dream. The spiny anteater has another oddity. He has the biggest prefrontal cortex (the thinking part) in relation to the rest of his brain, of all animals except humans. Yet he is stupid, and we are not. Why? He has to process all his thoughts in actual time, as they are happening, because he cannot work things out while dreaming. This must be a bigger job than we would think. His offspring could not evolve much farther in intelligence because their brains would have to become prohibitively large. Instead, they evolved dreaming. We humans dream, so our large brains can be used for more intelligent pursuits. This dreaming business is very essential to the formation of permanent memories.