Imagination
Sleep may have contributed the most important tool for the development of a robust imagination. During sleep, the body's muscles are disconnected from the brain's activity, otherwise we would act out our dreams as they occurred; running, jumping, screaming, attempting to fly. Indeed, this system of disconnection is not perfect, we've all seen someone's arms or legs twitch or even strike out as they are dreaming.
When we imagine throwing a ball or swinging a bat, our brain uses the same pattern of neurons as if we were actually performing the motion for real. It is only the fact that the muscles are disconnected from our thoughts, in some as yet unknown way, that prevents them from carrying out the neural orders. Our imagination allows us to visualize, practice, and perfect a motion or activity without actually performing it in the real world. Studies have been done that showed athletes improved their performance by watching other athletes practice and imagining themselves practicing, without actually practicing themselves.
Perhaps that's why we call it day dreaming. The mental state of imagining is very much like the quiet, relaxed feeling we have before falling asleep. And a peaceful, quiet atmosphere is conducive to the act of the imagination, whether it involves writing a story or planning what to do with the funds from winning the lottery. But the imagination is not strictly dependent on a quiet reserved moment. It is easy to imagine the flight of a ball before it is thrown, or the path of a running football player and where the ball needs to be thrown in order to put it within his grasp, a few moments in the future.
So the imagination helps us to predict the future. It also helps us decide what other people are thinking, to feel empathy. The imagination helps us plan and helps us determine what other people may be planning. The imagination is a rich virtual world that bestows many benefits. No wonder it has developed so richly in our own species, which now dominates the real world.
The next question is, will artificial intelligent machines have an imagination? Do they already?
