Question: why do we dream?

Kamal Bhattacharya answered on 16 Jan 2017:

I am not sure why. What I know is that we distinguish between two sleep phases, slow wave sleep (SWS) and rapid eye motion (REM) sleep. When you fall asleep you start with SWS, where your body relaxes, and brain activity slows down. This kind of makes sense, right? Your body regenerates, your heartbeat goes down, and your brain relaxes. But this is not where we dream. We dream in the REM phase, crazy activity, muscles paralyze, etc. There is no good reason why we do this. At least not to my best knowledge. BTW, every seen a dog in REM phase dreaming and barking muffled barks, you should observe that some time. It’s fascinating.