Question: Why do we dream ?

Ed Bracey answered on 6 Nov 2017:

Great question. We’re not entirely sure yet, but some scientists think it helps strengthen memories that we need to keep, like “which bus stop do I get off at” and weakening information we don’t need, like “the number of tiles in the bathroom at work”.

There are some cool experiments in mice and rats that show that some parts of the brain replay what they’ve have done earlier in the day.

But the replay is sometimes faster, and sometimes gets played backwards!