Four theories on why we dream
Even though you know plenty about how sleep works, what happens to your brain while you're sleeping, and what exactly dreams are, it sure would be nice if scientists could also explain exactly why you dream. Unfortunately, that explanation doesn't currently—and might not ever—exist. There are, however, lots of fun theories that take stabs at what the answer might be, and those are explored in more interesting detail, below
Theory #1: Dreams Act As Therapy
Often your dreams force you to face an emotional circumstance that's actually happening in your real life, and that allows you to deal with those emotions in a safe and protected environment (dreamland!). When you face an emotional issue in a dream, your brain makes connections that it most likely would not otherwise make, and that may help you look at a situation in a different light or understand something new about yourself. It may also help you get to the root of whatever may be causing you to feel anger, fear, or envy.
Theory #2: Dreams Let You Perfect Dealing With Threats
If you’ve ever woken up in a sweat from a dream that felt so real, you’re not alone. Scenarios that involve being chased or fighting are common—and with good reason. As it turns out, your amygdala (otherwise known as your “fight-or-flight” reflex) fires at a more rapid pace during REM sleep (the stage of sleep where most dreams occur) than it does during waking hours. And it fires in a way that replicates what would happen if your life were threatened. So humans might use their dreams as a way of practicing fight-or-flight responses—even while their limbs remain still.
Theory #3: Dreams Allow You to Practice a Skill
Whether you're stressing about a review at work, a piano recital, or simply a conversation that you don't want to have, your dreams give you an opportunity to practice for major life events that require extra concentration.
Theory #4: Dreams Let You Get Creative
Ever hear athletes credit their dreams for doing certain moves or hear musicians credit their dreams for writing particular songs? Sometimes dreams can help you think in imaginative ways. Writing down your dreams may help you think of a brand new idea.
Theory #5: Dreams Declutter Your Brain
Dreaming allows your brain to reshuffle everything that it’s remembered, keep the important connections that it has made, and get rid of the useless ones. In other words, it’s during dreams that your brain may reevaluate what’s important and what’s not, and take out the garbage, per se.