Eli5: Why can’t we hear our environment while we are asleep?
In: Biology
You can hear your environment while you sleep, that why you wake up from loud noices around you. You just dont notice it because you are sleeping. Same goes for every other sense other than sight because your eye lids are blocking your vision but for example touch you do notice as you wake up when someone “touches” you hard enough. And smell aswell you can wake up because of bad smell.
The brain filters out a lot of the white noise, tell mine that though… things like a dripping faucet can keep me up all night!
I like to listen to podcasts/youtube videos to fall asleep and I can 100% tell you that there is low level processing going on in the brain when it comes to audio, as what I listen to effects my dreams.
Let’s call it a muffle effect, the brain tends to drown out irrelevant sounds, but anything loud and sudden will wake most people, that is how alarms work. The brain has a good filter for working out what is a regular “nightime” sound and one that is not; it is a survival thing.
I have solo camped a lot and Whippoorwills are annoying as F, but the mind can drown that out; sticks breaking near your tent, the brain goes on alert! Our biology is really amazing!
Your brain is actually two layers.
The top layer – neocortex (new brain) – is mostly unique to mammals. This is what gives us emotions and forms family bonds and let’s us think.
The bottom layer is commonly called your “lizard brain”. It is pure instinct. No thought. But, that makes it much much faster to react.
All your senses filter through your lizard brain. This part runs a quick threat analysis and if it thinks there is a threat, will react accordingly. This is why you might be walking in the park and jump in fright only to realize it’s a stick not a snake. Your brain did a quick assessment and determined there was enough of a threat of a snake that you should jump back. If it waited for a full determination to make sure it really was a snake and it was actually dangerous it might take seconds which is far too slow.
Right, so on to sleep. All day you train your brain on what sounds in your house are dangerous and which are normal. Then when you sleep, your lizard brain is filtering through and only reacting to what is dangerous. This is also why a night in a new place isn’t as restful. Your brain is working extra hard on all the unfamiliar sounds.
Pretty sure you do, your brain just chooses to ignore it unless it detects something that might be dangerous. If it doesn’t hit a “danger” box it doesn’t alert you to it.
That being said, the reason I know you can at least sometimes is because I pretty much exclusively sleep with some type of media playing. And it’ll often “leak” into my dreams. I’ve been able to go back through my recently played lists and pick out things that 100% influenced my dreams.
I’m also a habitual “sleep through my alarm” person. I used a siren for an alarm for a while and it took me like 4 straight days of tornado nightmares and waking up 30 minutes late to realize I was quite literally hearing my alarm clock….and it inspired my dream to make a tornado warning followed by a terrifying flee from tornados.
Latest Answers