hey Vsauce Michael here and today we are
going to talk about why we dream what's
going on inside our brains the
scientific study of dreaming is called
Anaya ology and for most of history it
didn't really exist because you can't
hold a dream it's difficult to measure a
dream you can't taste it you can't see
other people's dreams and if you ask
them to tell you what they dreamt the
results are almost always unreliable in
fact it's estimated that we forget 95%
of the dreams we have especially within
the first 10 minutes of having them but
then in 1952 something amazing happened
researchers at the University of Chicago
found this it's a unique type of
electrical activity that occurs during a
certain stage of a person's sleeping
when researchers awoke people during
this stage they almost always reported
that they had been dreaming also at the
same time during this stage people's
eyeballs are going crazy rapidly darting
all over the place underneath their
eyelids you can actually see this
happening if you watch people sleep like
I usually do during REM sleep some
pretty bizarre stuff happens if you look
at the electrical activity of a brain
that is in REM sleep that almost exactly
mimics the way the brain acts when it's
awake
the biggest difference being that the
production of chemicals inside the brain
like norepinephrine serotonin and
histamine is almost completely blocked
and that causes the muscles to stop
moving which is why you can dream about
flying or running around or fighting
ninjas but your body doesn't move people
who have a disorder achieving complete
REM a topia move around in their sleep
and act out their dreams they can even
get out of bed and sleepwalk oh before
you move forward I should say two things
one is that it's possible to wake up and
not be able to move your body because
you're still in rem a topia you're
completely conscious and you know that
you're awake but your body is not ready
to move on the flipside you can also be
inside a dream and know that you're
dreaming this phenomenon is known as
lucid dreaming and it's particularly
attractive because while I'm in a lucid
dream I can
conscious decisions about what I do I
can go fly to wherever I want or I can
have a tea party with Abraham Lincoln
I'm in control but achieving a lucid
dream is quite elusive Howcast has a
great video which I've put in the
description that gives some tips and
tricks on how to achieve one researchers
were able to deprive mice of REM sleep
by using this inverted inside a tub of
water way up to the tippy top meaning
that the mouse was only able to sit
right on top of this little tiny surface
when that happens the mouse can still
fall into non REM sleep but as soon as
they reach REM sleep and their muscles
relaxed they fall off the platform into
the water waking up what they found was
that when mice are not allowed to
achieve REM sleep they have an
incredible amount of trouble remembering
things
this happens in humans too if you have
people remember word pairs and then you
don't allow them to sleep the next day
their memory for that stuff is
incredibly terrible but memory and REM
does not stop there if a person learns a
difficult new task during the day say a
new instrument or a new type of
difficult puzzle you can measure the
electrical activity in their brain while
they do that and then while they sleep
that night whether they know it or not
their brain replays those electronic
impulses many popular theories about why
we dream are variations on the idea that
while we sleep the unconscious part of
our brain is busy organizing memories
and strengthening connections from the
day before that we need in the future
while getting rid of the junk that would
otherwise clog the brain now so the
theory goes these electrical impulses
are detected by our conscious brain and
our cortex freaks out and doesn't know
what it means and so it tries it's best
to create a cohesive story creating a
dream this would explain why dreams are
often so fantastic and seemingly random
they're not supposed to make sense
they're not an actual message from our
brain it's just the results of our
cortex is trying to synthesize the noise
coming from all the work being done back
in the unconscious under this way of
thinking dreams are an epiphenomena
they're not a primary process that has a
purpose instead they're the accidental
result of a more important process
is going on behind the conscious brain
but some researchers don't believe that
they believe the dreams serve a primary
purpose and that purpose is to prepare
us for threats they think this because
the most prevalent emotions felt during
dreams are negative abandonment anger
and the most common of all anxiety the
theory goes like this back when we were
early humans especially we had no idea
what kind of threats we might encounter
during the day and so to prepare us our
brain would simulate anxieties while we
slept to make us better prepared for
that feeling in the real world so people
who had terrifying dreams were better at
dealing with anxiety in the real world
and had stronger genes
all right so the theories we discussed
today are quite popular but they don't
really enjoy a consensus not everyone
agrees on them and they barely scratched
the surface of scientific thought about
dreams but that's kind of the cool thing
about dreams think of it like this
here is the Eagle Nebula a giant
structure in outer space 6,500 light
years away but despite its distance we
pretty much know what it's made out of
we know that it's a hundred trillion
kilometres tall we know what caused it
and we know where it's gonna be in 750
million years but last night I had
dreams and no one really knows why or
for what reason and that's pretty cool
and that's why thanks for watching
if you want to learn more about the
world I highly recommend smarter every
day it's a show here on YouTube by a guy
named Destin who I've met he's awesome
I've learned a lot from him he's the guy
who did the chicken thing from the
Leanback
he's also studied what causes poop
splash slow motion water balloons and
has a lot of guns and explosions what
more could you ask for so do me a favor
and go check it out and subscribe if you
like it and if you haven't seen it yet
go check out what's what's review of my
beard I've got that in the description
and as always thanks for watching