Why Do Humans Dream?

The human brain is full of mysteries, and why we dream is a big one. Learn the leading theories about why we dream in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:02):
Welcome to brain stuff. From how stuff Works, Hey, brain Stuff,
Loring Vogel Bomb. Here the human brain is a mysterious
little ball of gray matter. After all these years, researchers
are still baffled by many aspects of how and why
it operates like it does. Scientists have been performing sleep
and dream studies for decades now, and we still aren't
a hundred percent sure about the function of sleep or

(00:24):
exactly how and why we dream. We do know that
our dream cycle is typically most abundant and best remembered
during the R E M stage of sleep. It's also
pretty commonly accepted among the scientific community that we all dream,
though the frequency in which dreams are remembered varies from
person to person. The question of weather dreams actually have
a physiological, biological, or psychological function has yet to be answered,

(00:47):
but that hasn't stopped scientists from researching and speculating. There
are several theories as to why we dream. One is
that dreams work hand in hand with sleep to help
the brain sort through everything it collects. During the waking hours.
Your brain is met with hundreds of thousands, if not millions,
of inputs every day. Some are minor sensory details like
the color of a passing car, while others are far

(01:08):
more complex, like the big presentation you're putting together for
your job or class. During sleep, the brain works to
plow through all of this information to decide what to
hang onto and what to forget. Some researchers think that
dreams play a role in this process. It's not just
a stab in the dark, though. There is some research
to back up the ideas that dreams are tied to
how we form memories. Studies indicate that as we're learning

(01:29):
new things in our waking hours, our dreams increase while
we sleep. Participants in a dream study who are taking
a language course showed more dream activity than those who
were not. In light of such studies, the idea that
we use our dreams to sort through and convert short
term memories into long term memories has gained some momentum
in recent years. Another theory is that dreams typically reflect

(01:50):
our emotions during the day, our brains are working hard
to make connections to achieve certain functions. When posed with
a tough math problem, your brain is incredibly focused on
one thing, and the brain doesn't only serve mental functions.
If you're building a bench, your brain is focused on
making the right connections to allow your hands to work
in concert with the saw in the wood to make

(02:10):
an exact cut. The same goes for simple tasks like
hitting a nail with a hammer. Have you ever lost
focus and smashed your finger because your mind was elsewhere.
Some researchers have proposed that while sleeping, everything slows down.
We aren't required to focus on anything during sleep, so
our brains make very loose connections. It's during sleep that
the emotions of the day battle it out in our

(02:31):
dream cycle. If something is weighing heavily on your mind
during the day, chances are you might dream about it,
either specifically or through some kind of imagery. For instance,
if you're worried about losing your job due to company downsizing,
you may dream that you're a shrunken person living in
a world of giants, or that you're wandering aimlessly through
a great desert abyss. There's also a theory, definitely the

(02:51):
least intriguing of the bunch, that dreams don't really serve
any function at all, that they're just a pointless byproduct
of the brain firing wallaby slumber. We know that a
rear portion of our brain gets pretty active during r
M sleep, when most dreaming occurs. Some think that it's
just the brain winding down for the night, and that
dreams are random and meaningless firings that we don't have
when we're awake at the end of the day. As

(03:14):
long as the brain remains such a mystery, we probably
won't be able to pinpoint with absolute certainty exactly why
we dream. Today's episode was written by Charles W. Bryant
and produced by Tristan McNeil. For more on this and
lots of other dreamy topics, visit our home planet, how
Stuff Works dot com.