by Scotty Hendricks
May 21, 2021
A new paper suggests that dreaming helps us
generalize our experiences so that we can adapt to
Therefore, the strangeness of dreams is what makes
This idea is supported by some data, though new
experiments could help confirm it.
According to a
Makes them Useful...
Lots of animals dream, but nobody is quite sure why.
divided over if dreaming is a mere side effect of other brain
functions or if it serves its own purpose.
A number of theories attempting to explain dreaming exist.
These include the ideas
The leading contemporary
theory is that,
dreams are involved with or even caused by memory
processing and storage...
A new paper (The
Overfitted Brain - Dreams Evolved to Assist Generalization) published in the journal
Patterns proposes a new
dreaming is the brain's attempt to generalize our
experiences, much like how randomness must be used to teach
computers how to recognize real world-data.
The paper also proposes
ways to test it...
Perchance to dream?
The author, Erik Hoel, calls his idea the "overfitted brain
It is based in part on
the learning process of artificial neural networks, which are
computer algorithms that seek to find patterns in large data sets.
These systems are often given training data that is similar, but not
identical, to the data that they will analyze later.
Practice data is often
purposefully contaminated with extra noise and chaos.
This is done in order to
prevent "overfitting" - in other words, to prevent the neural
network from becoming too "narrow minded" and hence unable to
identify the bigger picture.
Dr. Hoel's new hypothesis argues that your brain does something
similar through dreaming.
category-breaking, and fabulist quality of dreams" allow our brains
to introduce "warped or 'corrupted'" sensory input for
In this way, the strangeness of our dreams is a feature rather than
By presenting us with occasionally
bizarre takes on the world, our
brains keep us from getting too fixed on the specifics of a task and
make us better able to generalize.
Dr. Hoel summarizes this
rather poetically by saying,
"Dreams are there to
keep you from becoming too fitted to the model of the world."
dream hypothesis be tested?
Dr. Hoel suggests that evidence for this already exists.
It has been shown that
repeatedly performing a novel task while awake is a good way to
assure that you'll dream about it that night. He proposes that
actions like this trigger the brain's defense against overfitting,
and the weird dreams are the result.
Dr. Hoel's idea does not necessarily exclude other hypotheses about
sleep or dreaming that currently have a fair amount of empirical
proposes a few ways to test the predictions made by his hypothesis...
If it is correct, then the effects of sleep deprivation on the
ability to memorize would be different from its effects on the
ability to generalize.
Dr. Hoel suggests that a well designed test
examining if sleep or dream deprivation impacts the ability of mice
to generalize fears could provide evidence for his hypothesis.
Tracking synaptic changes
in response to dreams could also be an avenue worth exploring.
Additionally, Dr. Hoel proposes that dream-like stimuli, such as
virtual reality or video, could provide similar benefits as dreaming
if the over-fitting theory is correct.
He explains that this
could also serve as the foundation of an experiment to test the
hypothesis as well as a possible application of it:
"For example, it may
be that a pilot who has been flying for a long period of time is
beginning to overfit to their task, and a quick but intense
exposure to an entirely different sort of visual stimulus (like
a dream-like nature scene in VR) could stave off some of the
effects of sleep deprivation.
The impact of
substitutions can be examined both behaviorally but also at the
neuro-physiological level of REM rebound."
If the hypothesis catches
on, we may expect to see future studies that seek to confirm or deny
the predictions it makes.
Until then, we can only speculate on the
idea's possible merits and failings within the framework of what we
already know to be true.
Though, I suppose we can also sleep on it...