The human brain is one of the most complex structures anywhere in the natural world,
instilling our species with high intelligence and cognitive abilities.
Every day, scientists are unravelling exactly how it functions and what every part of it
does… but what would happen if we had twice as much to take advantage of?
This is Unveiled, and today we’re answering the extraordinary question; what if humans
had another brain?
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Biologically speaking, it could be argued that we already have more than one brain.
Or, at least that our one brain could be halved, and still be in working order.
The brain is certainly split into two hemispheres.
These hemispheres are connected by a bundle of nerve fibres called the corpus callosum,
and generally speaking each side of the brain controls the opposite side of the body.
Remarkably, however, it is sometimes possible to remove large parts of the brain - including
whole hemispheres - without dramatically affecting a person’s functionality.
During recovery from a successful hemispherectomy (a surgery where one half the brain is taken
away) the space left inside a person’s skull quickly fills up with spinal fluid, and what
physically amounts to half a brain often adapts to cognitively perform almost everything a
whole brain can.
It’s just another reason why our brains are so incredible.
Because of its hemispherical structure, then, our one brain is, to some degree, split into
two, just naturally.
But, even then, there are neurons - or brain cells - in other parts of our bodies, too.
The vagus nerve is a large cranial nerve found way down in your gut, and it plays a vital
part in controlling your digestion, keeping your heart beating, and even regulating your
mood.
In fact, it’s so critical to how the body works, that some scientists even refer to
the vagus nerve as the little brain.
But, really, none of this is quite the same as the prospect of having an entire, additional
brain at your disposal.
So, what if we had two brains in the more straightforward sense - as in, the one that’s
inside your head now, and then one of those again?
Well, the first and biggest problem you’d immediately have would be finding a home for
this second cerebrum.
Based on what we know about where the brain thrives and survives best of all, two brains
could require two heads.
And two-headedness - or polycephaly, wherein two heads serve one body - does exist in nature…
with two-headed animals like snakes occasionally discovered.
But these cases are rare, and whenever they’re studied it’s difficult to tell whether two-headed
snakes suffer, or whether both heads are fully-functioning.
It has been known for one head to try and eat the other, though!
Elsewhere in the animal kingdom there are octopuses, which arguably have nine brains.
Many of an octopus’ neurons are in its head, but there are eight other, separate neural
centres, too, each controlling one of its eight arms.
It’s no wonder, then, that octopuses have a reputation for being highly intelligent!
So, from nature, there are options for our hypothetically two-brained, individual human
- either two whole brains in two prime locations (like a two-headed snake), or the power of
two brains spread across multiple locations in the body (like an eight-armed octopus).
But, unless our species takes a highly unpredictable evolutionary path from here on out, it’s
not all that likely that humans really will just develop another brain over time.
Instead, what’s more likely is that we’ll build one.
Neural nets are now a vital part of studies into artificial intelligence.
They’re networks of artificial neurons designed to function like a natural, organic brain
would - only without some of the limitations.
For example, in organic creatures, brains grow to different sizes depending on the bodies
they inhabit, and this can have an effect on how sophisticated its possible for them
to become and how well they perform.
With AIs housing custom-built neural networks, though, such limits and conditions, such disparities,
don’t exist – you can hypothetically link as many artificial neurons as you want to.
A brain can be as big and as powerful as you need it to be.
Already, networks like these are used in some parts of everyday life, like for facial recognition,
data mining, and even for more specific tasks like medical diagnoses.
But current neural networks aren’t yet perfect, and some of the flaws so far reported include
that they can show bias, prejudice and inaccuracy.
If, then, we had a second brain and it was an artificial one, yes, we could have total
control over how it performs… deciding what it focuses on, and how it shares the load
with our organic brains.
But the door would also be open for our brains to digitally malfunction or corrupt over time.
And, more than that, there could even be opportunity for someone to deliberately misuse their second
brain, potentially even to the point of weaponizing it.
The whole exercise does throw up an interesting paradox, though, because if you had a second
brain, but that second brain had been built using the knowledge housed in your original
brain… then could it ever be considered that different from what you always had?
In this way, an AI brain might only ever be an extension of rather than an outright addition
to our bodies, with its existence and performance totally shaped by the brain that came before
it; the one that made it.
If AI doesn’t do it for you, then, and you’d prefer another organic brain, there could
still be options for you in the future.
Though the science is very much in its infancy, so-called mini-brains have been grown in labs
using stem cells - including as part of a 2018 study, at the University of California.
These brains, or “organoids”, aren’t much to speak of yet - they’re just tiny
blobs of tissue - but they have been shown to exhibit electrical brain activity.
We’re still a long way away from growing whole, alive and conscious brains in this
way, but it’s now not quite so farfetched to imagine that future humans could have themselves
a backup for even the most complex of their internal organs.
But, what could you actually do with that back-up?
We already have enough brain matter to control our bodies and carry out complex functions,
so how would this extra space be best used?
Well, there’s some evidence that the amount of grey matter a person has influences how
intelligent they are… so, if everyone had double the amount, we’d all potentially
be twice as smart.
By our current standards, everybody on Earth could actually be a genius.
And, with billions of genuine geniuses just walking around the place, who knows how much
more advanced our science and technology could become?
Current scientific mysteries like finding a cure for cancer, or developing interstellar
space travel, might all be solved with all that extra brain power.
Humanity, as a species, could advance at a much-increased rate.
We could also all drastically improve our memory.
The science of memory is famously difficult to unravel, but it’s been found that children
tend to have significantly better memories than adults do.
That, generally speaking, memory degrades over time.
Eidetic memory (where you can perfectly recall images), is also an ability that, if you ever
had it, tends to gradually weaken as you get older… but, with access to a second brain,
you could choose to preserve cognitive skills like these within your backup cortex.
It would be the ultimate memory machine - meaning that nothing you ever knew, or saw, or thought
about, would ever be forgotten.
But would all these potential changes actually be for the better?
On the face of it, higher intelligence would be no bad thing.
If we all put our second brains together for a better world, we could wind up in some kind
of sci-fi Utopia where everyone’s always happy and no-one ever dies.
But, on the other hand, how long before a society full of geniuses begins to distort
into something else?
Something unrecognisable, and maybe something worse?
Say our extra brains existed apart from our bodies, for example, on machines or in purpose-built
storage facilities.
These brain libraries would be a prime target for thieves and attacks.
With so much more knowledge in the world, there could be so much more to fight about.
And, if this alternate reality played out so that not everyone had a second brain, only
a chosen few, then social division would be greater than ever before.
Even just with regard to memory, there are positives but also negatives.
Happily, you could easily remember all of the best days and moments of your life, using
your second brain to retrieve photographic recollections of them whenever you please.
But the same would also be true of your worst memories, which could return again and again
and again, each time as clearly as the last.
Ultimately, people could end up becoming addicted to their second brains, constantly revisiting
the information they’d contain, and neglecting everything else that their original brains
encounter.
If society went in this direction, then it could mean widespread personality changes
and, rather than a broadening of our horizons, there’d actually be a narrowing of our world
view.
It’s an alternate reality in the balance.
We’d be potentially smarter, potentially healthier, and potentially happier… but
there’d also be potential for things to go wrong.
And that’s what would happen if humans had two brains.
What do you think?
Is there anything we missed?
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