According to science fiction,
a bigger brain means
superhuman intelligence.
It means you could solve some of the
world's most complex problems
in a matter of seconds.
But would a bigger brain
really make you smarter?
The average human brain
weighs about 1,300 - 1,400 g (about 3 lbs).
If that were to double to 2,700 g (about 6 lbs),
that would mean a lot more weight
for our bodies to deal with.
Our necks would need to be
larger and stronger.
Our shoulders would have to be broader
to support that extra weight,
and as a whole,
our bodies would need to be much thicker.
They might not seem like that big of a deal,
but these new physical features
could cause a lot of problems.
For instance,
what kind of effects would they have
on childbirth?
It might seem a little far-fetched
to think of our brains as
continuously changing in size,
but in reality, it's been happening throughout
our entire evolution.
Our ancient relatives, Homo habilis,
had a brain one third the size of ours.
And over the past two million years,
it evolved to be the size it is today.
Using this example, you might be thinking,
"well we are clearly more intelligent
than they were, and we have bigger brains,
so therefore a bigger brain
equals more intelligence."
But that's not the case.
Our brains stopped growing about
20,000 years ago,
when we developed stone tools.
And we'd like to think we've become
a bit more intelligent since then.
But during the past 20,000 years
of human progress and development,
our brains have shrunk by 10%.
A meta-analysis of over 8,000 brains
was conducted in 2015.
The researchers found that
the size of our brains
accounted for only about 6%
of the difference in IQ between people.
Researchers from
the University of the Witwatersrand
in South Africa found that
the rate of blood flow to the brain
may be a better indicator of intelligence.
The rate of blood flow to the brain
seems to have increased in all
primate lineages over time.
But in the hominin lineage,
the one that led to us,
it increased quicker.
This increase went side by side with
the development of tools,
the use of fire,
and communication within small groups.
So if your brain were to double in size,
it's not likely that your intelligence
would double along with it.
Sorry about that.
Instead,
it would just introduce a lot of problems.
As we mentioned,
our bodies would become thicker
overall to support
the greater weight in our heads.
This would likely be good news
for the massage industry,
because our necks and shoulders would
likely feel sore more often.
But it would be bad news
for expectant mothers.
Not only would each fetus
need much higher amounts of nutrients,
but vaginal births would
also become extremely difficult.
They might become obsolete,
and C-sections could be the new normal.
And the issues don't stop there.
Because of the extra energy
we'd need to support our
bigger, heavier brains,
people could become less mobile.
And our bodies might grow much slower,
and we might not get as tall.
So maybe we don't want a larger brain after all.
Who knows if our brains will
continue to shrink,
or if they'll start getting bigger again?
Whichever direction evolution decides
to take us,
you can be sure that technology
will play a big part in it.
Maybe one day we'll just
upload our brains into some
giant cloud computer.
But that's a story for another WHAT IF.