You are your brain. Without it you wouldn’t exist. Finding out how
these three pounds of greyish-pink, spongy tissue give rise to you
remains one of science’s greatest challenges. Some clues reside in the
brain’s sheer physical complexity. Superlatives are hard to resist when
it comes to an organ boasting more brain cell connections than there
are stars in the galaxy. For technophiles who like to marvel at the full
specifications, that’s around one hundred billion neurons forming five
hundred trillion connections (a five, with fourteen zeroes after it). And
we shouldn’t forget the brain’s housekeeping cells, the glia, of which
there are upwards of one hundred trillion. All this hardware comes at
a price. The brain accounts for just two percent of our body mass and
yet consumes a whopping twenty percent of our energy.
But let’s not be too reverential. As David
Linden points out in his book The Accidental
Mind, it’s an organ built out of yesterday’s
parts. Like the car engine with its irration-
ally sized components and other oddities,
the brain is what engineers would call a
“kluge”. It’s a clumsy design, inelegantly
constructed, that nonetheless gets the job
done. The reason the brain is a kluge is
that it never had a designer. It emerged
piecemeal as a result of evolution by natural
selection. It’s why we find brain areas asso-
ciated with human-like thought plonked
atop of more primitive regions also found
in many animals, and why we find many
parallel systems and “redundancy” – that is, the same or similar func-
tions fulfilled by more than one brain region or system.
Your brain
“... at every level of
brain organization,
from regions and
circuits to cells
and molecules, the
brain is an inelegant
and inefficient
agglomeration
of stuff, which
nonetheless works
surprisingly well.”
David Linden, The
Accidental Mind (2007)