HOMO INSAPIENS:
THE SHRINKING HUMAN
BRAIN
by
Mike McInnes
T
he human brain is shrinking for
the first time in our evolutionary history – for 2 reasons, one
positive and one wholly negative. In an
upright bipedal species with a narrow
pelvis (Homo sapiens), the brain has
reached its limit of size, because a larger
brain would not exit the pelvic canal at
birth. Therefore the only way that the
brain may continue to evolve and develop is to become smaller and smarter, a
selective advantage that has been underway for around 15,000 years. In this very
short time span the human brain has lost
around 150mls – that is around 10% of its
volume.
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