Ispectrum Magazine Ispectrum Magazine #06 - Page 29

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. 28