The Meme Machine

CHAPTER 6
The big brain
The human brain is enormous. Why? Nobody knows for sure. Certainly there
have been many theories of the origins of the huge human brain, but still none is
universally accepted and a mystery remains. Most theorists assume that the big
brain must have evolved by natural selection, such as the American
neuroscientist and anthropologist Terrence Deacon (1997) who ways ‘It cannot
be doubted that such a robust and persistent trend in brain structure evolution
reflects forces of natural selection’ (p. 344) – but if so we must be able to
identify the selection pressures involved. So what are they? The answer is not
obvious, and the explanatory task to be performed is great. It is basically this.
Origins of the human brain
Human brains today are capable of extraordinary feats quite beyond the abilities
of any other species on the planet. Not only do we have language but we have
invented fridge-freezers, the internal combustion engine and rocket technology;
we can (well, some of us can) play chess, tennis and Mega-Death 6; we listen to
music, dance and sing; and we have created democracy, social security systems
and the stock market. What possible evolutionary advantage could these things
have? Or more precisely what selective advantage could there have been for a
brain capable of such things? We seem to have a brain ‘surplus to requirements,
surplus to adaptive needs’ (Cronin 1991, p. 355).
In Darwin’s time this question so vexed Alfred Russel Wallace that, despite
having independently discovered the principle of natural selection, he concluded
that it could not account for man’s higher abilities (Wallace 1891). Primitive
hunter-gatherers could not possibly have needed brains such as these, he
reasoned, so there must have been some kind of supernatural intervention.
Wallace supported the spiritualists who were claiming to be able to
communicate with the surviving spirits of the dead, while Darwin fought against
them. Wallace believed that the intellectual and spiritual nature of man was so
far above that of the animals that we were different in kind from them.
Although our bodies were developed by continuous modification of ancestral