The Meme Machine

MEME–GENE COEVOLUTION 97
requirement for grooming becomes impossibly high until there are simply not
enough hours in the day. Baboons and chimpanzees live in groups of about fifty
to fifty-five and spend up to a fifth of their time grooming, but humans live in
even bigger groups. We may be able to recognise up to a couple of thousand
people, but the more important group size, argues Dunbar, whether in social life,
the armed forces or industry, is about one hundred and fifty. Extrapolating from
monkeys and apes suggests that we would have to spend an impossible 40 per
cent of our time grooming each other to maintain such large groups.
That, says Dunbar, is why we need language. It acts as ‘a cheap and ultraefficient
form of grooming’ (1996, p. 79). We can talk to more than one person
at once, pass on information about cheaters and scoundrels, or tell stories about
who makes a reliable friend. So, Dunbar rejects ideas about language being
primarily a male-dominated function used for hunting or fighting strategies and
suggests instead that it is all about cementing and maintaining our human
relationships.
But the obvious question now is why there was selection pressure for larger
groups. Dunbar’s answer is that our ancestors faced increasing predation as they
moved out of the African forests and into the grasslands; safety in numbers
would have been a valuable strategy for survival and they had already reached
group sizes too large for any more grooming. But many other species have
managed other ways of living in the grasslands, some in large herds and others
in smaller groups. So could this pressure for larger groups really explain all the
drastic and expensive changes required? Dunbar’s theory hinges on this point.
Other theories emphasise the evolution of using symbols (e.g. Deacon 1997;
Donald 1991). The Harvard neuroscientist Terrence Deacon proclaims humans
‘the symbolic species’. He argues that symbolic reference provided the only
conceivable selection pressure for the evolution of hominid brains – and by
symbolic reference he means the use of arbitrary symbols to stand for something
else. Among the advantages of symbolic communication are mother-infant
communication, passing on foraging tricks, manipulating competitors, collective
warfare and defence, passing on toolmaking skills, and sharing past experiences
– ‘there are too many compelling options to choose from’ he says (p. 377) – but,
he argues, these could only have come into play once the ‘symbolic threshold’
was already crossed. Once true symbolic communication was possible simpler
languages (now extinct) would have created a selection pressure for bigger and
better brains able to understand them and extend them, leading ultimately to our
modern kind of language. But we had to cross ‘the symbolic threshold’ in the
first place.