The Meme Machine

90 THE MEME MACHINE
Brain lateralisation apparently began with the earliest appearance of Homo but is
not proof of language.
The brain is not the only part of the body that has been modified for speech.
Exquisite control of breathing is needed and this meant changes in the muscles
of the diaphragm and chest. We have to be able to breathe automatically, as do
all land mammals, but then to override the mechanism when speaking, which
requires cortical control over the muscles. The larynx is also much lower in
humans than in related primates, which makes possible a greater variety of
sounds, and the base of the skull is a different shape.
When did these changes take place? Neither larynx nor muscles fossilise, but
other clues can be used. One is the base of the skull, the shape of which affects
the range of sounds that can be made. It appears flat in australopithecines,
slightly flexed in H. erectus, and only becomes fully flexed as it is in modern
humans, in archaic H. sapiens, suggesting that only modern humans could make
the full range of sounds that we use now. Another clue comes from the
thickness of the spinal cord. Modern humans have much larger thoracic spinal
cords than apes or early hominids, presumably because speech requires precise
cortical control over breathing. The palaeontologist Alan Walker made a
detailed study of a 1.5-million-year-old H. erectus skeleton – the ‘Nariokotome
Boy’ found near Lake Turkana in Kenya. This skeleton was well preserved in
just the right parts of the spine and showed no thoracic enlargement. In this
respect, the Nariokotome Boy was more ape-like than human. As Walker got to
know the boy through his ancient remains he became more and more convinced
that erectus was speechless, and the boy less like a human trapped in an ape’s
body and more like an ape in a human body. ‘He may have been our ancestor,
but there was no human consciousness within that human body. He was not one
of us,’ concluded Walker (Walker and Shipman 1996, p. 235).
All these clues do not give a final answer. Even if we thoroughly understood
the anatomical changes involved in producing speech we would not necessarily
understand the psychological changes. As psychologist Merlin Donald (1991)
points out, there is much more to modern symbolic cultures than language alone,
and more than language separates us from our ancestors and from other living
primates. Language evolution needs to be understood in relation to the rest of
our cognitive evolution.
Perhaps the best we can conclude for now is that language did not appear
suddenly, as some linguists have suggested. The evolutionary changes which