Book review: The Human Story (Robin Dunbar)

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Robin Dunbar

THE HUMAN STORY

A new history of mankind's evolution

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Book review by Anthony Campbell. Copyright © Anthony Campbell (2004).
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Robin Dunbar is Professor of Evolutionary Psychology at the University of
Liverpool. This short book is aimed at a non-professional audience and scores
high for readability, but it is very much one man's view of how we have got
where we are today. This becomes evident at the outset, when, after a brief
impressionistic sketch of human origins, starting with the Australopithecines,
Dunbar unequivocally dismisses the Neandertals as a separate species, partly on
the basis of recent DNA evidence. He takes the "out of Africa" hypothesis to be
the settled view and does not consider any alternatives. His main focus of
interest, in any case, is on the origins of modern human consciousness.

Central to his approach is the concept of "intentionality", which refers to
mind states such as believing, hoping, intending and so on. There can be orders
of intentionality. Simply understanding that other people have thoughts is
second-order intentionality, but things can get more complicated. To use
Dunbar's example, Iago had to intend [1] that Othello would believe [2] that
Desdemona wanted [3] to love another for his plot to work. Moreover, we, the
audience, need fourth-order intentionality to understand the play, and
Shakespeare needed fifth-order intentionality to be able to write the play so
as to produce the appropriate response in us.

Modern humans are capable of fifth-order and sometimes of sixth-order
intentionality. Chimpanzees and other anthropoid apes can apparently manage
only second-order intentionality at best, it seems, and Dunbar thinks that this
is the main reason why they have not acquired language. The crucial factor
here, he believes, is the typical group size in which the different species
live. Larger group sizes in early human societies promoted the growth of larger
brains, with the capacity for higher-order intentionality and ultimately the
development of language.

Dunbar has an interesting discussion of the origins of language. How far back
does it go, and what about our old friends, the Neandertals? We can get some
clues from comparative anatomy. The motor nerve to the tongue (the hypoglossal)
emerges through a canal at the base of the skull, so it is possible to gauge
its size in fossil skulls. Both the Neandertals and the Cro-Magnons had large
canals, whereas those Australopithecine skulls in which the diameter can be
measured had ape-sized canals, but there are too few suitable fossils to allow
us to be certain about when the change occurred. Another anatomical clue comes
from estimates of the diameter of the spinal canal in the upper thoracic
vertebrae. An enlargement here may be related to the fine control of breathing
needed for speech; it is found in both modern humans and the Neandertals.
Taking these two measurements together, Dunbar suggests that the latest
possible date for the development of at least some form of speech must be about
half a million years ago.

Dunbar also looks at the development of speech from a different, and less
conventional, direction. He regards speech in humans as having arisen to take
the place of grooming in other primates, and thinks that in its earliest form
it may have consisted of singing ("chorusing") and laughter rather than the
communication of information, which came later. He constructs a rather
elaborate argument to relate brain size to the amount of time that a group of
hominids would have to spend on grooming in order to maintain social stability.
The maximum amount of time (allowing for finding food) that monkeys and apes
devote to grooming is 20 per cent of total daylight time. Once our ancestors
found that, because of group size, they needed to exceed this limit, a vocal
element would have been introduced. Grooming plus "chorusing" would take them
to the equivalent of 30 per cent of their time, and beyond this point they
required speech.

I find this is an intriguing speculation, if difficult to verify, and it
prompts other thoughts. The relative absence of physical grooming, outside
family or sexual contexts, in modern human societies certainly calls for
comment, and it seems quite possible that part of the success of manual
therapies such as osteopathy and even acupuncture may be due to the fact that
they provide a setting in which physical contact between relative strangers is
considered acceptable.

As language developed, more elaborate forms of culture also became possible.
Chimpanzees do seem to have the beginnings of culture, but Dunbar thinks that
their inability to perform at higher levels of intentionality explains why they
can never acquire complex cultures of the human kind. No chimpanzee could
follow the plot of Othello. And it is, he believes, this human capacity for
high-level intentionality that has led to the invention of religion in every
human societies that we know of.

Dunbar doubts that there is any good evidence for religion or belief in an
after-life among the Neandertals. This is rather surprising, given that their
average brain size was as large as ours or even a little larger. If they really
lacked religion, he suggests, this may have been because their frontal lobes
(needed for abstract thought) were relatively undeveloped although they had
larger occipital lobes (connected with vision). This may indicate that they had
a lower order of intentionality and hence less complex language than the
Cro-Magnons. And, finally, if they did not have religion, their society may
have been less cohesive than that of the Neandertals and this may explain their
failure to survive.

This is an interesting discussion and Dunbar's view of religion is similar to
that of David Lewis-Williams in The Mind in the Cave, which he cites. However,
there do seem to be rather a large number of assumptions in the chain of
argument, but if it is right, we face today, as Dunbar remarks, something of a
dilemma. Our evolutionary success appears to have been linked with the
development of religion as a cohesive social force, and there is quite a lot of
evidence to show that societies which are firmly based in religion are more
stable and have better psychological health than less traditional societies. Is
it possible to produce these effects in a secular society, or does the rise of
rationalism threaten our social stability? And does this help to explain the
rise of religious fundamentalism in so many parts of the world today? Perhaps
T.S.Eliot (himself a Christian) was right, though not in the way he meant, when
he wrote: "Human kind cannot bear / very much reality."

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%T The Human Story
%S A new history of mankind's evolution
%A Robin Dunbar
%I faber and faber
%C London
%D 2004
%G ISBN 0-571-19133-9
%P 216 pp
%K evolution
%O illustrated with line drawings
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