4.6 Critical thinking and science 165
typically live with only three or four others,
groom for 5 per cent of their day at most.
Baboons, meanwhile, live in groups of 50 or
more and can spend as much as 20 per cent
of their time grooming. However, as group size
and time spent grooming increases, this
social effort is concentrated on fewer and
fewer partners.
Although we use grooming in intimate
relationships, the very intimacy of the activity
makes it ineffective as a tool for bonding our
large social groups. Instead, we have evolved
alternative ways to create the same endorphin
surge on a bigger scale. One of these is
laughter, another is communal music-making.
Language, too, plays an important role – not
only can we speak to many people at the
same time, we can also exchange information
about the state of our networks in a way that
other primates cannot. Gossip, I have argued,
is a very human form of grooming.* ‘Grooming’ means tidying, removing dirt or
nits from fur, etc.DOC C
Primates with a large social network have
bigger brains*** Neocortex ratio = neocortex volume divided
by volume of the rest of brain* In Doc C ‘bigger brains’ means more than just
brain volume. It is the proportion of the whole
brain that is associated with higher functions
like perception and communication. This is
called the ‘neocortex’. In humans the neocortex
is the part of the brain which enables language,
reasoning and conscious thought.HumansApesMonkeys1000100101
12
Neocortex ratio**345Mean group sizeNow that you have had a chance to discuss
and think about the issues and terms involved,
we can turn to a text which deals with the
subject on a more scientific level.
A scientific study
A scientist who has undertaken extensive
research in this area is Robin Dunbar, Professor
of Evolutionary Anthropology at the
University of Oxford. His research focuses on
the evolution of sociality in the primates: the
order that includes apes, monkeys and
humans. He is particularly interested in the
structure and dynamics of human social
networks. The following extracts are from an
article published in New Scientist. Although
they all come from the same article, they are
presented here as four separate documents to
make them easier to refer to in the activity
which follows.
DOC A
We tend to think of social networks as being
distinctly human. In fact, they occur wherever
animals live in ‘bonded’ groups – where
individuals gather together because of their
personal relationships rather than being forced
to by environmental factors such as a food
source or safe sleeping site. Bonded groups
are found among all primates and a few other
mammals... Such networks have benefits,
but they are also costly to maintain and are
only an option for the smartest of species.DOC B
Monkeys and apes create and nurture social
relationships by grooming* each other. The
physical action of being groomed is rather like
massage and triggers the release of
chemicals called endorphins. This creates a
light euphoria that seems to make it possible
for animals that groom each other to build a
relationship based on friendship and trust.
The average time spent grooming by members
of a species correlates with the size of their
social group. Those, such as gibbons, which