Making a Difference

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Review of 'The Human Story', Robin Dunbar, Faber & Faber £12.99

Ever since Charles Darwin proposed that humans and apes share a common evolutionary ancestor, we have been fascinated to understand what distinguishes us from our simian cousins. One of the most astonishing facts of modern genetics, confirmed this year by the completion of the chimpanzee genome project, is that there is only 1.2 percent divergence between our genes and those of the chimp. How such an apparently tiny biological difference can account for everything we take for granted about human existence - cities, transport, science and technology, literature and music - is one of the most important unanswered questions of science.

In this book Robin Dunbar asks how humans came to be different from other animals. One way to approach this question is to use the evidence of bones and tools, or more recently DNA sequences, to uncover the stages of human evolution. Dunbar provides a very readable and up-to-date introduction to such studies, and his book is worth reading for this alone. However, he is most concerned about what we can learn about humans from comparisons between ourselves and apes.

One important human characteristic that Dunbar highlights is our ability to work out what other humans are thinking and to modify our behaviour accordingly. He draws attention to what he calls 'intentionality of mind', of which there are different degrees. Zero-order intentionality means not even being aware of the contents of one's own mind. This would certainly be true of an amoeba, or a computer for that matter. Dunbar believes many animals possess first-order intentionality in that they 'know' they are hungry or 'believe' that there is a predator hiding under a nearby bush. However, he is far more sceptical about whether they have any awareness of what might be going on in the heads of other members of their species.

In contrast, humans can imagine not only what others might be thinking but also what they themselves are thinking about the desires and beliefs of others. The big question is whether apes are hovering on the edge of such higher-order intentionality. Certainly some intriguing studies have suggested they have very complex social relations that can involve trying to persuade or deceive others. But this is still a world away from being able to understand and interpret the thoughts of others as even very young human children learn to do.

One interesting section of the book is when Dunbar discusses how capable other animals are at passing on skills to future generations. It used to be thought that only humans could pass on new ways of doing things to others. However, this assumption was dealt a blow in the 1950s by the observation that blue tits, having acquired the ability to break open the old cardboard tops of milk bottles, were apparently passing this knowhow on to other tits. Then a scientific study found that wild macaque monkeys seemed to be passing on another useful learned behaviour - the use of sea water to wash the gritty sand from sweet potatoes.

So far, so good. But Dunbar questions whether this is really analogous to human social transmission of ideas and skills. One big difference is that while humans seem to learn by genuine copying of others, both blue tits and apes notice that their fellow animals are up to something, but then learn the skill not by copying but by a laborious process of trial and error. There also seems to be little evidence of genuine teaching in the animal world.

Given it is focused primarily on understanding what makes the human mind unique, one of the most disappointing aspects of this book is how little grasp Dunbar seems to have of the role that language plays in shaping our thoughts. It is not that Dunbar ignores language - rather that he seems to be unaware of what makes it unique. So there is lots here about the role that language plays in helping humans bond as a group, echoing Dunbar's previous book Grooming, Gossip and the Evolution of Language.

But there seems to be little awareness that language as a system of abstract symbols is what allows us to create a conceptual framework of the world around us, as well as to imagine worlds that we have never experienced. This, and our proficient use of tools, is surely what lies behind our ability to transform the world around us in such a unique way. Maybe this is why Dunbar reaches the astonishing and erroneous conclusion that of all human attributes, and that includes the arts and sciences, it is only really religion that qualitatively distinguishes us from apes.