Jeremy Taylor’s aim in this book is to show how a fashionable idea among scientists and science communicators – that the gap between human and chimpanzee cognition and behaviour is almost negligible – is in fact hugely mistaken.
The belief that there is little difference between humans and chimpanzees in terms of cognition and behaviour is significantly based on genetic studies of recent years which have appeared to show that the human and chimpanzee genomes are roughly 98.4% identical. But as Taylor points out in the earlier sections of the book, genetic similarities don’t necessarily entail cognitive and behavioural similarities, especially when only a small handful of genes can have the ability to make one species dramatically different from another. In any case, these earlier sections explain, there is good reason to believe that the 98.4% figure is misleading: when we study more closely the two species’ genomes, we notice, for example, that many of the genes we share with chimpanzees are active in chimps but are no longer active in humans; that identical genes are expressed differently in humans and chimps; and that some of the genes we share with chimps have been duplicated in human beings, increasing the effects of these genes in humans.
Added to this, we find out later in the book that there is no clear evidence that chimps possess a theory of mind like the human capability. This enables us to appreciate the hidden intentions, beliefs and desires of somebody else by merely observing their actions. We find, indeed, that crows are in many respects more cognitively advanced than chimps. All of these fascinating insights go to show how far we are set apart from chimps, and they mean that it is not difficult for us to account for unique traits in humans like artistic creativity and the ability to develop complex languages.
Throughout the book, Taylor presents the material in a way that is accessible to the general reader, and the amount of research he describes and brings together makes his arguments, by and large, very convincing, and means the book is likely to be appealing even to experienced primatologists.
There is one respect in which the book could have been a little stronger, and this is where the focus moves away from the science and on to the question of whether we should extend certain human rights to chimpanzees – the right to life and to protection from torture, for example – as some, like the philosopher Peter Singer, have suggested. Taylor criticises this view given the differences between the species mentioned above but, at times, gives the impression that people like Singer want us simply to view chimpanzees as fully human, which no one is suggesting. Ultimately, here, there is a slight tendency here not to appreciate the arguments and positions of the other side and to oversimplify the issues.
Only a small portion of the book is dedicated to that discussion, however, and Taylor’s clear and comprehensive coverage of the science more than makes up for any shortcomings elsewhere. There is much in the book we need to bear in mind when thinking about our relationship with chimpanzees and the rest of the animal kingdom, and I would recommend it.