Introduction

The relationship between language and thought is a classical problem of psychology and philosophy. Can we learn anything about it from a comparative perspective? Is there such a thing as a language-and-thought issue in non-human animals? A first problem for such a comparative approach is that, although most scientists would accept that there is some degree of continuity between our closest evolutionary relatives – non-human primates – and ourselves in terms of our intellectual abilities, this is hardly considered to be the case with linguistic abilities. Although we can identify something like rudimentary ‘thought’ or ‘intelligence’ in non-human animals, it seems that there is nothing worth the name of language in them.

Our sympathy towards intellectual continuity is due, in my view, to the convincing nature of classical findings like those of Köhler (1927) and Goodall (1968), showing that one of our most cherished expressions of intelligence – tool use and problem solving – is present in both captive and wild chimpanzees. Of course there can be controversy about the extent to which there are qualitative differences between ape and human intelligence. But, even assuming that considerable differences exist, there is a relatively non-problematic acceptance of continuity in relation to the origins of thought. After all, continuity does not imply identity.

This is clearly not the case with one of the all-time favourite enigmas of science: the origins of language. An influential view in recent decades has been that language is such a radically new evolutionary product that, in contrast to intelligence, no traces of it can be found in non-human primates.