It is now well known that the appearance of tools precedes that of man, and furthermore, that tools are not the exclusive attribute of the Hominidae. Recent research in animal behaviour shows that many species, not only our closest ‘cousins’ the chimpanzees and other great apes, are capable of selecting a branch or a stone to obtain food which is not directly accessible to them and that, in some cases, they may go elsewhere to look for a suitable instrument, or put it aside for later use. Memory, the choice of a suitable instrument, and the medium-term retention of information are the intellectual faculties necessary for the construction of a chaîne opératoire. It seems, however, that only some of the great apes are capable of making or reworking a tool (Beyries and Joulian 1990).

The chaîne opératoire, however, is not limited to the domain of tools: the building of a nest or a beaver lodge, and the hoarding of food supplies for hibernation, are other examples. The behaviour of certain animal species thus reveals systems of technology which have to be compared with those of humans if we wish to understand what distinguishes innate and learned capabilities. The study of the slow evolution of human intelligence over three million years is clearly one of the research directions which the cognitive sciences must explore in order to understand the dialectical relationship between intellectual activities, which we define as logically-based (analysis of information by induction and deduction), and those which are non-logical (coding of information based on perception and memory, selection, comparison, recoding, etc.).