The end of the War saw an expansion in the aims and contents of technology. Upon his appointment to the University of Lyon, Leroi-Gourhan quickly acquired fieldwork and training experience in ethnology and also in prehistoric archaeology. This led him to pay greater attention to the achievements of experimental flintknapping (as notably practised by François Bordes). Studying the different techniques used throughout prehistory for knapping stone tools could serve to characterize distinct epochs and civilizations, but also, so claimed Leroi-Gourhan from 1950 onwards, to ‘follow the gestures, flake by flake, [so as] to reconstruct with certainty an important part of the mental structure of the maker’. This innovative search for the ‘prehistoric mentality’ sets Leroi-Gourhan as a forerunner of ‘cognitive archaeology’, and it also led him to formulate the concept of the chaîne opératoire, which follows processes of manufacture and use from raw material to finished product.