Leroi-Gourhan suggested the concept of technical tendency, considering that it is independently articulated to the ethnical logic that is associated to human sociability. Its fulfilment was made possible through technical facts (L'Homme et la matière - 1943). Later, in his essay Milieu et techniques (1945), Leroi-Gourhan showed a general theorisation of the relationship between technical tendency and the ethical dynamics associated to human sociability. Human groups relate to the outside environment (geography, climate, animals and vegetation) through technical objects (an outer skin) as if these were living organisms possessing a living environment made of memory and culture. Technical tendency thus appears as a flux in which the inner environment gets increasingly greater anchoring as to the outside environment through technical facts. In Le geste et la parole (1964-65) he held that, in order to understand human evolution, the importance of man’s transition to erectness, as he freed his hands to manual activity and the face for gestures and human language, should be stressed, as it paved the way to the development of the cerebral cortex, to increasingly more complex technology and to the language of linguistic signs Leroi-Gourhan essentially used archaeological research to posit the criteria that define the human. In his own words, "freeing the hand meant almost subsequently different technical activity from that of monkeys and its freedom during locomotion, together with a short face with no offensive canines, commands the use of the artificial organs constituted by utensils. An erect position, short face, free hand during locomotion and the possession of movable utensils are truly humankind’s fundamental criteria" (Leroi-Gourhan, 1990: 26). According to André Leroi-Gourhan, "the human conditions of the vertical position have consequences in the neuropsychical development which cause the development of the human brain to be more than a simple increase in volume. The relationship between the face and the hand is still as intimate to the development of the brain as the utensil was to the hand and language to the face used to be two sides of the same device" (Leroi-Gourhan, 1990: 27). Tools and technology therefore become a kind of external memory, added to the genetic memory of the DNA and of each individual’s brain, which characterise humankind.
André Leroi-Gourhan, O gesto e a palavra, vol. 1 - Técnica e linguagem, Lisboa, Edições 70, 1990
André Leroi-Gourhan, O gesto e a palavra, vol. 2 - Memória e Ritmos, Lisboa, Edições 70, 1971.
Several, “André Leroi-Gourhan”, in Wikipedia English http://en.wikipedia.org/wiki/Andr%C3%A9_Leroi-Gourhan [30 July 2008].