[Alfred Binet and the first 'measures' of intelligence (1905-1908)].

Alfred Binet (1857-1911) is considered the most representative exponent of the second generation of French experimental psychologists. His scientific work was inspired both by the experimentalism that Théodule Ribot and Hippolyte Taine introduced in France at the end of the 1870s, and by that of Wundt. Drawing from numerous sources, Binet was able to elaborate a psychology that focused on experiments and a controlled observation of pathological phenomena, with the objective of differentiating them from normal phenomena. His scientific production was moreover characterized by the emphasis placed upon the experimental study of "superior" psychic phenomena and, in particular, on their measurement. The aim of this paper is to describe the stages and sources of the "psychological" study of intelligence, which constituted precisely the fil rouge that had indispensably to be followed in order to fully understand the originality of all of Binet's research, whose most mature product was undoubtedly represented by the development of the Echelle métrique de l'intelligence, the first intelligence test in the history of psychology.