This paper examines the first moments of the emergence of “psychometrics” as a discipline, using a history of the Binet–Simon test (precursor to the Stanford–Binet) to engage the question of how intelligence became a “psychological object.” To begin to answer this, we used a previously-unexamined set of French texts to highlight the negotiations and collaborations that led Alfred Binet (1857–1911) to identify “mental testing” as a research area worth pursuing. This included a long-standing rivalry with Désiré-Magloire Bourneville (1840–1909), who argued for decades that psychiatrists ought to be the professional arbiters of which children would be removed from the standard curriculum and referred to special education classes in asylums. In ...