The History of Psychology is a privileged field of reflection on the processes of construction and transformation of the discourses and practices of psychology over time, allowing put into perspective the complex diversity of our discipline. The story that follows this article aims to describe, analyze and explain the conditions that allowed the emergence of Applied Psychology [Psicotecnia] and its first applications. The origins of the “Psicotecnia” are located at the beginning of the twentieth century and were based on referrals of experimental psychology and the contributions of the psychology of individual differences. With tools derived from this crossing, psychology began to address social and business demands. The First World War marked a period of expansion and consolidation of “Psicotecnia”. Each of the countries participating in the war, called for psychology to resolve issues related to the selection, training and rehabilitation of their troops. After the end of the Second World War, the term “Psicotecnia” associated with the defeated or weakened countries during the war, literally disappears from the international arena. Instead, the term Applied Psychology –that traditionally had US backing– is imposed.
Keywords: History, Applied Psychology, discipline, war