In the context of vocational training, transactional analysis and neuro-linguistic programming have been promoted to the ranks of communication science. To understand this phenomenon, the author proposes a critical analysis of the social uses of this knowledge. He shows that the success of its diffusion can be explained by various factors, including opacity of the sector, social characteristics of teachers, unconditional adherence to common sense, and «psychologization» of social relations.Dans le cadre de la formation professionnelle continue, l'analyse transactionnelle et la programmation neurolinguistique ont été promues au rang de science de la communication. Pour comprendre cet engouement, l'article propose une analyse critique des usa...