Description: The Belgian educational reformer Ovide Decroly (1871-1932) acquired worldwide renown thanks to his new school, founded in 1907, and the progressive educational method named after him. Actually, perhaps he acquired this renown primarily because he, like Maria Montessori, developed his educational method on the basis of his psychological and physiological insights into the so-called abnormal child. In other words, he owed his status as pioneer and hero of (new) education first and foremost to his background as neurologist and professor of child psychology. Within his scientific research he paid attention to clinical observations, medico-pedagogical records and inquiries, biometrical examinations, various kinds of tests and, last but not least, cinematic (psychological) studies of the child. In this paper we will focus on the latter, for this kind of research was rather unique in the world (at the time) and this allows us to add a new issue to the topic of visualization, one of the major themes of the past few years within the Histories of Education Network.My research question will point at the interpretation levels one can distinguish within this kind of films. At first sight Decroly's films seemed to be just a particular scientific method that opened up several possibilities with regard to the observation of the child. The problem is that we not only have to take into consideration what we see on the screen, but also what we NOT see. After all, Decroly was also one of the pioneers of the New Education Fellowship (NEF), which was in the period between the First and the Second World War the forum par excellence for new education (mainly) in Europe. In 1927 the International New Education Film Association (INEFA) was established within the NEF, with Decroly as one of the founding members. The objects of this association were to provide films of new schools in different countries and films dealing with child psychology for use in educational institutions; to supply the public with information by means of films; to collaborate with first-class film producers in financing the publication of films expressing the aims of the Association. So, the question is: do we really have to distinguish between those films dealing with child psychology and the films of new schools? Don't we have to consider both types of films as being technologies of one and the same propaganda campaign? Methodology: In order to answer this question we will try to contextualize Decroly's psychological films with the help of his publications, for these were partially based on his films and provide us information about the use/aims of the films. Especially we will focus on one particular film dealing with child psychology for (1) this film was presented at a conference which was related to new education and (2) this film has been analyzed and contextualized within Decroly's own publications. Conclusions: Our analysis will demonstrate that Decroly's psychological films not only showed a scholar who was enthusiastic about the technical and scientific aspects, but who was also concerned about the propagandist means of the films he provided. Through his films scientific knowledge on the child was transformed into a propaganda campaign for promoting new education. We'll also gain an insight into the relationship between the pioneer and the adept, between the scholar and the educational reformer Decroly.