Contribution à l'étude de la construction des concepts scientifiques au cours de l'apprentissage par problèmes en médecine

 The Problem-based learning (PBL) approach was developed, in its contemporary form, at the Faculty of Medicine, of MacMaster University in Ontario (Canada) in the late 1960s. Very quickly, this new active pedagogical approach, student-centered and based on biomedical problems, will be adopted by many medical schools around the world and used also in other disciplines. Despite its apparent success, however, PBL is also a controversial approach, particularly in medical education, where it has been blamed for promoting superficial learning. Furthermore, it has been documented that students trained by this approach, tend to be less successful at tests assessing the acquisition of basic scientific concepts.To what degree doctors trained by PBL excel in their work as doctors, remains to be determined as well.  To better understand these results, this study sought to explore further the construction of scientific concepts, in the context of PBL, at the Faculty of Medicine, of Université de Montréal. The study is grounded in Vygotsky’s sociocultural theory and its inherent treatment of concepts’ formation as a complex construction process of meaning.  We conducted a case study, multiple cases in the same site, the cases being two groups of nine medical students with their tutor that we followed during a full session, from mid-November to mid-December 2007.   Two major objectives guided the study: First, we sought to offer a detailed study of the process of meaning making and development of scientific concepts by medical students in the context of PBL. Second, we studied students’ individual work that followed initial tutor mediated discussion of the case, and preceded the return session. We tried to answer to the following research question: How do the dynamics of PBL in medicine support students’construction of scientific concepts? The study was qualitative in nature, and data were collected through various means: no participant observation, video recordings of PBL tutorial sessions, semi-structured interviews of students, discussion with tutors and the consultation of their manuals. Analysis entailed the verbatim transcriptions of the observed problem solving sessions and interviews, and in turn inductive data analysis of concept formation accross time and over session. Through the grouping and classification of data and study of evolution of concepts over time, insights could be gathered into students’development of scientific concepts and the tutor’s role in this construction.   Analysis suggests that PBL approach is generally well received, and discussions are lively, with an average of three to four exchanges per minute.         Considering the first goal, we offered detailed explanations of the dynamics of concepts’ building that extends in all three phases of the PBL, namely the initial phase, the individual student research phase and the return phase. For each case studied, we highlighted the initial conceptual representations, resulting of students’ interactions, under the guidance of the tutor, and followed their transformation, through discussions at return phase.   The choice of social constructivist theoretical framework of Vygotsky has allowed us to reflect on the mediation role played by components of the interactive system of PBL, that we considered as a zone of proximal development (ZPD) in a broader sense, and which are the problem, the tutor, the student and his peers, resources, including graphics artifact conceptual map, used extensively in all tutorials, to support the construction of scientific concepts. Our research has shown that students developed three kinds of conceptual representations: correct concepts, incomplete concepts and misconceptions, returning from their research.  So, it is necessary, through social interaction, that attributes of scientific theoretical concepts be validated by facing the practical problem. In this interaction the tutor plays a key complex role of facilitator, mediator, mainly through language. Thematic analysis of his interventions helped to distinguish five themes: group management, arguments, questions of different types, modeling and conclusions. We have shown the link between tutor’s questions and the type of student responses, to recommend a better balance between different types of tutor’s questions. Students, also by verbal exchanges and by the collective construction of initial and final concept maps participate in the co-construction of these concepts. Analysis of their interactions enabled us to identify different functions of language, to emphasize the importance of argumentative interactions, markers of in depth collaborative work.   We also showed interest of concept maps not only to visualize the concepts, but also as artifacts and tools of psychic mediation that play both, communicative and semiotics functions, in the development of scientifically sound concepts.  Regarding the second objective, the exploration of students’ personal work, we found that first year students pursued a more thorough search, and relied on more effective reading strategies than their second year colleagues. These second year students relied more on reference books, reading simply and relying heavily on the summaries made by their predecessors, which is suggestive of a more superficial learning. Those students also, relied more on tutor.  By using textbooks essentially as information source, debates were marked by cognitive low level exchanges, leading to little argumentative exchange and lack of deep and engaging collaborative work.   Overall, however, the research suggests PBL is a unique, worthwhile pedagogical approach, offering students with opportunities to construct new conceptual understandings of complex medical concepts with help of a team within the zone of proximal development. But it requires to be improved by interventions concerning both tutors and students.

Keyphrases: Concepts quotidiens, Problem-based Learning, Every day concepts, Scientific concepts, Mediation, Medical education, Zone of proximal development ZPD