Problem-based learning (PBL) is an active instructional method based on the shift of the learning process from the teacher to the student and the class. PBL has its roots in the late 1950s, and its implementation grew in response to dissatisfaction with the traditional medical education practice at McMaster University in Canada (1,2). PBL aimed to overcome the limitations of an education system based on lectures and heavy memorization of fragmented biomedical knowledge, altogether deemed as passive, demotivating and inefficient for long-term retention of the acquired knowledge (3). Promoters of PBL proposed a radically opposite method, based on problem-focused, student-centered, self-directed and self-reflective approaches (4).
PBL is based on constructivist assumptions regarding:
- i) knowledge: knowledge is created by the learner via their own interpretation;
- ii) meaning-making: the perception of the knowledge and in general of the external, physical world is unique to the knower;
- iii) learning: what we learn is fundamentally bound to the situation in which we learned it, and learning is strongly stimulated by the perception of a dissonance between what we know and what we see in the environment – hence, the fundamental role of questioning and problem-solving (5).
These foundations were developed into a pedagogical approach that is first problem-centered. The problem is presented in the form of a vignette, case scenario, or other, and represents the key motor of the didactic experience. PBL is fully student-centered, meaning that the students must take responsibility for their own learning, identifying the key questions to be addressed to solve the problem, determine the knowledge required to address the problem, and find the resources to access such necessary knowledge. The process of problem-solving happens in small groups, as to enhance students’ collaboration and communication capabilities. In this approach, teachers act as facilitators, and not as sources of knowledge. Overall, PBL is expected to stimulate students’ motivation, enhance their communication and collaboration capabilities, boost their independence, create knowledge in a real-life set-up, and possibly generate a unique body of knowledge that would go beyond what could be transmitted by a lecturer in a traditional lecture situation (1).
From the implementation of PBL, both its foundations and its effectiveness have been frequently assessed and challenged. The promoters of PBL state that PBL indeed leads to more effective learning since knowledge acquired in a relevant context would be better remembered and more easily mobilized. Moreover, acquisition of knowledge via “prior examples” would facilitate pattern recognition while facing real-life problems, and PBL would facilitate the future reactivation of prior-knowledge, thus facilitating the processing of new information. Finally, the learning process would be more effective as the elaboration of the knowledge occurs at the same time of learning (6–8). Others, however, strongly criticized the foundations of PBL, accusing it of ignoring basic features of human memory-related processes. In particular, PBL has been criticized for not recognizing the difference between working memory and long-term memory. PBL would place heavy demands on working memory for the problem-solving tasks themselves, impairing working memory from converting the knowledge in long-term memory, thus harming the overall learning process (9). PBL would thus be an effective approach to solve problems, but not to alter long-term memory, i.e. to learn (9,10). In addition, PBL detractors often underline how erroneous it can be to assume that the pedagogical content of the process of learning (pedagogy) is analogous to the processes and methods of the discipline (i.e. the epistemology) (11).
Despite appealing, the numerous discussions on the theoretical bases of PBL would be of little importance compared to actual, robust evaluations of its effectiveness in the didactical practice and in the subsequent application of the acquired knowledge. There is a vast literature focusing on the comparison between PBL and traditional lectures as concerns their effectiveness. Most of these studies however appear flawed in many regards. Firstly, implementation of PBL itself is extremely diverse, making therefore difficult the definition of PBL as a homogeneous variable to be subjected to any comparative study (3). Similarly, the traditional lectures PBL is supposed to be compared to are highly diverse as well. In particular, since long time most traditional courses in the biomedical sciences are accompanied by various types of active learning, in the form of participative exercises, laboratory activities, or others – thus making the comparison of PBL or “active learning” versus “traditional learning” of very little practical relevance. The evasive nature of the didactic approaches flaws even highly influential studies, such as a recent and very highly cited article, which openly placed under the category “active learning” “courses with at least some ”active learning”, and “traditional teaching” any course without any type of active learning (12). Interpretation of such studies must be performed very carefully, as the definition of traditional lecturing can be restricted to now very rare, nearly stereotypical teaching approaches. Overall, despite their abundance, it appears that no study was performed at a level of rigour, design and sample size sufficient to convincingly evaluate and demonstrate eventual differences in outcome between PBL and traditional courses (3,9,13,14). This failure can be also in part attributed to the difficulty in evaluating intrinsically different pedagogical methods in a consistent manner, and the uncertainty surrounding the concept of “learning” itself, which any study assessing pedagogical methods must indeed face (15).
In the author’s opinion, based on personal evaluation of the available literature, PBL has a theoretical advantage on the side of students’ engagement, enhancement of problem-solving and collaboration skills, acquisition of knowledge via real-life scenarios and effective contextualization of the acquired knowledge. At the same time however, this didactic approach has an apparent disadvantage in content-intensive courses, which would benefit in the authors’ opinion from at least an initial, rapid, traditional flow of complex concepts and knowledge from lecturers to students. In addition, PBL places a significant burden at the level of cost, both regarding time and resources. Increased personnel are in fact required to tutor small groups properly; moreover, the creation of knowledge by students via PBL requires significantly more time and places a higher workload on the students’ side when compared to traditional lecturing (16). Great availability of resources, careful evaluation and curricula design, and continuous support from university institutions seem irrefutable conditions for a PBL approach to be successfully implemented in any field.
References
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