Theoretical underpinnings of PBL

Schmidt, H.G. (1993). Foundations of problem-based learning: Some explanatory notes. Medical Education, 27: 422-432.

This paper presents the theoretical premises that underlie decisions to use PBL as part of an approach to develop critical thinking. A key premise is that knowledge cannot be transferred, as in a lecture. The learner has to “master it”. An important aspect of learning is that the topic being studied must actually be understood.

The paper identifies 6 fundamental principles of learning derived from cognitive neuroscience and educational psychology, which show how this understanding can be achieved.

  1. Prior knowledge of a subject is the most important determinant of the nature and amount of new information that can be processed. The amount of prior knowledge available determines the extent to which something new can be learned. Cases must therefore be iterative i.e. they must build on what came before. This is either in the form of sections within cases, where each new section is scaffolded onto what came before, or in the form of cases that build on previous cases.
  2. The availability of relevant prior knowledge is a necessary condition for understanding and remembering new information. This prior knowledge needs to be activated by cues in the context in which the current information is being studied. Cases must therefore offer cues that cause prior knowledge to be activated. This is the reason for the “What do I already know”? question.
  3. Knowledge is structured and the way in which it is structured in memory makes it more or less accessible. “Knowledge” is stored as a relationship between two or more concepts. This is known as a semantic network and it allows us to impose a structure on what would otherwise be an undifferentiated mass of isolated facts. Facilitators should therefore always ask students to represent their knowledge and understanding as a relationship between concepts e.g. “This is the way it is because of the way this other thing is”. The way that students present their understanding allows us to “see” their misunderstanding, which helps facilitators guide them towards a more accurate knowledge structure. Semantic networks are therefore not necessarily accurate representations of reality but they provide a means by which we can understand the world. The depth and accuracy of this understanding is a function of the quality of the semantic networks we have. We should therefore not think of the semantic network as “book knowledge” i.e. a set of facts. Rather, it is a reflection of a person’s experiences, views and ideas. One of the problems in the clinical environment is that knowledge learned in the classroom (“book knowledge” -> isolated facts) is that there are few opportunities for students to develop the semantic network that establishes relationships between concepts / facts.
  4. Storing information in memory and retrieving it can be improved when, during learning, elaboration of the material takes place. “Elaboration” is to actively establish and expand on the relationship between concepts. This process creates multiple “retrieval paths” to understanding. The more “paths” exist, the more likely it is that a concept will be retrieved. Facilitators should therefore aim to question students’ on their reasoning behind articulated statements e.g. “Explain to me why you think that technique is appropriate for this patient”?
  5. The ability to activate knowledge in long-term memory and make it available for use depends on contextual cues. Learning about topics in the context in which they are likely to be needed increases knowledge retention. Information that is intentionally learned and incidental information about context are simultaneously stored in memory. This is called the “contextual dependency of learning”. Cases and their discussion should therefore be conducted using the language and culture of the profession as tools to guide and scaffold the process. Students must present findings and articulate understanding to each other and facilitators as if they were on the ward.
  6. To be motivated to learn, prolongs the amount of processing time put in, and therefore improves achievement. In other words, someone who feels the urge to learn will be better prepared to spend more time on learning than someone who feels less inclined. Facilitators should therefore spend time developing students’ curiosity and motivation to learn, as part of a general approach to developing lifelong learners. Avoid simply “getting the task done”. Rather try to get students to develop an active and focused curiosity on the topic. When group work is aimed at stimulating interest and engagement, students are more likely to follow up with their own research. Group discussion aimed at clarifying one’s own point of view and being confronted with other perspectives stimulates focused curiosity.

Problem-based learning is therefore an approach to teaching and learning where students work together in small groups, with guidance from a facilitator, and try to solve problems (in our context, clinical cases).

In order to activate prior knowledge, the clinical problem must first be discussed by the students without them having “the answers”, or reference to the literature. The goals of this preliminary discussion are:

  1. To mobilise the knowledge that they already have available.
  2. To help elaborate on that knowledge i.e. to establish conceptual relationships.
  3. To contextualise the available knowledge within the current case.
  4. To engage the students’ curiosity to find out more.

It is clear therefore, that students should not have the facts given to them (e.g. with a lecture) prior to discussion of the case in their small groups. They should also be discouraged from simply identifying and allocating research questions to cover individually. The discussion is an essential aspect of the process, based on established theories of learning that aim to drive understanding.

If the clinical case is well-designed, students will begin to identify areas where they lack understanding and will soon begin to ask questions that need answers before they can proceed. The questions that are derived after the discussion will help them to find information that will therefore build on prior knowledge.

Upon returning to their groups with the new information, obtained by finding answers to questions derived in the first discussion, students then share and discuss their new information, which helps to structure the new knowledge in new semantic networks. Central to this process is the idea that while thinking, studying and talking about the clinical case, students are building a context-sensitive cognitive structure, which may help them to understand more complex clinical problems that they encounter later.

Conclusion The problem-based approach to teaching and learning is premised on 6 fundamental theories of learning that are derived from cognitive neuroscience and educational psychology. These principles include:

  1. Activating prior knowledge (basing current tasks on previous ones)
  2. Elaborating prior knowledge (forming relationships between concepts)
  3. Discussing problems in small groups (constructing semantic networks)
  4. Designing problems that are contextually relevant (solve problems in classroom that are cognitively similar to other spaces e.g. clinical)
  5. Fostering curiosity (so that students are internally motivated to spend more time on tasks)