Back to list of research papers
Jessie Mathisen
What is PBL, and how does it
work?
Problem-based learning has been defined as lessons where “questions or problems organize and drive activities in the classroom” (Jones, et al., 1997). Problem-based learning questions are ill-structured and answered primarily by students rather than teachers; in other words PBL requires that students actively seek solutions to problems that do not have any simple or “right” answers in the absolute sense. Success is usually defined by student understanding of the issues at hand and their ability to use this understanding to suggest and defend workable solutions to the problems.
There are many variations of problem-based learning which are slightly different from each other, but in general, a problem-based lesson includes these elements:
A) An ill structured problem. Ill-structured problems have many possible solutions, none of which are absolutely correct or obvious. The problem may be teacher-generated, student-generated, or generated by teachers and students working together. Often problems are “authentic”, or based in issues that we face in the real world. An example is: “Taking into account environmental, economic, and safety concerns, develop a ten-year plan to reliably supply New York City with electricity.”
B) Group work. Students almost always work on problems in small groups (although it is common for some work to be done independently).
C) Interdisciplinary content. Complex problems such as those tackled in PBL frequently can be answered most satisfactorily by pulling information and ideas from several disciplines that are normally kept separate in traditional education. (Jones, et al., 1997)
D) Extended time periods. Problems are usually dealt with over an extended period of time (from a couple of class periods to several months). This allows for time to consider and synthesize information that is generally necessary for creative solutions (Sternberg & Lubart,1995).
Ill-structured problems are the foundation of problem-based learning. Ill-structured problems are messy and compelling, require inquiry, information gathering, reflection, can change, and have no simple, “right” answer (http://www.imsa.edu/team/cpbl/whatis/whatis/slide6.html). The advantage of such problems is that they are more “authentic” than traditional end-of-the-chapter style questions. One difficulty in education is the poor transfer of knowledge learned in one context to another context. PBL seeks to address this by making the situation that learning occurs as similar to the real-world situation where that knowledge will have to be applied as possible.
Group work has both advantages and difficulties. Ideally, the discussions, negotiations, and debates that occur in groups keep students actively involved in learning and encourage critical thinking skills in addition to content mastery. In addition, group work has been shown to have social benefits, including an increased feeling of camaraderie among classmates and greater acceptance of students who are ethnically different or handicapped. Group work can also improve student’s social skills, and use social intelligence. Unfortunately, group work also has the potential to be unfair, for instance if one student does the bulk of the work. Research in cooperative learning has developed ways to maximize the probability of having functional groups. It is important to set up situations in which the goal of the group is not to do something as a team, but rather to learn as a team. In addition, it is necessary for there to be group rewards and individual accountability (Slavin, 1995). However, even the best set-up does not guarantee that groups will work well together, and one danger of group-work is individuals will not necessarily be sufficiently rewarded for their hard work and overall comprehension of the material while other individuals receive grades that are higher than what they earned.
The paper “Dan Tries Problem-Based Learning: A Case Study” (White, 1996) (http://www.udel.edu/pbl/dancase3.html) offers a discussion of problem-based learning that focuses particularly on the group dynamics of a classroom in the context of a college-level anthropology class. In this case study (which is fictionalized, but based on real events), an experienced instructor decides to change a successful lecture class into one based on PBL. He does this because he is concerned that students were not retaining the content of the course, and is largely pleased with the subject master that students achieve in the reworked PBL class. However, problems emerge related to the group nature of much of the work. Three out of five groups generally cooperate and work together well, however the other two groups have difficulties. In one group, the difficulties centered around one student with the inconsistent attendance and lack of participation of one student. In the other group, the problem was less clearly centered around one person; although everyone was involved at least superficially, one person in the group complained of doing the bulk of the work, and the most talkative group members lacked thoughtfulness.
By organizing subject matter around particular problems, rather than disciplines, curriculum has a natural tendency to become interdisciplinary. An example of an interdisciplinary problem can be found on the “Global Perspectives: A Remote Sensing & World Issues Site”(http://www.cet.edu/earthinfo/classroom/problems/MPtopicBK1.html), which offers pre-written problems to teachers along with information to provide a starting point for student research. The site as a whole emphasizes the usefulness of remote sensing, which deals with technology and science. One of the problems on this site deals with rebuilding war-torn areas in the Balkans. Students are asked to tackle questions centered on various re-building projects, including the construction of a new, multi-cultural, model city. In building the city, the location, name, type of government, employment opportunities for residents, and ethnic diversity must all be taken into account. Potentially, students could get into subjects as varied as geology and law, although in this problem, history is the dominant discipline (Fig.1).
The time-consuming nature of problem-based learning is one of its greatest strengths and one of its greatest weaknesses. There are a number of ways in which learning that occurs over a longer time period is more effective than learning that occurs in a short time period. Studies of expert vs. novice learners have found that in all domains, the development of expertise not only takes time, but the amount of material learned is roughly proportional to the amount of time spent learning. Furthermore, when only a small amount of time is spent on a topic, there is a tendency for the student to learn only individual facts without forming the connections between them, that could possibly make those facts into useful knowledge (Bransford, et al., 1999, ch.3).
Spending more time on each subject may also be necessary to encourage creative thinking. Creativity is dependant on many factors, one of which is a “tolerance for ambiguity”. A tolerance for ambiguity is important because very often when an individual or group is coming up with something new, there is a period of uncertainty and groping. At this time, it is not clear what the ultimate solution to the problem is, and sometimes it may not even be certain whether a satisfactory solution will be found at all. In traditional education where it is rare for much time to elapse between an assignment and a due date, students cannot allow themselves to tolerate this sort of ambiguity, because if they wait to resolve it before handing in work, their work will usually be late (Sternberg & Lubart, 1995).
In educational settings where there is a strictly limited amount of time to cover a proscribed number of topics, it is quite easy to see how the time-consuming nature of problem-based learning could be problematic. There are several approaches to using problem-based learning successfully with real world time constraints. Some practitioners use problem-based learning as only a very small part of the curriculum. One study of urban, minority, low-income middle school students found that there were measurable benefits from using problem-based learning enrichment activities for only 2% of the curriculum. The problems were ungraded, focused mainly on biology and health issues, and resulted in significantly better behavior and science grades (Gordon et al., 2001). Other times, curriculum standards are incorporated into problems on a much larger scale. One fairly typical example of this is a study done comparing traditional and problem-based methods of instruction in a high school economics class. Although the problem-based learning group focused on understanding concepts rather than defining them, which may have handicapped that group when they took tests, it was found that there was no significant difference between the treatment and control groups. This suggests that problem-based learning can be used effectively to teach content outlined in standards in limited time periods, while still reaping the benefits of the method.
Problem-based learning grows out of cognitive theory. Constructivism as described by Piaget and Bruner is of primary importance, but Sternberg’s information processing theory and Vygotsky’s theory of social interaction are relevant as well.
Cognitive theory is one of the three major branches of learning theory. From the perspective of problem-based learning, the most important aspect of cognitive theory is the emphasis it places on learning being an active process. Unlike behaviorists, who exclusively focus on observable activities and who believe that the environment is the sole source of learning, cognitive theorists are interested in the internal mental activities of the student and believe that learning occurs when the individual and the environment interact. Humanists emphasize the importance of the emotional state of the student in the learning process.
Constructivist theories state that there are qualitatively different cognitive stages that people go through as they develop. Different theorists have developed different names and somewhat different definitions for these stages, but the common thread that runs through the different theories is that at earlier stages of development, people are less able to deal effectively with abstract ideas. With experience (rather than simply the passage of time), an individual has the potential to move from a very physical, literal way of viewing the world to a progressively more abstract view of the world that relies on symbols to be understood. It is entirely possible for a person to be at one developmental stage in one domain, and an entirely different stage in a different domain (i.e., physics professors are at an advanced, highly abstract in their thinking in physics, but may be in an early, more literal stage in their understanding of literature). According to constructivist thinking, children actively seek out experiences to help them construct their own view of the world, and which cumulatively help them move from less advanced to more advanced cognitive stages (Hartman, 1997b).
Bruner is a constructivist who actively promoted problem-based learning in the classroom. In his theoretical framework, problem-based learning is called discovery learning. He believes that this type of learning is valuable because it makes the content more meaningful to students than it would be if the information were presented to them in a prepared form by the teacher. Brunner does not believe that discovery learning should be used as the only method in the classroom because of its time-consuming nature, and suggests that the most effective use of discovery learning is in teaching students to be aware of their own thinking. In particular, it is useful for promoting awareness of how ideas interconnect, and how prior knowledge is related to new knowledge (Hartman, 1997b).
Piaget believed that children go through four qualitatively distinct developmental stages as they mature. They will give different explanations for their experiences and observations and they require different types of sensory input during each of these stages. For instance, very young children (approximately 0-2 years) need to manipulate physical objects to make sense of the world. Older children (approximately 8-11) are able to use logical reasoning, but need to refer to concrete examples, and even older children (approximately 12-15) have the potential to engage in purely abstract thought. Piaget’s theories are very relevant to problem-based learning because he believed that children move from one stage to the next though a process called adaptation, which very actively engages the learner in asking questions and seeking answers about the world. Furthermore, because Piaget’s stages are developmental rather than strictly age-based, it is important to give children the opportunity to actively ask questions and seek answers so that they will have the opportunity for cognitive development (http://tip.psychology.org/piaget.html).
Sternberg’s theory of triarchic intelligence states that there are three types of intelligence: analytical, creative, and practical. Analytical intelligence is defined as being the intelligence used to analyze, evaluate, judge, and compare and contrast. Creative intelligence is the ability to create, invent, discover and imagine. Practical intelligence is the ability to apply, utilize, implement, and activate. Everyone has different proportions of these three types of intelligence, and those people with successful intelligence are aware of their strengths and weaknesses, and figure out how to make the most of their strengths and compensate for their weaknesses. Sternberg believes that in conventional academic situations, analytical intelligence is highly valued while creative and practical intelligences are neglected. Because problem-based learning involves a much wider range of activities than traditional classroom activities, it has the potential to make use of creative and practical intelligence. (http://www.yale.edu/pace/teammembers/personalpages/bob.html).
Vygotsky’s theory of social interaction is very compatible with, although perhaps not integral to, problem-based learning. His theories emphasize the importance of social interaction in the development of cognition, and suggest that the range of skills a child can develop alone is smaller than what the child can develop with adult guidance or collaboration with peers (http://tip.psychology.org/vygotsky.html). In problem-based learning, students usually (although not always) tackle difficult problems in cooperative groups. The reasoning behind having students work on problems in groups rather than alone is rarely stated explicitly, but it seems reasonable to assume that at least part of the reason for this structure being so common is that students stimulate each other intellectually and help each other work out difficult problems.
The modern history of problem-based learning began as a reform of medical education. Since then, problem-based learning has been moving into non-science disciplines (most often business education, but it is now found to some degree in all disciplines) and into undergraduate, secondary, and elementary education. Much of the research on problem-based learning has been done on medical students. One meta-analysis of problem-based learning in medical school (Albanese and Mitchell, 1993 in: Mergengoller, Maxwell, Bellismo, 2000) found that although medical students in a problem-based learning program occasionally scored lower than their peers on basic science exams, they did as well or better on clinical exams and faculty evaluations. In addition, students found problem-based learning to be more nurturing and enjoyable than traditional coursework.
My education has been quite varied; for me, City College is school #8. I have been exposed to a wide variety of teaching methods and philosophies in everything from large public institutions to tiny private schools. Some of my schools were in the inner city while others were in privileged suburbs. I have been in honors classes, bottom-of-the-barrel classes, and non-tracked classes with teachers who ranged from utterly brilliant to dreadful in ways that bordered on the illegal (not to mention everything in between). Many of my classes involved at least some problem-based learning. When I think back on the classes that involved problem-based learning, it is striking to me that almost all of them were good. Certainly, I have taken many good classes that had no PBL (and there were even a few lousy classes that had an element of PBL) but the contrast is still stark. This may explain why I am strongly biased in favor of this learning strategy.
I think that the main advantage of PBL is that it promotes actual thinking. When I have been given problems that interested me, or better yet, when I was allowed to chose my own topic within certain parameters, I’ve almost always pursued them with real interest and pleasure. Because of the genuine interest I developed in many of the topics, I often went quite a bit deeper into the problem than I had to, and really learned something. When I think about some of the problems I’ve worked on, I am amazed at how clearly I remember some of the work that I did, even though I may not have touched the subject for five or ten years.
One potential difficulty with PBL is that it requires the teacher to relinquish some control. I can imagine that it can be quite scary for a teacher to allow students to seek out their own information, draw their own conclusions, and perhaps even ask their own questions. What if they don’t do anything? What if they stumble onto irreputable, false, information? What if they ask bad questions, or questions that can’t be answered? I don’t think it’s a coincidence that my teachers who embraced PBL were the ones who seemed to trust and respect their students. These were often the teachers who had relatively successful classes regardless of what teaching method they were using at any given time.
Another potential problem with PBL that I have encountered is that when I have gotten deep into a problem, I sometimes immersed myself into it deeply enough so that my other work suffered. I rationalized this to myself by saying that I wasn’t going to let my education interfere with learning, and I have no regrets. Realistically speaking however, there were several semesters when my overall GPA was much lower than it should have been. So far, I have not noticed any repercussions from letting my grades in college suffer, but I suspect that when I let my grades in high school slip because I was so involved in a particular problem, it did have a somewhat negative impact on my college applications. I don’t know how common this phenomenon is, but it seems like something that high school teachers should at least be aware of when they consider assigning major PBL projects.
One final note: while working on this paper, almost all of the research I did either emphasized the role of cooperative learning in PBL, or assumed that cooperative learning is an integral part of PBL. While I would certainly agree that cooperative learning meshes very well with PBL, I have done quite a few successful PBL projects entirely by myself. Frankly, I am a little confused by the overwhelming emphasis on group work in problem-based learning. Working in groups has many benefits and should not be under-rated, but I suspect there are also benefits to delving deeply into a subject on one’s own.
Bransford, J.D., A.L. Brown, R.R. Cocking
1999 How People Learn: Brain, Mind, Experience, and School. Washington, D.C.: National Academy Press.
CSU Faculty Development website
http://edweb.sdsu.edu/clrit/learningtree/PBL/DisPBL.html
Global Perspectives: A Remote Sensing & World Issues Site website
http://www.cet.edu/earthinfo/classroom/problems/MPtopicBK1.html
Gordon, P.R., A.M. Rogers, M. Comfort
2001 A taste of problem-based learning increases achievement of urban minority middle-school students. Educational Horizons 79:171-175
Harman, H.J.
1997b Human Learning & Instruction.
IMSA Center for Problem-Based Learning website
http://www.imsa.edu/team/cpbl/whatis/whatis/slide6.html
Jones, B.F., C.M. Rasmussen, M.C. Moffitt
1997 Real-life problem solving: a collaborative approach to interdisciplinary learning. Washington, D.C.: American Psychological Association.
Mergendoller, J.R., N.L. Maxwell, Y. Bellismo
2000
Comparing problem-based learning and traditional instruction in
high school economics. The
Journal of Educational Research. 93:374-382
Robert J. Sternberg’s website
(http://www.yale.edu/pace/teammembers/personalpages/bob.html
Slavin, R.E.
1995 Synthesis of research on cooperative learning. In: Contemporary Issues in Curriculum, A.C. Ornstein, L.S. Behar-Horenstein, ed. Boston: Allyn and Bacon
Sternberg, R.J., Lubart, T.I.
1995 Creating creative minds. In: Contemporary Issues in Curriculum. A.C. Ornstein, L.S. Behar-Horenstein, ed. Boston: Allyn and Bacon
Theory into Practice (TIP) website
http://tip.psychology.org/piaget.html
University of Delaware Problem-Based Learning website
http://www.udel.edu/pbl/dancase3.html
White, H.B.
1996 Dan tries problem-based learning. In: To Improve the Academy. L. Richlin ed. Stillwater, OK: New Forums Press