Metacognition and Cognitive Load in Teaching Sedimentary Geology
Peter Lea, Geology Department, Bowdoin College
Two of the major learning goals for undergraduate students in my Sedimentary Geology course are the following:
- Given sedimentary data in outcrop, measured sections, or other formats, you will be able to interpret depositional processes and environments.
- You will be able to form reasonable hypotheses about the roles of tectonism, sea level and climate, acting through sediment supply, base level, or subsidence, in generating sedimentary successions.
In detail, both goals involve some degree of mastery of complex, interwoven concepts that can be overwhelming to novice practitioners who have neither (1) relevant schema in long-term memory to help manage cognitive load (e.g., Sweller, van Merrienboer and Paas, 1998, Educational Psychology Review 10, 251-296), nor (2) extensive practice in metacognitive reflection and learning strategies. In recent iterations of this course, I have experimented with teaching approaches to help students overcome these obstacles. These approaches are presented below as works in progress that are still being refined and that could benefit from feedback from workshop participants.
Learning-Cycle Approach to Lab and Field-Trip Activities
A learning-cycle approach asks students for predictions before a lab or field trip, has them make observations during the lab/trip, and then asks for reflection on the correspondence between predictions and observations afterward—a structured metacognitive exercise. For example, prior to a field trip to a local barrier coast (http://serc.carleton.edu/NAGTWorkshops/sedimentary/activities/14170.html), students predict what bedforms they will find in various sub-environments and explain their reasoning, giving a snapshot of their understanding at that time. During the trip, students visit these same sub-environments at low tide and describe the actual bedforms and interpret the formative flows. They then compare their observations with their predictions and self-evaluate their conceptions and misconceptions, for example:
"Overall most of our predictions were either incomplete or entirely different than what we observed. It had not occurred to me that the flood would be stronger than the ebb nor had I thought to predict superimposed ripples as a result of changing water levels and speeds. It was very insightful to observe and think about water moving through the whole delta and inlet and how it changes with each tide."
An additional advantage to this approach is that students have a clear observational framework when they visit the field, which reduces extraneous cognitive load and allows them to focus on the learning goal at hand.
A similar approach can be used for indoor labs. For example, students are asked to make predictions on outcomes of settling experiments in water and shampoo, giving their reasons for and degree of confidence in their predictions, e.g.,:
"Grains will settle faster in water than shampoo. The shampoo is more dense therefore slowing the rate of displacement...[but] I'm uncertain as to the factors that will slow the particles in the shampoo. What are the controlling forces?"
In this case, the student is aware that she does not have a clear understanding of the forces involved, and can later compare her incorrect attribution of density as being the controlling factor to the concepts of viscosity and fluid drag.
In-Class Case Studies
In order to give students more practice in interpreting sedimentary successions, and to expose their thinking to themselves and to me, I have them tackle case studies in class. For example, after learning about fluvial systems, students were presented with two Jurassic examples drawn from the literature in which the style of fluvial channel changes up-section and/or the ratio of accommodation space to sediment supply changes over time. Initially, I tried an adaptation of the "reciprocal teaching" strategy pioneered by Palincsar and Brown (1984, Cognition and Instruction 1, 117-175), in which students take turns orally interpreting, summarizing, and asking clarifying questions about successive stratigraphic intervals, inviting comments from classmates. Although helpful, this approach did not sufficiently emphasize metacognitive strategies. In a later iteration, I had each student first write out their interpretation of the section, and then had a whole-class discussion that began with the question: "What did you find difficult about interpreting this section?" This invitation to reflect on their thinking and points of confusion—along with the overt expectation that they would find the problem difficult—prompted a focused discussion on what they did and did not understand and led to many clarifications.
Although the examples here are specific to Sedimentary Geology, there are several conclusions and recommendations that can inform geoscience instruction in general:
- Be explicit with students about the cognitive difficulties involved in mastering complex problems and the need to develop appropriate cognitive and metacognitive strategies that will allow them to progress from novices toward mastery;
- Where practical, consider a learning-cycle approach that asks students to expose their thinking to themselves and to the instructor, and has them monitor explicitly the evolution of their understanding;
- Practice in class, with peer interaction, the problem-solving skills that you expect them to master on exams. Repeated practice on problems that have some elements in common but also include variations on a theme allow students to build and strengthen schema and reinforce difficult concepts;
- Be aware that the strategies above can be very time-consuming, so that the instructor may have to adjust course content accordingly.