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Choose-Your-Own Experiment: Active Learning in Introductory Biology Courses

What should undergraduate students learn in an introductory biology class? Traditionally, these classes seek to give students a broad background in basic biology, and they often require a great deal of memorization. Memorization-heavy courses tend to be difficult and unpopular, leading many students to choose non-STEM majors. These types of courses also fail to teach students the problem-solving skills needed in more advanced classes or graduate-level studies.

To reform undergraduate science education, researchers and scientific societies like the American Association for Advancement of Science (AAAS) have called for inquiry-based scientific education. Such methods promote student engagement, creative thinking, and positive attitudes toward science, but they can be difficult to implement in large lecture classes. A new study in PLOS Biology describes a real-life case study successfully implemented in biology classes with more than 175 students. Not only did 100% of surveyed students enjoy this “choose-your-own-experiment” activity, but over 99% (344 of 346) said it was useful to their learning.

An Inexplicable Disease: A Case Study with a Twist

The case study An Inexplicable Disease begins with an introduction to the three major types of disease epidemics: infectious, environmental, or genetically inherited. After this short primer, students learn about a mysterious disease that has arisen in an unnamed isolated island tribe. Tribe members experience sudden onset symptoms – first a strange walk, then slurred speech, facial tics, and uncontrollable laughter. Once the first symptoms occur, death is certain within 3-6 months. Students are placed into roles as physicians and anthropologists, instructed to gather information about the cause of the disease, with the goal of presenting at a conference in two years experimental time.

As students dive into the case, they can choose how to approach the problem. Options include trying to study the disease in lab animals, beginning a microbiological or epidemiological study, or learning more about the behaviors and culture of the tribe. With each choice comes more information about the disease (Figure 1), and student groups collaborate at the mock-conference to try to fit the pieces together. While traditional case studies ask students to determine why researchers made a certain decision, An Inexplicable Disease casts the students as researchers, allowing them to see firsthand the challenges and complexities of practical science.

Figure 1. Choose-your-own-experiment options available to students in the physician group. Students must choose from different types of experiments, balancing time and feasibility. Figure from Serrano et al., licensed under a Creative Commons Attribution 4.0 International License.

In An Inexplicable Disease, students are unable to acquire all the information necessary to solve the problem at hand, despite performing logical experiments. At the end of the interactive activity period, the instructor reveals that the mystery disease is kuru and introduces students to Carleton Gajdusek, the scientist from the case study. Gajdusek was unable to unravel the mystery of kuru until he met William Hadlow, a scientist studying scrapie, a degenerative brain disease affecting sheep. Since kuru and scrapie have similar symptoms, Hadlow hypothesized that kuru was infectious, like scrapie, and encouraged Gajdusek to conduct experiments in non-human primates. It took eight years from Gajdusek’s first visit to the island to show that kuru was infectious.

Based on their findings from the interactive activity, students understand that kuru is not a typical infectious disease. In part II of the mini-lecture, the instructor discusses Stanley Prusiner’s work on protein-only disease agents (prions). Students then learn about the evidence for prion agents causing scrapie and kuru, as well as the prion-like behavior of amyloid beta. As amyloid beta plays a role in Alzheimer’s disease pathology, this example shows students that prions are relevant to their lives.

Kuru as a Teaching Tool

To learn more about the inspiration for and success of An Inexplicable Disease, I spoke to Justin Hines, the author of the case study. Now an assistant professor at Lafayette College, Hines designed An Inexplicable Disease as a postdoctoral fellow participating in the Wisconsin Program for Scientific Teaching. He had read Richard Rhodes’ Deadly Feasts, which chronicles Gajdusek’s investigation of the kuru outbreak, and wondered if he could “present that information in a way that would allow students to feel [Gajdusek’s] confusion.”

Hines said he was pleasantly surprised by the student response to An Inexplicable Disease. “In general, the reaction to [An Inexplicable Disease] has been just wonderful…students love the mystery and the game-like nature of the activity.” To spread the word and obtain feedback from other instructors, Hines presented the case study at multiple meetings of the Society for the Advancement of Biology Education Research (SABER). At each meeting, he provided his email address and asked instructors interested in the activity to contact him. In total, Hines estimated that 70-80 instructors have used the activity, again with uniformly positive feedback. “The really surprising thing was that there were no revisions. I never once got a comment saying that I should do this differently.”

In my mind, An Inexplicable Disease is an ideal case study because it allows students to practice science using real-life research scenarios. Students must collaborate and cooperate to learn more about the disease rather than passively retracing a scientist’s steps. For Hines and his colleagues, the choose-your-own experiment style shows students that the process of scientific inquiry is important, even if you’re not able to answer the question originally posed. Students also get a taste of how difficult scientific research is; the limited time and resources they’re allotted echo the practical and financial constraints familiar to researchers.

It’s not just the style of An Inexplicable Disease that makes it so effective – I find that the subject matter also plays an important role. Kuru and other prion diseases represent a paradigm shift in microbiology. All other infectious agents carry genetic material so that they can replicate and spread – in contrast, prions can propagate with just protein. In choosing an atypical, surprising topic, Serrano et al. demonstrate to students that science is not static, but ever-evolving. Learning about the messiness of biology makes the subject much more tangible and exciting to students, and 96% of those surveyed said that the activity changed their view of scientific inquiry.

To further quantify how this activity benefited students, Serrano et al. conducted an analysis of student attitudes towards science using questions from the Colorado Learning Attitudes About Science – Biology (CLASS-BIO) survey. This well-established survey compares student-provided answers to true-false questions to those given by scientists; an answer matching the scientist response is considered expert-like. For seven of nine questions asked, the percentage of students with an expert-like response improved significantly after the kuru activity, indicating that they better understood and were more excited about scientific inquiry (Figure 2). Based on the success of An Inexplicable Disease, Hines says he has since written other case studies that he incorporates into his classes.

Figure 2. An Inexplicable Disease improved student perceptions of science. This sub-analysis of 195 students took place over 2 years and included students in five independent sections of introductory biology. Questions 1-7 were taken from CLASS-Bio; questions 8-9 were developed by Serrano et al. Figure from Serrano et al., licensed under a Creative Commons Attribution 4.0 International License.

When designing An Inexplicable Disease, Hines’ goal was to create a concise case study that could be completed in a single lecture period. Instructors have then taken this activity and used it in different ways, for example, alongside lectures on protein structure, or as a first day of class activity. An Inexplicable Disease can serve as an introduction to active learning, helping students feel more comfortable with problem-solving and class discussion. The case study also translates well to lectures >100 students, although TA assistance may be necessary to help distribute materials and answer individual questions.

As an early career researcher, I believe that introductory science courses aren’t just about acquiring knowledge; they should also teach students how to think critically and scientifically by developing and testing hypotheses. Even if they don’t choose a STEM major, students who experience the process of scientific inquiry are more likely to become science literate adults interested in supporting scientific research. Fittingly, Serrano et al. have used An Inexplicable Disease in a variety of class types, including microbiology for non-majors, introductory biology, and advanced biochemistry. Their flexible content works in many settings because it makes the scientific method real and exciting for students.

As institutions around the world work to build better science curricula, I feel that interactive activities like An Inexplicable Disease should be given space alongside traditional classroom lectures. For this reason, Hines and his colleagues chose to publish their approach in the open access journal PLOS Biology. “The idea is that by publishing it we can reach broad audience of biology educators. We’ve provided enough material that people can try out the activity if they’re interested.”

References and Additional Reading

Featured image: Science Careers in Search of Women 2009, by Argonne National Laboratory – licensed under a CC BY-SA 2.0 license.

Serrano A, Liebner J, and Hines JK. Cannibalism, Kuru, and Mad Cows: Prion Disease as a “Choose-Your-Own-Experiment” Case Study to Simulate Scientific Inquiry in Large Lectures. PLoS Biol 14(3): e1002425.

AAAS. Vision and Change in Undergraduate Biology Education: A Call to Action. 2011.

Brandforth SE et al. University Learning: Improve Undergraduate Science Education. Nature. 15 Jul 2015.

Waldrop MM. Why We Are Teaching Science Wrong, and How to Make it Right. Nature. 15 Jul 2015.


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