Problem-Based Learning
by Evelyn Beck
WHEN DAWN LANGLEY Simmons was born in 1937, the doctors
decided she was a male. However, this “boy” was later re-identified as a girl and, according to some accounts, ultimately gave birth to a child. Students in Kim Finer’s human genetics course at Kent State University, Stark Campus, use this real case to learn how gender is assigned at birth. Over two class periods, they discuss sexual dimorphism and developmental biology, engaging in a debate or writing position papers about the possibility or impossibility of Dawn’s giving birth.
Case studies like this one, a vital part of problem-based
learning (PBL), have long been a regular feature of courses in law, medicine, and business. Now they are also gaining popularity as a teaching tool for humanizing science and for helping students think critically as they work their way through the scientific method in solving a problem.
In addition, they are a great way for on-line science teachers to encourage critical thinking, discussions, writing assignments,
and group projects–excellent complements to fact-based Web
presentation of material.
PBL offers real-world cases to students, who can work individually
or in teams to unravel the solutions. Clyde Herreid, a biology
professor and director of The National Center for Case Study
Teaching in Science at SUNY Buffalo, has identified three kinds of case studies: dilemmas (such as deciding whether an AIDS drug with serious side effects should be made available to the public), appraisals (such as analyzing the effects of the Valdez oil spill), and histories (such as examining the Tuskegee syphilis study, a secret government project in which hundreds of African-Americans with syphilis were studied but not treated).
“Students are obviously more interested in learning material that is taught in context rather than as isolated facts,” says Herreid. “The use of case study teaching in science is very new and people that have tried it in the classroom are usually very enthusiastic about how it captures students’ interest.”
One excellent source of scientific case studies is available
at SUNY Buffalo’s Web site: http://ublib.buffalo.edu/libraries/projects/cases/ubcase.htm.
There, you can find scenarios from many areas of science that
can be used for class discussion, debate, team projects, or
research studies. Here are a few examples, along with the
name of the educator who wrote each one:
Anatomy& Physiology: Use forensics to identify the sex, age, andheight of a skeleton. (Alease Bruce, University of Massachusettsat Lowell);
Chemistry: How safe are polycarbonate baby bottles? (Michael A. Jeannot,St. Cloud State University);
Ecology: Who should manage the St. Croix River? (Pamela Locke Davis,University of Minnesota);
Geology: What are the ethics involved in publicizing scientific discoveries too quickly, such as NASA’s 1996 announcement that life existed on Mars? (Bruce C. Allen and Clyde F. Herreid, University at Buffalo);
Physics: Use Newtonian mechanics to figure out how a cheerleader can lift up a 300-pound football player. (Malati Patil, University at Buffalo, State University of New York).
While few educators would disagree that these kinds of real-life
examples awaken student interest, many worry that the greater
amount of time needed for this method of instruction crowds
out other essentials.
“My answer to that is, ‘What good is it to cover material
if students do not learn it?'” says Herreid. “And the evidence is in on that score. Even ‘A’ students usually forget much of what they learned in a lecture course within a few weeks after the final exam.”
When instructors do opt to try the case-study method, they
must choose carefully. Herreid recommends that each case use
dialogue to tell a good story and that it be relevant, contentious,
recent, and short. Here’s an example of a case study that meets all these criteria. Called “To Vaccinate, or Not to Vaccinate: That is the Question,” it was written by Carmen Shapiro at D’Youville College in Buffalo, N.Y., and appears on the University at Buffalo’s Web site.
Students read the story below and then investigate the issues
involved in vaccination.
Paula Highsmith was quite distraught. She had returned from a routine checkup for her four-week-old daughter Jennifer. The pediatrician, Dr. Feiller, had informed Paula that he would begin giving Jennifer her DTP shots at her next appointment in a month.
Paula phoned her mother, Marion Johnson. “Oh, Mother, I don’t know what to do.”
“You were vaccinated as a child, and you didn’t have any problems,” replied Mrs. Johnson.
“You know my friend Julie? Her oldest son Sam had a seizure after getting the DTP shot when he was Jennifer’s age. And what about that couple on television that said the rubella vaccine was responsible for their son’s autism?”
“I don’t know about that couple,” replied Mrs. Johnson,
“but Sam was vaccinated ten years ago. If the vaccine
was really the problem, I’m sure they would have a different vaccine now.”“But now there are so many shots and, besides, the diseases they prevent have practically disappeared, so why do I have to have Jennifer vaccinated?”
“Jennifer will be required to show evidence of vaccination before she’ll be allowed to go to school and perhaps even some daycare centers. Don’t you remember the article in the Buffalo News about the couple whose son wasn’t allowed to register for school because he hadn’t had his vaccinations. His parents said they had refused to have him vaccinated for religious reasons.”
Does this kind of approach work? Absolutely, says Debra Gerdes,
professional development coordinator for PBL at the Illinois
Mathematics and Science Academy Center for Problem-Based Learning in Aurora. With case studies, she has found, “‘Real’
learning (i.e., understanding) seems to be taking place.”
