Reaction positive to peer-led problem-solving

Experiment yields good chemistry for teaching and learning

By Steven Schultz

Princeton NJ -- In 1997, Princeton chemist Maitland Jones conducted one of the boldest experiments in his career. For 30 years, he had been breaking new ground in organic chemistry, synthesizing new molecules and untangling complex chemical reactions. The subject of this experiment, however, was not a test tube of molecules; it was a class of 230 undergraduates.

As the instructor of "Organic Chemistry," one of the most dreaded and anxiety-producing classes on any college campus, Jones had a proposition for his students: Stop coming to lectures.

Sophomore Andrea Wang (standing) is one of 10 undergraduates serving as teaching assistants in the peer-led organic chemistry class. Here, she answers questions during a problem-solving session in the Wu dining hall of Butler College. The class has proven to be a popular alternative to the traditional lecture course.


For most students, he would still give lectures, but for any who took him up on his offer he organized problem-solving sessions, four days a week at 8 a.m. The students would work in small groups, while Jones and some postdoctoral fellows and graduate students would be on hand to help direct the work and answer questions. But there would be no lectures.

"No double-dipping allowed," said Jones. "If they signed up for the problems group, I asked them not to come to the lecture."

Five years later, the idea is no longer an experiment. After an enthusiastic response in the first year and continuing demand, Jones now teaches his two-semester class, Chemistry 301/302, almost entirely without lectures. At the start of the year, Jones gives introductory lectures, but immediately starts phasing in problem sessions, until, by the middle of the first semester, there are no scheduled lectures.

"Our goal is to teach people to think for themselves," said Jones. "By April, the level of discourse in these groups -- dealing with some very tough problems -- is really high. It is very impressive. And the dependence on teachers is down." At the same time, Jones builds a one-on-one connection with students that is virtually impossible in a large lecture course.

The popularity of the no-lecture approach also brought a problem. The course required a lot of teaching help, and the chemistry department could not afford to hire enough postdocs or graduate students to accommodate the number of students who wanted to go the no-lecture route. Chemistry department chair George McLendon suggested a solution: Hire undergraduates. Today the class is staffed by Jones, one postdoc and a group of about 10 undergraduates who excelled in the class in previous years. The student teaching assistants do no grading, but in any given class session, most of a student's interactions could be with fellow undergraduates.


Professor Maitland Jones (right) spends his time in "Organic Chemistry" making the rounds during problem-solving sessions rather than lecturing. He hopes to encourage other faculty members to try such alternative formats with their classes.

Many benefits

This peer-led system has myriad benefits, said Jones. Students benefit enormously from the practical wisdom of fellow students who struggled with the same problems only one or two years earlier. And both the students and TAs gain the deeper understanding that comes from trying to explain something to others.

"If you buy into this system, it's the best way to learn," said Jones. "But it's also clear that it's not for everyone. It demands a lot of everyone."

For one thing, students cannot skip the assigned reading or miss a problem session. "That is fatal," said Jones. Even though the sessions are now three days a week at 8:45 a.m., those requirements are difficult for some, which is one reason why the chemistry department still offers a lecture-based course.

After the first year of Jones' experiment, the department divided the course into two tracks. Professor Martin Semmelhack teaches the lecture class, which has an increased concentration on biology, while Jones leads the course with the more classical focus on organic chemistry. This year, Semmelhack has 167 students, while Jones has 92. Both courses use a textbook that Jones wrote.

The peer-led course is an important undertaking, Semmelhack said, because organic chemistry teachers face a unique challenge. "Orgo," as the course is known, is required for many students, particularly pre-meds, who are not chemistry majors, yet it is a 300-level course. "So Mait and I both face the issue of how you deal with that," said Semmelhack.

Jones' commitment to finding a better way of teaching the class is particularly notable because his course scored highly among students even before he made the change. "He's a spellbinding lecturer," said Semmelhack. "He can make you just listen to him talk about organic chemistry even if you're not that motivated. He's just really good."

In addition to being demanding of students, the problem-solving format is a challenge to the teacher, who cannot rely on a fixed lesson plan and is closely engaged with the students. "There is no distance," said Jones. "You're right down in the trenches with them. When someone isn't doing well, you feel it much more."

Learning about teaching

At a recent Monday morning problem session, in the Wu dining hall of Butler College, the sense of focus among students was palpable. The class had no marked beginning; students arrived and immediately set to work in their groups. The undergraduate TAs and postdoctoral fellow Lee Friedman started circling the room. Soon students began to raise their hands, and, one-by-one, TAs peeled off to help. They gave guidance with a reassuring tone here, a challenging question there, the students nodding with a half-beat lag as they struggled to absorb the ideas.

Jones also made the rounds, dragging a chair from group to group. He stayed a little longer than the TAs, exploring and quizzing. He has become skilled at sensing how the class is coping. "You can tell by the noise level," he said. "If it's noisy, they're doing alright. Some days it gets pretty quiet and that's not good." On those occasions, he sometimes breaks for a "microlecture," wheeling out a movable blackboard to make a point.

As they packed up to go at the end of an hour and a quarter, sophomores Rachel Cheng and Stefanie Naski felt they had made progress. "I love problem sessions," said Cheng. "With lectures, you can get the same thing from the book. This is like practice exams."

"You learn a lot more," said Naski.

It does not matter, they said, whether the person coming by to help is Jones, Friedman or the undergraduates. "I really don't care, so long as they know what they are doing," said Cheng.

"Today, we were stuck on a problem for an hour and a (student) TA came by and walked us through it," said Naski. "He didn't just sit there and tell us the answer. He said 'What if you think about it this way? Try another way.'"

For the TAs, the challenge is not so much knowing answers to problems as guiding students toward the important concepts. "The more you do it, the more you realize that the specifics are less important than the overall way of approaching the problems," said TA Adler Perotte, a junior. "That is what Mait is trying to get across -- a way of thinking."

"As a TA, I've learned more about learning and studying than about orgo," said Sarah Milgrom, a senior who is a TA for the second time. "It's easier to see the mistakes people make when you are looking at it from the other side. I see people getting overwhelmed, and I am sure that I have done the same thing. You can really become fixated on one little point."

Jazzing up instruction

Those are the kinds of stories Jones likes to hear, but he also would like to back up his impressions with statistics. In that first experimental year, he selected a "control" group from the students who stayed in the lecture course and whose test scores closely matched those of students who chose the problem sessions. In the end, the groups performed identically, which Jones took as a good sign, "because we made a lot of mistakes."

After several years of refinement, Jones believes the problem-solving group would do even better, but with the course split into two tracks, it is no longer possible to create a sufficiently large control group to continue the head-to-head experiment.

Gathering solid evidence is important to Jones because he wants to encourage similar chemistry courses at other universities or similar courses in other disciplines at Princeton. This year, a visiting fellow, Paul Rablen of Swarthmore, is observing the class with hopes of incorporating at least some of the method into his own teaching.

Any teacher going that route has to be prepared to give up the security of lectures in exchange for the improvisation that comes with letting students grapple with the material themselves.

"The model for teaching is not classical music. It's jazz," said Jones. And as a jazz fan whose office has copies of Downbeat magazine stacked next to chemistry journals, Jones would not want it any other way.


November 18, 2002
Vol. 92, No. 10
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Page one
Experiment yields good chemistry for teaching and learning
Psychologists and mathematicians put heads together on brain research

Early decision is back in the news
Initiatives implemented for post-enrolled graduate students

Five new full professors named to the faculty
People, briefs, spotlight

By the numbers
Nassau Notes
Calendar of events

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