Debate lessons improve critical thinking skills


© 2011 Gwen Dewar, Ph.D., all rights reserved

Kids benefit when we teach them critical thinking skills.

What’s the best way to do it?

Studies suggest that explicit lessons in logic and reasoning are effective, so much so that they may actually improve a child’s IQ.

But few kids encounter such lessons, even in high school.

Yes, students might pick up logical principles as they study mathematics or science. They are frequently asked to present arguments in the form of written essays. And, yes, these experiences can be helpful. 

Experiments suggest that students are more likely to master a topic when they are forced to explain it to another person. And most of us have noticed that the act of writing can clarify our thoughts.

Writing can make us aware of gaps in our understanding. It can force is to notice gaps in our explanations. Missing information. Logical flaws. In principle, writing may encourage students to construct better arguments.

But it’s not clear how many kids improve their critical thinking skills through writing. Based on the studies I’ve seen, I don’t think writing alone is very effective.

Maybe that’s because students lack the perspective to critique their own work.

Ask students to argue a case, and they might be pretty good at naming a few reasons in support of their argument. But they rarely consider counterarguments, disconfirming evidence, or the merits of the opposing view.

These are the points raised by researchers Deanna Khun and Amanda Powell. They think students need someone to argue against. They need an intelligent critic. A person to play Devil’s advocate.

And that’s where debate comes into it. Not the silly, sloppy, emotional exchanges that pass for debate on TV and the internet. But the real thing: Disciplined, logical, responsive, evidence-based argumentation with another person.

Should we be training kids in the art of debate? As Kuhn and Powell note, debate forces kids to consider two perspectives, not just their own. It encourages kids to anticipate objections to their arguments. To answer counterarguments. To weigh the evidence on both sides.

So the researchers designed and tested a 3-year debate curriculum on a group of lower income, American, middle school students.

Here’s how.

The kids started the program when they were in the 6th grade. Forty-eight kids were assigned to a philosophy class that emphasized debate. A control group of 28 kids were assigned to attend a similar course that featured teacher-led discussion and essay writing, but lacked any training or practice in debate.

At the beginning of the study, kids were tested on their ability to reason about a controversial issue. Then the coursework begin: Two fifty-minute lessons each week.

What kids did in class

For kids in the debate-based course, lessons were organized around four controversial topics. Each topic took about 13 weeks to complete.

Teachers would begin each 13-week term by presenting a controversy—like euthanasia—and asking kids to take sides. Then the teams worked in groups to prepare for a debate.

Team members would spend several sessions building a case in support of their position. They’d think of reasons and evaluate them. They’d try to anticipate what the opposition would argue, and prepare counterarguments and rebuttals. Then they’d rehearse—pairing off with other members of their team holding mock debates on the computer, via software for instant messaging.

Why the computer? The researchers knew that adolescents were well-acquainted with instant messaging, and the typed dialogs gave researchers a written record of the students’ reasoning. Kuhn and Powell also thought that a written dialog would encourage kids to reflect.

Each term culminated in a showdown between teams. The debate was led by two spokespeople—one elected from each team—who could confer with their teammates for help. Like the practice runs, the real debate took place on the computer.

What kids learned

At the end of each school year, kids were tested on their reasoning abilities. Their scores were compared with the scores of the control group—kids who has spent the year discussing and writing about similar controversial issues, but without any practice in debate.

How did things turn out?

When asked to write essays about a new controversy, the kids with the debating experience showed more sophistication.

Debate-trained students submitted more dual-perspective arguments–i.e., arguments that mentioned the claims of opposing points of view.

At the end of the third year, students in the debate group went even further: They submitted essays that discussed the costs and benefits of each position.

Kuhn and Powell call this an integrative perspective, and it was significantly less common among kids in the control group.

The debate kids also distinguished themselves in another way. They seemed better at figuring out what new data would help resolve the controversy.

Researchers asked kids to consider their need for evidence:

“Are there any questions you would want to have answers to that would help you make your argument?”

The debate-trained kids came up with more such questions. In addition, their questions were more pertinent to forming a general judgment about the issue.

No quick fix

The debate program developed by Kuhn and Powell seems successful. But it’s no quick fix. And doing it right means getting the details right. For instance:

1. Kids didn’t begin the program with an appreciation for evidence. They had to be taught.

At the end of Year One, teachers started presenting students with questions that were pertinent to the debate. Questions like “How humanely are animals treated in laboratories?” or “Has animal research led to any cures?” In subsequent years, students were encouraged to generate and research their own questions. Gradually, kids began to see how important it was to answer these questions. But it took time and practice.

2. Kids were given explicit teacher feedback about the strength and weaknesses of their arguments.

For the final session of each term, teachers debriefed students, going over transcripts of the debate and creating a diagram that summarized what was effective or ineffective about each team’s presentation. Teams were rewarded points for good moves and demerits for bad moves—like unwarranted assumptions and unconnected responses. The points were tallied and the winning team was declared.

An investment worth making?

Did Kuhn and Powell create the optimal program? Perhaps not. This is only the first study of its kind to get published. More research should help us tease apart which aspects of the program were the most effective. But Kuhn and Powell have taken an important first step.

Meanwhile, they make a persuasive case for teaching debate.

Informal classroom discussion doesn’t seem to be an especially effective way to foster critical thinking skills. And I suspect that debate lessons might help shrink the achievement gap between students of lower and higher socioeconomic status.

In many middle class families, parents attempt to mold behavior by reasoning with their kids. They encourage give and take. They explain the reasons for rules and invite kids to negotiate—as long as they can make persuasive, well-reasoned arguments. I remember one anthropologist’s quip that the American intelligentsia train their children to talk like lawyers.

Presumably, children of professional thinkers would profit from lessons in debate. But kids from backgrounds of lower socioeconomic status—where negotiation and debate are often discouraged—might profit even more.

So I’m inclined to think that adding debate to the curriculum is a good investment for society as a whole. We might be laying the foundation for a more enlightened culture, with better-informed voters, more rational jurors, and citizens more appreciative of science.

References: Debate improves critical thinking skills

Kuhn D and Powell A. 2011. Dialogic Argumentation as a Vehicle for Developing Young Adolescents’ Thinking. Psychological Science. March 21 [Epub ahead of print]

For references regarding the common practices of middle class parents, see my article about authoritative parenting.