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