Think Again

DON’T STEP ON THEIR TOES
Harish’s next advantage stemmed from one of his disadvantages. He would
never have access to as many facts as the computer. When the audience was
polled afterward about who taught them more, the overwhelming majority
said they learned more from the computer than from Harish. But it was
Harish who succeeded in swaying their opinions. Why?
The computer piled on study after study to support a long list of
reasons in favor of preschool subsidies. Like a skilled negotiator, Harish
focused on just two reasons against them. He knew that making too many

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points could come at the cost of developing, elaborating, and reinforcing his
best ones. “If you have too many arguments, you’ll dilute the power of each
and every one,” he told me. “They are going to be less well explained, and I
don’t know if any of them will land enough—I don’t think the audience will
believe them to be important enough. Most top debaters aren’t citing a lot of
information.”
Is this always the best way to approach a debate? The answer is—like
pretty much everything else in social science—it depends. The ideal
number of reasons varies from one circumstance to another.
There are times when preaching and prosecuting can make us more
persuasive. Research suggests that the effectiveness of these approaches
hinges on three key factors: how much people care about the issue, how
open they are to our particular argument, and how strong-willed they are in
general. If they’re not invested in the issue or they’re receptive to our
perspective, more reasons can help: people tend to see quantity as a sign of
quality. The more the topic matters to them, the more the quality of reasons
matters. It’s when audiences are skeptical of our view, have a stake in the
issue, and tend to be stubborn that piling on justifications is most likely to
backfire. If they’re resistant to rethinking, more reasons simply give them
more ammunition to shoot our views down.
It’s not just about the number of reasons, though. It’s also how they fit
together. A university once approached me to see if I could bring in

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donations from alumni who had never given a dime. My colleagues and I
ran an experiment testing two different messages meant to convince
thousands of resistant alumni to give. One message emphasized the
opportunity to do good: donating would benefit students, faculty, and staff.
The other emphasized the opportunity to feel good: donors would enjoy the
warm glow of giving.
The two messages were equally effective: in both cases, 6.5 percent of
the stingy alumni ended up donating. Then we combined them, because two
reasons are better than one.
Except they weren’t. When we put the two reasons together, the giving
rate dropped below 3 percent. Each reason alone was more than twice as
effective as the two combined.
The audience was already skeptical. When we gave them different
kinds of reasons to donate, we triggered their awareness that someone was
trying to persuade them—and they shielded themselves against it. A single
line of argument feels like a conversation; multiple lines of argument can
become an onslaught. The audience tuned out the preacher and summoned
their best defense attorney to refute the prosecutor.
As important as the quantity and quality of reasons might be, the
source matters, too. And the most convincing source is often the one closest
to your audience.
A student in one of my classes, Rachel Breuhaus, noticed that although
top college basketball teams have rabid fans, there are usually empty seats
in their arenas. To study strategies for motivating more fans to show up, we
launched an experiment in the week before an upcoming game targeting
hundreds of season ticket holders. When left to their own devices, 77
percent of these supposedly die-hard fans actually made it to the game. We
decided that the most persuasive message would come from the team itself,
so we sent fans an email with quotes from players and coaches about how