The Rule of Threes
by Site Author
On July 27, 2004, a state senator from Illinois approached the dais at the National Democratic Convention. Barack Obama had been chosen to give the keynote address. It was his big break, his first real opportunity on the national stage. Obama wrote the speech himself, writing the first draft longhand. And the 20-minute speech killed. The speech was so moving that one cable news anchor remarked that night, “I have seen the first black president.” Four years later, Obama became president.
In preparing for the speech, Obama watched old videos of Ronald Reagan and Bill Clinton. And indeed, the speech included many tricks of the trade. One that interests me is the “rule of threes.” Again and again, Obama illustrated his points with three examples. Take for instance, this paragraph, which led to one of the many applause breaks.
A belief that we’re all connected as one people.  If there’s a child on the south side of Chicago who can’t read, that matters to me, even if it’s not my child.  If there’s a senior citizen somewhere who can’t pay for their prescription drugs and having to choose between medicine and the rent, that makes my life poorer, even if it’s not my grandparent.  If there’s an Arab-American family being rounded up without benefit of an attorney or due process, that threatens my civil liberties. It is that fundamental belief—I am my brother’s keeper, I am my sister’s keeper—that makes this country work.
Or take the following famous passage.
The pundits like to slice-and-dice our country into Red States and Blue States; Red States for Republicans, Blue States for Democrats. But I’ve got news for them, too.  We worship an awesome God in the Blue States, and we don’t like federal agents poking around our libraries in the Red States.  We coach Little League in the Blue States, and yes we’ve got some gay friends in the Red States.  There are patriots who opposed the war in Iraq and there are patriots who supported the war in Iraq. We are one people, all of us pledging allegiance to the stars and stripes, all of us defending the United States of America.
Or, to round it out, take a third example, in which Obama describes John Kerry’s personal history.
From his  heroic service in Vietnam to  his years as prosecutor and lieutenant governor,  through two decades in the United States Senate, he has devoted himself to this country.
Why have three of everything? There’s a long history of writers relying on the number three. But, more recently, there’s actually been some research.
The psychologists Suzanne Shu And Kurt Carlson recently wrote a paper that tried to test the rule of threes. They presented 521 undergraduates with descriptions of cereal. One group was given the following hypothetical scenario.
“Imagine that you are shopping at the grocery store and you notice that a brand of cereal you sometimes buy has a new package design. As you look closer you discover that they have also changed the product itself. The packaging says that it now is ‘Healthier, better tasting, crunchier, and with higher quality ingredients.’”
The other group was given an alternative scenario.
“Imagine that you read a Consumer Reports article about a brand of cereal you sometimes buy. The article says that the brand of cereal has been changed and that it now is ‘Healthier, better tasting, crunchier, and with higher quality ingredients.’”
They called the first description, about the cereal’s packaging, the “persuasion” scenario, and labeled the scenario involving Consumer Reports as the “no persuasion” scenario. The authors then experimentally varied the number of claims in each scenario. Some students saw three claims: “healthier, better tasting, and crunchier,” while other students saw two: “healthier and better tasting.”
At the end of the experiment, they asked the undergraduates to rate their impression of the cereal, and they found an interesting pattern.
It seems as though the seller’s effectiveness peaked with three claims. But for Consumer Reports, the more claims the better. The implication is that persuasive arguments are most effective with three claims, and “non-persuasive” arguments might be best with as many claims as possible.
Now, to be sure, this one study hasn’t been replicated. And there’s a growing concern in psychology that studies like this one don’t stand up to replication. This evidence is much more suggestive than conclusive.
And, for that matter, there are likely other reasons why writers so often rely on the number three. There’s a symmetry to three elements, a balance, a rhythm. The best speeches are written by writers who understand these hidden ways to move people. President Obama is one such writer.