Always Make Promises

Living up to a social contract is inordinately valuable, and there's no pressure to exceed it.

Nicholas Epley recently made news when he paid commuters $5 to talk to a stranger on a Chicago train. The people were happier for having done it. But the point of his experiment was to shatter expectations. Most people presumed they would be happier sitting alone than talking to a stranger; but they were not. They also expected, on average, that fewer than half of their fellow passengers would be willing to talk with them. When people actually tried talking, though, no one was rebuffed.

Epley is a broad-shouldered professor of behavioral science at the University of Chicago Booth School of Business. He studies prosocial behavior in ways fascinating and a little unnervingly manipulative, of necessity. In a recent lecture he recounted that people tend to evaluate one another in two general dimensions: how interpersonally warm we seem to be, and how competent we seem to be. His latest work suggests that the way to deliver on both without going overboard on effort is to make promises.

In the journal Social Psychological and Personality Science, Epley and Ayelet Gneezy at University of California at San Diego perform three experiments that explain why promises can be helpful in business, and in limiting the burden of expectations in a world where enough is never enough and more is more. I spoke with Epley recently by phone about broken promises, and the importance of trust. 

"You're late," he told me upon answering, exactly at 10:00 A.M.

That was the time I had on my calendar. I panicked, confused. "I'm so sorry." 

Luckily it was just a joke, he explained, based on the nature of our interview. The ice broke all around us, and we sank into the frigid depths of pop psychology.

In Epley's latest social experiment, people were asked to consider a hypothetical scenario in which a friend had promised to give feedback on a paper. Either the friend did just as promised, gave really exceptional comments, or did less than they promised. "People were no more positive when someone did more than they said they would," Epley explained. "Breaking a promise seemed to hurt, but exceeding a promise didn't seem to help."

The same thing was true for remembered promises. The researchers asked people to recall promises kept, broken, and exceeded. People were less happy when someone broke a promise than when they kept it, but, again, exceeding the promise didn't create a big gain. At least, not one that was of the same magnitude as the damage of breaking a promise. "Breaking a promise was bad," Epley essentially reiterated. "Exceeding a promise? Meh. Not that much better than just keeping it."

Then in the pièce de résistance, part three, researchers made real promises to subjects in a lab, then broke those promises and evaluated the subjects' reactions. 

"For a scientist, this was the most compelling demonstration, by far," Epley said, a staid appraisal of the thrill of a calculated lie for the greater good. To the researchers' knowledge, everything in prior psychology research had involved imagined or recalled promises. No one had actually created a laboratory experiment that manipulated promise keeping. "These promises may not have the ecological validity of a promise made out in the world, but they have the benefit of really happening, right there." 

The experimenters gave subjects a set of 40 puzzles and told the subjects they would be paid on the basis of how many they completed. Then other people promised to help out by doing a certain number of the puzzles, pro bono. Some over and under-delivered on their promises. People were upset when the person didn't make good on their promise, but they were barely happier when the person over-delivered than when they did just what they said they would do.

I was surprised by how unimpressed people seem to be by that kind of unexpected boon. But Epley was surprised that I was surprised. He explained that there are actually a lot of findings of this kind in the psychological literature.

To make the point, Epley told me to think about an oil spill that kills a certain number of birds. I did, reluctantly. "How much should the oil company be fined?" he asked, rhetorically. "Well, if they killed 20,000 birds, they should obviously be fined more than if they killed only 2,000 birds. That's ten times more bird carnage." It's true; I did the math. But, he explained, if you ask people in experiments how much the oil company should be fined, and the people only see one of those numbers, the estimates are about the same. 

Presented by

James Hamblin, MD, is a senior editor at The Atlantic. He writes the health column for the monthly magazine and hosts the video series If Our Bodies Could Talk.

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