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The 6 Principles of Persuasion

Tips from the leading expert on social influence.

People are trying to influence you all the time. Sometimes they’re doing it in an annoying or underhanded way. I signed up for a credit card recently, and the bank that issued the card sent me a “thank you gift.” It sounded pretty good, a case of fine wines chosen by connoisseurs, themselves sponsored by the Wall Street Journal. I was inclined to be grateful, until I read the fine print. It was really a con designed to get me to sign up for a program in which I’m sent a case of wine every three months, and unless I specifically opt out, it’ll all be billed to my new credit card. Now instead of gratitude I feel anger, and I’ll be careful not to trust the bank or the Wall Street Journal so easily in the future.

With the exception of those of you hermits living in caves, you’re also trying to influence other people all the time. I myself have recently been involved in influence attempts large and small to get my 8-year-old son to sit still at the table and finish his homework, to get my 6-year-old grandson to use an “indoor voice” when he is joyfully screaming at his 8-year-old uncle in the back of the car, to get my wife to pick up the droppings with which her two dogs lovingly decorate our backyard, and to get my colleagues to hire another evolutionary psychologist for our department.

And well, I don’t know about you, but I’m not always too successful in my attempts to influence other people. But my colleague Bob Cialdini? Well, he's a different story. In fact, when I read the best-selling book Nudge by the behavioral economists Richard Thaler and Cass Sunstein, I saw that they referred to Cialdini as the “great guru of social influence.” One time, I sat next to a fellow on the plane who had read Cialdini’s book Influence, and when I told him Cialdini had been my advisor in grad school, the fellow acted as if I’d just let it drop that I was a disciple of the Dalai Lama.

Just a few weeks ago, I saw Cialdini’s name mentioned in the New York Times, under the rather impressive heading “Academic Dream Team Helped Obama’s Effort.” The following week, several people mentioned to me that they’d heard Bob on NPR’s Morning Edition, offering his expert opinion on the psychological principles behind the exchange of Christmas cards.

Besides being part of Obama’s “dream team,” Cialdini has been called upon by Al Gore and the British government to develop techniques to encourage energy conservation, and been quoted on various topics in sources as wide-ranging as Scientific American, the BBC, Harvard Business Review, and the Wall Street Journal. What’s especially impressive is that despite having consulted for Fortune 500 tycoons, Cialdini has managed not to sell out his scientific credentials. Indeed, throughout his career, he’s published first-rate scientific articles in rigorous journals, and he still has serious respect in the academic world.

Cialdini came from a working class family in Milwaukee, and he worked as a garbage collector to put himself through college. When my fellow graduate students and I first met him, we were unimpressed. He was wearing high-water bell-bottom trousers, a dashiki shirt, and puka beads, and his haircut made him look like the early Eric Burdon (lead singer to the Animals, and, in case you’re too young to have caught them singing House of the Rising Sun on Hullaballoo, not exactly a fashion icon). In those days, Cialdini drove this souped-up looking orange Plymouth Duster, which bore a striking resemblance to the hillbilly hot rod later depicted on the Dukes of Hazzard. And he resided in a low rent apartment complex, where a mobster was murdered in the parking lot, and a young girl was found dead in a dumpster.

Back then, Cialdini was a green-behind-the-ears assistant professor in a tiny start-up program in social psychology at a second-rate university in Tempe, Arizona. And although he was later offered higher-paying jobs at more prestigious institutions, Cialdini stuck it out at Arizona State.

So, here’s the mystery: How in the world did it happen that this guy became the “Guru of Social Influence?” (and not incidentally, enhance the reputation of ASU's psych department along the way)

Cialdini’s working class background may have helped. A typical academic social psychologist in those days studied social influence in the laboratory, doing rigorous experiments on college sophomores. If you’ve ever taken a psychology class, you’ve heard about some of those experiments, like Solomon Asch’s study in which a hapless subject hears seven other guys say that the shorter of two lines is really the longer, or Stanley Milgram’s study in which an even more hapless subject is led to believe he’s delivering electric shocks to a screaming fellow in the next room who is complaining about his heart condition. Cialdini learned how to conduct these kinds of experiments, how to set up rigorous control groups and remove any extraneous factors other than the variable of interest. But one day while he was on a temporary appointment at Ohio State analyzing data from one of his own experiments, he heard the roar of the OSU football fans outside, and had a conversion experience. Out there in the real world, he realized, there was some very real social influence going on.

Cialdini did not forsake the laboratory, but he had the idea that he could better understand social influence if he went back and forth between the uncontrolled real world, where causal factors were messy but effects were big, and the controlled laboratory, where the effects were subtle, but causality was easier to isolate.

One of his ideas was to dirty his hands working with real influence professionals. He even took part-time jobs working in various sales positions, some of them pretty sleazy operations, and he observed how religious cults recruit innocent young people to happily march out and trick you into donating your money to buy their leader another limousine. Then he went back to the lab to test the principles he thought he saw working out there in the real world. After several years of study, Cialdini came up with six principles of social influence — common themes that normally underlie our legitimate attempts to persuade one another.

In brief, we are inclined to go along with someone's suggestion if we think that person is a credible expert (authority), if we regard him or her as a trusted friend (likeability), if we feel we owe them one (reciprocity), or if doing so will be consistent with our beliefs or prior commitments (consistency). We are also inclined to make choices that we think are popular (consensus), and that will net us a scarce commodity (scarcity). We follow these general rules because they usually work to lead us to make the right choice. But because we often use them unthinkingly they are commonly exploited by compliance professionals and con artists, many of them wearing nice business suits, religious robes, or reassuringly friendly smiles.

To get a better feel for the power of each of these principles, and the evidence supporting them, check out this great link to a new animated video in which Cialdini and Steve Martin tell you about the principles first-hand (Martin not only has a charming British accent, but, along with UCLA’s Noah Goldstein, is a coauthor of Cialdini's more recent book Yes: 50 Scientifically Proven Ways to Be Persuasive).

The link is well worth checking out, they concisely describe some very clever studies, like one showing how waiters can increase their tips 23% just by changing a few words in the way they hand you the bill.

Secrets from the Science of Influence, by Robert Cialdini and Steve Martin.

Douglas Kenrick is the author of Sex, Murder, and the Meaning of Life: A psychologist investigates how evolution, cognition, and complexity, are revolutionizing our view of human nature.

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