Harnessing the Science of Persuasion

No leader can succeed without mastering the art of persuasion. But there’s hard science in that skill, too, and a large body of psychological research suggests there are six basic laws of winning friends and influencing people.

If leadership, at its most basic, consists of getting things done through others, then persuasion is one of the leader’s essential tools. Many executives have assumed that this tool is beyond their grasp, available only to the charismatic and the eloquent. Over the past several decades, though, experimental psychologists have learned which methods reliably lead people to concede, comply, or change. Their research shows that persuasion is governed by several principles that can be taught and applied. The first principle is that people are more likely to follow someone who is similar to them than someone who is not. Wise managers, then, enlist peers to help make their cases. Second, people are more willing to cooperate with those who are not only like them but who like them, as well. So it’s worth the time to uncover real similarities and offer genuine praise. Third, experiments confirm the intuitive truth that people tend to treat you the way you treat them. It’s sound policy to do a favor before seeking one. Fourth, individuals are more likely to keep promises they make voluntarily and explicitly. The message for managers here is to get commitments in writing. Fifth, studies show that people really do defer to experts. So before they attempt to exert influence, executives should take pains to establish their own expertise and not assume that it’s self-evident. Finally, people want more of a commodity when it’s scarce; it follows, then, that exclusive information is more persuasive than widely available data. By mastering these principles–and, the author stresses, using them judiciously and ethically–executives can learn the elusive art of capturing an audience, swaying the undecided, and converting the opposition.

A lucky few have it; most of us do not. A handful of gifted “naturals” simply know how to capture an audience, sway the undecided, and convert the opposition. Watching these masters of persuasion work their magic is at once impressive and frustrating. What’s impressive is not just the easy way they use charisma and eloquence to convince others to do as they ask. It’s also how eager those others are to do what’s requested of them, as if the persuasion itself were a favor they couldn’t wait to repay.

The frustrating part of the experience is that these born persuaders are often unable to account for their remarkable skill or pass it on to others. Their way with people is an art, and artists as a rule are far better at doing than at explaining. Most of them can’t offer much help to those of us who possess no more than the ordinary quotient of charisma and eloquence but who still have to wrestle with leadership’s fundamental challenge: getting things done through others. That challenge is painfully familiar to corporate executives, who every day have to figure out how to motivate and direct a highly individualistic work force. Playing the “Because I’m the boss” card is out. Even if it weren’t demeaning and demoralizing for all concerned, it would be out of place in a world where cross-functional teams, joint ventures, and intercompany partnerships have blurred the lines of authority. In such an environment, persuasion skills exert far greater influence over others’ behavior than formal power structures do.

Which brings us back to where we started. Persuasion skills may be more necessary than ever, but how can executives acquire them if the most talented practitioners can’t pass them along? By looking to science. For the past five decades, behavioral scientists have conducted experiments that shed considerable light on the way certain interactions lead people to concede, comply, or change. This research shows that persuasion works by appealing to a limited set of deeply rooted human drives and needs, and it does so in predictable ways. Persuasion, in other words, is governed by basic principles that can be taught, learned, and applied. By mastering these principles, executives can bring scientific rigor to the business of securing consensus, cutting deals, and winning concessions. In the pages that follow, I describe six fundamental principles of persuasion and suggest a few ways that executives can apply them in their own organizations.

The Principle of Liking:

People like those who like them.

The Application:

Uncover real similarities and offer genuine praise.

The retailing phenomenon known as the Tupperware party is a vivid illustration of this principle in action. The demonstration party for Tupperware products is hosted by an individual, almost always a woman, who invites to her home an array of friends, neighbors, and relatives. The guests’ affection for their hostess predisposes them to buy from her, a dynamic that was confirmed by a 1990 study of purchase decisions made at demonstration parties. The researchers, Jonathan Frenzen and Harry Davis, writing in the Journal of Consumer Research, found that the guests’ fondness for their hostess weighed twice as heavily in their purchase decisions as their regard for the products they bought. So when guests at a Tupperware party buy something, they aren’t just buying to please themselves. They’re buying to please their hostess as well.

What’s true at Tupperware parties is true for business in general: If you want to influence people, win friends. How? Controlled research has identified several factors that reliably increase liking, but two stand out as especially compelling—similarity and praise. Similarity literally draws people together. In one experiment, reported in a 1968 article in the Journal of Personality, participants stood physically closer to one another after learning that they shared political beliefs and social values. And in a 1963 article in American Behavioral Scientists, researcher F. B. Evans used demographic data from insurance company records to demonstrate that prospects were more willing to purchase a policy from a salesperson who was akin to them in age, religion, politics, or even cigarette-smoking habits.

Managers can use similarities to create bonds with a recent hire, the head of another department, or even a new boss. Informal conversations during the workday create an ideal opportunity to discover at least one common area of enjoyment, be it a hobby, a college basketball team, or reruns of Seinfeld. The important thing is to establish the bond early because it creates a presumption of goodwill and trustworthiness in every subsequent encounter. It’s much easier to build support for a new project when the people you’re trying to persuade are already inclined in your favor.

Praise, the other reliable generator of affection, both charms and disarms. Sometimes the praise doesn’t even have to be merited. Researchers at the University of North Carolina writing in the Journal of Experimental Social Psychology found that men felt the greatest regard for an individual who flattered them unstintingly even if the comments were untrue. And in their book Interpersonal Attraction (Addison-Wesley, 1978), Ellen Berscheid and Elaine Hatfield Walster presented experimental data showing that positive remarks about another person’s traits, attitude, or performance reliably generates liking in return, as well as willing compliance with the wishes of the person offering the praise.

Along with cultivating a fruitful relationship, adroit managers can also use praise to repair one that’s damaged or unproductive. Imagine you’re the manager of a good-sized unit within your organization. Your work frequently brings you into contact with another manager—call him Dan—whom you have come to dislike. No matter how much you do for him, it’s not enough. Worse, he never seems to believe that you’re doing the best you can for him. Resenting his attitude and his obvious lack of trust in your abilities and in your good faith, you don’t spend as much time with him as you know you should; in consequence, the performance of both his unit and yours is deteriorating.

The research on praise points toward a strategy for fixing the relationship. It may be hard to find, but there has to be something about Dan you can sincerely admire, whether it’s his concern for the people in his department, his devotion to his family, or simply his work ethic. In your next encounter with him, make an appreciative comment about that trait. Make it clear that in this case at least, you value what he values. I predict that Dan will relax his relentless negativity and give you an opening to convince him of your competence and good intentions.

The Principle of Reciprocity:

People repay in kind.

The Application:

Give what you want to receive.

Praise is likely to have a warming and softening effect on Dan because, ornery as he is, he is still human and subject to the universal human tendency to treat people the way they treat him. If you have ever caught yourself smiling at a coworker just because he or she smiled first, you know how this principle works.

Charities rely on reciprocity to help them raise funds. For years, for instance, the Disabled American Veterans organization, using only a well-crafted fund-raising letter, garnered a very respectable 18% rate of response to its appeals. But when the group started enclosing a small gift in the envelope, the response rate nearly doubled to 35%. The gift—personalized address labels—was extremely modest, but it wasn’t what prospective donors received that made the difference. It was that they had gotten anything at all.

What works in that letter works at the office, too. It’s more than an effusion of seasonal spirit, of course, that impels suppliers to shower gifts on purchasing departments at holiday time. In 1996, purchasing managers admitted to an interviewer from Inc. magazine that after having accepted a gift from a supplier, they were willing to purchase products and services they would have otherwise declined. Gifts also have a startling effect on retention. I have encouraged readers of my book to send me examples of the principles of influence at work in their own lives. One reader, an employee of the State of Oregon, sent a letter in which she offered these reasons for her commitment to her supervisor:

He gives me and my son gifts for Christmas and gives me presents on my birthday. There is no promotion for the type of job I have, and my only choice for one is to move to another department. But I find myself resisting trying to move. My boss is reaching retirement age, and I am thinking I will be able to move out after he retires… [F]or now, I feel obligated to stay since he has been so nice to me.

Ultimately, though, gift giving is one of the cruder applications of the rule of reciprocity. In its more sophisticated uses, it confers a genuine first-mover advantage on any manager who is trying to foster positive attitudes and productive personal relationships in the office: Managers can elicit the desired behavior from coworkers and employees by displaying it first. Whether it’s a sense of trust, a spirit of cooperation, or a pleasant demeanor, leaders should model the behavior they want to see from others.

The same holds true for managers faced with issues of information delivery and resource allocation. If you lend a member of your staff to a colleague who is shorthanded and staring at a fast-approaching deadline, you will significantly increase your chances of getting help when you need it. Your odds will improve even more if you say, when your colleague thanks you for the assistance, something like, “Sure, glad to help. I know how important it is for me to count on your help when I need it.”

The Principle of Social Proof:

People follow the lead of similar others.

The Application:

Use peer power whenever it’s available.

Social creatures that they are, human beings rely heavily on the people around them for cues on how to think, feel, and act. We know this intuitively, but intuition has also been confirmed by experiments, such as the one first described in 1982 in the Journal of Applied Psychology. A group of researchers went door-to-door in Columbia, South Carolina, soliciting donations for a charity campaign and displaying a list of neighborhood residents who had already donated to the cause. The researchers found that the longer the donor list was, the more likely those solicited would be to donate as well.

To the people being solicited, the friends’ and neighbors’ names on the list were a form of social evidence about how they should respond. But the evidence would not have been nearly as compelling had the names been those of random strangers. In an experiment from the 1960s, first described in the Journal of Personality and Social Psychology, residents of New York City were asked to return a lost wallet to its owner. They were highly likely to attempt to return the wallet when they learned that another New Yorker had previously attempted to do so. But learning that someone from a foreign country had tried to return the wallet didn’t sway their decision one way or the other.

The lesson for executives from these two experiments is that persuasion can be extremely effective when it comes from peers. The science supports what most sales professionals already know: Testimonials from satisfied customers work best when the satisfied customer and the prospective customer share similar circumstances. That lesson can help a manager faced with the task of selling a new corporate initiative. Imagine that you’re trying to streamline your department’s work processes. A group of veteran employees is resisting. Rather than try to convince the employees of the move’s merits yourself, ask an old-timer who supports the initiative to speak up for it at a team meeting. The compatriot’s testimony stands a much better chance of convincing the group than yet another speech from the boss. Stated simply, influence is often best exerted horizontally rather than vertically.

The Principle of Consistency:

People align with their clear commitments.

The Application:

Make their commitments active, public, and voluntary.

Liking is a powerful force, but the work of persuasion involves more than simply making people feel warmly toward you, your idea, or your product. People need not only to like you but to feel committed to what you want them to do. Good turns are one reliable way to make people feel obligated to you. Another is to win a public commitment from them.

My own research has demonstrated that most people, once they take a stand or go on record in favor of a position, prefer to stick to it. Other studies reinforce that finding and go on to show how even a small, seemingly trivial commitment can have a powerful effect on future actions. Israeli researchers writing in 1983 in the Personality and Social Psychology Bulletin recounted how they asked half the residents of a large apartment complex to sign a petition favoring the establishment of a recreation center for the handicapped. The cause was good and the request was small, so almost everyone who was asked agreed to sign. Two weeks later, on National Collection Day for the Handicapped, all residents of the complex were approached at home and asked to give to the cause. A little more than half of those who were not asked to sign the petition made a contribution. But an astounding 92% of those who did sign donated money. The residents of the apartment complex felt obligated to live up to their commitments because those commitments were active, public, and voluntary. These three features are worth considering separately.

There’s strong empirical evidence to show that a choice made actively—one that’s spoken out loud or written down or otherwise made explicit—is considerably more likely to direct someone’s future conduct than the same choice left unspoken. Writing in 1996 in the Personality and Social Psychology Bulletin, Delia Cioffi and Randy Garner described an experiment in which college students in one group were asked to fill out a printed form saying they wished to volunteer for an AIDS education project in the public schools. Students in another group volunteered for the same project by leaving blank a form stating that they didn’t want to participate. A few days later, when the volunteers reported for duty, 74% of those who showed up were students from the group that signaled their commitment by filling out the form.

The implications are clear for a manager who wants to persuade a subordinate to follow some particular course of action: Get it in writing. Let’s suppose you want your employee to submit reports in a more timely fashion. Once you believe you’ve won agreement, ask him to summarize the decision in a memo and send it to you. By doing so, you’ll have greatly increased the odds that he’ll fulfill the commitment because, as a rule, people live up to what they have written down.

Research into the social dimensions of commitment suggests that written statements become even more powerful when they’re made public. In a classic experiment, described in 1955 in the Journal of Abnormal and Social Psychology, college students were asked to estimate the length of lines projected on a screen. Some students were asked to write down their choices on a piece of paper, sign it, and hand the paper to the experimenter. Others wrote their choices on an erasable slate, then erased the slate immediately. Still others were instructed to keep their decisions to themselves.

The experimenters then presented all three groups with evidence that their initial choices may have been wrong. Those who had merely kept their decisions in their heads were the most likely to reconsider their original estimates. More loyal to their first guesses were the students in the group that had written them down and immediately erased them. But by a wide margin, the ones most reluctant to shift from their original choices were those who had signed and handed them to the researcher.

This experiment highlights how much most people wish to appear consistent to others. Consider again the matter of the employee who has been submitting late reports. Recognizing the power of this desire, you should, once you’ve successfully convinced him of the need to be more timely, reinforce the commitment by making sure it gets a public airing. One way to do that would be to send the employee an e-mail that reads, “I think your plan is just what we need. I showed it to Diane in manufacturing and Phil in shipping, and they thought it was right on target, too.” Whatever way such commitments are formalized, they should never be like the New Year’s resolutions people privately make and then abandon with no one the wiser. They should be publicly made and visibly posted.

More than 300 years ago, Samuel Butler wrote a couplet that explains succinctly why commitments must be voluntary to be lasting and effective: “He that complies against his will/Is of his own opinion still.” If an undertaking is forced, coerced, or imposed from the outside, it’s not a commitment; it’s an unwelcome burden. Think how you would react if your boss pressured you to donate to the campaign of a political candidate. Would that make you more apt to opt for that candidate in the privacy of a voting booth? Not likely. In fact, in their 1981 book Psychological Reactance (Academic Press), Sharon S. Brehm and Jack W. Brehm present data that suggest you’d vote the opposite way just to express your resentment of the boss’s coercion.

This kind of backlash can occur in the office, too. Let’s return again to that tardy employee. If you want to produce an enduring change in his behavior, you should avoid using threats or pressure tactics to gain his compliance. He’d likely view any change in his behavior as the result of intimidation rather than a personal commitment to change. A better approach would be to identify something that the employee genuinely values in the work-place—high-quality workmanship, perhaps, or team spirit—and then describe how timely reports are consistent with those values. That gives the employee reasons for improvement that he can own. And because he owns them, they’ll continue to guide his behavior even when you’re not watching.

The Principle of Authority:

People defer to experts.

The Application:

Expose your expertise; don’t assume it’s self-evident.Two thousand years ago, the Roman poet Virgil offered this simple counsel to those seeking to choose correctly: “Believe an expert.” That may or may not be good advice, but as a description of what people actually do, it can’t be beaten. For instance, when the news media present an acknowledged expert’s views on a topic, the effect on public opinion is dramatic. A single expert-opinion news story in the New York Times is associated with a 2% shift in public opinion nationwide, according to a 1993 study described in the Public Opinion Quarterly. And researchers writing in the American Political Science Review in 1987 found that when the expert’s view was aired on national television, public opinion shifted as much as 4%. A cynic might argue that these findings only illustrate the docile submissiveness of the public. But a fairer explanation is that, amid the teeming complexity of contemporary life, a well-selected expert offers a valuable and efficient shortcut to good decisions. Indeed, some questions, be they legal, financial, medical, or technological, require so much specialized knowledge to answer, we have no choice but to rely on experts.

Since there’s good reason to defer to experts, executives should take pains to ensure that they establish their own expertise before they attempt to exert influence. Surprisingly often, people mistakenly assume that others recognize and appreciate their experience. That’s what happened at a hospital where some colleagues and I were consulting. The physical therapy staffers were frustrated because so many of their stroke patients abandoned their exercise routines as soon as they left the hospital. No matter how often the staff emphasized the importance of regular home exercise—it is, in fact, crucial to the process of regaining independent function—the message just didn’t sink in.

Surprisingly often, people mistakenly assume that others recognize and appreciate their experience.

Interviews with some of the patients helped us pinpoint the problem. They were familiar with the background and training of their physicians, but the patients knew little about the credentials of the physical therapists who were urging them to exercise. It was a simple matter to remedy that lack of information: We merely asked the therapy director to display all the awards, diplomas, and certifications of her staff on the walls of the therapy rooms. The result was startling: Exercise compliance jumped 34% and has never dropped since.

What we found immensely gratifying was not just how much we increased compliance, but how. We didn’t fool or browbeat any of the patients. We informed them into compliance. Nothing had to be invented; no time or resources had to be spent in the process. The staff’s expertise was real—all we had to do was make it more visible.

The task for managers who want to establish their claims to expertise is somewhat more difficult. They can’t simply nail their diplomas to the wall and wait for everyone to notice. A little subtlety is called for. Outside the United States, it is customary for people to spend time interacting socially before getting down to business for the first time. Frequently they gather for dinner the night before their meeting or negotiation. These get-togethers can make discussions easier and help blunt disagreements—remember the findings about liking and similarity—and they can also provide an opportunity to establish expertise. Perhaps it’s a matter of telling an anecdote about successfully solving a problem similar to the one that’s on the agenda at the next day’s meeting. Or perhaps dinner is the time to describe years spent mastering a complex discipline—not in a boastful way but as part of the ordinary give-and-take of conversation.

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Granted, there’s not always time for lengthy introductory sessions. But even in the course of the preliminary conversation that precedes most meetings, there is almost always an opportunity to touch lightly on your relevant background and experience as a natural part of a sociable exchange. This initial disclosure of personal information gives you a chance to establish expertise early in the game, so that when the discussion turns to the business at hand, what you have to say will be accorded the respect it deserves.

The Principle of Scarcity:

People want more of what they can have less of.

The Application:

Highlight unique benefits and exclusive information.

Study after study shows that items and opportunities are seen to be more valuable as they become less available. That’s a tremendously useful piece of information for managers. They can harness the scarcity principle with the organizational equivalents of limited-time, limited-supply, and one-of-a-kind offers. Honestly informing a coworker of a closing window of opportunity—the chance to get the boss’s ear before she leaves for an extended vacation, perhaps—can mobilize action dramatically.

Managers can learn from retailers how to frame their offers not in terms of what people stand to gain but in terms of what they stand to lose if they don’t act on the information. The power of “loss language” was demonstrated in a 1988 study of California home owners written up in the Journal of Applied Psychology. Half were told that if they fully insulated their homes, they would save a certain amount of money each day. The other half were told that if they failed to insulate, they would lose that amount each day. Significantly more people insulated their homes when exposed to the loss language. The same phenomenon occurs in business. According to a 1994 study in the journal Organizational Behavior and Human Decision Processes, potential losses figure far more heavily in managers’ decision making than potential gains.

In framing their offers, executives should also remember that exclusive information is more persuasive than widely available data. A doctoral student of mine, Amram Knishinsky, wrote his 1982 dissertation on the purchase decisions of wholesale beef buyers. He observed that they more than doubled their orders when they were told that, because of certain weather conditions overseas, there was likely to be a scarcity of foreign beef in the near future. But their orders increased 600% when they were informed that no one else had that information yet.

The persuasive power of exclusivity can be harnessed by any manager who comes into possession of information that’s not broadly available and that supports an idea or initiative he or she would like the organization to adopt. The next time that kind of information crosses your desk, round up your organization’s key players. The information itself may seem dull, but exclusivity will give it a special sheen. Push it across your desk and say, “I just got this report today. It won’t be distributed until next week, but I want to give you an early look at what it shows.” Then watch your listeners lean forward.

Allow me to stress here a point that should be obvious. No offer of exclusive information, no exhortation to act now or miss this opportunity forever should be made unless it is genuine. Deceiving colleagues into compliance is not only ethically objectionable, it’s foolhardy. If the deception is detected—and it certainly will be—it will snuff out any enthusiasm the offer originally kindled. It will also invite dishonesty toward the deceiver. Remember the rule of reciprocity.

Putting It All Together

There’s nothing abstruse or obscure about these six principles of persuasion. Indeed, they neatly codify our intuitive understanding of the ways people evaluate information and form decisions. As a result, the principles are easy for most people to grasp, even those with no formal education in psychology. But in the seminars and workshops I conduct, I have learned that two points bear repeated emphasis.

First, although the six principles and their applications can be discussed separately for the sake of clarity, they should be applied in combination to compound their impact. For instance, in discussing the importance of expertise, I suggested that managers use informal, social conversations to establish their credentials. But that conversation affords an opportunity to gain information as well as convey it. While you’re showing your dinner companion that you have the skills and experience your business problem demands, you can also learn about your companion’s background, likes, and dislikes—information that will help you locate genuine similarities and give sincere compliments. By letting your expertise surface and also establishing rapport, you double your persuasive power. And if you succeed in bringing your dinner partner on board, you may encourage other people to sign on as well, thanks to the persuasive power of social evidence.

The other point I wish to emphasize is that the rules of ethics apply to the science of social influence just as they do to any other technology. Not only is it ethically wrong to trick or trap others into assent, it’s ill-advised in practical terms. Dishonest or high-pressure tactics work only in the short run, if at all. Their long-term effects are malignant, especially within an organization which can’t function properly without a bedrock level of trust and cooperation.

That point is made vividly in the following account, which a department head for a large textile manufacturer related at a training workshop I conducted. She described a vice president in her company who wrung public commitments from department heads in a highly manipulative manner. Instead of giving his subordinates time to talk or think through his proposals carefully, he would approach them individually at the busiest moment of their workday and describe the benefits of his plan in exhaustive, patience-straining detail. Then he would move in for the kill. “It’s very important for me to see you as being on my team on this,” he would say. “Can I count on your support?” Intimidated, frazzled, eager to chase the man from their offices so they could get back to work, the department heads would invariably go along with his request. But because the commitments never felt voluntary, the department heads never followed through, and as a result the vice president’s initiatives all blew up or petered out.

This story had a deep impact on the other participants in the workshop. Some gulped in shock as they recognized their own manipulative behavior. But what stopped everyone cold was the expression on the department head’s face as she recounted the damaging collapse of her superior’s proposals. She was smiling.

Nothing I could say would more effectively make the point that the deceptive or coercive use of the principles of social influence is ethically wrong and pragmatically wrongheaded. Yet the same principles, if applied appropriately, can steer decisions correctly. Legitimate expertise, genuine obligations, authentic similarities, real social proof, exclusive news, and freely made commitments can produce choices that are likely to benefit both parties. And any approach that works to everyone’s mutual benefit is good business, don’t you think? Of course, I don’t want to press you into it, but, if you agree, I would love it if you could just jot me a memo to that effect.

Robert B. Cialdini is the Regents’ Professor of Psychology at Arizona State University and the author of Influence: Science and Practice (Allyn & Bacon, 2001), now in its fourth edition. Further regularly updated information about the influence process can be found at www.influenceatwork.com .

This classic article appeared in the October, 2001 issue of Harvard Business Review.

Copyright 2001 Harvard Business School Publishing Corporation. Distributed by The New York Times Syndicate.