Influence: The Psychology of Persuasion

by Robert B. Cialdini

there are many normal responses to food besides salivation, one of them being a good and favorable feeling. Therefore, it is possible to attach this pleasant feeling, this positive attitude, to anything (political statements being only an example) that is closely associated with good food.

Rather than trying to recognize and prevent the action of liking factors before they have a chance to work, we might want to let them work. Our vigilance should be directed not toward the things that may produce undue liking for a compliance practitioner but toward the fact that undue liking has been produced. The time to call up the defense is when we feel ourselves liking the practitioner more than we should under the circumstances.

Our proper response, then, is a conscious effort to concentrate exclusively on the merits of the deal and the car Dan has for us. Of course, when we make a compliance decision, it is always a good idea to separate our feelings about the requester from the request. Once immersed in even a brief personal and sociable contact with a requester, however, we may easily forget that distinction.

People prefer to say yes to individuals they like. Recognizing this rule, compliance professionals commonly increase their effectiveness by emphasizing several factors that increase their overall likability. One such feature is physical attractiveness. Although it has long been suspected that physical beauty provides an advantage in social interaction, research indicates the advantage may be greater than supposed. Physical attractiveness engenders a halo effect that leads to the assignment of other traits such as talent, kindness, and intelligence. As a result, attractive people are more persuasive both in terms of getting what they request and changing others’ attitudes. A second factor that influences liking and compliance is similarity. We like people who are like us, and we are more willing to say yes to their requests, often in an unthinking manner. Another such factor is praise. Compliments generally enhance liking and, hence, compliance. Two particularly useful types of genuine compliments are those delivered behind the recipient’s back and those selected to give the recipient a reputation to live up to, by continuing to perform the desired behavior. Increased familiarity through repeated contact with a person or thing is yet another factor that normally facilitates liking. This relationship holds true principally when the contact takes place under positive rather than negative circumstances. One positive circumstance that works especially well is mutual and success...

that people are more likely to be persuaded by information, including social-proof information, when they think it is not intended to persuade them

All the levers of influence discussed in this book work better under some conditions than others. If we are to defend ourselves adequately against any such lever, it is vital that we know its optimal operating conditions in order to recognize when we are most vulnerable to its influence. In the case of social proof, there are three main optimizing conditions: when we are unsure of what is best to do (uncertainty); when the evidence of what is best to do comes from numerous others (the many); and when that evidence comes from people like us (similarity).

In general, when we are unsure of ourselves, when the situation is unclear or ambiguous, when uncertainty reigns, we are most likely to accept the actions of others—because those actions reduce our uncertainty about what is correct behavior there.

Often an emergency is not obviously an emergency. Is the man lying in the alley a heart-attack victim or a drunk sleeping one off? Is the commotion next door an assault requiring the police or an especially loud marital spat where intervention would be inappropriate and unwelcome? What is going on? In times of such uncertainty, the natural tendency is to look around at the actions of others for clues. From the principle of social proof, we can determine from the way the other witnesses are reacting whether the event is or is not an emergency. What is easy to forget, though, is that everybody else observing the event is likely to be looking for social evidence to reduce their uncertainty. Because we all prefer to appear poised and unflustered among others, we are likely to search for that evidence placidly, with brief, camouflaged glances at those around us. Therefore, everyone is likely to see everyone else looking unruffled and failing to act. As a result, and by the principle of social proof, the event will be roundly interpreted as a nonemergency.

Social scientists have a good idea of when bystanders will offer emergency aid. First, once uncertainty is removed and witnesses are convinced an emergency situation exists, aid is very likely.

In general, then, your best strategy when in need of emergency help is to reduce the uncertainties of those around you concerning your condition and their responsibilities. Be as precise as possible about your need for aid. Do not allow bystanders to come to their own conclusions because the principle of social proof and the consequent pluralistic-ignorance effect might well cause them to view your situation as a nonemergency. Of all the techniques in this book designed to produce compliance with a request, this one is the most important to remember. After all, the failure of your request for emergency aid could mean the loss of your life.

Observers of male–female confrontations often assume the pair is romantically involved and that intervention would be unwanted or inappropriate. To combat this perception and get aid, the woman should shout, “I don’t know you.”

These twin needs—to foster social acceptance and to escape social rejection—help explain why cults can be so effective in recruiting and retaining members. An initial showering of affection on prospective members, called love bombing, is typical of cult-induction practices. It accounts for some of the success of these groups in attracting new members, especially those feeling lonely or disconnected. Later, threatened withdrawal of that affection explains the willingness of some members to remain in the group: After having cut their bonds to outsiders, as the cults invariably urge, members have nowhere else to turn for social acceptance.

The principle of social proof operates most powerfully when we are observing the behavior of people just like us. It is the conduct of such people that gives us the greatest insight into what constitutes correct behavior for ourselves.

After an extensive review of environmental behavior change, the economist Robert Frank stated, “By far the strongest predictor of whether we install solar panels, buy electric cars, eat more responsibly, and support climate-friendly policies is the percentage of peers who take those steps.”

The strongest influence on market share, 80 percent, was due to geographical region. People’s brand choices moved in line with the choices of those like them, around them. The effects of distinct regions were so large that the researchers questioned the concept and relevance of “national brands.”

when informed that only a minority performs one of these desired actions, people are reluctant to perform it themselves. However, if they learn that within the minority, more and more others are engaging in it, they jump on the bandwagon and begin enacting the behavior too.

Because we assume they will continue in the same direction, trends don’t just tell us where others’ behaviors have been and are now; we think they also tell us where others’ behaviors will be. Thus, trends give us access to a special and potent form of social proof—future social proof. When we asked the subjects in our study to predict the percentage of their colleagues who would conserve water at home over the next six years, only those who learned of the trend toward conservation predicted an increase. Indeed, many of these subjects predicted that by then, conservation would be the majority behavior. On the basis of these results, I no longer give my previous advice to individuals who have something new to offer that possesses limited current popularity. Rather than urging them away from the principle of social proof and toward one of the other principles, I ask if over a reasonable period of time, they have honest evidence of growing popularity. If yes, I recommend making that fact the central feature of their messaging—because, as their audiences will presume, such evidence will be an indicator of genuine worth and future popularity.

Because autopilots can be engaged and disengaged at will, we can cruise along trusting in the course steered by the principle of social proof until we recognize that inaccurate data are being used. Then we can take the controls, make the necessary correction for the misinformation, and reset the autopilot.

SUMMARY The principle of social proof states that one important means people use to decide what to believe or how to act in a situation is to examine what others are believing or doing there. Powerful such effects have been found among both children and adults and in such diverse activities as purchase decisions, charity donations, and phobia remission. The principle of social proof can be used to stimulate a person’s compliance with a request by communicating that many other individuals (the more, the better) are or have been complying with it. Therefore, simply pointing to the popularity of an item elevates its popularity. Social proof is most influential under three conditions. The first is uncertainty. When people are unsure, when the situation is ambiguous, they are more likely to attend to the actions of others and to accept those actions as correct. In ambiguous situations, for instance, the decisions of bystanders to offer emergency aid are much more influenced by the actions of other bystanders than when the situation is a clear-cut emergency. A second condition under which social proof is most influential involves “the many”: people are more inclined to follow the lead of others in proportion to the others’ number. When we see multiple others performing an action, we become willing to follow because the action appears to be more (1) correct/valid, (2) feasible, and (3) socially acceptable. The third optimizing condition for social-proof information is similarity....

People judge those dressed in higher quality apparel, even higher quality T-shirts, as more competent than those in lesser quality attire—and the judgments occur automatically, in less than a second. Other examples of trappings, such as high-priced jewelry and cars, can have similar effects.

people were unable to predict correctly how they or others would react to authority influence. In each instance, the effect of the influence was grossly underestimated. This property of authority status may account for much of its success as a compliance device. Authority influence not only works forcefully on us but does so without our awareness.

Whenever I’ve attended programs designed to teach influence skills, they’ve stressed that being perceived as trustworthy is an effective way to increase one’s influence and that it takes time for that perception to develop. Although the first of these claims remains verified by research, a separate body of research indicates that there is a noteworthy exception to the second. It turns out a communicator can rapidly acquire perceived trustworthiness by employing a clever strategy. Rather than succumbing to the tendency to describe all the most favorable features of a case upfront and reserving mention of any drawbacks until the end of the presentation (or never), a communicator who references a weakness early on is seen as more honest. The advantage of this sequence is that, with perceived truthfulness already in place, when the major strengths of the case are then advanced, the audience is more likely to believe them. After all, they’ve been conveyed by a trustworthy source, one whose honesty has been established by a willingness to point at not just positive aspects but negative ones as well.

Rather, I am suggesting two things. First, if there is a drawback to be acknowledged, it should be presented relatively early in a message so the credibility it provides will color the rest of the appeal. Second, within a persuasive communication, there is an ideal place for one’s strongest argument or feature, which can undercut or overwhelm the downside. It is in the moment immediately following the admission of a shortcoming of one’s case when, bolstered by resulting source credibility, the highly favorable element is likely to be processed most deeply and accepted most fully.

training participants to focus on the true credentials of a spokesperson in an ad did, in fact, make them better evaluators of ads they experienced much later. They became not only less persuaded by subsequent ads featuring spokespeople with no relevant credentials (an actor, Arnold Schwarzenegger, promoting a type of internet technology, and a game-show host, Alex Trebek, touting the health properties of milk) but also more persuaded by spokespeople with relevant credentials (an MD director of a pain institute, recommending a pain reliever, and a CEO, describing his company’s years of good experience with a brand of business insurance). The lesson? To defend ourselves against misleading appeals containing ersatz authorities, we should always ask, Is this authority truly an expert? We shouldn’t presume we are too smart to be tricked by mere symbols of authority. Those symbols operate automatically on us. In my team’s research, it was only the participants who, recognizing their susceptibility to this automatic process, were able to disrupt it by questioning communicators’ relevant expertise. And it was only those participants who weren’t fooled.

By wondering how an expert stands to benefit from our compliance, we give ourselves another shield against undue and automatic influence. Even knowledgeable authorities in a field will not persuade us until we are satisfied their messages represent the facts faithfully.

In the Milgram studies, we see evidence of strong pressures for compliance with the requests of an authority. Acting contrary to their own preferences, many normal, psychologically healthy individuals were willing to deliver dangerous levels of pain to another person because they were directed to do so by an authority figure. The strength of the tendency to obey legitimate authorities comes from systematic socialization practices designed to instill in members of society the perception that such obedience constitutes correct conduct. In addition, it is adaptive to obey the dictates of genuine authorities because such individuals usually possess high levels of knowledge, wisdom, and power. For these reasons, deference to authorities can occur in a mindless fashion as a kind of decision-making shortcut. When reacting to authority in an automatic fashion, people have a tendency to do so in response to mere symbols of authority rather than to its substance. Three kinds of symbols effective in this regard are titles, clothing, and trappings such as automobiles. In studies, individuals possessing prestigious forms of one or another of the symbols (and no other legitimizing credentials) were accorded more deference or obedience by those they encountered. Moreover, in each instance, those individuals who deferred or obeyed underestimated the effect of the authority pressures on their behaviors. Authority influence flows from being viewed as either in authority or an authority. But...

Officials with the power to punish rule violators were more likely to do so on the violators’ birthdays, and this was especially so when violators used their birthday status to plead for leniency. Why? Because the officials felt their freedom to decide on punishment was restricted by this circumstance—a classic reactance reaction.

The intriguing finding within the effects of censored information on an audience is not that audience members want to have the information more than before; that seems natural. Rather, it is that they come to believe in the information more, even though they haven’t received it. For example, when University of North Carolina students learned that a speech opposing coed dorms on campus would be banned, they became more opposed to the idea of coed dorms. Thus, without ever hearing the speech, the students became more sympathetic to its argument. This raises the worrisome possibility that especially clever individuals holding a weak or unpopular position can get us to agree with the position by arranging to have their message restricted. The irony is that for such people—members of fringe political groups, for example—the most effective strategy may not be to publicize their unpopular views but to get those views officially censored and then to publicize the censorship.

One influence tactic has been developed specifically to reinstate recipients’ freedom to choose when they are targets of an influence attempt. It’s called the “But you are free” technique, and it operates by emphasizing a request-recipient’s freedom to say no. In a set of forty-two separate experiments, adding to a request the words “But you are free to decline/refuse/say no” or a similar phrase, such as “Of course, do as you wish,” significantly increased compliance. Moreover, this was the case for a wide variety of requests:

newly experienced scarcity is the more powerful kind applies to situations well beyond the bounds of the cookie study. For example, behavioral scientists have determined that such scarcity is a primary cause of political turmoil and violence. Perhaps the most prominent proponent of this argument is James C. Davies, who states that revolutions are more likely to occur when a period of improving economic and social conditions is followed by a short, sharp reversal in those conditions. Thus, it is not the traditionally most downtrodden people—those who have come to see their deprivation as part of the natural order of things—who are especially likely to revolt. Instead, revolutionaries are more likely to be those who have been given at least some taste of a better life. When the economic and social improvements they have experienced and come to expect suddenly become less available, they desire them more than ever and often rise up violently to secure them.

research shows parents who enforce and discipline inconsistently produce characteristically rebellious children.

One is when we are in an amorous frame of mind. In a situation with romantic possibilities, we want to differentiate ourselves so as to attract the interest of potential partners—for example, by exhibiting greater creativity. When in such a mood, we even prefer to visit places that allow us to stand out. Along with fellow researchers, I helped design an advertisement urging people to visit the San Francisco Museum of Art, which included the name and a photo of the museum. When the ad also featured the phrase “Stand Out from the Crowd,” the intention to visit the museum by viewers of the ad skyrocketed; however, this was the case only if they had just seen a clip from a romantic movie. If they hadn’t been exposed to the romance-rousing clip, the idea of visiting the (Stand Out from the Crowd) museum was not as attractive.

But even in matters of taste, group pressures can be strong, especially from an in-group. One study examined what members of such groups do to balance the desire to conform against the desire to demonstrate their individuality. If the majority of our in-group favors a brand of an item we are likely to do the same—while simultaneously differentiating ourselves along a visible dimension, such as the item’s color. Leaders would be well advised to take this desire for uniqueness into account when ensuring that all team members conform to core work goals, by also ensuring that members aren’t made to do so in exactly the same way.

The joy is not in the experiencing of a scarce commodity but in the possessing of it. It is important that we not confuse the two. Whenever we confront scarcity pressures surrounding some item, we must also confront the question of what it is we want from the item. If the answer is that we want the thing for the social, economic, or psychological benefits of possessing something rare, then, fine; scarcity pressures will give us a good indication of how much we should want to pay for it—the less available it is, the more valuable to us it will be. However, often we don’t want a thing for the pure sake of owning it. We want it, instead, for its utility value; we want to eat it or drink it or touch it or hear it or drive it or otherwise use it. In such cases, it is vital to remember that scarce things do not taste or feel or sound or ride or work any better because of their limited availability.

According to the scarcity principle, people assign more value to opportunities that are less available. The use of this principle for profit can be seen in such compliance techniques as the “limited number” and “deadline” tactics, wherein practitioners try to convince us that if we don’t act now, we will lose something of value. This engages the human tendency for loss aversion—that people are more motivated by the thought of losing something than by the thought of gaining something of equal value. The scarcity principle holds for two reasons. First, because things difficult to attain are typically more valuable, the availability of an item or experience can serve as a shortcut cue to its quality; and, because of loss aversion, we will be motivated to avoid losing something of high quality. Second, as things become less accessible, we lose freedoms. According to psychological reactance theory, we respond to the loss of freedoms by wanting to have them (along with the goods and services connected to them) more than before. As a motivator, psychological reactance is present throughout the great majority of the life span. However, it is especially evident at a pair of ages: the terrible twos and the teenage years. Both of these times are characterized by an emerging sense of individuality, which brings to prominence issues of control, rights, and freedoms. Consequently, individuals at these ages are especially averse to restrictions. In addition to its effect on the valuation...

Psychologists have long recognized a desire in most people to be and look consistent within their words, beliefs, attitudes, and deeds. This tendency for consistency is fed from three sources. First, good personal consistency is highly valued by society. Second, aside from its effect on public image, generally consistent conduct provides a beneficial approach to daily life. Third, a consistent orientation affords a valuable shortcut through the complexity of modern existence. By being consistent with earlier decisions, one reduces the need to process all the relevant information in future similar situations; instead, one merely needs to recall the earlier decision and to respond consistently with it. Within the realm of compliance, securing an initial commitment is the key. After making a commitment (that is, taking an action, stand, or position), people are more willing to agree to requests in keeping with the prior commitment. Thus, many compliance professionals try to induce people to take an initial position that is consistent with a behavior they will later request from these people. Not all commitments are equally effective in producing consistent future action. Commitments are most effective when they are active, public, effortful, and viewed as internally motivated (voluntary), because each of these elements changes self-image. The reason they do so is that each element gives us information about what we must truly believe. Commitment decisions, even erroneous ones...

People are inclined to say yes to someone they consider one of them.

Recipients with nonrational, hedonistic goals should be matched with messages containing nonrational elements such as musical accompaniment, whereas those with rational, pragmatic goals should be matched with messages containing rational elements such as facts. In his outstanding book, Persuasive Advertising, marketing expert J. Scott Armstrong reported that in an analysis of 1,513 TV commercials, 87 percent incorporated music. But this routine addition of music to the message may well be flawed, as Armstrong also reviewed the relevant research and concluded that music should only be used to advertise familiar, feelings-based products (such as snack foods and body scents) in an emotional context—that is, where thinking is unlikely. For products that have high personal consequences and strong supportive arguments (such as safety equipment and software packages)—that is, for which hard thinking is likely to be undertaken and productive—background music actually undercuts ad effectiveness.

Might it be possible to deter malevolent members of “we”-based work groups from the self-dealing activity we see in alliances as diverse as business units, labor unions, and religious organizations? I believe so, but it would require that each such alliance take three steps: (1) recognize that its corrupt actors presume they are protected by “we”-groups’ willingness to excuse members who breach ethical rules, (2) announce to all concerned that such leniency will not be forthcoming in this particular “we”-group, and (3) establish a consequent no-tolerance policy of dismissal for proven abuses.

People say yes to someone they consider one of them. The experience of “we”-ness (unity) with others is about shared identities—tribe-like categories that individuals use to define themselves and their groups, such as race, ethnicity, nationality, and family, as well as political and religious affiliations. Research into “we”-groups has produced three general conclusions. Members of these groups favor the outcomes and welfare of fellow members over those of nonmembers. “We”-group members also use the preferences and actions of fellow members to guide their own, which enhances group solidarity. Finally, such partisan tendencies have arisen, evolutionarily, as ways to advantage our “we”-groups and, ultimately, ourselves. These three constants have surfaced in a wide range of domains, including business, politics, sports, and personal relationships. The perception of belonging together with others is one fundamental factor leading to feelings of “we”-ness. This perception is generated by commonalities of kinship (amount of genetic overlap) as well as by commonalities of place (including one’s home, locality, and region). The experience of acting together in unison or coordination is a second fundamental factor leading to a sense of unity with others. Shared musical experience is one way people can act together and feel consequent unity. Other ways involve repeated reciprocal exchange, joint suffering, and co-creation. It may be possible to use the unifying effects of belongin...

When those single features are truly reliable, there is nothing inherently wrong with the shortcut approach of narrowed attention and automatic responding to a particular piece of information. The problem comes when something causes the normally trustworthy cues to counsel us poorly, to lead us to erroneous actions and wrongheaded decisions. As we have seen, one such cause is the trickery of certain compliance practitioners, who seek to profit from the mindless and mechanical nature of shortcut responding. If, as it seems, the frequency of shortcut responding is increasing with the pace and form of modern life, we can be sure that the frequency of this trickery is destined to increase as well. What can we do about the intensified attack on our system of shortcuts? More than evasive action, I urge forceful counterassault; however, there is an important qualification. Compliance professionals who play fairly by the rules of shortcut responding are not to be considered our adversaries; to the contrary, they are our allies in an efficient and adaptive process of exchange. The proper targets for counter-aggression are only those who falsify, counterfeit, or misrepresent the evidence that naturally cues our shortcut responses. Let’s take an illustration from what is perhaps our most frequently used shortcut. According to the principle of social proof, we often decide to do what other people like us are doing. It makes all kinds of sense because, most of the time, an action that ...

Modern life is different from that of any earlier time. Owing to remarkable technological advances, information is burgeoning, alternatives are multiplying, and knowledge is exploding. In this avalanche of change and choice, we have had to adjust. One fundamental adjustment has come in the way we make decisions. Although we all wish to make the most thoughtful, fully considered decision possible in any situation, the changing form and accelerating pace of modern life frequently deprive us of the proper conditions for such a careful analysis of all the relevant pros and cons. More and more, we are forced to resort to another decision-making approach—a shortcut approach in which the decision to comply (or agree or believe or buy) is made on the basis of a single, usually reliable piece of information. The most reliable and, therefore, most popular such single triggers for compliance are those described throughout this book. They are commitments, opportunities for reciprocation, the compliant behavior of similar others, feelings of liking or unity, authority directives, and scarcity information. Because of the increasing tendency for cognitive overload in our society, the prevalence of shortcut decision-making is likely to increase proportionately. Compliance professionals who infuse their requests with one or another of the levers of influence are more likely to be successful. The use of these levers by practitioners is not necessarily exploitative. It only becomes so when t...