Robert H Gass & John S Seiter. 21st Century Communication: A Reference Handbook. Editor: William F Eadie. Sage Publication. 2009.
Persuasion is both ancient and modern, an art and a science. It probably dates back 50,000 years or so, when hominids first developed language (Wade, 2006). If one counts nonverbal cues, then the practice of persuasion is even older. One can easily imagine a stone-age fellow, Lothar, grunting and gesturing to borrow his neighbor’s flint to make a fire. Regardless of its date of origin, the study of persuasion in Western civilization dates back to at least 399 BCE, when Aristotle wrote Rhetoric. The advent of controlled laboratory experiments on persuasion dates back to the 1940s and 1950s. Much of the credit for research in this era goes to Carl Hovland and the Yale Attitude Change Program, a think tank devoted to the study of persuasion (Hovland, Janis, & Kelley, 1953).
The Vitality of Persuasion
The study of persuasion is fascinating. Part of the attraction is that persuasion is all around us. Estimates of the amount of advertising we’re exposed to range from 300 to 3,000 messages per day. And that’s just the tip of the iceberg. Most influence attempts take place in interpersonal settings rather than advertising. Some of the allure is because so much remains to be learned about persuasion. As Henry Ford once remarked, “Half the money spent on advertising is wasted, but we don’t know which half.” A good deal is known about persuasion, but it is hardly an exact science.
Why learn about persuasion? First, persuasion is all around us and will persist in the “real world,” whether studied as an academic discipline or not. Since a good deal of human communication is persuasive in nature, it is important to know how processes of social influence operate. Second, learning about persuasion can assist one in becoming a more effective persuader. Finally, a better knowledge of persuasion can make one a more discerning consumer of persuasive messages, especially unscrupulous forms of influence.
With this in mind, we provide an overview of research on persuasion. Our approach is social scientific in nature, which is to say we are interested in empirical, quantitative research. We cover both traditional and contemporary theories, concepts, principles, and processes. We also examine some newer, “cutting-edge” topics in persuasion. We try to touch the major bases, but because the field of persuasion is vast, we cannot include everything.
Macro Theories and Models of Persuasion
Persuasion scholars are interested in discovering how and why persuasion works. A variety of “umbrella” theories and models provide explanatory frameworks for how persuasion functions. We examine some of the best-known ones here.
The Elaboration Likelihood Model and the Heuristic-Systematic Model
The elaboration likelihood model (ELM; Petty & Cacioppo, 1986) and the heuristic-systematic model (HSM; Eagly & Chaiken, 1993) are dual-process models of persuasion. While the models are distinct in important ways, here we focus on their commonalities. Specifically, both models suggest that there are two basic modes by which people process persuasive messages. First, people might not put forth much thought or effort while processing a message. For instance, a consumer might rely on a name brand or celebrity endorser to make a decision. ELM calls this peripheral processing, while HSM calls it heuristic processing. Second, people might exert a lot of mental energy while processing a message, carefully analyzing evidence and scrutinizing message content. ELM calls this central processing, while HSM calls it systematic processing.
By way of example, let’s say Loretta is pondering which brand of music player to buy. If she compares their features, looks up reviews on each brand, and reads about their warranties, she is using central orsystematic processing. Suppose Luke also wants to buy a music player. Rather than agonizing over his decision, however, Luke buys the same brand as Loretta, because he trusts her judgment. Luke is using peripheral or heuristic processing.
Both the ELM and the HSM suggest that to use central/systematic processing, an individual must have the motivation and ability to do so. Motivation tends to be stronger if an issue affects a person directly. The person must also be able to understand and process the message. If a persuasive message were too technical, for example, a person might want to analyze the message but may be unable to do so.
The evidence suggests that persuasion that takes place via central/systematic processing is more lasting, whereas persuasion based on peripheral/heuristic processing is more temporary. Thinking about a message seems to cement it in the recipient’s mind. Persuasion that occurs through central/systematic processing is also more resistant to change. Thus, a persuader who wants his or her message to stick should foster central/systematic processing of the message.
Both the ELM and the HSM are useful explanatory and predictive models of persuasion. Dozens of studies have been carried out using these two models, on a wide variety of topics and issues, such as condom use, conservation, nuclear power, and vegetarianism. Neither theory is without its flaws, but both have held up well under testing.
The Theory of Reasoned Action and Planned Behavior
Two interrelated theories developed by Martin Fishbein and Icek Ajzen focus on behavioral intentions, or what a person plans to do, as the most effective means of predicting actual behavior (Ajzen, 1991; Ajzen & Fishbein, 1980). The theory of reasoned action (TRA) and the theory of planned behavior (TPB) presume that people are rational decision makers who make use of the information available to them. Behavioral intentions are based on three key elements. The first is a person’s attitudes toward the behavior in question. The second is subjective norms, which depend on what the person perceives others think about the behavior. The third is perceived behavioral control, or whether the person thinks she or he has the ability to perform the behavior in question. Combining these three elements, suppose Naomi is contemplating whether to become a vegan. The first element would be her attitude toward a vegan diet and lifestyle. Does she believe that a vegan diet is healthier, kinder to animals, and better for the environment? The second element would be Naomi’s beliefs about how others view veganism. Does she believe that other people look favorably on vegans, or think vegans are cool? The third element would be whether she believed she could adhere to a vegan diet and lifestyle. How hard would it be to eschew all meat and dairy products? Could she do without leather clothing? Taken together, these three elements would form Naomi’s behavioral intention to become a vegan.
A few caveats regarding the TRA and TPB are in order. One is that the person’s behavior must be volitional. In many persuasive situations, a person’s choices are constrained by other factors, such as the cooperation of others. Another limitation is that the model focuses on rational information processing and, hence, cannot explain irrational thinking, such as phobias and prejudices. Nevertheless, this theory has held up well under testing on a variety of topics, including brand loyalty, cheating by students, condom use, breast cancer prevention, flu vaccinations, and seat belt use.
Attitude Change Theories
The study of how attitudes are formed and changed has fascinated persuasion researchers for over 50 years. Attitudes are important because they explain and predict behavior reasonably well. Because attitudes tend to correspond with behavior, changing a person’s attitudes may also change the person’s behavior. Attitudes can be measured as well, by using a variety of scales.
People’s attitudes are often entrenched. Therefore, it is usually easier to align a persuasive message with an audience’s existing attitudes than to change audience’ attitudes, just as it is easier to tailor a suit to fit the customer than it is to change the customer’s physique to fit the suit. It also is easier to nudge receivers’ attitudes in a series of smaller steps than in one full swoop. As is the case with all persuasion, when attempting to change attitudes, a persuader may only achieve some of what she or he is after. Changes in attitudes also may be transitory.
Cognitive Consistency Theories
Attitudes don’t exist in isolation, they occur in clusters. A person’s attitudes toward gay adoption, for instance, would probably correlate with the person’s attitudes toward gay marriage. Changes in one attitude tend to reverberate throughout related attitude structures. A variety of consistency theories, which we’ve melded into one general framework here, explain this process.
People tend to strive for consistency among their attitudes. If a person loves cats, it would be better if his or her significant other liked cats too. As such, the consistency principle can be used by persuaders quite effectively. A persuader might point out that a person holds conflicting attitudes by saying, “If you say you are against torture, then how can you be in favor of ‘water-boarding’? Even the UN condemns ‘water-boarding’ as a form of torture.” A persuader might also point out that holding a particular attitude is inconsistent with another’s behavior. For instance, one might say, “You claim to be opposed to illegal immigration, but your nanny has no green card. Why don’t you practice what you preach?” A persuader can also try to demonstrate that attitudes held by another are not conflicting but rather consistent with each other. A person might argue, “Science and religion are not mutually exclusive. One can believe in science and god at the same time.”
Cognitive Dissonance Theory
Cognitive dissonance theory focuses on the anxiety that accompanies decision making. The theory explains “buyer’s remorse,” or the angst associated with second-guessing an important decision (Festinger, 1957). We don’t relish finding ourselves in a situation where someone says, “I told you so” or we think to ourselves, “I should have known better.” To reduce dissonance, people engage in a variety of strategies, such as denial, bolstering, and rationalization. People also can change their behavior or try to change another’s behavior. The magnitude of dissonance one experiences hinges on how much freedom one has in making a decision; the freer the choice, the greater the dissonance. The amount of time and effort that one puts into a decision also affects the severity of the dissonance; the greater the energy or sacrifice involved, the greater the dissonance.
Another intriguing feature of cognitive dissonance theory involves the role of counter-attitudinal advocacy (CAA). If a person voluntarily advocates a position contrary to his or her own personal views, the person will tend to experience dissonance. This causes the person’s attitudes to shift, though not entirely, in the direction of the counter-attitudinal position. The person must freely choose to engage in CAA, however. If the person is bribed or coerced into doing so, little or no dissonance will be aroused.
Social Judgment Theory
Carolyn and Muzafer Sherif’s social judgment theory (Sherif, Sherif, & Nebergall, 1965) explains that the more ego involved a person is in a topic, the more the person will tend to distort persuasive messages on that issue. The theory posits that on any given topic, there is a range of positions that can be advocated. The position a person finds most acceptable serves as an anchor point or benchmark by which other messages are judged. When exposed to a persuasive message, a person initially perceives the message as falling into his or her latitude of acceptance (LOA), latitude of rejection (LOR), or latitude of non-commitment (LNC).
A message that falls within the range of positions that a person judges as acceptable is within the person’s LOA. A persuader who advocates such a message is “preaching to the choir.” A message that falls outside the range of tolerable positions is in the person’s LOR. A persuader who advocates such a message faces a hostile audience. Issues on which the person has no opinion fall within the person’s (LNC). Importantly, the more ego involved a person is in an issue, the narrower his or her LOA and the wider his or her LOR are.
Social judgment theory maintains that persuasive messages tend to be distorted by receivers. Specifically, a message that falls within a receiver’s LOA is distorted favorably and perceived as closer to the receiver’s anchor position than it really is (assimilation effect). A message that falls inside a receiver’s LOR is distorted negatively and perceived as farther from the receiver’s anchor position than it really is (contrast effect).
A persuader is best advised not to advocate a position that falls within the receiver’s LOR. Such a message will likely be rejected out of hand. Instead, a persuader should advocate a position that is discrepant from the receiver’s anchor yet still close enough to the receiver’s anchor to trigger the assimilation effect. This is where message discrepancy enters the picture. The greater the disparity between a persuader’s position and the receiver’s anchor, the more the attitude change that occurs, but—and this is important—only if the message does not cross the line and fall within the receiver’s LOR (Siero & Jan Doosje, 1993). Effective persuasion, then, is rarely a one-shot effort. A person’s attitudes must be “nudged” along via a series of messages that are different from, but not too different from, the person’s own position.
Traditional Research Foci
Traditional research on social influence focuses on several key components in the persuasion process. Notably, Berlo (1960) identified the source, the message itself, the channel by which the message is transmitted, and the receiver as primary components in communication and persuasive interactions. This section examines the role of each.
Source credibility, perhaps the most studied concept in the field of persuasion, refers to how believable audiences perceive a communicator to be. It would seem intuitive that the source of a message has a good deal to do with the message’s persuasiveness. That is why companies pay handsomely for credible spokespersons to endorse their goods and services. Not any celebrity can sell any product, however. The match-up hypothesis (Kamins, 1990) suggests that the source and the brand must be a good fit.
Source credibility is a perceptual phenomenon. It exists in the eye of the beholder. Related to this is the recognition that credibility is also situational. A source might be regarded as credible in one persuasive context but not in another. Source credibility is also dynamic. It can change over time or even during the course of a single speech.
Researchers have argued for some time over what the fundamental dimensions of credibility are. There is now general agreement that there are three primary dimensions. These dimensions, identified by James McCroskey, are expertise (sometimes labeled competence), trustworthiness (sometimes called character), and goodwill (also known as perceived caring) (McCroskey & Teven, 1999). These dimensions almost always play a role in the evaluation of sources. If you had a serious medical condition, for example, you would want a physician who was highly knowledgeable about your condition (expertise). You would also want a doctor you could trust, one who wouldn’t overbill you or recommend unnecessary treatment (trustworthiness). You would also want a doctor with a good “bedside manner,” one who took an interest in your personal well-being (goodwill).
Credibility is almost always beneficial for a persuader. Since credibility is often a peripheral cue, receivers with low involvement are more likely to succumb to source influence than receivers with high involvement. Source credibility is not as great an asset if receivers use central processing. Credibility is not always a peripheral cue, however. There are occasions when receivers use central processing to scrutinize a source’s credentials, knowledge, and understanding of an issue. Evaluating the veracity of a witness’s statements in a criminal trial, for example, would require jurors to use central processing.
Quintillian, the great Roman rhetorician, noted that just as generals must strategically place their troops on a battlefield, so too should persuaders strategically place their arguments within a speech (Corbett, 1971). This section provides a glimpse of other ways in which the order of messages affects persuasion.
First, imagine you are preparing a speech and have several arguments—some stronger, some weaker—that you plan to include in the speech. Where should you place them? Most research on this topic advises putting your best arguments either first (anticlimax order) or last (climax order) rather than sandwiching them in the middle (pyramidal order). Of course, this assumes that the audience is capable of distinguishing between strong and weak arguments. Unfortunately, this is not always the case. For example, a study by Petty and Cacioppo (1984) found that people who were not involved in a topic were more persuaded by the quantity of arguments (a peripheral cue) than by their quality (a central cue).
A second issue has to do with the order in which an audience is exposed to opposing messages. For example, if two people are arguing on different sides of an issue, who should speak first? The research results are mixed. Some studies suggest that the material presented first has more influence, a primacy effect, while other studies suggest that the material presented last has an advantage, a recency effect. Even so, the nature of the persuasive encounter can tip the scales one way or another. One condition, for example, is timing. Specifically, when people hear back-to-back messages and then wait some time before making a decision, the first message tends to be more influential. On the other hand, if people hear one message, wait some time before hearing the opposing message, and then decide immediately afterward, the second message tends to be more influential (see Miller & Campbell, 1959).
The material presented first has the additional advantage of facilitating inoculation. Inoculation theory is based on a biological metaphor (McGuire, 1964). In the same way that being exposed to a small dose of a virus defends you against subsequent exposure to the virus (think flu shots), being exposed to a small dose of a persuasive argument, made weak through refutation, defends you against the argument later on.
Two key components of inoculation are threat and refu-tational preemption (Pfau & Szabo, 2004). Threat, or warning people that existing attitudes are about to be challenged, motivates them to strengthen their attitudes. Refutational preemption, the process of raising and refuting challenges, provides the ammunition required to bolster the attitudes against attack. By way of example, a parent might tell a child, “When other kids tell you that smoking is cool (threat), remember that cigarettes are a leading cause of cancer, which definitely isn’t cool (refutation).” Previous literature suggests that inoculation is not only robust under the proper conditions, it also enjoys widespread application to a number of persuasive contexts. What’s more, inoculating people against one set of arguments increases their resistance to other, different arguments on the same issue.
One-Sided versus Two-Sided Messages
The importance of the refutational component of inoculation is underlined by a related area of research on message sidedness. Such research asks whether persuaders should present only their side of the argument or opposing arguments as well. The answer depends on the nature of the arguments that are presented. Specifically, two-sided messages (those including both supportive and opposing arguments) are more persuasive than one-sided arguments but only if the opposing arguments are refuted (Allen, 1998). When opposing arguments are raised but not refuted, then one-sided messages are more persuasive. Thus, the best bet is to use a two-sided, refutational approach.
Mere Exposure Effect
Up to this point, we have examined what happens when audiences are exposed to multiple arguments presented in some order. What happens, though, when audiences are presented with the same message repeatedly? According to the Mere Exposure Effect (Zajonc, 1968), the more we are exposed to an unfamiliar stimulus, the more favorably we evaluate it. Perhaps you’ve noticed that after hearing a song several times, you like it more than you did at first. The same is often true of TV commercials too.
One explanation for the Mere Exposure Effect is perceptual fluency, which posits that positive feelings are generated by the increasing ease with which a stimulus is processed. Of course, any message will wear out eventually, and some messages are annoying even at first exposure. Even so, research shows that incidental messages (banner ads, pop-ups) can be viewed up to 20 times before wear-out occurs (Fong, Singh, & Ahluwalia, 2007).
Narrative versus Statistical Evidence
Earlier, we noted that when an audience has low involvement in an issue, the sheer quantity of arguments matters the most. When an audience is highly involved in an issue, the quality of arguments is what counts. A related concern has to do with what form of proof is the most effective, narrative or statistical evidence? Narrative evidence is anecdotal evidence, told in narrative form, presented as a case study, or related as personal accounts. Statistical evidence consists of averages, percentages, and other numerical proof.
Numerous studies have compared the effectiveness of these two forms of proof. The most reliable generalization to date is that statistical proof has a slight edge over narrative proof (Preiss & Allen, 1998). Nevertheless, a well-crafted narrative can be quite compelling, and numbers don’t always speak for themselves. The best advice we can offer is to combine the two. Begin with a narrative example, then use statistics to demonstrate that the example is not an isolated case.
Fear and other Motivational Appeals
When a coach gives a half-time locker room speech, she or he often employs motivational appeals to fire up the team. Motivational appeals are “external inducements, often of an emotional nature, that are designed to increase an individual’s drive to undertake some course of action” (Gass & Seiter, 2007, p. 271). A variety of motivational appeals have been studied, including fear appeals, guilt appeals, humorous appeals, patriotic appeals, pity ploys, and sex appeals. For brevity’s sake, we focus on fear appeals here.
Arousing fear in people depends on their level of perceived vulnerability. Vulnerability hinges on receivers’ perceptions of the probability, severity, and immediacy of the fearful consequences. Kim Witte has built on previous research to develop the extended parallel process model (EPPM), which explains how and when fear appeals are most likely to be effective (Cho & Witte, 2004). The EPPM is a dual-process model, which posits two methods of processing a fear-arousing message. The first, danger control, is a constructive response, which focuses on ways of avoiding or minimizing the danger. The second, fear control, is a counterproductive response, such as panic or freezing. To facilitate danger control, a fear appeal must provide specific recommendations that are perceived as efficacious or workable. Perceived efficacy includes response efficacy, which consists of identifying a practical, feasible remedy, and self-efficacy—whether a receiver believes she or he, personally, can undertake that course of action.
To illustrate, let’s say a physician is trying to convince an elderly patient to get an influenza vaccination. To increase perceived vulnerability, the doctor might mention the number of flu-related deaths annually and the susceptibility of seniors to the flu. To promote danger control, the doctor could emphasize that flu shots are safe and reasonably effective (response efficacy). To encourage self-efficacy, the doctor could say, “I can give you an inoculation today, you won’t need to reschedule a visit, and it’s covered by your health plan (self-efficacy).” Scaring the patient without providing a practical solution would likely result in fear control.
Considerable research has been conducted on fear appeals. The preponderance of research shows that they work quite well. To maximize their effectiveness, however, a persuader must concentrate on triggering danger control rather than fear control.
The means by which a message is transmitted—whether spoken, printed, televised or, more recently, online—is an important consideration when studying persuasion. A good deal of work has examined the role of language and nonverbal communication in the persuasion process. This section highlights some of that work.
Two important features of language are intensity and power. Language intensity refers to how emotional, metaphorical, opinionated, forceful, and evaluative language is. For example, saying “This corporation is emitting pollution” is less intense than saying “This corporation is raping the environment.” One theory that explains when and under what circumstances intense language is more effective is the language expectancy theory (LET) (see Burgoon & Siegel, 2004). LET argues that when persuaders use intense language, they violate our expectations about social norms regarding communication. If the source is perceived positively (e.g., the source is attractive or credible), intense language is more persuasive. If the source is perceived negatively, the reverse is true.
A second feature of language is the degree to which it is perceived as powerless. Among other mannerisms, powerless language is characterized by hesitations (e.g., “Uh,” “You know”), hedges (e.g., “I guessI sort of agree”), inten-sifiers (e.g., “I really agree very much”), and polite forms (e.g., “Excuse me. If you wouldn’t mind …”). In general, such tendencies decrease a source’s credibility and persua-siveness. A study by Johnson and Vinson (1990), for example revealed that even a few instances of powerless speech reduced the overall persuasiveness of a message.
While it is common for people to think of words when they consider persuasion, nonverbal behavior has as much, if not more, persuasive impact. The direct effects model of immediacy (Andersen, 2004) asserts that nonverbal behavior is particularly persuasive when it communicates warmth and involvement with other people. Immediacy behaviors such as eye contact, appropriate touch, open body positions, smiling, and pleasant tone of voice are related to increased compliance in a variety of contexts. Nonverbal cues also can foster a halo effect, whereby people assume that one positive aspect of a person generalizes to other favorable qualities of the person. For instance, an attractive person also might be perceived as more intelligent or capable, which, in turn, aids her or him in gaining compliance.
Not all research, however, presents such a simple picture of the relationship between nonverbal behavior and persuasion. Earlier, we noted that intense language may violate people’s expectations and, as a result, can produce positive or negative effects depending on how the source is perceived. Expectancy violations theory (Burgoon, 1994) suggests that the same process takes place when a source violates people’s expectations for nonverbal behavior. Thus, a source who stands closer to a person than normally would be expected may be more or less persuasive depending on whether the violation is perceived positively or negatively. A high-credibility source can therefore get away with “bending the rules” better than a low-credibility source.
Effective persuaders do not move the audience to the message; they move the message to the audience. This involves more than simply paying attention and adjusting to factors such as the age, educational level, intelligence, or size of the audience. Sometimes other audience characteristics come into play. The search for a single trait or characteristic that makes people persuadable has been unsuccessful. Nevertheless, a number of less global characteristics have been identified as important. In this section, we briefly touch on a few of them.
Although some early research suggested that females were more persuadable than males, later work showed no differences and, instead, tried to explain when gender differences could be expected. Some work, for instance, found support for a cross-sex effect, whereby people were more easily influenced by members of the opposite sex than by members of the same sex.
Cultural differences play a major role in the way people respond to influence attempts. Some cultures are individualistic, valuing independence and the goals of the individual over those of the group, while others are collectivistic, valuing harmony, conformity, and concern for others. As such, messages that appeal to personal benefits and success tend to be more effective in individualistic cultures, while those that emphasize family and group goals tend to be more effective in collectivistic cultures (Han & Shavitt, 1994).
A number of personality traits affect the way persuasive messages are processed. To illustrate, we briefly mention two. First, people high in the need for cognition enjoy effortful thinking more than those low in the need. Because they pay more attention, they tend to be persuaded by strong, compelling arguments while their counterparts are more likely to be persuaded via peripheral cues (attractive source, brand loyalty). Second, dogmatic/authoritarian people see the world in “black and white” and follow authoritative leaders blindly. As such, they tend to be rigid and difficult to persuade, unless the source happens to be a respected authority.
While traditional persuasion research tends to focus on mass persuasion and attitude change, compliance-gaining research tends to focus on interpersonal influence in “face-to-face” contexts and, as its name implies, on actual behavioral compliance. This section examines research on message selection and production, the principles underlying why people comply with requests, and sequential persuasion tactics.
The Selection of Compliance-Gaining Messages
Early studies sought to identify what types of compliance-gaining strategies people are likely to select. A typical research design presented participants with hypothetical scenarios and asked them to report which strategies they were likely to employ. Depending on the study, some participants generated their own strategies, while others selected strategies from a predetermined list. Results of such studies yielded typologies of compliance-gaining tactics. For example, Marwell and Schmitt’s (1967) seminal study identified 16 different strategies (such as promise of reward, threat of punishment, liking, and debt). Despite the contributions of such research, it has been criticized for being atheoretical and for not reflecting the strategies people use in “real life.”
Goals and the Production of Compliance-Gaining Messages
More recent research has attempted to understand how goals influence the production of compliance-gaining messages. Two noteworthy examples are politeness theory (Brown & Levinson, 1987) and the goals-plans-action (G-P-A) model (Dillard, 2004). First, according to politeness theory, people seek approval (known as positive face) and try to avoid disapproval (known as negative face). Because compliance-gaining goals may differ in the degree to which they threaten face needs, such goals play an important role in shaping compliance-gaining behavior. For example, because asking a friend to help you paint your house may threaten face more than asking the friend to pay back $20, when seeking help in painting, you may be less direct and provide more reasons for the imposition.
Similarly, the G-P-A model suggests that although people have the primary goal of gaining compliance, a number of secondary goals also influence their choice of strategies. For example, even if you thought that a threat might be effective at gaining compliance (primary goal), you might refrain from using it if you thought it might damage your relationship with the other person (secondary goal).
Principles Underlying why People Comply with Requests
Based on his observations of successful, real-life persuaders (e.g., salespeople, fund-raisers, advertisers, recruiters), Robert Cialdini (2001) identified several principles explaining why people comply with requests. First, the principle of reciprocity suggests that people should return favors. A person who has received a favor is likely to feel indebted and, in turn, comply with a request for a return favor. Second, the principle of scarcity states that people value things that are in short supply. According to this principle, if shoppers believe that the items they are examining are limited, they would be more anxious to purchase the items. The third principle, consistency/commitment, suggests that once people become committed to some idea or cause, they are likely to behave consistently with it. For instance, a person who was committed to Mac computers would be unlikely to buy a PC. The fourth and fifth principles—authority and similarity/liking—suggest that we are more likely to comply with requests from credible sources who are likable and similar to us. The next principle, contrast, suggests that judgments are relative to one another. For instance, a $3,000 diamond ring may seem expensive when compared with a $100 ring but cheap when compared with a $40,000 ring. Finally, the principle of social proof suggests that we are more likely to respond favorably to popular items (e.g., best-selling books) than to unpopular ones. We will discuss this notion in more detail later.
Although using a direct request is probably the most common approach to compliance gaining, compliance-gaining attempts are often more elaborate. A large body of research illustrates that successful compliance gaining often occurs in stages. In this section, we discuss four commonly studied sequential approaches to compliance gaining.
The two sequential approaches to seeking compliance that have probably received the most research attention are the foot-in-the-door (FITD) and the door-in-the-face (DITF) tactics, which are essentially mirror images of one another. Specifically, in the first (FITD), a persuader follows a small request, which must be agreed to, with a larger one; in the second (DITF), a persuader follows a large request, which is denied, with a smaller one. In both cases, exposure to the initial request makes one much more likely to comply with a subsequent request. A common explanation for the FITD effect is that people who comply with the small request perceive themselves as being helpful, agreeable, or altruistic. To remain consistent, they go along with the second request. In contrast, the reciprocity and contrast principles are common explanations for the DITF effect. Specifically, if the larger, second request is perceived as a concession, persuadees may feel obligated to reciprocate by agreeing to the second request. On the other hand, people may comply with the follow-up request because, when contrasted with the initial request, it seems smaller than it normally would have.
Two additional sequential compliance-gaining tactics are the lowball and the bait-and-switch. Both of these ethically unsavory tactics work by first getting persuadees to commit to something that seems desirable but then changing the deal, ultimately getting them to agree to something that is less desirable. In the lowball procedure, once people agree to perform some behavior (e.g., buy a computer for $1,000), they are asked to perform the same behavior at a higher cost (e.g., buy the same computer for $2,000).
In the bait-and-switch procedure, once people agree to perform some behavior (e.g., buy a stereo for $1,000), they are asked to perform a different, less desirable behavior (e.g., buy a different, inferior computer for $1,000). A common explanation for both procedures is that once people agree to the initial request, they become psychologically committed and have difficulty altering their decision.
Earlier, we mentioned the principle of social proof, which suggests that we use other people’s behavior as evidence when making decisions about how we will behave. In other words, if other people have behaved in a certain way, we tend to follow suit. Although this idea is not new, recently it has become the basis of a common marketing strategy often referred to as “buzz marketing” or “viral marketing.” In his best-selling book The Tipping Point, Gladwell (2002) explained that in the same way a contagious person can spread an epidemic, small groups of influential people can cause fashion trends or increase the popularity of a new product. Based on this assumption, companies hire people to create a buzz about their products. For example, attractive people might be hired as “poseurs” to hang out in trendy bars and clubs and say nice things about a particular brand of beer. These “undercover” consumers are trained to make the product seem exciting while adapting their communication to whoever they are persuading. This approach to persuasion is also well suited to the Internet. For example, personal blogs provide an opportunity for everyday persuaders to reach more potential consumers about new products. We predict that such approaches will be an important, fertile ground for new research on persuasion.
The Future of Persuasion Research
Persuasion research has a long and venerable history. Although it is difficult to know what the future holds, some educated guesses can be made about likely research avenues for the next decade or so. Just as the concept of tipping points influenced the past decade, the concept of microtrends may shape the next decade. Penn and Zalesne (2007) have stressed the importance of looking at distinctive niche groups to predict societal trends. These include “extreme commuters,” “cougers,” “vegan children,” and “archery moms,” among others. Even small trends, including countertrends, can have a powerful effect on society.
Persuasion on the Internet holds considerable promise as a topic of research. Studies on the impact of blogging and social networking sites such as MySpace and Facebook are already under way. And because people are increasingly reliant on cellphones (via voice, texting, and images) research on the nature and impact of “mobile persuasion” would seem fruitful.
Visual persuasion is becoming an important area of investigation as well. As more people view, rather than read, persuasion messages, visual influence is becoming a vital arena for research. A phenomenon dubbed the Streisand Effect has already sparked attention. Similar to the scarcity principle, when demands are made to remove videos or documents on the Web, hits for those materials increase dramatically. It seems a “forbidden fruit” is all the more attractive. The Streisand Effect is so named because the singer-actress filed a lawsuit, which was denied, against a photographer who took aerial photos of the Malibu coastline, including her estate.
Physiological measures of persuasion also may play a prominent role in future research. During the last Superbowl, researchers conducted brain scans of viewers watching Doritos and Emerald Nuts commercials. The Doritos spots elicited much more brain activity. Brain scans may become as popular as focus groups now are for marketing.
We believe that no matter what direction(s) the study of persuasion takes, it will remain a fascinating field of inquiry. A good deal is known about persuasion, but it is hardly an exact science. Many questions remain to be answered, and some important questions have to be asked.