11.5 Theories of Persuasion

Understanding how people are persuaded is very important to the discussion of public speaking. Thankfully, a number of researchers have created theories that help explain why people are persuaded. While there are numerous theories that help to explain persuasion, we are only going to examine three here: social judgment theory, cognitive dissonance theory, and the elaboration likelihood model.

Social Judgment Theory

Muzafer Sherif and Carl Hovland (1980) created social judgment theoryattempts to determine what types of communicative messages and under what conditions communicated messages will lead to a change in someone’s behavior by comparing it with current attitudes. In essence, Sherif and Hovland found that people’s perceptions of attitudes, values, beliefs, and behaviors exist on a continuum including latitude of rejection, latitude of non-commitment, and latitude of acceptance.

Sherif and Hovland found that persuasive messages were the most likely to succeed when they fell into an individual’s latitude of acceptance. For example, if you are giving your speech on majoring in a foreign language, people who are in favor of majoring in a foreign language are more likely to positively evaluate your message, assimilate your advice into their own ideas, and engage in desired behavior. On the other hand, people who reject your message are more likely to negatively evaluate your message, not assimilate your advice, and not engage in desired behavior.

In an ideal world, we’d always be persuading people who agree with our opinions, but that’s not reality. Instead, we often find ourselves in situations where we are trying to persuade others to attitudes, values, beliefs, and behaviors with which they may not agree. To help us persuade others, what we need to think about is the range of possible attitudes, values, beliefs, and behaviors that exist. For example, in a foreign language scenario where students are being persuaded to major in this major, we may see the following possible opinions from our audience members:

1. Complete agreement. Let’s all major in foreign languages.
2. Strong agreement. I won’t major in a foreign language, but I will double major in a foreign language.
3. Agreement in part. I won’t major in a foreign language, but I will minor in a foreign language.
4. Neutral. While I think studying a foreign language can be worthwhile, I also think a college education can be complete without it. I really don’t feel strongly one way or the other.
5. Disagreement in part. I will only take the foreign language classes required by my major.
6. Strong disagreement. I don’t think I should have to take any foreign language classes.
7. Complete disagreement. Majoring in a foreign language is a complete waste of a college education.

These seven possible opinions on the subject do not represent the full spectrum of choices but give us various degrees of agreement with the general topic. So what does this have to do with persuasion? Well, we’re glad you asked. Sherif and Hovland theorized that persuasion was a matter of knowing how great the discrepancy or difference was between the speaker’s viewpoint and that of the audience. If the speaker’s point of view was similar to that of audience members, then persuasion was more likely. If the discrepancy between the idea proposed by the speaker and the audience’s viewpoint is too great, then the likelihood of persuasion decreases dramatically.

Cognitive Dissonance Theory

In 1957, Leon Festinger proposed another theory for understanding how persuasion functions. Cognitive dissonance theory is an aversive motivational state that occurs when an individual entertains two or more contradictory attitudes, values, beliefs, or behaviors simultaneously. For example, maybe you know you should be working on your speech, but you really want to go to a movie with a friend. In this case, practicing your speech and going to the movie are two cognitions that are inconsistent with one another. The goal of persuasion is to induce enough dissonance in listeners that they will change their attitudes, values, beliefs, or behaviors. Frymier and Nadler (2013) noted that for cognitive dissonance to work effectively there are three necessary conditions: aversive consequences, freedom of choice, and insufficient external justification.

First, for cognitive dissonance to work, there needs to be a strong enough aversive consequence, or punishment, for not changing one’s attitudes, values, beliefs, or behaviors. For example, maybe you’re giving a speech on why people need to eat more apples. If your aversive consequence for not eating apples is that your audience will not get enough fiber, most people will simply not be persuaded, because the punishment isn’t severe enough. Instead, for cognitive dissonance to work, the punishment associated with not eating apples needs to be significant enough to change behaviors. If you convince your audience that without enough fiber in their diets they are at higher risk for heart disease or colon cancer, they might fear the aversive consequences enough to change their behavior.

The second condition necessary for cognitive dissonance to work is that people must have a freedom of choice. If listeners feel they are being coerced into doing something, then dissonance will not be aroused. They may alter their behavior in the short term, but as soon as the coercion is gone, the original behavior will reemerge. It’s like the person who drives more slowly when a police officer is nearby but ignores speed limits once officers are no longer present. As a speaker, if you want to increase cognitive dissonance, you need to make sure that your audience doesn’t feel coerced or manipulated, but rather that they can clearly see that they have a choice of whether to be persuaded.

The final condition necessary for cognitive dissonance to work has to do with external and internal justifications. External justification refers to the process of identifying reasons outside of one’s own control to support one’s behavior, beliefs, and attitudes. Internal justification occurs when someone voluntarily changes a behavior, belief, or attitude to reduce cognitive dissonance. When it comes to creating change through persuasion, external justifications are less likely to result in change than internal justifications.

Imagine that you’re giving a speech with the specific purpose of persuading college students to use condoms whenever they engage in sexual intercourse. Your audience analysis, in the form of an anonymous survey, indicates that a large percentage of your listeners do not consistently use condoms. Which would be the more persuasive argument: (a) “Failure to use condoms inevitably results in unintended pregnancy and sexually transmitted infections, including AIDS”—or (b) “If you think of yourself as a responsible adult, you’ll use condoms to protect yourself and your partner”? With the first argument, you have provided external justification for using condoms (i.e., terrible things will happen if you don’t use condoms). Listeners who reject this external justification (e.g., who don’t believe these dire consequences are inevitable) are unlikely to change their behavior. With the second argument, however, if your listeners think of themselves as responsible adults and they don’t consistently use condoms, the conflict between their self-image and their behavior will elicit cognitive dissonance. In order to reduce this cognitive dissonance, they are likely to seek internal justification for the view of themselves as responsible adults by changing their behavior (i.e., using condoms more consistently). In this case, according to cognitive dissonance theory, the second persuasive argument would be the one more likely to lead to a change in behavior.