Principles of Persuasion -- Persuasion is the process of influencing attitudes and behavior. Thousands of articles and books -- crammed with theories, descriptions, observations, and experimental tests -- have been written about persuasion. Offered here is only a very small sampling of the principles of persuasion.

The Credibility Principle

-- A speaker will be more persuasive if the audience perceives her or him as credible. This means that the audience should perceive the speaker as being competent or knowledgeable, of good character, and charismatic or dynamic. If you project these characteristics, you will have a much greater chance of being believed than if you are seen not to possess them. You know this is true from your own experience; there are certain people that you believe and others that you do not believe, and that these decisions to believe or not to believe exist apart from any consideration of what is being said. (See also credibility.)

The Attractiveness Principle

-- Even though traditional manners says we should never judge a book by its cover, it seems to be human nature to do so. Human beings are more persuaded by people who look attractive to them. To be persuasive, a speaker needs to look his or her best.

The Selective Exposure Principle

-- Audience will generally follow the "law of selective exposure." It has at least two parts: (1) that listeners will actively seek out information that supports their opinions, beliefs, values, decisions, behaviors, and the like and (2) that listeners will actively avoid information that contradicts their existing opinions, beliefs, attitudes, values, behaviors, and so on. There are a few qualifications to this "law" that are interesting to note. For example, if a person is very sure of himself or herself (that is, very sure that the opinions and attitudes held are logical, valid, and productive), then this person might not bother to seek out the support of others or may not actively avoid nonsupportive messages. Selective exposure is exercised most often when confidence in one's opinions and beliefs is weak.

-- This principle of selective exposure suggests a number of implications of the speaker.For example, if you are attempting to persuade an audience that holds very different attitudes from your own, anticipate selective exposure operating and proceed inductively; that is, hold back on your main purpose until they have assimilated some of your evidence and argument and only then relate it to your main (and initially contrary) proposition. If you were to present them with your thesis first, they might just tune you out without giving your position a fair hearing. Another implication is that you must be thoroughly knowledgeable about the attitudes of your audience if you are to succeed in making the necessary adjustments and adaptations. Still another implication is that if you, as a speaker, have been successful in weakening the confidence of the listeners in their initial position, they will seek out other sources of information to restore that confidence. In many instances they will seek out the very information that will contradict what you have been persuading them to accept. Thus, at the end of your speech, it may appear that you have been successful. But you may find that the additional information exposure subsequent to the speech convinces the listeners even more of their initial position than before you began speaking. In this instance it is necessary to reinforce your point of view repeatedly like advertisers do, or to somehow make the audience feel comfortable with their potentially new attitudes and beliefs.

The Inoculation Principle

-- The principle of inoculation may be explained with the biological analogy on which it is based. Suppose you lived in a germ-free environment. Upon leaving this germ-free environment and upon exposure to germ, you would be particularly susceptible to infection because you body has not built up immunity -- it has no resistance. Resistance, the ability to fight off germs, might be achieved by the body, if not naturally, through some form of inoculation.You would, for example, be injected with a weakened dose of the germ so that your body begins the fight by building up antibodies that create an "immunity" to this type of infection. Your body, then, because of its production of antibodies, is able to fight off even powerful doses of this germ.

-- The situation in persuasion is similar to this biological process. Some of our attitudes and belief have existed in a germ-free environment, in an environment in which these attitudes and beliefs have never been attacked or challenged. For example, many of us have lived in an environment in which the values of a democratic form of government, the importance of education, and the traditional family structure have not been challenged. Consequently, we have not been "immunized" against attacks on these values and beliefs. We have no counterarguments (antibodies) prepared to fight off these attacks on our beliefs, so, if someone were to come along with strong arguments against these beliefs, we might be easily persuaded.

-- Contrast these "germ-free" beliefs with issues that have been attacked and for which we have a ready arsenal of counterarguments: our attitudes on the draft, nuclear weapons, college athletics, and thousands of other issues have been challenged in the press, on television, and in our interpersonal interactions.As a result of this exposure, we have counterarguments ready for any attacks on our belief concerning these issues.We have been inoculated and immunized against attacks should someone attempt to change our attitudes or beliefs.

-- The major implications of the inoculation principle for persuasion should be clear. First, if you are addressing an inoculated audience you must take into consideration the fact that they have a ready arsenal of counterarguments to fight your persuasive assault. Be prepared, therefore, to achieve only small gains; don?t try to totally reverse the beliefs of a well-inoculated audience.

-- Second, if you are trying to persuade an uninoculated audience, your task is much simpler in that you do not have to penetrate a fully developed immunization shield.You also must recognize that even when an audience has not immunized itself, they take certain beliefs to be self-evident and may well tune out any attacks on such cherished beliefs or values. Again, proceed slowly and be content with small gains. Further, an inductive approach would suit your purposes better here. Attacking cherished beliefs directly will create impenetrable resistance; instead, build your case by first presenting your arguments and evidence and gradually work up to your conclusion.

-- Third, if you are attempting to strengthen an audience?s belief, give them the antibodies they will need if ever under attack. Consider raising counterarguments to this belief and then demolishing them. Much like the injection of a small amount of a germ will enable the body to build an immunization system, presenting counterarguments and then refuting them will enable the listeners to effectively immunize themselves against future attacks on these values and beliefs. This procedure has been fount to confer greater and longer-lasting resistance to strong attacks than by merely providing the audience with an arsenal of supporting arguments.

(William J. McGuire, "Inducing Resistance to Persuasion: Some Contemporary Approaches" in Advances in Experimental Social Psychology. I. Leonard Berkowitz, ed. (New York: Academic Press 1984). Pp. 191-220. Mary John Smith, Persuasion and Human Action: A Review and Critique of Social Influence Theories (Belmont, Calif.: Wadsworth, 1982).

The Magnitude of Change Principle

-- The greater and more important the change desired by the speaker, the more difficult its achievement will be. The reason for this is simple enough: We normally demand a greater number of reasons and lots more evidence before we make important decisions—career changes, moving our families to another state, or investing our life savings in certain stocks. On the other hand, we may be more easily persuaded (and demand less evidence) on relatively minor issues.

-- Generally, people change gradually, in small degrees over a long period of time.And although there are cases of sudden conversions, this general principle seems to be valid more often than not.Persuasion, therefore, is most effective when it strives for small changes and works over a considerable period of time.Persuasion that attempts to convince the audience to radically change their attitudes or to engage in behaviors to which they are initially opposed will frequently backfire on the speaker. During this type of situation, the audience will frequently tune out the speaker, closing its ears to even the best and most logical arguments.

The Audience Participation Principle

-- Persuasion is greatest when the audience participates actively. In experimental tests, for example, the same speech is delivered to different audiences. The attitudes of one audience are measured before and after the speech, the difference being a measure of the speech?s effectiveness.The attitudes of another group are measured before and after the speech, but they are also asked, for example, to paraphrase or summarize the various arguments of the speaker. It is consistently found that those listeners who participated actively (as in paraphrasing or summarizing) were more persuaded than those who passively received the message. Demagogues and propagandists who succeed in arousing huge crowds often have the crowds chant slogans, repeat catch phrases, and otherwise participate actively in the persuasive experience.

The Motivational Principle

-- Listeners are best persuaded when your propositions are positively linked to their motives—their desires, wants, wishes, and needs. You will be persuasive to the extent that you can relate the attitudes and behaviors you wish the audience to exhibit with such motives as status, financial gain, affection, love, friendship, sex, attraction, self-esteem, individuality, independence, competition and so on.