People have been studying the methods of persuasion since the days of the ancient Greeks. They have found that listeners accept a speaker's ideas for one or more of four reasons—because they perceive the speaker as having high credibility, because they are won over by the speaker's evidence, because they are convinced by the speaker's reasoning, or because they are moved by the speaker's emotional appeals. Credibility is affected by many factors, but the two most important are competence and character. The more favorably listeners view a speaker's competence and character, the more likely they are to accept her or his ideas. Although credibility is partly a matter of reputation, you can enhance your credibility during the speech by establishing common ground with your listeners and by letting them know why you are qualified to speak on the topic. You can also build your credibility by presenting your speeches fluently and expressively. If you hope to be persuasive, you must also support your views with evidence—examples, statistics, and testimony used to prove or disprove something. As you prepare your speech, try at each point to imagine how your audience will react. Anticipate their doubts and answer them with evidence. Regardless of what kind of evidence you use, it will be more persuasive if it is new to the audience, if it is stated in specific rather than general terms, and if it is from credible sources. Your evidence will also be more persuasive if you state explicitly the point it is supposed to prove. No matter how strong your evidence, you will not be very persuasive unless listeners agree with your reasoning. In reasoning from specific instances, you move from a number of particular facts to a general conclusion. Reasoning from principle is the reverse—you move from a general principle to a particular conclusion. When you use causal reasoning, you try to establish a relationship between causes and effects. In analogical reasoning, you compare two cases and infer that what is true for one is also true for the other. Whatever kind of reasoning you use, you want to make sure that you avoid fallacies such as hasty generalization, false cause, and invalid analogy. As both a speaker and listener, you should also be on guard against the red herring, ad hominem, either-or, bandwagon, and slippery slope fallacies. Finally, you can persuade your listeners by appealing to their emotions—fear, anger, pity, pride, sorrow, and so forth. One way to generate emotional appeal is by using emotion-laden language. Another is to develop vivid, richly textured examples that personalize your ideas and draw listeners into the speech emotionally. Neither, however, will be effective unless you feel the emotion yourself and communicate it by speaking with sincerity and conviction. As with other methods of persuasion, your use of emotional appeal should be guided by a firm ethical rudder. Although emotional appeals are usually inappropriate in speeches on questions of fact, they are legitimate—and often necessary—in speeches that seek immediate action on questions of policy. Even when trying to move listeners to action, however, you should never substitute emotional appeals for evidence and reasoning. You need to build a good case based on facts and logic in addition to kindling the emotions of your audience.
