Stephen E. Lucas

C H A P T E R

McGraw-Hill © 2007 Stephen E. Lucas. All rights reserved.

Methods of Persuasion

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Methods of Persuasion• Building credibility• Using evidence• Reasoning• Appealing to emotions• Principles of suggestions,benefits.

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CredibilityThe audience's perception of whether a speaker is qualified to speak on a given topic.

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EthosThe name used by Aristotle for what modern students of communication refer to as credibility.

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Factors of Credibility

• Competence• Character

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Competence How an audience regards a

speaker’s intelligence, expertise, and knowledge of the subject.

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CharacterHow an audience regards a speaker’s sincerity, trustworthiness, and concern for the well-being of the audience.

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Types of Credibility

• Initial• Derived • Terminal

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Initial Credibility

The credibility of a speaker before she or he starts to speak.

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Derived Credibility

The credibility of a speaker produced by everything she or he says and does during the speech.

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Terminal Credibility

The credibility of a speaker at the end of the speech.

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Tips for Enhancing Credibility

• Explain your competence• Establish common ground with

your audience• Deliver your speeches fluently,

expressively, and with conviction

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LogosThe name used by Aristotle for the logical appeal of a speaker. The two major elements of logos are evidence and reasoning.

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EvidenceSupporting materials used to prove or disprove something.

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Tips for Using Evidence

• Use specific evidence• Use novel evidence• Use evidence from credible sources• Make clear the point of your evidence

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ReasoningThe process of drawing a conclusion on the basis of evidence.

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Four Types of Reasoning

• Reasoning from specific instances• Reasoning from principle• Causal reasoning• Analogical reasoning

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Reasoning from Specific Instances

Reasoning that moves from particular facts to a general conclusion.

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Guidelines for Reasoning from Specific Instances

• Avoid hasty generalizations• If your evidence does not justify a

sweeping conclusion, qualify your argument

• Reinforce your argument with statistics or testimony

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Reasoning from PrincipleReasoning that moves from a general principle to a specific conclusion.

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Guidelines for Reasoning from Principle

• Make sure listeners will accept your general principle

• Provide evidence to support your minor premise

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Causal ReasoningReasoning that seeks to establish the relationship between causes and effects.

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Guidelines for Causal Reasoning

• Avoid the fallacy of false cause• Do not assume that events have

only a single cause

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Analogical ReasoningReasoning in which a speaker compares two similar cases and infers that what is true for the first case is also true for the second.

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Guidelines for Analogical Reasoning

Above all, make sure the two cases being compared are essentially alike

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FallacyAn error in reasoning.

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Fallacies

• Hasty generalization• False cause• Invalid analogy • Red herring

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Fallacies

• Ad hominem• Either-or• Bandwagon• Slippery slope

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Hasty GeneralizationA fallacy in which a speaker jumps to a general conclusion on the basis of insufficient evidence.

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Hasty Generalization“Last year alone three members of our state legislature were convicted of corruption. We can conclude, then, that all of our state's politicians are corrupt.”

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False Cause

A fallacy in which a speaker mistakenly assumes that because one event follows another, the first event is the cause of the second.

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False Cause

“I'm sure the stock market will rise this year. It usually goes up when the American League wins the World Series.”

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Invalid AnalogyAn analogy in which the two cases being compared are not essentially alike.

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Invalid Analogy“Of course Lisheng can prepare great Italian food; his Chinese cooking is fabulous.”

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Red HerringA fallacy that introduces an irrelevant issue to divert attention from the subject under discussion.

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Red Herring

“Why should we worry about endangered animal species when thousands of people are killed in automobile accidents each year?”

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Ad HominemA fallacy that attacks the person rather than dealing with the real issue in dispute.

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Ad Hominem “The governor has a number of

interesting economic proposals, but let’s not forget that she comes from a very wealthy family.”

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Either-OrA fallacy that forces listeners to choose between two alternatives when more than two alternatives exist.

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Either-Or“The government must either raise taxes or reduce services for the poor.”

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BandwagonA fallacy that assumes that because something is popular, it is therefore good, correct, or desirable.

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Bandwagon

“The President must be correct in his approach to domestic policy; after all, polls show that 60 percent of the people support him.”

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Slippery SlopeA fallacy that assumes that taking a first step will lead to subsequent steps that cannot be prevented.

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Slippery Slope “Passing federal laws to control the amount of violence on television is the first step in a process that will result in absolute government control of the media and total censorship over all forms of artistic expression.”

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Emotional AppealsAppeals that are intended to make listeners feel sad, angry, guilty, afraid, happy, proud, sympathetic, reverent, or the like.

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Pathos

The name used by Aristotle for what modern students of communication refer to as emotional appeal.

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Tips for Generating Emotional Appeal

• Use emotional language• Develop vivid examples• Speak with sincerity and

conviction

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Using Emotional Appeal Ethically

• Make sure emotional appeal is appropriate to the speech topic

• Do not substitute emotional appeal for evidence and reasoning

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