1. business and industrial
2. business operations
3. business plans

C h a p t e r
17
• Methods of Persuasion
Methods of Persuasion/Ch 16
Slide 1
Introduction to Public Speaking
Methods of Persuasion
• Building credibility
(ethos)
• Using evidence
• Reasoning
(logos)
• Appealing to emotions
(pathos)
Methods of Persuasion/Ch 16
Slide 2
Introduction to Public Speaking
Ethos
The name used by Aristotle for what
modern students of communication
refer to as credibility.
Methods of Persuasion/Ch 16
Slide 3
Introduction to Public Speaking
Credibility
The audience's perception of whether
a speaker is qualified to speak on a
given topic.
Methods of Persuasion/Ch 16
Slide 4
Introduction to Public Speaking
Factors of Credibility
• Competence
• Character
Methods of Persuasion/Ch 16
Slide 5
Introduction to Public Speaking
Competence
How an audience regards a
speaker’s intelligence, expertise, and
knowledge of the subject.
Methods of Persuasion/Ch 16
Slide 6
Introduction to Public Speaking
Character
How an audience regards a speaker’s
sincerity, trustworthiness, and
concern for the well-being of the
audience.
Methods of Persuasion/Ch 16
Slide 7
Introduction to Public Speaking
Types of Credibility
• Initial
• Derived
• Terminal
Methods of Persuasion/Ch 16
Slide 8
Introduction to Public Speaking
Initial Credibility
The credibility of a speaker
before she or he starts to speak.
Methods of Persuasion/Ch 16
Slide 9
Introduction to Public Speaking
Derived Credibility
The credibility of a speaker
produced by everything she or he
says and does during the speech.
Methods of Persuasion/Ch 16
Slide 10
Introduction to Public Speaking
Terminal Credibility
The credibility of a speaker at the
end of the speech.
Methods of Persuasion/Ch 16
Slide 11
Introduction to Public Speaking
Tips for Enhancing Credibility
• Explain your competence
• Establish common ground with
your audience
• Deliver your speeches fluently,
expressively, and with conviction
Methods of Persuasion/Ch 16
Slide 12
Introduction to Public Speaking
Logos
The name used by Aristotle for the
logical appeal of a speaker. The two
major elements of logos are evidence
and reasoning.
Methods of Persuasion/Ch 16
Slide 13
Introduction to Public Speaking
Evidence
Supporting materials used to prove
or disprove something.
Methods of Persuasion/Ch 16
Slide 14
Introduction to Public Speaking
Tips for Using Evidence
•
•
•
•
Use specific evidence
Use novel evidence
Use evidence from credible sources
Make clear the point of your
evidence
Methods of Persuasion/Ch 16
Slide 15
Introduction to Public Speaking
Reasoning
The process of drawing a conclusion
on the basis of evidence.
Methods of Persuasion/Ch 16
Slide 16
Introduction to Public Speaking
Four Types of Reasoning
•
•
•
•
Reasoning from specific instances
Reasoning from principle
Causal reasoning
Analogical reasoning
Methods of Persuasion/Ch 16
Slide 17
Introduction to Public Speaking
Reasoning from Specific
Instances
Reasoning that moves from particular
facts to a general conclusion.
Methods of Persuasion/Ch 16
Slide 18
Introduction to Public Speaking
Reasoning from Specific Instances
Example:
Contrary to what the chemical industry argues,
limiting pesticide use does not threaten the food
supply. (1.)Sweden has cut back on pesticides by 50
percent over the last few years with almost no
decrease in its harvest. (2.)The Campbell Soup
Company uses no pesticides at all on tomatoes grown in
Mexico, and they reap as much fruit as ever. (3.)
Many California farmers who practice pesticide-free
agriculture have actually experienced increases in
their crop yields.
1 example
+1 example
+1 example
= conclusion
Methods of Persuasion/Ch 16
Slide 19
Introduction to Public Speaking
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
Methods of Persuasion/Ch 16
Slide 20
Introduction to Public Speaking
Reasoning from Principle
Reasoning that moves from a general
principle to a specific conclusion.
Methods of Persuasion/Ch 16
Slide 21
Introduction to Public Speaking
Reasoning from Principle
Example:
Reasoning must be valid and all of the premises
must be true.
1. To be elected President of the United
States, a person must be at least 35 years
of age.
2. Bill Clinton was elected President of the
United States.
3. Therefore, Bill Clinton was at least 35 years
of age when elected.
Methods of Persuasion/Ch 16
Slide 22
Introduction to Public Speaking
Guidelines for Reasoning
from Principle
• Make sure listeners will accept your
general principle (premise)
• Provide evidence to support your
minor premise
Methods of Persuasion/Ch 16
Slide 23
Introduction to Public Speaking
Causal Reasoning
Reasoning that seeks to establish
the relationship between causes
and effects.
Methods of Persuasion/Ch 16
Slide 24
Introduction to Public Speaking
Causal Reasoning
Example:
Because the ice was on the
step, I fell and broke my leg.
Methods of Persuasion/Ch 16
Slide 25
Introduction to Public Speaking
Guidelines for Causal
Reasoning
• Avoid the fallacy of false cause
• Do not assume that events have
only a single cause
Methods of Persuasion/Ch 16
Slide 26
Introduction to Public Speaking
Analogical Reasoning
Reasoning in which a speaker
compares two similar cases and
implies that what is true for the
first case is also true for the
second.
Methods of Persuasion/Ch 16
Slide 27
Introduction to Public Speaking
Analogical Reasoning
Example:
Almost every industrialized nation in the
world except for the United States has
a national curriculum and national tests
to help ensure that schools throughout
the country are meeting high standards
of education. If such a system can work
elsewhere, it can work in the United
States as well.
Methods of Persuasion/Ch 16
Slide 28
Introduction to Public Speaking
Guidelines for Analogical
Reasoning
Above all, make sure the two cases
being compared are essentially alike
Methods of Persuasion/Ch 16
Slide 29
Introduction to Public Speaking
Fallacy
An error in reasoning.
Methods of Persuasion/Ch 16
Slide 30
Introduction to Public Speaking
Fallacies
• Hasty
generalization
• False cause
• Invalid analogy
• Red herring
Methods of Persuasion/Ch 16
•
•
•
•
Slide 31
Ad hominem
Either-or
Bandwagon
Slippery slope
Introduction to Public Speaking
Hasty Generalization
A fallacy in which a speaker jumps
to a general conclusion on the basis
of insufficient evidence. (associated
with reasoning from specifics)
Methods of Persuasion/Ch 16
Slide 32
Introduction to Public Speaking
Example: 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.”
1 member
+ 1 member
+ 1 member
= all politicians
Methods of Persuasion/Ch 16
Slide 33
Introduction to Public Speaking
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.
(associated with causal reasoning)
Methods of Persuasion/Ch 16
Slide 34
Introduction to Public Speaking
Example: False Cause
“I'm sure the stock market will rise
this year. It usually goes up when
the American League wins the
World Series.”
Methods of Persuasion/Ch 16
Slide 35
Introduction to Public Speaking
Invalid Analogy
An analogy in which the two
cases being compared are not essentially
alike. (associated with analogical reasoning)
Methods of Persuasion/Ch 16
Slide 36
Introduction to Public Speaking
Example: Invalid Analogy
“Of course Lisheng can prepare great
Italian food; his Chinese cooking is
fabulous.”
Methods of Persuasion/Ch 16
Slide 37
Introduction to Public Speaking
Red Herring
A fallacy that introduces an
irrelevant issue to divert attention
from the subject under discussion.
Methods of Persuasion/Ch 16
Slide 38
Introduction to Public Speaking
Example: Red Herring
“Why should we worry about
endangered animal species when
thousands of people are killed in
automobile accidents each year?”
Methods of Persuasion/Ch 16
Slide 39
Introduction to Public Speaking
Ad Hominem
A fallacy that attacks the person
rather than dealing with the real
issue in dispute.
Methods of Persuasion/Ch 16
Slide 40
Introduction to Public Speaking
Example: Ad Hominem
“The governor has a number of
interesting economic proposals, but
let’s not forget that she comes
from a very wealthy family.”
Methods of Persuasion/Ch 16
Slide 41
Introduction to Public Speaking
Either-Or
A fallacy that forces listeners to
choose between two alternatives when
more than two alternatives exist.
Methods of Persuasion/Ch 16
Slide 42
Introduction to Public Speaking
Example: Either-Or
“The government must either raise
taxes or reduce services for the
poor.”
Methods of Persuasion/Ch 16
Slide 43
Introduction to Public Speaking
Bandwagon
A fallacy that assumes that because
something is popular, it is therefore
good, correct, or desirable.
Methods of Persuasion/Ch 16
Slide 44
Introduction to Public Speaking
Example: Bandwagon
“The President must be correct in
his approach to domestic policy;
after all, polls show that 60
percent of the people support him.”
Methods of Persuasion/Ch 16
Slide 45
Introduction to Public Speaking
Slippery Slope
A fallacy that assumes that taking
a first step will lead to subsequent
steps that cannot be prevented.
Methods of Persuasion/Ch 16
Slide 46
Introduction to Public Speaking
Example: 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.”
Methods of Persuasion/Ch 16
Slide 47
Introduction to Public Speaking
Pathos
The name used by Aristotle for what
modern students of communication
refer to as emotional appeal.
Methods of Persuasion/Ch 16
Slide 48
Introduction to Public Speaking
Emotional Appeals
Appeals that are intended to make
listeners feel sad, angry, guilty,
afraid, happy, proud, sympathetic,
reverent, etc.
Methods of Persuasion/Ch 16
Slide 49
Introduction to Public Speaking
Tips for Generating
Emotional Appeal
• Use emotional language
• Develop vivid examples
• Speak with sincerity and conviction
Methods of Persuasion/Ch 16
Slide 50
Introduction to Public Speaking
Using Emotional Appeal
Ethically
• Make sure emotional appeal is
appropriate to the speech topic
• Do not substitute emotional appeal
for evidence and reasoning
Methods of Persuasion/Ch 16
Slide 51
Introduction to Public Speaking
True-False Quiz
1. The more favorably listeners view a speaker’s
competence and character, the more likely
they are to accept what the speaker says.
2. Because it moves from a general principle to a
specific conclusion, reasoning from principle is
the opposite of reasoning from specific
instances.
3. Research shows that skeptical listeners are
more likely to be persuaded by evidence they
are already familiar with than by evidence
that is new to them.
Methods of Persuasion/Ch 16
Slide 52
Introduction to Public Speaking
True-False Quiz
4. It is usually inappropriate for persuasive
speakers to refer to their personal experience
in an attempt to bolster their credibility.
5. The red herring fallacy refers to statements
that introduce an irrelevant issue to divert
attention from the subject under discussion.
6. A speaker can have high credibility for one
audience and low credibility for another
audience.
Methods of Persuasion/Ch 16
Slide 53
Introduction to Public Speaking
True-False Quiz
7. Arguments guilty of the ad hominem fallacy
attack the person rather than dealing with the
real issue in dispute.
8. Studies have shown that speakers with low
initial credibility need to use more evidence
than speakers with high initial credibility.
9. According to your textbook, emotional appeals
are often appropriate in persuasive speeches
on questions of policy.
Methods of Persuasion/Ch 16
Slide 54
Introduction to Public Speaking
True-False Quiz
10. The following statement is an example of
reasoning by analogy: “The United Nations
charter establishes the right of all people to
live free of political repression. The
government of North Korea subjects its people
to political repression. Therefore, the
government of North Korea is violating the
U.N. charter.”
Methods of Persuasion/Ch 16
Slide 55
Introduction to Public Speaking
Review Methods of Persuasion
Methods of Persuasion/Ch 16
Slide 56
Introduction to Public Speaking