I. How scientific principles protect us from common persuasive techniques
A. Science vs. Bandwagon technique (science demands observable evidence)
B. Science vs. the Testimonial--or talk show guest
1. External validity: Too small a sampleC. Science vs. many informal polls
2. Construct validity
a. Lying3. Internal validity: People might have changed on their own even without the treatment.
b. Biased perceptions (People often think they've grown wiser or more mature when they haven't)
1. External validity
a. Small sample2. Construct validity
b. Biased sample (1-900 numbers, mail polls, Hite report)
a. Lying3. Internal validity: People don't know why they act the way they do.
b. Misinterpreting questions
II. How scientific principles can improve on "ordinary logic"
A. External validity questions
1. False consensus effect: "Is everybody really doing it"
2. Beware of stereotyping based on small, nonrepresentative samples
B. Internal validity: "False cause" errors
1. Are the variables even related? We sometimes see illusory correlations.
2. Are we confusing causes with effects?
3. Are both factors side effects of some other cause?
4. Beware of "before-after "stories: People can change on their own
5. Beware of stories that claim to assess the effects of a treatment even though they are comparing "apples and oranges "
a. Assess Head Start program by comparing Head Start children with middle-class children
b. Assess illegal drug's effect by comparing drug users with non-users
C. Construct validity: Beware of labels
- Tests in magazines may not measure what they claim to measure.
- Everyday judgments of people based on their behavior: good, bad, lazy, stupid
- Drugs and therapies may work because of placebo effects rather than because of their specific ingredients