Faulty Thinking

Avoid oversimplifying/overgeneralizing/fallacies

Psychological thinking requires that observations and conclusions based on observations avoid simplistic, fallacious reasoning. Common fallacies in our reasoning include the following:

Appeal to ignorance. Argues that some claim is true because it cannot be proven to be false, or the opposite: that some claim must be false because it cannot be proven to be true.

Ex: No one has proved that animals dream, so it must not be true.

Slippery slope. If the first step in a "possible" series of events occurs, the other possible steps in the series must inevitably occur.

Ex: Once someone uses an illegal drug like marijuana, they will become heroin addicts eventually.

False alternatives.(also known as False Dilemma) This involves "either/or" thinking in which some classification is presumed to be exclusive or exhaustive, such as when we overlook the alternatives that exist between the extremes of two poles.

Ex: Any experience that does not kill you will make you stronger.

Hasty generalizations. If we tend to form a general conclusion based on an exceptional case, or on a very small sample, or on a biased sample, we may have overgeneralized.

Ex: I know that boys raised by single mothers are effeminate, because thats what happened to my cousin Michael.

Questionable analogies. We may sometimes try to compare apples to oranges, or try to make two situations seem more similar that they are.

Ex: When you put a bridge girder under too much stress, it breaks. The same thing happens with people.

The statements below and others like them are common in discussions of human behavior and psychology. Identify the fallacies they represent.

1. If a child gets attention for crying, before long the child will be crying more and more and will start misbehaving in other ways to get attention.

Fallacy: ____________________

2. We cannot conclusively prove the existence of the unconscious mind, there fore it is a fiction: it does not exist.

Fallacy: ____________________

3. Schizophrenia is either an inherited brain disease or the result of neglectful parenting.

Fallacy: ____________________

4. Freud, after careful and extensive analysis of five of his patients,

concluded that most peoples level of anxiety in life is motivated by unconscious, repressed impulses and memories.

Fallacy: ____________________

5. Since the therapists client had no memory of childhood abuse,

she concluded that no abuse had ever taken place.

Fallacy: ___________________

6. The brains of elderly rats exposed to a boring, unchallenging environment shrink in size and weight, which is good argument for not putting elderly people in lifeless, unstimulating nursing homes.

Fallacy: ___________________

7. Parents who reward their children for good grades should recognize that bribing them wont make them like school. You can lead a horse to water but you cant make him drink.

Fallacy: ____________________

8. We dont know for sure that homosexuality is biologically caused, so we can only conclude that its a choice that a person makes and can therefore changed with therapy.

Fallacy: ____________________

9. Little kids who are curious about sex and observed touching themselves should be placed into therapy before they grow up to be perverts and rapists.

Fallacy: ____________________

10. If Abe Lincoln can raise himself above poverty and odd looks to become one of the greatest Americans who ever lived, anyone can do the same.

Fallacy: ____________________

11. I dont let any student take a make-up test, because if I let one student do it, pretty soon others are asking to make-up test, and before long Im giving make-up test to almost everyone.

Fallacy: ____________________

12. There are two kinds of people: " Type A" ( workaholics and go-getters) and

"Type B" (relaxed and unmotivated)

Fallacy: ____________________

13. Why do people need to go to a psychologist? Heck, back in grandpas day people didnt have any psychologists and they seemed to get by just fine.

Fallacy: ____________________

14. Both Uncle Albert and cousin Mary Ann committed suicide, which makes me think it must run in my family.

Fallacy: ____________________

15. I believe in reincarnation because no one can know for sure that it doesnt happen.

Fallacy: ____________________

Answers:

1.slippery slope 6. questionable analogy 11. slippery slope

2. appeal to ignorance 7. questionable analogy 12. false alternatives

3. false alternatives 8. false alternatives 13. ???? analogy

4. hasty generalization 9. slippery slope 14. hasty generalization

5. appeal to ignorance 10. hasty generalization 15. appeal to ignorance

For instructors, a more complete explanation of these and other fallacies can be found on the Critical Thinking Across the Curriculum Project Web site at:

(http://www.kcmetro.cc.mo.us/longview/ctac/fallacy.htm)

Copyright © 1996 Andrew Geoghegan,
Critical Thinking Across the Curriculum Project
Longview Community College , Lee's Summit, Missouri - U.S.A.
One of the Metropolitan Community Colleges
An Equal Opportunity/Affirmative Action Employer

Permission to reproduce these resource pages is granted for
non-profit educational use provided the above information
is retained on all copies.

Inquiries to: michael.connelly@mcckc.edu
Last modified: 03/02/04