PRINCIPLES OF CRITICAL THINKING IN PSYCHOLOGY

The Scientific Method

1.  Observe -- Realize there is an idea that deserves study.
2.  Hypothesize -- Develop a cause-effect prediction to explain what you observe. Your prediction must be testable, i.e., stated in observable, measurable terms.
3.  Test -- Design an experiment to collect information that verifies or disproves your prediction.
"Principle of falsifiability" = the true scientist must state an hypothesis in such a way that it can be refuted/disproved by counterevidence.
4.  Modify -- Refine your hypothesis (or theory) based on the results of your experimental test.
5.  Repeat or Replicate -- Repeat: Test your refined hypothesis or theory by making new predictions and by testing again.
Or in the case of replication, repeat your test to ensure you obtain the same basic results.
Replication increases our confidence in the accuracy of our results, our hypotheses, and our theories.

What is Critical Thinking?

the ability and willingness to evaluate claims and make objective judgments on the basis of well-supported reasons.

Quotes about Critical Thinking

"Most people would rather die than think--many do." -- Bertrand Russell
"We enjoy the comfort of opinion without the discomfort of thought." -- John F. Kennedy
"The price you pay for not thinking about something important in your life is that there will always be someone else eager to do your thinking for you." -- Marianne Williamson
"Fuzzy thinking is just one step above not thinking at all." -- Marianne Williamson
"We have become through the electronic media, one global brain." -- Marianne Williamson

Guidelines to Critical Thinking (Tavris & Wade; Smith)

1.  Maintain an air of healthy skepticism.  Ask questions and be willing to wonder.

2.  Examine the available evidence before drawing conclusions.

3.  Be able to separate facts from opinions.

4.  Evaluate the assumptions and biases that underlie arguments.  Be particularly wary of the "confirmation bias" = tendency to look for or pay attention only to information that confirms one's beliefs.

5.  Avoid emotional reasoning: "If I feel this way, it must be true."  Instead, use logical reasoning.

6.  Don't oversimplify. The "law of parsimony" states that usually the simplest scientific explanation will be true; however, resist the overly simple.

7.  Learn to tolerate ambiguity and uncertainty.

Timothy Lawson's Critical Thinking Questions to
aid you in B.S. (Bogus Science) Detection

1.  What is the quality of the evidence to support the claim? (In general, the evidence is very weak if the person has only testimonial or anecdotal evidence or no evidence at all; the evidence is quite strong if the person's findings have been published in a respectable scientific journal and other researchers have replicated the findings.)

2.  Could the event or relationship have occurred by chance (coincidence) (e.g., you just happened to have a car accident on the day that a psychic predicted your car would be damaged)?

3.  Is there a control or comparison group against which to assess the performance of the experimental group?

4.  Is the person concluding there is a causal relationship on the basis of correlational data?

5.  Are there confounding variables that might account for the findings (e.g., participants selecting themselves into groups, experimenter expectancies, demand characteristics, or some other variable that varies systematically with the independent variable)?

6.  Is the person trying to generalize the findings to a larger group based on a biased or unrepresentative sample?

7.  Did the person ask questions of participants in a biased manner (e.g., leading questions, loaded or emotional wording, confusing wording)?

8.  Has the person made it impossible to falsify his or her theory or hypothesis (principle of falsifiability)?  Does he or she consider positive evidence as support for the theory, but negative evidence as not being relevant (confirmation bias)? Doe he or she claim that the phenomenon disappears once you try to test it?

9.  Is the person claiming to have found the cause of some behavior or phenomenon? (Most complex behaviors or phenomena have multiple causes.)

Beth Benoit adds:

10.  Consider the source. Was it reported in a refereed scientific journal, the newspaper, or a grocery store tabloid?  Of course, a drug company will claim that their brand works best; and so will the actors they hire.  What are the credentials of the person? Does the individual really have a Ph.D. in psychology? Is it a nationally respected scientist or a disrespected researcher "kicked out" of the American Psychological Association for committing biased, fraudulent research?