When one makes a claim, one is stating that something is a fact. In other words, a claim is a statement that is thought by some people to be true, but that may turn out to be false. In your everyday life, you probably often have heard claims made about mind and behavior, and you probably think that you already know quite a bit about psychology--the scientific discipline that studies the mind and behavior. In order to get a sense of what you might know about psychology, please take the following brief test.

Which of the following claims are true?

• dream images are known to have particular meanings, which often involve unconscious desires and conflicts
• eating sugar causes children to become temporarily hyperactive
• most people use only 10% (or less) of their brains
• a person who commits suicide must have been clinically depressed
• there are more admissions to mental hospitals during full moons than at other times
• completely detailed memories of every event we have ever experienced are stored permanently in our minds and can be accessed with hypnosis
• a person who exhibits two or more personalities is diagnosed with schizophrenia
• low self-esteem is known to cause most self-destructive behaviors
• most mental disorders can be cured by remembering and "reliving" distressing experiences from one's past
• waking a sleepwalker is dangerous for him or her

You may be surprised to learn that none of these claims is known to be true. In fact, most are known to be false and a few are, at best, highly controversial. In order to avoid basing our decisions on false claims, we all need to learn to think critically about the claims we hear in our everyday lives. In the science of psychology, researchers think critically about claims made about mind and behavior. In these lessons, you will learn how to think like a psychological researcher when you hear such claims.

Skepticism and Empiricism

Tara states that she has been abducted many times by extraterrestrial beings. She claims that, on at least one occasion, she was flown to a distant planet. The aliens, she says, have placed devices into her brain that allow them to track her and to monitor her activities at all times. Tara remembers being physically examined by the aliens and operated on a number of times. She believes that they are performing reproductive experiments on humans in order to develop a hybrid species--one that is part-alien and part-human. She has concluded that the aliens are trying to help humans evolve into beings who will have all sorts of strange and wonderful powers.

In Chapter 1 of the textbook, it was stated that scientific psychologists are trained to be skeptical--to doubt a claim unless it is supported by adequate evidence. For example, if someone claimed that she had been abducted by aliens from another planet and flown to a distant planet, most of us would doubt her claim until we had seen good evidence to support it. Regarding the nature of that evidence, scientific psychologists are trained to be empirical--to make direct observations relevant to a claim. For example, we might decide to closely examine physical evidence (perhaps brain implants) that would show, beyond a reasonable doubt, that her story was true. (In Critical Thinking Lesson 2A, you will begin to learn about the kinds of observations that scientific psychologists rely on when testing claims.)

In the Critical Thinking Application at the end of Chapter 1, you learned two basic lessons about critical thinking that are related to skepticism. First, when an answer to a question is proposed, a critical thinker always considers other possible answers. For example, in Tara's case, we might ask the following question: why does she state that she has been abducted by extraterrestrials? One possible answer is that she really has been abducted many times by creatures from another planet. Another possible answer is that Tara is lying, perhaps to gain attention from others. A third possible answer is that Tara has a mental disorder characterized by delusional thinking and hallucinations. When you consider a number of alternative answers, you are more likely to closely examine the evidence in order to see which answer is best supported by it.

The second lesson you learned in the Critical Thinking Application was that, when an answer to a question is proposed, a critical thinker looks to see if there is any evidence that contradicts the proposed answer. For example, if CT scans showed no evidence that Tara had an object implanted anywhere in her brain, or if a visual inspection of her body showed no evidence of surgical scars, this would contradict her claim that she was, indeed, abducted by aliens who performed medical procedures on her. This second lesson is actually skepticism in action: by looking for evidence that contradicts a proposed answer to a question, we try to see if there is a good reason to doubt the answer. In other words, we are trying to avoid a fundamental error in thinking that is referred to as the "confirmation bias."

The Confirmation Bias

It was a beautiful Spring day, with clear blue skies and a cool breeze coming off the lake near Rachel's house. She decided that it would be a perfect day to wash her car, which had become very dirty during a recent trip she had taken. After returning from the car wash, she noticed clouds building in the western sky. Within an hour, a dust storm rolled through town, which was followed by a brief thunderstorm. Afterwards, her car looked as if it had never been washed and waxed just a few hours before. Rachel complained to her friend: "Of course it rained. That's because I just washed my car!"

Rachel seems to be saying here that, in some unknown way, washing her car caused a storm to develop that day. In fact, this is a common superstitious belief shared by many people. And it seems to Rachel that this superstitious belief was just confirmed.

Our prior beliefs--our preconceptions--cause us to pay attention to particular conjunctions (combinations) of events and to interpret them in particular ways. Because of her superstitious belief, Rachel noticed the conjunction of washing the car and rain, and interpreted this conjunction in terms of a causal relationship: washing the car causes it to rain. She probably never has noticed that there have been many occasions on which she washed her car and it did not rain afterwards; or that, on cloudy days, the sky sometimes has cleared after she has washed her car. Rachel's preconception that washing the car causes it to rain has led her to pay attention primarily to those occasions on which the two events occur together and to ignore (or to explain away if she does, in fact, notice) those occasions on which the two events do not occur together.

In general, we have an automatic tendency to pay attention to or seek out information that is in agreement with (confirms) our preconceptions, and to ignore, distort, or avoid information that contradicts (disconfirms) our preconceptions, a tendency that is called the confirmation bias. The confirmation bias serves to maintain and strengthen the beliefs that we already hold by causing us to automatically (that is, without being aware that we are doing so) perceive and remember experiences that confirm these beliefs, and to ignore or reinterpret those that disconfirm them. Because we tend to seek out only confirming evidence, our beliefs over time become so well confirmed in our minds that we come to think of them as "obviously true." In order to avoid the confirmation bias, we must force ourselves to look for evidence that disconfirms our beliefs.

One technique for forcing ourselves to pay attention to disconfirming evidence involves setting up a table that includes both confirming and disconfirming information. To be specific, we count up all the instances in which two events about which we hold a preconception either occur together or do not. In Rachel's case, for example, she might have set up the following table in order to see if the claim, washing the car causes it to rain, was true or false:

CRITICAL THINKING QUESTIONS FOR LESSON 1

Critical thinking refers to a way of thinking about a question or problem, not to the answer or solution that one obtains. Two people may both think critically about a particular question but come up with different answers. This may be because they have weighed information in different ways or considered different types of information when thinking about the question or problem. In the questions below and in the rest of the lessons, "suggested answers" will be provided in order to give you an example of how to think critically about the question being asked. You may often find that your own attempts at thinking critically lead you to choose a different answer as the best one. The fact that you reached a different conclusion does not necessarily mean that you did not think critically. Given the information in the question, your answer also may be a credible one.

Question 1-1
Generate at least two alternative explanations of each of the following sets of observations:

• Alfred, who is 69 years old and lives alone, is awakened each morning just before 2:00 am by a voice somewhere in his house that says, "I won't take the lift down." The voice continues saying this for 15 seconds and then stops. Alfred has even tape-recorded the voice, but no one else who has ever visited his house has heard the voice.
  Suggested Answer
• Lottery numbers are chosen at random, typically once a week in many states. One week, the following five winning numbers were drawn in a certain state: 12, 32, 4, 78, and 63. A week later, the same five numbers were again drawn in this state.
  Suggested Answer
• Monroe was driving past an intersection at which he had almost been killed in a head-on collision ten years earlier. Suddenly, he heard his three-year-old son say, "crash, bang, boom" and then the words, "I'm dead." Monroe was shocked because no one had ever told his son about his near-fatal car accident.
  Suggested Answer
  
• Gordon took a medication that was supposed to help him sleep. Instead, he started to feel very anxious and could not sleep at all that night.
  Suggested Answer
• Nicotine is highly addictive and, when heavy smokers stop for even a short time, they begin to feel strong cravings for the drug. Jason smoked three packs of cigarettes a day for 10 years. Last month, he quit. He has had no desire to smoke since then.
  Suggested Answer
• Dee's father had died about two months ago and she was still grieving his death. One night when she was feeling particularly upset, Dee found herself thinking about the host of a popular children's television show that she had enjoyed watching when she was young. She thought to herself, "he must be pretty old by now and, so, he probably will die soon." She was amazed when she awoke the next morning and, while watching the television news, found out that this person had indeed died during the night.
  Suggested Answer

Question 1-2
Sequences of numbers may be generated by "rules." For example, we may start with the following rule: any descending series of three numbers that differ from each other by one. Examples of sequences that follow this rule are:

• 5, 4, 3
• -1, -2, -3
• 1000, 999, 998

John was asked to examine the following two sequences of numbers:

• 2 4 6
• 18 20 22

He was asked to figure out what rule was used to generate these two sequences, and answered: "the rule is any ascending series of three consecutive even numbers, such as 6, 8, 10, or 100, 102, 104."

John then was asked to test whether or not the rule he chose was actually the rule used to generate the two sequences. The test involved choosing a third sequence of numbers (from the two below), after which he would be told if the sequence he chose actually followed the rule used to generate the two sequences above. If John's goal was to make sure that the rule he formulated was actually the rule used to generate the two sequences of numbers presented above, which of the following sequences should he have chosen as his "test sequence"?

• 7 9 11
• 12 14 16

Suggested Answer

Question 1-3
When we develop a theory, we are developing a set of ideas that help us to explain (in terms of causes) an event or set of events. Read the following description and develop two alternative theories related to it:

Sarah began to drink a large amount of alcohol and to use various drugs about one year before she was diagnosed with schizophrenia--a mental disorder characterized by auditory hallucinations (hearing things, usually voices, that are not really there), bizarre delusions (rigidly held beliefs that could not possibly be true), and illogical thinking.

Suggested Answer

Question 1-4
Let's say that you are asked to look at four cards laid out on a table (Schick and Vaughn, 2002). On one side of each card is a letter and on the other side is a number. You are able to see the following letters and numbers on the cards:

You are asked to test the following claim: if a card has a vowel on one side, it has an even number on the other. Keeping in mind the discussion above about the need to look for evidence that disconfirms a claim ("a critical thinker looks to see if there is any evidence that contradicts the proposed answer"), which cards would you need to turn over in order to test this claim?
Suggested Answer

Question 1-5
By using a table like the ones described above, design a way of testing the following superstitious belief:

In order to have a happy marriage, the bride must wear "something old, something new, something borrowed, and something blue."

Suggested Answer

Bibliography and References

Carroll, R. T. (2002). Precognition. The Skeptic's Dictionary. Retrieved March 16, 2003, from http://skepdic.com/precog.html

Ezard, J (2003, February 5). Spider-Man haunts pensioner. Guardian Unlimited. Retrieved March 2, 2003 from http://film.guardian.co.uk/News_Story/Guardian/0,4029,889208,00.html

Schick, Jr., T., & Vaughn, L. (2002). How to think about weird things: Critical thinking for a new age (3rd ed.). Boston: McGraw-Hill.

Weiten, W., & Lloyd, M. A. (2003). Psychology applied to modern life: Adjustment in the 21st century (7th ed.). Brelmont, CA: Wadsworth/Thomson.