Rational and Irrational Thought: The Thinking that IQ Tests Miss
Why smart people sometimes do dumb things
Jan 1, 2015 |By Keith E. Stanovich
In Brief, Who are You Calling “Smart”?
It is useful to get a handle on dysrationalia and its causes because we are beset by problems that require increasingly more accurate, rational responses. In the 21st century, shallow processing can lead physicians to choose less effective medical treatments, can cause people to fail to adequately assess risks in their environment, can lead to the misuse of information in legal proceedings, and can make parents resist vaccinating their children. Millions of dollars are spent on unneeded projects by government and private industry when decision makers are dysrationalic, billions are wasted on quack remedies, unnecessary surgery is performed and costly financial misjudgments are made.
IQ tests do not measure dysrationalia. But as I show in my 2010 book, What Intelligence Tests Miss: The Psychology of Rational Thought, there are ways to measure dysrationalia and ways to correct it. Decades of research in cognitive psychology have suggested two causes of dysrationalia. One is a processing problem, the other a content problem. Much is known about both of them.
The Case of the Cognitive Miser
The processing problem comes about because we tend to be cognitive misers. When approaching a problem, we can choose from any of several cognitive mechanisms. Some mechanisms have great computational power, letting us solve many problems with great accuracy, but they are slow, require much concentration and can interfere with other cognitive tasks. Others are comparatively low in computational power, but they are fast, require little concentration and do not interfere with other ongoing cognition. Humans are cognitive misers because our basic tendency is to default to the processing mechanisms that require less computational effort, even when they are less accurate.
Are you a cognitive miser? Consider the following problem, taken from the work of Hector Levesque, a computer scientist at the University of Toronto. Try to answer it yourself before reading the solution:
1. Jack is looking at Anne, but Anne is looking at George. Jack is married, but George is not. Is a married person looking at an unmarried person?
More than 80 percent of people choose C. But the correct answer is A. Here is how to think it through logically: Anne is the only person whose marital status is unknown. You need to consider both possibilities, either married or unmarried, to determine whether you have enough information to draw a conclusion. If Anne is married, the answer is A: she would be the married person who is looking at an unmarried person (George). If Anne is not married, the answer is still A: in this case, Jack is the married person, and he is looking at Anne, the unmarried person. This thought process is called fully disjunctive reasoning—reasoning that considers all possibilities. The fact that the problem does not reveal whether Anne is or is not married suggests to people that they do not have enough information, and they make the easiest inference (C) without thinking through all the possibilities.
Most people can carry out fully disjunctive reasoning when they are explicitly told that it is necessary (as when there is no option like “cannot be determined” available). But most do not automatically do so, and the tendency to do so is only weakly correlated with intelligence.
Here is another test of cognitive miserliness, as described by Nobel Prize–winning psychologist Daniel Kahneman and his colleague Shane Frederick:
2. A bat and a ball cost $1.10 in total. The bat costs $1 more than the ball. How much does the ball cost?
Many people give the first response that comes to mind—10 cents. But if they thought a little harder, they would realize that this cannot be right: the bat would then have to cost $1.10, for a total of $1.20. IQ is no guarantee against this error. Kahneman and Frederick found that large numbers of highly select university students at the Massachusetts Institute of Technology, Princeton and Harvard were cognitive misers, just like the rest of us, when given this and similar problems.
Another characteristic of cognitive misers is the “myside” bias—the tendency to reason from an egocentric perspective. In a 2008 study my colleague Richard West of James Madison University and I presented a group of subjects with the following thought problem:
3. Imagine that the U.S. Department of Transportation has found that a particular German car is eight times more likely than a typical family car to kill occupants of another car in a crash. The federal government is considering resticting sale and use of this German car. Please answer the following two questions: Do you think sales of the German car should be banned in the U.S.? Do you think the German car should be banned from being driven on American streets?
Then we presented a different group of subjects with the thought problem stated a different way—more in line with the true data from the Department of Transportation at the time, which had found an increased risk of fatalities not in a German car but in an American one:
Why smart people sometimes do dumb things
Jan 1, 2015 |By Keith E. Stanovich
In Brief, Who are You Calling “Smart”?
- Traditional IQ tests miss some of the most important aspects of real-world decision making. It is possible to test high in IQ yet to suffer from the logical-thought defect known as dysrationalia.
- One cause of dysrationalia is that people tend to be cognitive misers, meaning that they take the easy way out when trying to solve problems, often leading to solutions that are wrong.
- Another cause of dysrationalia is the mindware gap, which occurs when people lack the specific knowledge, rules and strategies needed to think rationally.
- Tests do exist that can measure dysrationalia, and they should be given more often to pick up the deficiencies that IQ tests miss.
It is useful to get a handle on dysrationalia and its causes because we are beset by problems that require increasingly more accurate, rational responses. In the 21st century, shallow processing can lead physicians to choose less effective medical treatments, can cause people to fail to adequately assess risks in their environment, can lead to the misuse of information in legal proceedings, and can make parents resist vaccinating their children. Millions of dollars are spent on unneeded projects by government and private industry when decision makers are dysrationalic, billions are wasted on quack remedies, unnecessary surgery is performed and costly financial misjudgments are made.
IQ tests do not measure dysrationalia. But as I show in my 2010 book, What Intelligence Tests Miss: The Psychology of Rational Thought, there are ways to measure dysrationalia and ways to correct it. Decades of research in cognitive psychology have suggested two causes of dysrationalia. One is a processing problem, the other a content problem. Much is known about both of them.
The Case of the Cognitive Miser
The processing problem comes about because we tend to be cognitive misers. When approaching a problem, we can choose from any of several cognitive mechanisms. Some mechanisms have great computational power, letting us solve many problems with great accuracy, but they are slow, require much concentration and can interfere with other cognitive tasks. Others are comparatively low in computational power, but they are fast, require little concentration and do not interfere with other ongoing cognition. Humans are cognitive misers because our basic tendency is to default to the processing mechanisms that require less computational effort, even when they are less accurate.
Are you a cognitive miser? Consider the following problem, taken from the work of Hector Levesque, a computer scientist at the University of Toronto. Try to answer it yourself before reading the solution:
1. Jack is looking at Anne, but Anne is looking at George. Jack is married, but George is not. Is a married person looking at an unmarried person?
- A) Yes
- B) No
- C) Cannot be determined
More than 80 percent of people choose C. But the correct answer is A. Here is how to think it through logically: Anne is the only person whose marital status is unknown. You need to consider both possibilities, either married or unmarried, to determine whether you have enough information to draw a conclusion. If Anne is married, the answer is A: she would be the married person who is looking at an unmarried person (George). If Anne is not married, the answer is still A: in this case, Jack is the married person, and he is looking at Anne, the unmarried person. This thought process is called fully disjunctive reasoning—reasoning that considers all possibilities. The fact that the problem does not reveal whether Anne is or is not married suggests to people that they do not have enough information, and they make the easiest inference (C) without thinking through all the possibilities.
Most people can carry out fully disjunctive reasoning when they are explicitly told that it is necessary (as when there is no option like “cannot be determined” available). But most do not automatically do so, and the tendency to do so is only weakly correlated with intelligence.
Here is another test of cognitive miserliness, as described by Nobel Prize–winning psychologist Daniel Kahneman and his colleague Shane Frederick:
2. A bat and a ball cost $1.10 in total. The bat costs $1 more than the ball. How much does the ball cost?
Many people give the first response that comes to mind—10 cents. But if they thought a little harder, they would realize that this cannot be right: the bat would then have to cost $1.10, for a total of $1.20. IQ is no guarantee against this error. Kahneman and Frederick found that large numbers of highly select university students at the Massachusetts Institute of Technology, Princeton and Harvard were cognitive misers, just like the rest of us, when given this and similar problems.
Another characteristic of cognitive misers is the “myside” bias—the tendency to reason from an egocentric perspective. In a 2008 study my colleague Richard West of James Madison University and I presented a group of subjects with the following thought problem:
3. Imagine that the U.S. Department of Transportation has found that a particular German car is eight times more likely than a typical family car to kill occupants of another car in a crash. The federal government is considering resticting sale and use of this German car. Please answer the following two questions: Do you think sales of the German car should be banned in the U.S.? Do you think the German car should be banned from being driven on American streets?
Then we presented a different group of subjects with the thought problem stated a different way—more in line with the true data from the Department of Transportation at the time, which had found an increased risk of fatalities not in a German car but in an American one:
