"My doctor told me to stop having intimate dinners for four. Unless there are three other people." - Orson Welles
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Rational and Irrational Thought: The Thinking That IQ Tests Miss:
"I coined the term dysrationalia (analogous to "dyslexia"), meaning the inability to think and behave rationally despite having adequate intelligence, to draw attention to a large domain of cognitive life that intelligence tests fail to assess. Although most people recognize that IQ tests do not measure important mental faculties, we behave as if they do. We have an implicit assumption that intelligence and rationality go together - or else why would we be so surprised when smart people do foolish things?...
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 if 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...
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...
My goal in proposing the term dysrationalia is to separate intelligence from rationality, a trait that IQ tests do not measure. The concept of dysrationalia, and the empirical evidence indicating that the condition is not rare, should help create a conceptual space in which we value abilities at least as important as those currently measured on IQ tests - abilities to form rational beliefs and to take rational action."
He also talks about the egocentric fallacy, the base rate fallacy, the failure to understand the scientific method (hypothesis testing and controls) and confirmation bias.