Most of the experiments recounted in Thinking, Fast and Slow aren’t as prima facie silly, but Kahneman, a literal-minded soul, often seems to miss the fundamental point of why his subjects fall for his little hoaxes so often:
“Steve is very shy and withdrawn, invariably helpful but with little interest in people or in the world of reality. A meek and tidy soul, he has a need for order and structure and a passion for detail.
“Is Steve more likely to be a librarian or a farmer?”
Wrong! Kahneman scoffs at your intuition: “Did it occur to you that there are more than 20 male farmers for each male librarian in the United States?”
Well, no, actually, I didn’t know. Come to think of it, nor do I know the measured frequency of the traits listed among either farmers or librarians. Give me that information, and I can calculate the conditional probabilities. As it is, though, the only correct answer to the question as written is: insufficient information.
Did it occur to Kahneman that anybody who isn’t trying to deceive us would have added, “So, Steve’s just not cut out for his life of slopping hogs” or the like? As con men, conjurors, and comedians demonstrated long before Kahneman, most people trust in the speaker’s good faith. They play along and try to guess what is being implied. So it’s easy to pull the rug out from under us.
Yes, but there is still such a thing a critical thinking. For instance, here is another Kahneman problem from Michael Lewis’ Vanity Fair review that Steve quotes:
“Linda is thirty-one years old, single, outspoken, and very bright,” they wrote. “She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in antinuclear demonstrations.”
Which alternative is more probable?
(1) Linda is a bank teller.
(2) Linda is a bank teller and is active in the feminist movement.
The vast majority—roughly 85 percent—of the people they asked opted for No. 2, even though No. 2 is logically impossible. (If No. 2 is true, so is No. 1.) The human mind is so wedded to stereotypes and so distracted by vivid descriptions that it will seize upon them, even when they defy logic, rather than upon truly relevant facts. Kahneman and Tversky called this logical error the “conjunction fallacy.”
Well said, and I would add that this is exactly the kind of problem that tests use to measure critical thinking skills. Unfortunately, Kahneman mixes bogus problems like the first in with true logic challenges like the second in an effort to show that stereotypes are worthless.