Smart People and Dumb Answers

I considered writing about David Brooks latest NYT column, but I thought the following subject might be a useful prelude: smart people can be really dumb. This is true even when the stakes are purely intellectual. Daniel Kahneman got a Nobel Prize for studying this stuff. The fundamental conclusion is that we love to make mental shortcuts, and that often gets us in trouble. A frequently cited example goes like this:

Here’s a simple arithmetic question: A bat and ball cost a dollar and ten cents. The bat costs a dollar more than the ball. How much does the ball cost?

Of course this really is a simple arithmetic problem, or perhaps algebra problem, but lots of people get it wrong. If you weren't a bit suspicious to start, even you, my cunning readers, might have felt the wrong answer jump into your head for a second or so. From Jonah Lehrer's New Yorker Article:

The vast majority of people respond quickly and confidently, insisting the ball costs ten cents. This answer is both obvious and wrong. (The correct answer is five cents for the ball and a dollar and five cents for the bat.)

The oddity is that most would not have made the error if the question had said instead that the bat cost, say 70 cents more than the ball. They thought they saw a shortcut and took it. That sort of short cut is in our nature - thinking is expensive, math is hard, and most of us avoid it when we think we can get away with it.

A surprising follow up - smart people, or at any rate those with higher IQs - are even bigger suckers for this sort of thing than their more humbly endowed fellows.

And here’s the upsetting punch line: intelligence seems to make things worse. The scientists gave the students four measures of “cognitive sophistication.” As they report in the paper, all four of the measures showed positive correlations, “indicating that more cognitively sophisticated participants showed larger bias blind spots.” This trend held for many of the specific biases, indicating that smarter people (at least as measured by S.A.T. scores) and those more likely to engage in deliberation were slightly more vulnerable to common mental mistakes. Education also isn’t a savior; as Kahneman and Shane Frederick first noted many years ago, more than fifty per cent of students at Harvard, Princeton, and M.I.T. gave the incorrect answer to the bat-and-ball question.

My theory, not evidently the author's, is that smart people know more shortcuts, and hence are more likely to think they know one that works.


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