Rats smarter than Yale undergrads

From Everybody’s An Expert by Louis Menand. The article is a book review of Philip Tetlock's Expert Political Judgment: How Good Is It? How Can We Know? The basic point of the book and the article is that experts and pundits are no better than a well informed public in terms of forecasting outcomes of different real-world scenarios. A couple of snippets.

Tetlock also found that specialists are not significantly more reliable than non-specialists in guessing what is going to happen in the region they study. Knowing a little might make someone a more reliable forecaster, but Tetlock found that knowing a lot can actually make a person less reliable. “We reach the point of diminishing marginal predictive returns for knowledge disconcertingly quickly,” he reports. “In this age of academic hyperspecialization, there is no reason for supposing that contributors to top journals—distinguished political scientists, area study specialists, economists, and so on—are any better than journalists or attentive readers of the New York Times in ‘reading’ emerging situations.” And the more famous the forecaster the more overblown the forecasts. “Experts in demand,” Tetlock says, “were more overconfident than their colleagues who eked out existences far from the limelight.”

[snip]

The experts’ trouble in Tetlock’s study is exactly the trouble that all human beings have: we fall in love with our hunches, and we really, really hate to be wrong. Tetlock describes an experiment that he witnessed thirty years ago in a Yale classroom. A rat was put in a T-shaped maze. Food was placed in either the right or the left transept of the T in a random sequence such that, over the long run, the food was on the left sixty per cent of the time and on the right forty per cent. Neither the students nor (needless to say) the rat was told these frequencies. The students were asked to predict on which side of the T the food would appear each time. The rat eventually figured out that the food was on the left side more often than the right, and it therefore nearly always went to the left, scoring roughly sixty per cent—D, but a passing grade. The students looked for patterns of left-right placement, and ended up scoring only fifty-two per cent, an F. The rat, having no reputation to begin with, was not embarrassed about being wrong two out of every five tries. But Yale students, who do have reputations, searched for a hidden order in the sequence. They couldn’t deal with forty-per-cent error, so they ended up with almost fifty-per-cent error.

[snip]

Tetlock’s experts were also no different from the rest of us when it came to learning from their mistakes. Most people tend to dismiss new information that doesn’t fit with what they already believe. Tetlock found that his experts used a double standard: they were much tougher in assessing the validity of information that undercut their theory than they were in crediting information that supported it. The same deficiency leads liberals to read only The Nation and conservatives to read only National Review. We are not natural falsificationists: we would rather find more reasons for believing what we already believe than look for reasons that we might be wrong. In the terms of Karl Popper’s famous example, to verify our intuition that all swans are white we look for lots more white swans, when what we should really be looking for is one black swan.

Also, people tend to see the future as indeterminate and the past as inevitable. If you look backward, the dots that lead up to Hitler or the fall of the Soviet Union or the attacks on September 11th all connect. If you look forward, it’s just a random scatter of dots, many potential chains of causation leading to many possible outcomes. We have no idea today how tomorrow’s invasion of a foreign land is going to go; after the invasion, we can actually persuade ourselves that we knew all along. The result seems inevitable, and therefore predictable. Tetlock found that, consistent with this asymmetry, experts routinely misremembered the degree of probability they had assigned to an event after it came to pass. They claimed to have predicted what happened with a higher degree of certainty than, according to the record, they really did. When this was pointed out to them, by Tetlock’s researchers, they sometimes became defensive.