Tuesday, December 2, 2014

Confidence and Memory

In general, we take confidence as a measure of accuracy; the more certain someone is that something is right, the more we trust that person.
It’s no accident that Oprah Winfrey’s latest best seller is called “What I Know For Sure,” rather than “Some Things That Might Be True.”
But as Christopher Chabris and Daniel Simons point out in the Times, when it comes to memory this is not true. Many studies have shown that in some circumstances the more certain people feel about what they remember, the less likely it is to be true. One of the main recommendations psychologists have about police line-ups is that the police must take note of how confident the witness feels at the time of making the identification. Because months later, after the witness has thought it over more and more, the memory of the face in the line-up completely replaces whatever memory there was from the scene of the crime, and many witnesses have claimed complete certainty in court about identifications that were very tentative when they were first made. One thing we know about memory is that it does not get better with time, so this is nonsense. But jurors are much more likely to be persuaded by a witness who claims to be certain than one who admits to uncertainty.

I would extend this to many other areas of life. When scientists leap to bold conclusions from single experiments, I shake my head. When politicians claim to be completely certain that their policies will improve the economy, I shrink back, because I do not think we have the sort of economic knowledge that such certainty would require. (This is why I don't admire Paul Krugman as much as my liberal friends seem to.) As Voltaire said,  “Doubt is not a pleasant condition, but certainty is an absurd one.”


Unknown said...

To be fair, what the authors say is that high confidence in an accurate memory is associated with greater accuracy, and high confidence in a false memory is associated with greater falseness. That is, high confidence in a memory is associated either with a very accurate or a very inaccurate memory. Uncertainty is associated with memories that are somewhat accurate, or somewhat inaccurate.

By this logic, Paul Krugman could either be very right, or very wrong.

Nice illustration: Napoleon was very right about Austerlitz, but very wrong about the 1812 Russian campaign, both occasions whose outcomes were clear and decisive, and in which he displayed great confidence. At the field of Borodino, he showed himself diffident, and Borodino, while a tactical victory for him, was pyrrhic and indecisive. Of course, for Borodino, I'm relying on my memory of a single witness' memory . . .

John said...

Napoleon is one of the cases that worries me, because I am sure that his great self-confidence was part of the secret of his success. Can a person with a realistic attitude ever achieve as much as a madman?

Shadow said...

Eye-witness testimony, forensic "science," fingerprints, and single scientific studies are all under attack. Then there is paid expert testimony, and expert coroner testimony based on photographs of the body, a Michael Baden specialty.

Makes you wonder.