What do ousted Wall Street chiefs Stan O'Neal and Chuck Prince have in common? Put aside the obvious. What we want to talk about today is that both men are married to blonde women. (That's Stan's wife Nancy on the left.) And that may have dumbed them down, at least if you believe the researchers mentioned in a story in the Times of London earlier this week.

[The blonde condition after the jump.]

Researchers discovered that male mental performance drops when they are in the presence of blonde women. Even a photograph of a blonde seems to reduce male scores on general knowledge tests.

The Université Paris X Nanterre scientists who undertook the study do not believe that blondes contaminate others with their stupidity. Indeed, there is scant evidence beyond the "dumb blonde" stereotype that blondes are actually less intelligent than other groups. (Although they do suffer disproportionately from learning disabilities.)

So how do blondes make men dumb? The simplest answer would seem to be that men are distracted by lighter hair, perhaps because they are frequently regarded as highly attractive. Surprisingly, however, the French scientists reject this hypothesis. Instead, they say that men begin to imitate a stereotype of the dumb blonde.

“This proves that people confronted with stereotypes generally behave in line with them,” Thierry Meyer, joint author of the study published in the Journal of Experimental Psychology, says. “In this case blondes have the potential to make people act in a dumber way, because they mimic the unconscious stereotype of the dumb blonde.”

We're not sure we buy this theory, which seems a bit convoluted and politically convenient. The idea that people's behavior is heavily influenced by questionable stereotypes is highly fashionable, for obvious reasons. We live in an age of world-improvers and this finding lends itself to social engineering. If it's just a culturally determined stereotype effect, perhaps it can be ameliorated by better education and less public emphasis on the stereotype.

That's far less awkward than a finding that would imply that men are hopelessly distracted by blondes, which might imply that workplace discrimination against them was rational, at least in cognitively demanding fields. Don't get us wrong. It's not exactly fashionable to worry about anti-blonde discrimination. But many people worry that once we open the door to this way of thinking, all sorts of other types of discrimination might be justified according to the same logic. And we can't have that.

(By the way, does anyone know how the stereotype of the dumb blonde got going? It seems to be of recent vintage. But we find that most stereotypes at least convey some advantage, especially when information about a particular individual is costly to obtain. Non-performing stereotypes don't become widespread, and many die off when better information becomes available. What was the advantage of considering blondes dumb?)

In any case, if the study is correct that viewing pictures of blondes makes men dumber we can only imagine what actually marrying one would do. Did Chuck and Stan lose control of their banks because of the cognitive disadvantage of being married to Peggy and Nancy? Should we start shorting companies led by men surrounded with blondes? What other CEOs are married to blondes?

As is usually the case, Goldman seems to have avoided this hazard. Lloyd Blankfein's wife Laura is decidedly dark maned.

You silly boys: blondes make men act dumb [The Times]