Ich kenne zwar einige Blondinen, von denen jede einen Großteil der männlichen Bevölkerung locker in den Sack steckt, aber vielleicht muss ich meine grundsätzliche Ansicht über Blondinen und ihre Umwelt-Interaktion überdenken...

Verständlich ausgedrückt liest sich das ungefähr so:

Blondes make men dumb
Not only does men’s intelligence drop when blonde women are around, but so too does women’s intelligence. Surrounded by blondes, men and women alike think they are in the company of dummies, and they relax their own thinking to match this.
The researchers set out to see how stereotypes affect the way we think. In this experiment, they showed volunteers photos of strangers, then asked them questions from a Trivial Pursuit game.
When most of the photos were of blonde women, the volunteers did not do very well. When the photos showed dark-haired women (and men), they scored better. Further analysis convinced the team that, rather than simply being distracted by the blonde locks, those who performed poorly had been unconsciously driven by social stereotypes to think blonde.
The researchers say it’s a variation of common behaviour. If we sit near someone who fiddles with a pen, we tend to fiddle with a pen, too. Also, if we think we are surrounded by the not-so-intelligent …
“We do not pretend that blondes are dumb or dumber than other women,” says the lead author, Clementine Bry. “There are absolutely no scientific studies to support this stereotype. Stereotypes are cultural beliefs about social groups, they are not truthful pictures of who people are. The reasons why such a stereotype emerged are unknown and were not the point of interest of our work.” The important lesson from this study, for students at least, is not to sit next to a blonde female in the exam room.(Blonde like me: When self-construals moderate stereotype priming effects on intellectual performance. J Exp Soc Psychol. 2007 doi:10.1016/j.jesp.2007.06.05).
Quelle

Das Abstract dazu - also die wissenschaftliche Variante - findet man hier