Dumb Blonde Jokes a Self Fulfilling Prophecy

"What do you call a blonde that dyes her hair? -- Artificial intelligence." "How do you make a blonde laugh on Saturday? -- Tell her a joke on Wednesday."

"Dumb blonde" jokes like these may seem like a harmless source of amusement, but German psychologists warn they're a self-fulfilling prophecy for blonde people, even making them perform poorly on tests.

"We found people tended to perform poorly when less was expected of them and that jokes about stupid blondes were therefore self-fulfilling," Jens Förster of Bremen University said.

Förster and his colleagues submitted 80 students -- half of them blonde -- to a test of speed and accuracy. Before sitting the test, half the blonde test group were confronted with negative stereotypes about blondes, including "dumb blonde" jokes. The blondes who were made aware of the stereotypes consistently performed worse than the others in the group, and were unable to answer as many questions in the allotted amount of time.

"No blonde woman believes she is stupid," said Förster. "But after exposure to negative social stereotypes about them, the fair-haired participants performed significantly more slowly in the tests."

The Bremen University team now want to use the study to examine how stereotypes impact academic performance, and work out strategies to fight against the damaging effects of stereotypes like the "dumb blonde."

"Maybe we can develop entirely practical training strategies to help people fight against negative influences," said Förster.