As pioneers in intelligence testing pointed out long ago, this is not necessarily true.

FORBES: Women Surpass Men In IQ, But Are Other Factors More Important?

An associate of mine was contracted to do intelligence testing on a sampling of postal workers.

FORBES: Why Your Postman May Be Smarter Than He Looks

We are all aware that these workers are the butt of endless jokes and real life horror stories, yet intelligence testing found them to be significantly smarter than the public as a whole.

FORBES: Why Your Postman May Be Smarter Than He Looks

The force said it used the combined tactics of high levels of testing, and intelligence-led operations.

BBC: North Wales Police breath tests most drivers in Wales

His testing found that the average intelligence of postal employees is significantly higher than the public at large with some in menial jobs having genius level IQs.

FORBES: Keep Geniuses Out of the Post Office

When U.S. intelligence tracked down Osama bin Laden, it was a function of brilliant, resourceful people asking questions and testing hypotheses using a variety of technologies.

CNN: People and computers need each other