There was no Viagra in 1918, but there were plenty of goats.
At the time, the alleged sexual prowess of goats enjoyed legendary status. So it was that Kansas physician John R. Brinkley made a small fortune surgically implanting goat testicles in men seeking to enhance or restore their own virility.
Never mind that the procedure failed to deliver the promised benefit; that Brinkley was a medical school dropout who bought a diploma for $100; or that most of his patients died during or shortly after surgery. A steady supply of men handed over their cash to Brinkley's scruples, and their privates to his scalpel.
I hope you agree with me that the decision to undergo Brinkley's procedure was irrational. The risks of infection, mutilation, sterility, and death were clear... yet otherwise presumably intelligent men convinced themselves to go ahead with implantation anyway.
Of course, you already know the answer. People who really, really want to believe, will believe—regardless of where the evidence points. Brinkley's patients really, really wanted the promised benefit, so they embraced his trumped-up "success stories," and disqualified the negative outcomes.
We haven't changed much in 90 years. Consider the people you know who set aside evidence and common sense in favor of staying in bad relationships, racking up charges on psychic hotlines, lending money to losers, or wearing magnets to ward off arthritis—all motivated by an acute desire to believe.
Or, consider marketers who believe that their programs are working, even when the evidence says otherwise or, more often, when there is no evidence at all.
Steve Cuno is chairman and founder of RESPONSE Agency (www.ResponseAgency.com), a direct-response marketing firm in the Salt Lake City area. He is author of Prove It Before You Promote It: How to Take the Guesswork Out of Marketing, due in bookstores December 2008 (John Wiley & Sons). Contact him via Steve@ResponseAgency.com.