IG NOBLE PRIZES

New Scientist - Tests of whether sodas such as Coke and Pepsi could be used as spermicides were among the many offbeat ideas celebrated at the 2008 Ig Nobel awards. Lap dancers' tips and armadillos' uncanny ability to wreak havoc at archaeological sites were also the subjects of prize-winning studies.

The tongue-in-cheek awards, presented at Harvard University, are organized by the humorous scientific journal, the Annals of Improbable Research, for research achievements "that make people laugh – then think".

Deborah Anderson of Harvard Medical School's birth-control laboratory took her first step towards the Ig Nobel chemistry prize in the 1980s when she asked medical student Sharee Umpierre what type of contraception had been used at the all-girl Catholic boarding school she had attended in Puerto Rico.

"Coca-Cola douches," Umpierre replied. Though that was the first Anderson had heard of the idea, her gynecologist colleague, Joe Hill, remembered a song of the same name by an outrageous 1960s band called The Fugs.

"Coca-Cola douches had become a part of contraceptive folklore during the 1950s and 1960s, when other birth-control methods were hard to come by," Anderson told New Scientist. "It was believed that the carbonic acid in Coke killed sperm, and the method came with its own 'shake and shoot applicator'" – the classic Coke bottle.

To see if Coke really worked, Anderson, Umpierre and Hill mixed four different types of Coke with sperm in test tubes. A minute later, all sperm were dead in the Diet Coke, but 41% were still swimming in the just-introduced New Coke (The New England Journal of Medicine, vol 313, p 1351).

But that's not good enough, Anderson warns. Sperm "can make it into the cervical canal, out of reach of any douching solution, in seconds" – faster than anyone could shake and apply a bottle of Diet Coke.

The three researchers shared the chemistry prize with Chuang-Ye Hong of the Taipei Medical University in Taiwan and his colleagues, whose similar experiment found both Coca-Cola and its arch-rival Pepsi-Cola useless as spermicides (Human Toxicology, vol 6, p 395). Costly cure

Another experiment with huge implications for health policy garnered the Ig Nobel medicine prize for Dan Ariely of Duke University in North Carolina.

While at the Massachusetts Institute of Technology, he gave two groups of volunteers identical placebos masquerading as painkillers, telling one group the pills cost $2.50 each and the other that the pills had been discounted to 10 cents each.

The volunteers didn't pay for the pills, but those who took the "more costly" fake medicine felt less pain from electric shocks than those who took the cheap fakes (Journal of the American Medical Association, vol 299, p 1016). Price affects people's expectations and thus their response to medicine, Ariely says – the more expensive the pill, the more relief they expect.

One Ig Nobel-winning experiment probing human nature has been featured in New Scientist: can women somehow signal when they are at their peak fertility? Most other female mammals do so openly, but men don't consciously recognise any such signal from women.

To investigate, University of New Mexico psychologists Geoffrey Miller, Joshua Tybur and Brent Jordan asked women working as lap dancers to report their nightly tips, and whether they were on hormonal contraceptives or menstruating naturally.

The two groups of women received similar tips when they were in non-fertile parts of their cycle, but when the naturally menstruating women reached their fertile days they earned significantly more (Evolution and Human Behavior, vol 28, p 375).