CAMBRIDGE, MASSACHUSETTS—A full bladder can be maddening, especially if you've got to go in the middle of a complex psychological experiment. But that's just what a team of researchers was counting on when it measured the impact of urination urgency on human decision-making. The study hasn't changed the world, but it was one of several honored here last night at Harvard University as part of the 2011 Ig Nobel Awards . The annual honors are meant to make people "laugh and then think," says Marc Abrahams, the Ig Nobel master of ceremonies and editor of the Annals of Improbable Research .
Other winners discovered that yawning among  tortoises , unlike in humans and other social mammals, is not contagious; invented a wasabi-based fire alarm  that can rouse deaf people from sleep; and made (incorrect) predictions that the world would end every few decades for the past century.
The study of urination urgency, which won the medicine Ig Nobel, revealed seeming contradictions about the mind. In the first of two experiments, an Australian and U.S. team revealed that a full bladder affected  short-term memory and attention span  as powerfully as 24 hours of sleep deprivation.
But a second experiment, conducted by a team in the Netherlands, found that for some mental abilities, a full bladder is sometimes a boon . When offered the choice between receiving $16 tomorrow or $30 in 35 days, people tend to grab the smaller reward, even though it makes more sense to delay gratification. But subjects who needed to pee were better able to control that impulse and choose the larger, later reward. That supports the aptly named theory of "inhibition spillover," the idea that inhibiting one impulse helps you control other, unrelated impulses.
On the theme of impulse control, a study of why male Buprestid beetles try to mate with a certain brand of Australian beer bottle netted the Ig Nobel biology prize for Darryl Gwynne and David Rentz, entomologists working for the Commonwealth Scientific and Industrial Research Organisation in Canberra. They found that the color and shape of the bottle was a turn-on for  the beetles  and that the series of bumps along the side of the glass seal the deal. The reason remains a mystery.
Although most of the Ig Nobel prizes go to recently published work, there are exceptions. The beetle study was published in 1983 in the Proceedings of the Royal Entomological Society of London. Since then, Rentz told the audience, "we have been waiting by the phone" for a call from the Ig Nobels.
The ceremony had a somber moment this year as two longtime Ig Nobel participants were memorialized. Mathematician Benoît Mandelbrot, 85 and pioneer of fractal geometry, and Harvard University chemist William Lipscomb, 91 and winner of a real Nobel Prize, both passed away since last year's ceremony. They were frequent participants in the traditional Ig Nobel "Win a Date With a Nobel Laureate" contest. This year, the prize was a date with Lou Ignarro (Nobel Prize for physiology or medicine 1998).