BOSTON (AP) — Driving while desperately needing to urinate isn’t a crime, but maybe it should be.

Peter Snyder and his colleagues found that having a bladder at its bursting point reduced attention span and the ability to make decisions to the same degree expected with low levels of alcohol intoxication or 24 hours of sleep deprivation. The research earned them the 2011 Ig Nobel prize for medicine.

“When people reach a point when they are in so much pain they just can’t stand it anymore, it was like being drunk,” said Snyder, a professor of neurology at Brown University in Providence, R.I.

“The ability to hold information was really impaired,” he said.

This year’s winners of the dubious distinction handed out at Harvard University for head-scratching scientific discoveries included a team of Japanese scientists who invented a fire alarm that smells like wasabi; a European mayor who solved his city’s parking problems with a piece of heavy military equipment; a Norwegian researcher who explored the science behind sighing; and the numerous people throughout history whose mathematical calculations to predict the end of the world have fallen flat.

The 21st annual awards sponsored by the Annals of Improbable Research were handed out by real Nobel laureates and featured the usual doses of silliness, including a mini-opera about the chemistry in a coffee shop and the ritual launching of paper airplanes.

The point of Snyder’s work was to determine the effects of pain on decision-making. Working with full bladders is a “low cost, low risk” way of causing pain that can be resolved easily, simply by going to the bathroom.

The research, done with scientists at Australian universities, was also fun. The group even crowned an unofficial withholding champion — the person who could go the longest before his bladder exploded. Australian researcher David Darby held out for three hours.

Vilnius, Lithuania Mayor Arturas Zuokas won the Ig Nobel peace prize for his heavy-handed way of dealing with parking scofflaws. He crushed their cars with a military armored personnel carrier.

“I just decided that it was time to teach bullies who had no respect for the rights of others a lesson that left an impression,” he said in an email.

In a video posted on YouTube, Zuokas crushes a Mercedes-Benz blocking not just a bicycle lane, but also a pedestrian crossing, in Vilnius’ picturesque Old Town.

Zuokas was coy when asked whether the car-crushing was a stunt — the well-dressed owner did not appear to be too angry — but said the plan appears to have worked. The city has returned to what the mayor calls “more standard and boring” means of controlling parking scofflaws: issuing tickets and towing vehicles.

But he warns he has the tank on standby.

The chemistry prize went to Japanese researchers who invented a fire alarm that emits the pungent odor of wasabi, the sinus-clearing green paste served with sushi.

“Wasabi odor is useful as a fire alarm to deaf people who failed to wake up with a conventional mode such as sound, vibration or flashing light,” said Makoto Imai, professor of psychiatry at Shiga University of Medical Science.

The key is allyl isothiocyanate, the compound in wasabi that gives out its distinctive smell and can be detected even during sleep.

The team settled on wasabi after trying about 100 odors, including rotten eggs.

Karl Teigen’s research, which won him the psychology prize, perhaps best embodies the spirit of the Ig Nobels. His study on why people sigh has no practical applications as far as he can determine. He and his students decided to study sighing simply because they found no one else had.

“People think that others’ sighs chiefly express sadness and sorrow, but that their own sighs are more often due to resignation and giving up,” said Teigen, a psychology professor at the University of Oslo in Norway. “We studied the giving up aspect experimentally by giving people puzzles that looked simple, but they could not solve. And they sighed. We think they sighed because they had to give up a hypothesis, an idea, a hope, or an attempt — and perhaps be ready for a new one.”