Intelligence — and the lack of it — was the theme of this year's Ig Nobel prize ceremony, which celebrated its tenth anniversary at Harvard University last week.

Once a year, scientists gather to poke fun at themselves and others, hopefully without hurting too many feelings or careers. This time, ten prizes were awarded to winners from eight countries.

American researchers David Dunning and Justin Kreuger took the psychology prize for their 1999 paper, “Unskilled and unaware of it: how difficulties in recognizing one's own incompetence lead to inflated self-assessments”.

Canadian biologist Richard Wassersug won the biology prize for his study, “On the palatability of some dry-season tadpoles from Costa Rica”. On claiming the award, Wassersug explained that the tadpoles were “neither dry nor seasoned”.

The physics prize went to Andre Geim of the Netherlands and Sir Michael Berry of England for using magnets to levitate both a frog and sumo wrestler. Magnets also featured in the medicine prize, awarded to Willibrord Weijmar Schultz, Pek van Andel and Eduard Mooyaart of the Netherlands for their MRI scans of male and female genitals in the act of coupling.

Inconvenient: Ig Nobel demonstrators remember to wear appropriate safety equipment. Credit: HARVARD

Scottish researchers Jonathan Wyatt, Gordon McNaughton and William Tullet captured the public health prize for their alarming report, “The collapse of toilets in Glasgow”. Wyatt told the audience that the research had been dismissed for years “as a flash in the pan”.

Three genuine Nobel laureates — Charles Clements (peace, 1997), Dudley Herschbach (chemistry, 1986), and Richard Roberts (physiology or medicine, 1993) — participated in the world premiere of The Brain Food Opera .

They took the stage to salute the King and Queen of Swedish Meatballs, asked the audience to stand for a “Moment of Science”, and judged the “Great Intelligence Debate”, in which participants squared off for 30 seconds, talking simultaneously.

The event ended with words of encouragement from master of ceremonies Marc Abrahams, editor of the Annals of Improbable Research: “If you didn't win an Ig Nobel prize tonight, and especially if you did, better luck next year.”