Spoof Nobel prizes that honour the humour in science were handed out at Harvard University, celebrating the physics of stepping on a banana skin and the neuroscience behind spotting Jesus in toast.
The 24th edition of the annual Ig Nobel Prizes were handed out to winners from across the world by genuine, if baffled, Nobel laureates in Cambridge, Massachusetts on Thursday.
The awards showcase "achievements that first make people laugh, and then make them think," said the organisers. The ceremony at Harvard's Sanders Theatre was attended by hundreds and broadcast live online.
The winners are serious scientists whose work is generally considered only unintentionally funny.
Japanese researchers won the physics prize for measuring the amount of friction between a shoe and a banana skin, and between a banana skin and the floor when a person steps on the discarded fruit peel.
Scientists in China and Canada won a neuroscience prize for trying to understand what happens in the brains of people who see the face of Jesus in a piece of toast.
The authors come from Beijing Jiaotong University's School of Computer and Information Technology, Xidian University, the Institute of Automation Chinese Academy of Sciences in Beijing, and the University of Toronto.
Australia, Britain and the United States shared the psychology prize for collecting evidence that people who habitually stay up late are, on average, more self-admiring, manipulative and psychopathic than early risers.
The public health prize was shared by the Czech Republic, India, Japan and the United States for investigating whether it is mentally hazardous to own a cat.
The Czech Republic also joined Germany and Zambia in winning the biology prize for documenting that when dogs defecate and urinate, they prefer to align their body axis with Earth's north-south geomagnetic field lines.
Italy took the art prize for measuring the relative pain people suffer while looking at an ugly rather than a pretty painting.
The Italian government's National Institute of Statistics walked away with the economics prize for increasing the official size of its national economy by including revenue from prostitution, illegal drug sales, smuggling, and other unlawful financial transactions between willing participants, organisers said. India and the United States shared the medicine prize for treating "uncontrollable" nosebleeds with strips of cured pork.
Germany and Norway won the Arctic science award for testing how reindeer react to seeing humans who are disguised as polar bears.