An analysis of the physics that gives a ponytail its shape, a machine that stops people from talking mid-sentence, and a study that shows monkeys recognize each other by buttocks the way humans recognize one another by face are among the winning entries in the 2012 Ig Nobel Prizes. The awards, organized by the Annals of Improbable Research magazine, honor the year’s 10 most unusual — if not downright strange — research findings in the fields of science, medicine and technology. Past winning research projects include a study of belly button lint, a red satin brassiere the morphs into a pair of face masks, and a washing machine for cats and dogs.

A woman who wears her hair in a ponytail while jogging does not move her head from side to side, yet her ponytail whips back and forth like a pendulum. A trio of American and British researchers who studied the physics behind this phenomenon earned themselves the Ig Noble’s 2012 Physics Prize. Their research examines the combination of forces — gravity, elasticity — that explain why human hair contained by an elastic sways even when the human does not.

Another Ig Nobel winner offers a polite way to get someone to stop talking. Instead of telling the person to “shut up,” you can use a machine that plays back the speaker’s voice on a short delay. Inventors Kazutaka Kurihara and Koji Tsukada of Japan found that hearing one’s own words played back will force the speaker into silence. The result of their findings is the SpeechJammer, a machine that can stop a person from speaking mid-sentence without causing any physical harm. The creators say the machine, which won the Acoustics Prize, can be used to prevent two people from talking over one another in debates or to reduce background noise in places like classrooms and trains.

The Ig Nobel Anatomy Prize went to the Netherland’s Frans de Waal and America’s Jennifer Pokorny. Humans can tell a lot from a person’s face: their mood, their approximate age and — almost always — you can determine their gender. Pokorny and de Waal found this is not true for certain species of monkeys, such as chimpanzees, which are more apt to identify the gender of other chimpanzees from seeing their rear ends. In addition to proving that chimps can differentiate between male and female behinds, their study also cast doubt that chimps can do the same from looking at another chimp’s face.

Featured photo credit: klohka/Shutterstock; Secondary photo credit: AJancso/Shutterstock