GERMAN RESEARCHERS have discovered a scientific basis for one of the hoariest of horror film cliches.
It’s a familiar scene. A group of teenagers get lost and wander aimlessly through the forest until, just before the knife-wielding maniac appears, one teenager asks: “Haven’t we been this way before?”
Now researchers at Germany’s prestigious Max Planck Institute for Biological Cybernetics have discovered that, when they lack clear landmarks, humans do indeed walk in circles.
The German team examined the paths taken by volunteers wearing GPS tracking devices in a dense forest near the French border and in the Sahara desert.
On days with clear conditions, volunteers kept a straight path – though they often veered from straight ahead – while in cloudy conditions, they began wandering in circles without realising.
The researchers then sent the volunteers out again, this time blindfolded. With no visual clues whatsoever, the volunteers walked in circles often of surprisingly small diameters of 20m (66ft) and less.
“Perception is not always reliable,” wrote Marc Ernst, one of the study’s authors. “People need to use reliable cues for walking direction in their environment, for example a tower or mountain in the distance or the position of the sun.”
They suggest the reason for walking in circles is that without visual cues, the brain has to fall back on other, less-developed senses – the inner-ear and interplay between muscles and bones – to give it a sense of where the body is going.
Their study, published in the journal Current Biology, was sparked by a question posed in the German popular science programme Kopfball(Head Ball).
The programme tried to test the old assumption that walking in circles was a result of physical differences in the length of a person’s legs.
But after correcting differences in leg length with shoe insoles, researchers found no basis for this assumption.
“Walking in circles isn’t caused by differences in leg length or strength, but more likely the result of increasing uncertainty about where straight ahead is,” said Jan Souman, the study’s second author.
The next scientific challenge: why do women being chased in horror films always sprain their ankle?