Lost People Naturally Hike in Circles (article)

[blueskies]

SYDNEY (Reuters Life!) - Ever got lost and felt you were going round in circles? You probably were, with a German study finding people do cover the same ground over and over when they don't have reliable direction cues.

Scientists from the Max Planck Institute for Biological Cybernetics in Tubingen, Germany, have presented the first empirical evidence that people do end up walking in circles if lost in unfamiliar terrain.

The study, published in the journal Current Biology, examined the trajectories of people who walked for several hours in the Sahara desert in Tunisia and in the Bienwald forest in Germany.

Researchers Jan Souman and Marc Ernst said the scientists used the global positioning system (GPS) to record these paths.

The results showed that the walkers were only able to keep a straight line when the sun or moon was visible.

As soon as the sun disappeared behind some clouds, people started to walk in circles without even noticing it.

Souman said one explanation offered in the past for people walking in circles was that most people have one leg longer or stronger than the other, which would produce a systematic bias in one direction.

To test this, the researchers asked people to walk straight while blindfolded which removed the effects of vision.

"Most of the participants in the study walked in circles, sometimes in extremely small ones," Souman said in a statement.

They found that these circles were rarely in a systematic direction, with the same person sometimes veering to the left and sometimes to the right.

"Walking in circles is therefore not caused by differences in leg length or strength, but more likely the result of increasing uncertainty about where straight ahead is," said Souman.

"Small random errors in the various sensory signals that provide information about walking direction add up over time, making what a person perceives to be straight ahead drift away from the true straight ahead direction."