Audio Transcript:

KATY CLARK: Now some advice for the less athletic among us. If you go for a stroll in the woods and get lost, think twice before you try to find your way out. A new study by scientists in Germany shows that people really do walk in circles when they lose their bearings. The World's Health and Science Editor David Baron explains.

DAVID BARON: Researcher Jan Souman admits most of his work can be rather dry. He's at the Max Planck Institute for Biological Cybernetics in southern Germany. He studies visual perception.

JAN SOUMAN: Normally we do that in like a dark laboratory where we do very boring experiments where people watch dots on a computer screen or something like that.

BARON: But for his latest study he got out of the lab. He and his colleagues recruited volunteers � took them one by one into a large forest and gave this instruction: Head that way � the scientists pointed � and walk for the next four hours.

SOUMAN: They thought they'd been walking pretty straight all the time.

BARON: Souman tracked the volunteers' movements with a GPS. Now those who were hiking on a clear day, those who could navigate by the sun, they stayed on a pretty straight trajectory. But Souman says those hiking on a cloudy day didn't fair so well.

SOUMAN: They all walked in circles.

BARON: And the circles tended to be quite small, perhaps three football field-lengths across.

SOUMAN: I mean one of them at some point realized that he crossed a spot where he'd been before and then he actually noticed like a Coke can lying in the middle forest somewhere and oh hang on, I've seen this Coke can before. So then he was kind of convinced he had been there before.

BARON: Souman conducted a similar experiment in the Sahara desert and got similar results. Those who hiked with the sun as a guide stayed on course. One who hiked at night veered all over the place. Souman says there's a lesson for those who think they can navigate through unfamiliar terrain.

SOUMAN: You can't rely on your senses because your sense often fool you so you really have to be prepared and use all possible tools that you could use to guide your way.

BARON: Like using a distant mountain peak as a guide. Or seeing which side of the trees the moss grows on. Or these days, you could always take out your cell phone and call for help. For The World I'm David Baron.

CLARK: We've posted a Google Earth image on our website that shows those German study subjects walking in circles. Check it out at The World dot org.

KATY CLARK: Now some advice for the less athletic among us. If you go for a stroll in the woods and get lost, think twice before you try to find your way out. A new study by scientists in Germany shows that people really do walk in circles when they lose their bearings. The World's Health and Science Editor David Baron explains.

DAVID BARON: Researcher Jan Souman admits most of his work can be rather dry. He's at the Max Planck Institute for Biological Cybernetics in southern Germany. He studies visual perception.

JAN SOUMAN: Normally we do that in like a dark laboratory where we do very boring experiments where people watch dots on a computer screen or something like that.

BARON: But for his latest study he got out of the lab. He and his colleagues recruited volunteers � took them one by one into a large forest and gave this instruction: Head that way � the scientists pointed � and walk for the next four hours.

SOUMAN: They thought they'd been walking pretty straight all the time.

BARON: Souman tracked the volunteers' movements with a GPS. Now those who were hiking on a clear day, those who could navigate by the sun, they stayed on a pretty straight trajectory. But Souman says those hiking on a cloudy day didn't fair so well.

SOUMAN: They all walked in circles.

BARON: And the circles tended to be quite small, perhaps three football field-lengths across.

SOUMAN: I mean one of them at some point realized that he crossed a spot where he'd been before and then he actually noticed like a Coke can lying in the middle forest somewhere and oh hang on, I've seen this Coke can before. So then he was kind of convinced he had been there before.

BARON: Souman conducted a similar experiment in the Sahara desert and got similar results. Those who hiked with the sun as a guide stayed on course. One who hiked at night veered all over the place. Souman says there's a lesson for those who think they can navigate through unfamiliar terrain.

SOUMAN: You can't rely on your senses because your sense often fool you so you really have to be prepared and use all possible tools that you could use to guide your way.

BARON: Like using a distant mountain peak as a guide. Or seeing which side of the trees the moss grows on. Or these days, you could always take out your cell phone and call for help. For The World I'm David Baron.

CLARK: We've posted a Google Earth image on our website that shows those German study subjects walking in circles. Check it out at The World dot org.