If you've ever been lost and got the feeling you were just retracing your steps, chances are you're right.
According to a new study, humans really do walk in circles when they're set loose in the wilderness -- at least on cloudy days. Worse, we don't even believe we're doing it when we're shown proof.
A group of scientists at the Max Planck Institute for Biological Cybernetics in Tubingen, Germany, decided to test the long anecdotal warning that hikers could circle their tracks without a map. So the researchers outfitted nine people with a Global Positioning System tracking device, and dropped them off either in a flat forest in Germany or the Sahara desert in southern Tunisia and told them simply to walk for several hours in a straight line in one direction.
Two people walking in the desert during daylight veered from their course, but didn't walk in circles. A third person walking in the desert, this time at night, walked in a straight line until the moon went behind some clouds.
"Once the moon disappeared behind the clouds, all of a sudden he turned 90 degrees, and turned 90 degrees again," said Jan Souman, the lead author of the study published today in the journal Current Biology. "In a desert you really can walk in a straight line, if you have the sun to guide you."
Souman and his colleagues decided to include the second forest experiment to see how well people could keep a straight course when they were forced to maneuver around objects. Not surprisingly, people in the forest fared even worse and again, cloud coverage made a difference.
The four volunteers who walked on a cloudy day in the forest repeatedly went in circles, sometimes every 10 minutes.
"They didn't really believe when we showed them afterwards," said Souman. "I think that's certainly a point to take away, people may feel very confident about the direction where they're going but it's not certain."
Tod Schimelpfenig, the curriculum director for the Wilderness Medicine Institute of the National Outdoor Leadership School (NOLS), said he was glad to see some science behind what he and many of his fellow wilderness experts see often in search and rescue missions.
"I think we've always thought it was a tendency we all have," said Schimelpfenig, who works in search and rescue in Wyoming and is also a former NOLS instructor.
"If there's terrain, then it gets complicated -- then people get funneled by the terrain," said Schimelpfenig. "If you were in the middle of a big flat, featureless place, that's when we tend to see this."
Souman said his study was the first to test the tendency to walk in circles outdoors; however other researchers have found people tend to walk in circles if they're blindfolded.
"If you look at the shapes of the trajectories outside, the circles had a diameter of about 200 to 300 meters," Souman said. "Blindfolded the circles were 15 to 60 meters in diameter. Those circles could be really, really small."
But Souman's work is intended to do more than make us feel inept as a species. Researchers have long been arguing over why we turn in circles, and Souman said the new study may rule out one of some of the leading hypothesis.
For example, since the people in the experiment tended to turn at random in any direction, Souman says it counters the theory that we walk in circles without visual cues because we have one leg that is stronger or longer than the other.