SSS 2009-08-20（在线收听）

Maybe it’s happened to you. You go for a walk in the woods and, after wandering around for a few hours trying to find your way back to the car, you realize that you’ve basically been walking in circles. Well, you’re not alone. Because scientists have found that, in the absence of visible landmarks or cues from the sun, people who are lost can’t walk a straight line.

The “disoriented traveler walking in circles” is faithfully trotted out in many fictional works. So scientists decided to put the tale to the test. They plopped six people into a German forest and told them to try to walk straight. And they monitored their subjects’ progress by GPS.

When the day was cloudy, the wanderers indeed walked in circles, but not by turning consistently in one direction. Instead they veered randomly left and right, repeatedly crossing their own paths. But when the subjects could see the sun, they maintained an almost straight course. And the same was true when volunteers were dropped into the Sahara Desert during the day and at night, results published in the journal Current Biology.

So if you want to walk the straight and narrow, especially after dark, don’t count on your conscience to guide you. Get a compass.