People Lost in the Woods Really Do Walk in Circles

August 31, 2009

The reason why people who are lost often feel like they're walking in circles, according to a recent study, is simple. They probably are walking in circles.

Jan Souman, Marc Ernst, and colleagues from the Max Planck Institute for Biological Cybernetics (Tubingen, Germany) used GPS devices to track volunteers in the Sahara desert and in the Bienwald forest in Germany. Instructed to try to walk in straight lines, the subjects nevertheless tended to follow circular trajectories when they lacked directional clues from the sun, the moon, or other physical features to orient themselves.

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

"The results from these experiments show that even though people may be convinced that they are walking in a straight line, their perception is not always reliable," Ernst added. "Additional, more cognitive, strategies are necessary to really walk in a straight line."

In future studies, Souman and Ernst plan to investigate how people orient themselves when they do have visual clues. The researchers will make use of state-of-the-art Virtual Reality equipment, including a CyberCarpet (an omnidirectional treadmill), to see how people navigate a virtual forest.

Souman, Ernst, Ilja Frissen, and Manish N. Sreenivasa reported their findings in the article "Walking Straight into Circles," which appeared in Current Biology (August 20, 2009).

Source: Max-Planck-Gesellschaft, Aug. 20, 2009.