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Aug 20, 2009 01:50 PM | 11
Yes, people really do walk in circles—but only when stripped of important visual clues, such as the sun or moon, according to a paper published online today in Current Biology.
To test the common wisdom, Jan Souman, a research scientist at the Max Planck Institute for Biological Cybernetics, and his team sent test subjects out into a German forest and the Sahara Desert to see if they could follow directions to walk in a straight line—some on sunny days others on cloudy days or at night. Subjects were monitored via GPS over the course of hours (and followed by an experimenter for safety).
Those traipsing about in the sun seemed to have little trouble keeping a relatively straight course. But once the sun (or night moon) disappeared, volunteers seemed to get hopelessly lost and meandered about aimlessly—even though they believed themselves to be keeping a steady bearing. Those in the forest turned several circles, often recrossing their own path unknowingly.
"Even though walking in a straight line seems like a very simple thing to do, it's actually very complicated," Souman says. "It's not a very natural thing to do." And because researchers can't very well give verbal instructions to lab rats or birds, it's hard to know whether animals would perform any better than humans at this exercise.
The sun, it seemed was a "really important cue for direction," says Souman, who suggests people used shadows to maintain their orientation. But even that didn't present a clear-cut explanation. In the experiments, subjects were walking for a few hours at a time, during which the sun would move about 50-60 degrees, he explains. A strict adherence to the sun's location would have meant a similarly bent course, but subjects somehow did seem to correct for the movement.
To see what would happen when people were totally without visual clues, the researchers blindfolded people and turned them lose in a large field. When told to walk in a straight line, volunteers ended up heading in directions that the paper describes as "highly random" and really turning in circles—some smaller than 20 meters in diameter. The results suggest that without visual or auditory clues, people would only end up traveling a total of 100 meters from their starting point regardless of the time they are given to wander.
So why all of this walking in circles? The study was too small to make any age, gender or other demographic correlation. The randomness of the patterns—along with strength tests—ruled out the theory that people tend to favor one side or leg over the other.
Souman thinks the behavior may be a function of sensory noise—all of the information that the brain receives related to getting around, from visual, to auditory, to muscular to possibly even the feel of airflow over the skin. "There's loads of different information sources that the brain can use to determine what direction you're walking in," he explains. "They're not 100 percent accurate…and if you limit input, those small errors in signals [could] build up over time," leading people to walk in all sorts of nonsensical ways.
Souman is now trying the experiments back in the lab, where they have an omnidirectional treadmill and virtual reality goggles. His hope is so recreate some of the same navigation challenges, such as the forest, in a more controlled setting. "It's really cool to do field experiments," says Souman, whose Sahara trip was made possible by Kopfball, a television show from the West German Broadcasting Company. "But it makes it really hard to study exactly what the factors are that contribute to these behaviors."
Other researchers have demonstrated humans' impressive inability—compared with animals as humble as hamsters—to navigate without landmarks. Testing people in a virtual reality maze, for example, Brown University professor William Warren found that people wandered through "womholes" in the mazes that took them to other locations near a recognizable target, but, he told New Scientist, "people didn't even notice anything amiss."
The take-away lesson is that even those who think they have a good sense of direction shouldn't count on it—especially in the wilderness. "They shouldn't necessarily rely on their subjective senses as to whether they're walking in a straight line," says Souman. "If you're just relying on your senses, you might be fooled."
Image courtesy of Ashley Pollak via Flickr
Watch an omnidirectional treadmill experiment
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11 Comments
Add CommentIt's not apparent how the CyberWalk video relates to this article.
Reply | Report Abuse | Link to thisIt's apparent enough. Since she wasn't always facing in the same direction her direction of walking was changing.
Reply | Report Abuse | Link to thisAs per the clip of the VR she was watching, she was not supposed to be walking in a straight line. She was exploring the VR environment. No?
Reply | Report Abuse | Link to thisExactly.
Reply | Report Abuse | Link to thisIt seems to fit with the article until you actually explore what the experiment is about. She was not intending to walk in a straight line, from my understanding she was simply exploring a virtual environment.
Here's where I'd disagree, though. The virtual environment seemed to be more or less a straight corridor with a few openings you could *look* into, but not stray as far off course as she did, which makes her complete (albeit gradual) 360 turns applicable to the article.
Reply | Report Abuse | Link to thisThe video illustrates the mention of an omnidirectional treadmill. In the experiments on whether people walk in circles, we use the same treadmill, but with a different virtual environment (a forest), where people have to walk in as straight a line as possible. In that case, that's also the only thing they can see (so they cannot see the room they're in).
Reply | Report Abuse | Link to thisThe omnidirectional treadmill video just serves as an illustration of what such a treadmill looks like. As mentioned by someone else, this person was just walking through a city-like environment. In the VR experiments on walking in circles, we now have participants walk on this treadmill, but what they see is a virtual forest and they have to try to walk in a straight line through it.
Reply | Report Abuse | Link to thisPerhaps it would have been more convincing if she could wonder freely rather than having doors and paths to head her in a specific direction. Therefore it even suggests that these paths led her in circular motions rather than all the environmental factors and physical characteristics of humans.
Reply | Report Abuse | Link to thisHowever, are there any great uses in knowing the fact people walk in circles? Perhaps walking in circles serves as a better method in staying in close proximity if you ever "get lost in a forest" (rather than wondering into thicker bush)
I understood that it could have just been an example of the type of equipment it takes to do an experiment of the sort.
Reply | Report Abuse | Link to thisI didn't understand why Katherine Harmon didn't illustrate that in her description of why the video is relevant. I'm not sure about you Jan, but I've come to expect more from the writers of Scientific American then lazily scribbling out "
Watch an omnidirectional treadmill experiment" for what is otherwise a mostly irrelevant video.
Correct, it doesn't really matter that much. I was just under the impression that comments where implemented with one of the goals of readers expressing their views on articles to improve the quality of future SciAm articles.
Of course I could still be wrong about the nature of the video...
I just wonder whether different people would walk into different direction, clockwise or counter-clockwise.
Reply | Report Abuse | Link to thisCan someone please explain the practical purpose of these experiments?
Reply | Report Abuse | Link to thisPeople walk in circles only without visual clues (such as blindfolding), SO WHAT?