- News Home
17 April 2014 12:48 pm ,
Vol. 344 ,
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
- About Us
Don't Fear the Edge
24 November 2009 (All day)
Some advice for those scared of heights: stand closer to the edge. A new study reveals that downhill slopes appear less steep the closer you get to the drop-off.
Psychologist Frank Durgin and his colleague Zhi Li first made the observation while walking around their campus at Swarthmore College in Pennsylvania. "There's a creek that has very high banks that go down very steeply on both sides," says Durgin, who studies how humans perceive visual information in natural environments. "So we went out to one of these paths along the top of one of these banks and just tried to see what happens [as we moved away]." The duo found that the banks appeared steeper as they retreated from the edge.
Durgin and Li took their puzzling observation back to the lab. They asked dozens of students to estimate the angle of a slope as they stood at various distances from a piece of inclined plywood. The students lifted up a smaller plywood board, hooked to a fishing line, to reflect what they thought the angle of the slope was. Then, in a virtual environment, the volunteers guessed the angle of a slope as they stood on top of what looked like a 14.5-meter-tall hill that plunged into a large lake. In both cases, as participants inched closer to the drop-off, they more accurately reported the slopes as less steep--ultimately by about 8 degrees, the team reported last month in the Journal of Vision.
Please download the latest version of the free Flash plug-in.
Durgin chalks the effect up to how we move our eyes and head. A geometric model he created shows that as we approach hills our head and gaze tilt downward, making the slope seem shallower than our initial gazes suggested.
The results are surprising, says Bruce Bridgeman, a psychologist at the University of California, Santa Cruz, because they contradict the "danger hypothesis." To keep us safe, he explains, one would expect our eyes to exaggerate the danger of a steep slope the closer we got to it. "It's actually the other way around."