Friday, December 5, 2008


Yesterday morning we visited the "Mystery Spot " which is located near Santa Cruz,California. It was opened in 1939. It is a place about 150 feet in diameter where the laws of physics and gravity do not apply .The guide provides a number of demonstrations in support of these claims. Tall redwood trees pole-vault to the sky and there is a nip in the air. Guides take groups of twelve persons and introduce us to the mystery.
Phenomena demonstrated by the tour guides (and by visitors using levels) include two people standing on opposite sides of a level surface who appear to change height as they switch positions. A ball appears to roll up a plank.Water droped from a bottle moves up--not down!.
At the site, an old shed which was on level when originally erected appears to have lost part of its foundation and is slanted and oddly angled. Tourists flock to the Mystery Spot to enjoy the "puzzling variations in gravity, perspective, height and more," leaving baffled and perplexed by the apparent exceptions to the laws of physics and gravity
The Mystery Spot is a gravity hill type of visual illusion . The phenomena that visitors to the attraction may experience result from the effects of forced perspective , optical adaptation and certain visual illusions in combination with the steep gradient of the site. That is, the tilted environment inside the Mystery Spot causes misperceptions in the height and orientation of objects. For example, visitors misperceive the height of individuals because they use the tilted background as their guide. Also, the tilt distorts the horizontal and as such, balls appear to be rolling up a plank when it is of course rolling with gravity.
As visitors travel through the site, they try to habituate to the tilted environment. The effects of this adaptation are then exploited, especially within closed structures, so that visitors may feel as though gravity does not operate as it should in the Mystery Spot. Also, visitors may feel light-headed or dizzy due to the attempt of the brain trying to adapt to the visual tilt. Additional claims of mystery are the growth patterns of trees and their branches within the Mystery Spot, the lack of animals such as dogs, rodents or even birds inside the compound and the distortion of magnetically calibrated measurement devices such as compasses.
The official website speculates that extraterrestrials buried unearthly metals or a spacecraft beneath the Spot, or that carbon dioxide seeps out of the earth.
Several similar illusions can be found elsewhere, including the identically named Mystery Spot in Michigan,in Beuna Park California, Gold Hill, Oregon,Ligonier in Pennsylvania and Spook Hill in Florida and other sites around the world. One hilly vista of the city of Jerusalem offers a similar effect, with cars there appearing to roll uphill without power.
For years, UCSC Psychology Professor Bruce Bridgeman has taken college students to the Mystery Spot, a popular local tourist attraction, to demonstrate how the human brain works.
Mystery Spot managers welcomed his research on the attraction, said Bruce Bridgeman, below.
But for Bridgeman, the site is a powerful--and entertaining--way to demonstrate the influence of the visual context on perception. "It shows that you can teach serious science in unexpected places," said Bridgeman, who has published a scholarly article that explains the perceptual effects at work at the Mystery Spot. Mystery Spot visitors will recognize the scene of Bridgeman's research: In a cabin on a steep hillside, an 8 kilogram weight hangs on a chain from the ceiling. Although the weight hangs vertically, the tilt of the cabin makes the weight appear to be suspended at an angle. Visitors find that pushing the weight one way is perceived as much more difficult than pushing it the other way. Rather than a magical defiance of gravity, the explanation lies in the "mismatch" between expectations and the actual weight: Expectations based on visual information override the proprioceptive experience of moving the weight. Far from spoiling the fun, Bridgeman said understanding the phenomenon adds to the enjoyment of a visit to the Mystery Spot. "To me, it's much more fun to have something that's real than not," said Bridgeman. "The real fun is that you can learn about how your mind works in an interesting setting."
In his study, seven subjects pushed the pendulum away from vertical in both directions and were asked to judge the required effort on a one-to-10 scale, with one described as "effortless" and 10 "immovable." All participants experienced the "effort illusion": perceived effort in pushing toward visual vertical was significantly greater than perceived effort in pushing away from visual vertical.
"The tilt of the cabin makes it appear that the pendulum is suspended in an impossible position," said Bridgeman. "It is as though some additional force holds the weight in this unstable position. That's why the visual illusion is so compelling, and why the expected force applied is so dramatically different from the actual force needed to move the weight." Pushing the weight toward what appears to be vertical will always require more force than expected, and pushing it away will always require less.
"The visual context strongly influences what you perceive, and you can't escape it, even if you know better," said Bridgeman. "Expectations and assumptions are as important to perceived weight as the actual effort required to move objects."
"We think of our perceptions as being pretty much accurate, but they seldom are," said Bridgeman, noting that people are notoriously inaccurate when they attempt to estimate things like distance and the slope of a hill, too. "The philosophy of the brain is not to be totally accurate but to reduce the chance of error. Perception in the service of action is error reduction."
Of interest to lovers of Comics is that Dennis the Menace visited the Mystery Spot and has his own unique delightful experience.
Several similar illusions can be found elsewhere, including the identically named Mystery Spot in Michigan,in Beuna Park ,California, in Gold Hill, Oregon,in Ligonier in Pennsylvania and Spook Hill in Florida .

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