A mystery no longer?

Posted on Tue, Jan. 03, 2006

http://www.mercurynews.com/mld/mercurynews/news/local/13538046.htm?template=contentModules/printstory.jsp


A mystery no longer?

By Ken McLaughlin
Mercury News

The Mystery Spot, for decades one of Santa Cruz's most alluring tourist sites, bills itself as a place where the laws of physics and gravity cease to exist.

At least one scientist has attributed the weird goings-on at the site to carbon dioxide seeping up through fissures caused by a landslide or earthquake. Flying saucer aficionados postulate that aliens once left strange metal cones deep below the earth. Others theorize that the bizarre phenomena are caused by a magnetic field, a hole in the ozone layer or an ancient meteorite.

But Bruce Bridgeman, a professor of psychology and psychobiology at the University of California-Santa Cruz, says the Mystery Spot isn't a mystery.

``Scientific psychology,'' he says, can explain all the illusions that visitors encounter there.

That's why Bridgeman uses the Mystery Spot to teach his students how the human brain works -- and deceives.

``The Mystery Spot is all about the power of perception,'' Bridgeman said as he recently joined three students on their first tour of the place.

The spot has been drawing tourists from around the world since 1940, a year after George Prather bought the property, located on a gradually steepening hillside about three miles northeast of downtown Santa Cruz. Tour guides tell this tale:

Prather wanted to build a cabin but became concerned when a surveyor's compass began going haywire. He built the cabin anyway, only to see it slide down the hill into a stand of redwoods -- where it sits today.

The cabin -- said to be at the center of a circular, 150-foot-diameter ``spot'' -- is the main attraction at the site. It is where, as tour guides put it, ``the force'' takes over. Balls appear to roll uphill, people's heights seem to magically change and kids literally climb the walls.

It is also the perfect place for Bridgeman to hold class.

``It would be too expensive to build a whole cabin, so it's cheaper to come down here and use this,'' he said with a dry chuckle. ``It's better than seeing something on a piece of paper or computer screen. The experience completely surrounds you.''

Bridgeman, 61, has been coming to the Mystery Spot since his two adult daughters were Girl Scouts.

Two decades ago, he started bringing his graduate and undergraduate psychology students, with the blessings of Mystery Spot owners.

Seven of Bridgeman's students took part in a formal experiment, the results of which he recently published in the Psychonomic Bulletin and Review. The title of his scholarly paper: ``Influence of Visually Induced Expectation on Perceived Motor Effort: A Visual-Proprioceptive Interaction at the Santa Cruz Mystery Spot.''

In simple terms, it's called the ``size-weight illusion.''

The professor first became intrigued with the concept 10 years ago when a colleague in Germany showed him a weighted matchbox and a large, empty cardboard box of equal weight. When people pick up both objects, they almost invariably perceive the matchbox to be heavier simply because they expect it to be lighter than the larger box.

The same is the case with the 18-pound metal ball hanging from a chain in the Mystery Spot cabin.

The ball hangs vertically from the ceiling. But because the cabin is tilted at a 17-degree angle, the ball appears to be suspended at a gravity-defying angle.

That part is somewhat easy to understand. What's more of a mystery is why people who push the weight one way find it more difficult than pushing it the other way. Answering that question was the focus of Bridgeman's scientific paper.

It is the same reason the matchbox seems heavier, he said. When people push the weighted ball toward the ``visual vertical'' (the way people think the ball should naturally be hanging from the ceiling), they find it is much harder than it looks. So it feels more difficult than pushing the ball in the opposite direction, even though the physical effort is exactly the same, all seven of the students in the experiment found.

All this is important to the field of psychology because ``it shows the limits of one's perception,'' Bridgeman said. ``The essential role of expectation in perception applies to everything -- not just weighted balls in cabins.''

It also shows how the human brain evolved.

Bridgeman said humans almost always make mistakes when judging distances, slopes of hills or other aspects of the layout of the world.

``Perception is not as realistic as it seems,'' he said. ``The job of perception is not to give you an accurate view of the world but something that helps your survival. . . . When you meet a bear in the forest, it's important to run the other way, but the precise position of the bear isn't critical.''

The science of illusion has numerous applications in industry and product development. Just one example: By knowing exactly how the brain distorts reality, engineers can minimize illusions -- and accidents -- when designing roads, highways and cars. In fact, one of Bridgeman's former doctoral students is now a designer for Volkswagen.

Some of his current students, meanwhile, are still struggling with Bridgeman's research debunking ``the force'' at the Mystery Spot.

``It kind of takes the fun out of the place,'' said junior Lily Kuang, 20, one of the students who accompanied Bridgeman on the recent tour. ``The Mystery Spot is supposed to be cool and mysterious.''

But Steven Macramalla, a graduate psychology student, disagreed that the thrill was gone. ``I get what the professor is saying intellectually,'' said Macramalla, 36. ``But understanding the illusion doesn't diminish it. The effect is so darn strong. It's pretty fascinating.''

That kind of attitude suits the tour guides and managers at the Mystery Spot just fine. They argue that the spot works whether you believe in mysteries or believe in illusions.

``Bruce is one of the most educated and brilliant people I've ever known,'' said Randall Fertig, who has given tours for eight years. ``Still, just because you understand something doesn't mean you understand it.''

Mac OS X 10.4: Stay away from the SyncServices folder

I saw this posted on a blog; I followed the link, and yup, this is what it said. I like documentation like this.

http://docs.info.apple.com/article.html?artnum=301920...

Mac OS X 10.4: Stay away from the SyncServices folder

As if it were a swarm of bees, you should stay away from the SyncServices folder in Mac OS X 10.4. Removing or modifying anything in it—or in subfolders within it—may cause unexpected issues. (This folder, just so you know, is located in your Application Support folder, in your Library folder, in your Home folder.)