See it before it happens

by Jeanna Bryner

Humans can see into the future, says a cognitive scientist. It's nothing like the alleged predictive powers of Nostradamus, but we do get a glimpse of events one-tenth of a second before they occur.

And the mechanism behind that can also explain why we are tricked by optical illusions.


Researcher Mark Changizi of Rensselaer Polytechnic Institute in New York says it starts with a neural lag that most everyone experiences while awake. When light hits your retina, about one-tenth of a second goes by before the brain translates the signal into a visual perception of the world.


Scientists already knew about the lag, yet they have debated over exactly how we compensate, with one school of thought proposing our motor system somehow modifies our movements to offset the delay.


Changizi now says it's our visual system that has evolved to compensate for neural delays, generating images of what will occur one-tenth of a second into the future. That foresight keeps our view of the world in the present. It gives you enough heads up to catch a fly ball (instead of getting socked in the face) and maneuver smoothly through a crowd. His research on this topic is detailed in the May/June issue of the journal Cognitive Science,


Explaining illusions


That same seer ability can explain a range of optical illusions, Changizi found.


"Illusions occur when our brains attempt to perceive the future, and those perceptions don't match reality," Changizi said.


Here's how the foresight theory could explain the most common visual illusions - geometric illusions that involve shapes: Something called the Hering illusion, for instance, looks like bike spokes around a central point, with vertical lines on either side of this central, so-called vanishing point. The illusion tricks us into thinking we are moving forward, and thus, switches on our future-seeing abilities. Since we aren't actually moving and the figure is static, we misperceive the straight lines as curved ones.


"Evolution has seen to it that geometric drawings like this elicit in us premonitions of the near future," Changizi said. "The converging lines toward a vanishing point (the spokes) are cues that trick our brains into thinking we are moving forward - as we would in the real world, where the door frame (a pair of vertical lines) seems to bow out as we move through it - and we try to perceive what that world will look like in the next instant."


Grand unified theory


In real life, when you are moving forward, it's not just the shape of objects that changes, he explained. Other variables, such as the angular size (how much of your visual field the object takes up), speed and contrast between the object and background, will also change.


For instance, if two objects are about the same distance in front of you, and you move toward one of the objects, that object will speed up more in the next moment, appear larger, have lower contrast (because something that is moving faster gets more blurred), and literally get nearer to you compared with the other object.


Changizi realized the same future-seeing process could explain several other types of illusions. In what he refers to as a "grand unified theory," Changizi organized 50 kinds of illusions into a matrix of 28 categories. The results can successfully predict how certain variables, such as proximity to the central point or size, will be perceived.


Changizi says that finding a theory that works for so many different classes of illusions is "a theorist's dream."


Most other ideas put forth to explain illusions have explained one or just a few types, he said.
The theory is "a big new player in the debate about the origins of illusions," Changizi told LiveScience. "All I'm hoping for is that it becomes a giant gorilla on the block that can take some punches."

Oil above $133 a barrel and rising

Oil rose above $133 a barrel Monday on persistent worries about global petroleum supplies and the outlook for the U.S. economy and the dollar.



Reports of an attack by militants on an oil pipeline in Nigeria, one of Africa's largest oil exporters, also helped boost prices.

Light, sweet crude for July delivery on the New York Mercantile Exchange was up 98 cents at $133.17 a barrel in electronic trading by afternoon in Europe. The contract rose $1.38 to settle at $132.19 a barrel on Friday.

Nymex floor trading was closed Monday for Memorial Day and it also was a holiday in Britain, resulting in lower trading volume than usual.

In London, July Brent crude futures rose $1.13 to $132.70 a barrel on the ICE Futures exchange.

The dollar has weakened over the last week after a modest recovery, and investors will be watching economic data out of the United States to be released over the next few days for further clues about the health of the world's biggest economy.

"The dollar's been swinging down again," said Mark Pervan, senior commodity strategist at Australia & New Zealand Bank in Melbourne, and that's "going to sway sentiment."

Oil and other hard commodities are seen as hedges against a weakening dollar and inflation. Also, a weak dollar, the currency of international oil trade, makes petroleum products less expensive to Asian and European buyers.

This week, investors will be watching for what implications U.S. consumer confidence, new home sales, gross domestic product and other economic data might have for the dollar and oil prices, he said.

"It's a pretty price sensitive week for economic data," Pervan said. "The data we're seeing out of the U.S. at the moment looks pretty weak. You'd expect that trend to continue, pushing further down on the dollar."

The dollar, one of the factors that has fed oil's rally from about $65 a year ago, was lower against the yen, but up a bit against the euro in currency trading during the afternoon in Europe after losing ground Friday in New York.

The euro slipped to $1.5764 compared with $1.5775 on Friday, while the dollar fell to 103.41 Japanese yen from 104.17 yen Friday.

Prices also were supported when militants in Nigeria, a major supplier to the U.S. market, claimed they destroyed an oil pipeline and killed 11 soldiers in a gunbattle.

The Movement for the Emancipation of the Niger Delta says it attacked the pipeline operated by a Royal Dutch Shell PLC joint venture early Monday. Shell officials were not immediately available for comment, and a military spokesman had no immediate confirmation of any overnight incidents.

Last week, a series of supply warnings shook markets, and Thursday, a report that the International Energy Agency — the energy watchdog for the most industrialized nations — is in the process of lowering its forecast for long-term global oil supply, sent crude futures rocketing to an all-time high of $135.09 a barrel.



Investors are also worried about a growing squeeze on global diesel supplies as demand in China surges has sparked a massive run up in heating oil prices.

Over the weekend, China's top economic planning agency again urged oil and power companies to make sure there are enough supplies for earthquake-hit areas and for the Beijing Olympic Games in August.

"They certainly want to have a buffer of supply ... so there's pressure on the upside from demand in Asia," Pervan said.

The U.S. driving season officially kicked-off with the long Memorial Day weekend there, and even if demand for gasoline and diesel is lower than it was a year ago, it will still be stronger than it was in the preceding months, he said.

In other Nymex trading, heating oil futures rose 7.89 cents to $3.9445 a gallon while gasoline prices rose 2.95 cents to $3.4255 a gallon. Natural gas futures rose 18.2 cents to $12.039 per 1,000 cubic feet.

___

AP Business Writer Thomas Hogue in Bangkok, Thailand, contributed to this report.