The eyes may be windows to the soul, but they provide a pretty good scientific view of the brain, too. Neurobiologist Christof Koch of the California Institute of Technology and colleagues report that the pupil — the circular opening at the center of the eye that contracts or dilates to regulate how much light enters — changes to correspond to the moment when the brain makes a simple decision.
Either interpretation is correct, but because the brain cannot process both views simultaneously, it flips back and forth between interpretations.
"Essentially, the switch occurs so that our brain can check out the other one," said Koch. "Bistable percepts are fascinating because nothing changes in the real world. Everything changes in your head."
Researchers noticed that participants' pupils significantly enlarged at the instant the brain switched between interpretations. Pupils commonly dilate in response to light levels, but they also react to changing brain chemistry, such as increased amounts of neurotransmitters involved in our "flight or fight" response.
"The pupil is not only there to regulate light but is linked to our emotional state," said Koch. "This may have evolved for us to monitor the emotional state of others and may offer a very simple way to track decision-making in general."
VERBATIM
If God meant for us to fly, he would have given us propellers on our noses.
- Science fiction writer Isaac Asimov (1920-1992)
What do the following words have in common?
Assess
Banana
Dresser
Grammar
Potato
Revive
Uneven
Voodoo
BRAIN SWEAT ANSWER
If you take the first letter and move it to the rear of the word, you get the same word when read backward.
PRIME NUMBERS
5 - Number of tons of carbon dioxide the average American car produces each year
191,200 - Price paid, in dollars, for the fossilized skull of a male four-tusk mastodon, estimated to be at least 10,000 years old
277 - Number of parrots found in cages attached to a bicycle abandoned by a man trying to import them illegally into Belarus last month. Authorities said they would offer the birds to pet stores.
Sources: U.S. Environmental Protection Agency; Science
When a male Anna's hummingbird wants to woo the opposite sex, it swoops down in a graceful dive accompanied by a loud chirp as high as the top note of a piano. The sound, though, isn't produced vocally. Researchers say it originates at the bird's tail - the finely tuned result of high-speed flight combined with rapidly flapping feathers.
ELECTRON INK
Great thinkers and visionaries
lucifer.com/(percent)7esasha/thinkers.html
Produced by a sciencephile named Alexander Chislenko, this site offers copious links to other sites highlighting some of the world's great scientific minds, past and present. It's just one man's opinion, and not all of the links seem to work, but it's an interesting place to peruse.
A "half-ironman triathlon" consists of a 1.2-mile swim, a 56-mile bicycle race and a half-marathon run (13.1 miles). The element iron has an atomic number of 26. Half of that is 13, which is the atomic number of aluminum. Shouldn't a half-ironman triathlon really be called an "aluminithon?"
WHAT IS IT ANSWER
A gray-faced elephant shrew (Rhynchocyon chrysopygus), a species recently discovered by scientists in the Udzungwa mountains of south-central Tanzania. In fact, the elephant shrew is related to neither elephants nor shrews, but belongs to a diverse group of mammals called sengis. As sengis go, it's elephantine: about 1.5 pounds and more than a foot long from the tip of its tail to the end of its elongated snout.
ANTHROPOLOGY 101
Throughout the Middle Ages, it was commonly believed that certain kings possessed supernatural abilities to heal the sick, usually by touch. In 1684, a huge crowd of the sick and lame gathered to be touched by King Charles II of England. The crowd grew so large and unruly that seven people were cured of their ailments by being trampled to death.
