Sunday February 3, 2013

Q: Can you tell by facial expression if a hungry cannibal intends to eat you?

A: This took on more than just theoretical interest for psychologist Paul Ekman years ago when he traveled to a remote part of New Guinea to study facial expressions among the Fore people, as he reported in "Science" magazine.

Which theory was correct: Darwin’s view that facial expressions of emotions are universal, or Margaret Mead’s claim that they vary with different cultures?

The Fore people were far removed from Western culture and generally untouched by outsiders; one of their traditions was cannibalism, where the community ate people they respected after death by natural causes.

A few weeks after his arrival, Ekman was sitting eating his lunch when a village elder approached him, followed by maybe 100 tribesmen. Stopping before Ekman, the man reached down and began pinching his thigh.

"To my horror, the villagers behind him began jumping and screaming with emotion. I scanned the crowd for weapons and tried to hide my panic."

Yet their facial expressions showed no anger and they were smiling and laughing. As Ekman learned later, the elder had announced "he planned to eat me when I died" -- a show of great respect! From then on, the villagers cooperated fully with Ekman’s research.

Concluded Ekman, "I had learned this the hard way. Facial expressions do transcend cultures.


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I left New Guinea before the elder tribesman could make good on his promise, but I hope at least he found my research palatable."

Q: What’s the uncommon word for mood rings changing colors with the wearer’s fluctuating body temperature, or baby bottles signalling when the milk inside is cool enough to drink?

You can also toss in a kid’s toy car of die-cast metal that turns purple when immersed in icy water, or blue when put in warm water, or both colors when half-dipped in each.

A: The word is "thermochromism" (from "thermo" for heat and "chrom" for color), possibly based on liquid crystals or a dye added to the paint, says reader Mike Follows of the United Kingdom in "New Scientist" magazine. The pigment can switch from one state to another depending on temperature, going from being transparent to absorbing light of a particular wavelength and subtracting out that color.

Q: What just might be the most "extreme" human activity of them all?

A: Astronauts in action would probably make the list, as would fighter pilots, free-fall parachutists, Formula 1 racing drivers, Acapulco cliff divers, says University of Cambridge mathematician John D. Barrow in "Mathletics: A Scientist Explains 100 Amazing Things about the World of Sports."

But the activity that gets Barrow’s vote is drag-car racing. Apt to be found now only on tracks at disused airfields or salt flats in the middle of nowhere, these cars are like rockets with wheels attached, able to traverse a quarter mile (400 meters) in 4.5 seconds from a stationary start.

Do the math and that’s faster than a NASA rocket launch!

"If a Formula 1 racing car were to pass the start at top speed when the drag car starts from stationary, it would still be beaten to the finish by the dragster!"

That measures 6 g of acceleration -- or 6 times gravity -- and greater than 6 g during deceleration after parachutes are released to slow the car.

So extreme is this that detached retinas are "a serious problem for competitors. The noise levels are also dangerous for spectators, technicians and drivers. Good ear protection is absolutely essential."

Send STRANGE questions to brothers Bill and Rich at Strangetrue@cs.com.