Random Samples

Science  27 Oct 2006:
Vol. 314, Issue 5799, pp. 573

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    In his 1872 book The Expression of the Emotions in Man and Animals, Charles Darwin related the tale of a man with a habit of raising his right arm while asleep and letting his wrist fall heavily on his nose. Years after the man's death, his son was found to do the same.

    This mom and her blind son both raise their right eyebrows when concentrating.


    There are many such anecdotal reports of gestures or facial expressions shared by family members, but researchers in Israel have now done a study showing that characteristic facial expressions run in families, ones even shared by blind people. The results, published online this week in the Proceedings of the National Academy of Sciences, suggest that such expressions are under genetic control.

    Evolutionary biologists at the University of Haifa at Oranim studied 21 congenitally blind people from different families, as well as one or two sighted relatives of each. Through techniques such as asking subjects to relate personal experiences, the researchers provoked 43 facial gestures covering six emotional states: sadness, anger, disgust, joy, surprise, and concentration.

    To gauge family similarity, the researchers carried out an exercise that study co-author Daniel Keren compares to finding the strongest individual in two rope-pull teams. The team used computers to analyze an individual blind person's facial expressions and compare them to those of two groups of 10 families each: one containing the family members and one without. The researchers found that the subjects were matched with the correct group 80% of the time, leading them to conclude that there is a “family facial expression signature.” The correct classifications were highest for people showing anger, indicating a particularly high heritability for this expression. In contrast, the researchers found less family resemblance for joy and sadness.

    The study is “a very creative attempt to get at the genetic underpinnings of facial expressivity,” says psychologist Nancy Segal, a twin researcher at California State University in Fullerton.


    Some players in the U.S. National Basketball Association (NBA) hate the new synthetic ball the league adopted this year, and a physicist has agreed to find out whether it really is different from the old leather-covered ball.


    NBA players complain that the new ball is slippery and bounces unpredictably. League officials counter that the new ball is more consistent and more durable than the old ball. At the request of the Dallas Mavericks team, Kaushik De, a particle physicist at the University of Texas, Arlington, and colleagues are testing both balls.

    De says that his very preliminary results suggest that a worn leather ball bounces higher than the synthetic ball, although the synthetic ball and a new leather ball bounce about equally. A worn leather ball also bounces truer than a new leather ball, which has deeper grooves and is embossed with logos, he says. Perhaps most important, the new synthetic ball does not absorb water, which means it gets slippery when wet. A leather ball absorbs moisture and actually gets stickier, De says. He notes that the ball's manufacturer, Spalding, designed it not to absorb water so as to maintain a constant weight: “In optimizing one variable, they seem to have affected the others.”



    A wolf pack can take down four elks a week. But male elks don't seem too concerned: They let females keep tabs on these predators. Indeed, males bother to look around only when they are worried about being cuckolded, says Mark Lung, a wildlife biologist at Western State College in Gunnison, Colorado.

    Lung and Michael Childress, a behavioral ecologist at Clemson University in South Carolina, used the 1995 introduction of wolves into northern Yellowstone National Park as a natural experiment assessing how the predators affect elk behavior. Over several springs, they tracked how often elks in herds in different locations in the park—and consequently, with varying exposure to wolves—stopped feeding to look around. This vigilance is thought to be a common antipredatory behavior. But when wolves came within sight of the herd, the males seemed oblivious, and it fell upon the females to prod browsing comrades to move to a safer spot. “Males didn't pay any attention to the increased risk at all,” says Childress.

    During the fall, however, male elks spend quite a lot of time scanning their surroundings. But it's other males, not predators, that grab their attention, Lung and Childress reported online last week in Behavioral Ecology. That's likely because fall is the rutting season, a time when males cordon off as many females for themselves as possible. The nonchalance to predators—males will also ignore a grizzly bear, whereas a female quickly leaves—and obsession with sex are all part of the male elk psyche, says Childress: “It's a live-fast-and-die-young strategy.”