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MONTREAL--When we're under immediate stress --say, we are about to give a speech or about to be mugged--we either fight or flee, or so scientists have long preached. But some psychologists are now suggesting that this scenario may apply mainly to males. Men get antisocial under pressure, but women tend to react in the opposite way: they "tend and befriend," engaging in nurturing and social networking, perhaps as a way to protect their offspring, according to a theory proffered by neuroscientist Shelley Taylor of the University of California, Los Angeles. Here at the Cognitive Neuroscience Society 2010 annual meeting, psychologist Mara Mather of the University of Southern California presented powerful new support for Taylor's hypothesis in the divergent ways that stressed men and women respond to faces. [More]

ERICE, Italy--If you think of Earth's poles as fraternal twins, the Arctic has been the wild one in recent years, while the Antarctic has been a steady plodder. Withered by summer heat, Arctic sea ice has shrunk to record low coverage several times since 2005, only to rebound to within 95 percent of its long-term average extent this winter. By comparison, Antarctica, with some 90 percent of the world's glacial reserves, has generally shed ice in more stately fashion.     [More]

A casual spin last night through the pile of ads inserted inside my local Sunday newspaper made it clear to me that the best possible thing we all can do this week to honor Earth is to shop till we drop. [More]

An experiment is gearing up in Texas to take on one of the universe's biggest mysteries by compiling a three-dimensional map of the early cosmos. The hope is that the survey will help inform astronomers and cosmologists about the nature of dark energy, a mysterious and hypothetical agent thought to constitute nearly three quarters of the universe's mass. [More]

What is the memory capacity of the human brain? Is there a physical limit to the amount of information it can store? --J. Hawes, Huntington Beach, Calif.

What goes on in the brain of the groom who says “I do,” then has an affair? Or the friend who pledges to repay a loan but never does? Breaking a promise is a complex neurobiological event, a new study shows--and a brain scan may be able to predict those who are making false promises before they break their word.

Using functional MRI, scientists at the University of Zurich in Switzerland scanned the brains of subjects playing an investment game. Subjects assigned to be “investors” had to decide whether to pledge to share their money with other players who were “trustees.” This arrangement boosted the amount of money in the pot, but it also could result in a loss to the investor if the trustee chose not to share. Nearly all the subjects said they would give to the trustee--but in the end, not everyone kept this promise.

The African island of Madagascar, situated some 430 kilometers off the coast of Mozambique, is famous for its unique fauna, particularly its charismatic primates, the lemurs. But how the lemurs and other land mammals got there has proved an enduring mystery. To that end, new evidence supports a theory that some experts once considered unlikely: namely, that the forerunners of Madagascar’s modern mammals reached the island millions of years ago by drifting from the African mainland across the Mozambique Channel on giant rafts of vegetation ripped from the shore and launched out to sea by violent storms.

Reconstructing ancient dispersal routes is a complex exercise. On Madagascar this puzzle is complicated by the fact that the fossil record of mammals from the past 65 million years is meager. Based on the paltry available clues, some researchers thought the ancestral mammalian stock arrived via a landbridge that later disappeared with the shifting of landmasses. But geologic evidence of such landbridges is weak at best. Moreover, this theory cannot account for why the island’s many endemic terrestrial mammal species represent only four of Africa’s broader mammal groups called orders. And all of Madagascar’s land mammals are relatively small--no elephants, lions or giraffes there. If landbridges existed, critics argued, why did only small mammals belonging to these four orders make the trip over?