Thanks to capitalism and a cultural heritage of individual freedom, Americans enjoy just about ever modern convenience imaginable and do almost anything they want. But, according to psychologists from Standford University and Swarthmore College, the amount of choice that results from such a decadent lifestyle may be unhealthy. The researchers say that too many choices cause Americans to ignore how the rest of the world feels about choice and may even make us selfish and depressed.

A new paper published in Zoologica Scripta argues that the distributions of the major primate groups are correlated with Mesozoic tectonic features and that their respective ranges are congruent with each evolving locally from a widespread ancestor on Pangea about 185 million years ago.

The new theory incorporates spatial patterns of primate diversity and distribution as historical evidence for primate evolution, while previous models of primate evolution had been limited to interpretations of the fossil record and molecular clocks, says author Michael Heads, a Research Associate of the Buffalo Museum of Science.

University of California, San Diego researchers say they have shown one way deadly brain tumors called gliomas evade drugs aimed at blocking the epidermal growth factor receptor (EGFR), a cell signaling protein that is crucial for tumor growth. They also say that a particular EGFR mutation is important not only to initiate the tumor, but for its continued growth as well. The findings appear this week in PNAS.

New insights about the scaly-foot gastropod, a tiny snail that lives near thermal vents on the floor of the indian ocean, could help scientists design better armor for soldiers and military vehicles, according to a new study appearing in PNAS.

MIT materials scientists report that the snail's shell is unlike any other naturally occurring or man made armor. Their study suggests that its unique structure dissipates energy that would cause weaker shells to fracture.

When a crab attacks a snail, it grasps the snail's shell with its claws and squeezes it until it breaks — for days if necessary. The claws generate mechanical energy that eventually fractures the shell, unless it is strong enough to resist.

Older people who suffer "mental lapses," or episodes when their thinking seems disorganized or illogical, may be more likely to develop Alzheimer's disease than people who do not have these lapses, according to a study published in the January 19, 2010, issue of Neurology.

These cognitive fluctuations, are common in a type of dementia called dementia with Lewy bodies, but researchers previously did not know how frequently they occurred in people with Alzheimer's disease and, equally important, what effect fluctuations might have on their thinking abilities or assessment scores.

Though it's commonly thought that most opioid overdoses occur among drug abusers and people who obtain the drugs illegally, a new study published in the Annals of Internal Medicine links the risk of fatal and nonfatal opioid overdose to prescription use—strongly associating the risk with the prescribed dose.