Health & Science

last updated 8 January 2015

A new species of elephant

Scientists have discovered that there are two species of African elephant. A new DNA analysis finds that the iconic savanna elephant and the much smaller forest elephant, long thought to be two distinct but closely related groups, are entirely separate species. “You can no more call African elephants the same species as you can Asian elephants and the mammoth,” study co-leader David Reich, a geneticist at Harvard Medical School, tells Nature.com. Previous studies have pointed to a similar conclusion, but the new results are based on a broader genetic comparison of the African elephants with Asian elephants and with DNA extracted from two extinct ancestors, a woolly mammoth and a mastodon. The data indicate that savanna and forest elephants diverged between 2.5 million and 5 million years ago. Conservationists hope that once the new distinction is officially recognized, it could help afford better protection to West Africa’s forest elephants, which make up only about one fifth of the continent’s elephant population and have been particularly hard hit by poaching for ivory.

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The eyes, a new study says, are windows to a person’s political beliefs. When two people converse, their gazes commonly wander, and each will often glance to see what the other is looking at. University of Nebraska researchers found that liberals are more likely to follow these “gaze cues” than conservatives are. The researchers asked subjects to view a face on a computer screen; from time to time another object would appear elsewhere on the screen. If the face appeared to be looking at the new object, subjects with politically liberal views were much faster to follow the face’s gaze, to see what it was looking at. The authors theorize that conservatives place a higher value on personal autonomy than liberals do, and so are less likely to be interested in other people’s opinions—hence their disinterest in gaze cues. The study doesn’t establish whether political orientation determines a person’s interest in other views or vice versa, psychologist and study author Michael Dodd tells LiveScience.com, but it’s “another piece of evidence that biology can influence political temperament.”

For the first time, engineers have created an invisibility cloak that can hide an object big enough to be seen by the naked eye. No longer limited to science fiction and the Harry Potter series, these devices work by bending light around an object, effectively rendering it invisible. Previous prototypes have used expensive, specially engineered substances to cloak microscopic objects from microwave light, which humans can’t see anyway. Now a team of MIT researchers in Singapore has built a “carpet cloak” capable of hiding a sliver of steel 38 millimeters long from visible light using cheap, naturally occurring materials. Their device employs two pieces of calcite crystal that bend the incoming and outgoing light by different amounts. In its current configuration, the cloak hides the object only to viewers looking at it from a particular direction, but further improvements are expected. “Governments could make a lot of use out of a cloak that can hide objects on the seabed—although I won’t speculate on exactly what they may want to hide,” team member George Barbastathis tells Nature.com. The total cost of materials? About $1,000, says study leader Baile Zhang. “It’s not quite easy enough to make at home, but it’s not too far off.”

The “placebo effect’’—pills with no active ingredients causing patients’ conditions to improve—has always been thought to rely on subjects thinking they’re getting the real thing. But that belief may be misplaced, a Harvard Medical School study suggests. Researchers recruited 80 people with irritable bowel syndrome and told them that they’d receive either no pills or placebos as part of a study into a “novel mind-body” therapy. Some of the subjects were instructed to take pills twice a day from bottles labeled “placebo pills” and were repeatedly reminded that the pills were inactive. “They were told so many times, they had it coming out their ears,” lead author Ted Kaptchuk tells ScienceMag.org. Yet after three weeks, 59 percent of people who took the placebos said their symptoms had improved—far more than the 35 percent who’d taken nothing. This suggests, Kaptchuk says, that the body’s own healing mechanisms can be triggered by simple attention from another person; placebos serve as an acknowledgment that a person is sick and wants to be well. Beyond “mere positive thinking, there may be significant benefit to the very performance of medical ritual,” he says. “My personal hypothesis is this would not happen without a positive doctor-patient relationship.”