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Why do some faces meant to be lifelike appear to be lifeless? (image courtesy of flickr user sally_monster)

Do you remember the doll Great-aunt Mary gave you for Christmas when you were six? You could never figure out why that doll made you uncomfortable. She was meant to be pretty and lifelike, but she stared at you from the top shelf in the bedroom and gave you the occasional nightmare. You couldn’t explain what was wrong—and your mom thought you were nuts—but now science may have determined why that doll was so creepy. It was the eyes.

We’ve evolved to see faces in just about anything; it makes sense since the things that can eat you generally come with two eyes and a mouth. But we also have to quickly determine which of those faces is real, and thus a potential threat, and which is just a false alarm. And so when we are looking at a face that isn’t alive but meant to look like it is—dolls, for example, or computer-generated characters in movies—some of them look more lifelike than others, and it isn’t always easy to pinpoint why.

Scientists from Dartmouth College, who report their findings in Psychological Science, set out to discover that line in perception, the point at which we perceive life in a face. They did this by having study participants evaluate a series of images, morphing from a completely human face to that of a mannequin (see video below). “The tipping point is consistently close to the human end of the continuum,” they write. “This suggests that people base animacy judgments of a face, at least in part, on how closely the structural proportions of the face fit a human prototype.”

When they examined which facial features are most important for imparting that lifelike quality, the eyes, followed by the mouth, correlated most often with animacy. “Eyes convey a wealth of information, from attention to emotion to intent; therefore it is no wonder that eyes have been the Achilles heel of CGI, with renderings of eyes described as ‘unnervingly without soul.’”

Young male and female chimps may play differently (photo courtesy of flickr user Tambako the Jaguar)

Young female chimps that live in a Ugandan park sometimes treat sticks in the same ways a little girl might treat her dolly, according to a new study in the journal Current Biology.

Studies have shown that human girls tend to play more with dolls and boys with toy vehicles and fake weapons. Captive monkeys also show a tendency to split along gender lines when they play with sex-stereotyped toys, but there has been no evidence that any young wild animals that play with toys play differently depending on whether they or male or female.

Scientists have been watching and recording the activities of the Kanyawara chimpanzee community in Uganda’s Kibale National Park for 14 years. These chimps use sticks in four different ways: as probes in holes that might contain honey or water; as weapons; during play; or in a behavior the researchers have named “stick-carrying”:

Stick-carrying consisted of holding or cradling detached sticks. The juveniles carried pieces of bark, small logs or woody vine, with their hand or mouth, underarm or, most commonly, tucked between the abdomen and thigh. Individuals carried sticks for periods of one minute to more than four hours during which they rested, walked, climbed, slept and fed as usual.

The researchers say that the behavior is “suggestive of rudimentary doll play” and, as with humans, more common among young females than young males. They think that with stick-carrying, the young chimps are imitating their mothers. And unlike other behaviors that employ sticks, stick-carrying always ceased when a young female had a baby of her own.

Stick-carrying is rare among the Kanyawara chimps and has never been reported elsewhere. If the behavior is unique to this population, says study co-author Richard Wrangham of Harvard University, “it will be the first case of a tradition maintained just among the young, like nursery rhymes and some games in human children.”

Could the same dryer sheets that keep your towels fresh and static free also repell bugs? (image courtesy of flickr user missmac)

It’s a modern old-wives tale: put a Bounce dryer sheet in your pocket while gardening and it’ll keep away the mosquitoes or gnats. This may seem a bit far-fetched to those of us who have never tried it, but researchers have now found that there could be some truth in it, when it comes to gnats, anyway.

The scientists, who published their findings this month in the journal HortScience, set up a simple experiment consisting of a large plastic container connected to two smaller plastic containers, one of which had a piece of a dryer sheet. Fungus gnats were placed in the center container and then the scientists checked where they were two days later. Each time they repeated the experiment, they found that the gnats tended to hang out in the two dryer-sheet-free containers.

In the second part of their experiment, they analyzed the chemical content of the dryer sheets with gas chromatography and found two substances that might be keeping away the gnats. The first was linalool, which is naturally found in lavender and basil and which cosmetic and perfume companies use in their products for its flower-like odor. Linalool is toxic to some types of insects, though it isn’t known to have any repellent qualities. The second compound was beta-citronellol, which is found in citronella and repels mosquitoes.

The researchers haven’t yet tested the distance over which the dryer sheets repel the gnats or whether they also repel mosquitoes, but it is interesting to see that the myth may be true. And perhaps I’ll try tucking a dryer sheet in my back pocket next year during mosquito season—it’s certainly easier than applying bug spray.

Two male polar bears spar near Hudson Bay. (Credit: Steven Amstrup, Polar Bears International)

In 2007, scientists from the U.S. Geological Survey said that if humans didn’t do anything to reduce greenhouse gas emissions, two-thirds of the world’s polar bears could be gone by the middle of this century. Now a new study has addressed the next question: Is there still time to help the bears? The study, published this week in Nature, provides some hope, and scientists have concluded that if we’re able to substantially reduce our emissions, we may be able to save enough sea ice to save the polar bear.

Polar bears (Ursus maritimus) depend on the sea ice to reach their prey, bearded seals and ring seals. As the summer sea ice has disappeared and the bears have lost opportunities for hunting, scientists have noted a decline in polar bear physical condition, survival and population size. The 2007 study concluded that under our current levels of greenhouse gas emissions, the summer sea ice would continue its precipitous decline, one that the polar bears would find hard to survive.

The latest study examined what would happen to the sea ice under other emissions scenarios, and whether there was some tipping point, a temperature increase beyond which the polar bear population would inevitably crash. They concluded that as long as temperatures did not increase beyond 2.25 degrees Fahrenheit, there would be enough sea ice for the polar bear population to survive through the end of the century.

“There’s still a fairly high probability … that polar bears could disappear” in two of the three regions where they live, said the study’s lead author Steven Amstrup, an emeritus researcher at the USGS and senior scientist with Polar Bears International. “But with mitigation and aggressive management of hunting and other direct bear-human interactions, the probability of extinction would now be lower than the probability that polar bear numbers will simply be reduced. …The benefit of mitigation to polar bears is substantial.”

Still from Close Encounters of the Third Kind. Credit: Everett Collection

No one knows when, or even if, we will discover alien life in the universe or what it might look like. But that hasn’t stopped those who are looking from planning on that eventuality, as I discovered when reporting “Ready for Contact,” one of the stories in Smithsonian‘s new special issue, Mysteries of the Universe. These scientists have a plan, and it involves telling everyone about their research and any discovery. “I think there’s a big misconception in the public that somehow this is all a cloak-and-dagger operation, and it’s not,” Arizona State University astrobiologist Paul Davies told me. “People are quite open about what they are doing.”

But what will happen after such an announcement is a true mystery. How will the media react, and the public? Will there be mayhem, or will we just yawn? The recent discovery of bacteria that can apparently use arsenic in place of phosphorus, however, has provided an interesting glimpse of what a discovery of alien life portends.

Our story starts on November 29, when NASA announced a December 2 press conference “to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life.” Almost immediately rumors began to swirl that NASA might have discovered extraterrestrial life itself. The frenzy reached such a point that I even received a press release from a betting web site about the odds they were giving on just what NASA’s finding might be. (They placed a 33 percent chance on the discovery of a life form on Mars and a 16 percent chance that NASA would announce that Area 51 had been used for alien studies.) Meanwhile, those of us with embargoed access to the Science study NASA was referring to just groaned—we knew the rumors were all wrong but couldn’t say a thing.

After all that, the actual announcement, though interesting, seemed somewhat of a letdown.

But things heated up again shortly thereafter as scientists and bloggers began criticizing the research. One microbiologist summarized the paper as “lots of flim-flam, but very little reliable information.” They questioned whether the paper was worthy of being published, especially in so prestigious a journal as Science, while others defended the peer review process. And the arguing continues.

If this had been a discovery of alien life, we could probably expect a similar progression of events, only everything would by hyped by a factor of a hundred, at least. Davies, who is associated with the SETI program, which searches for radio signals of alien life, told me, “if there’s a ghost of a chance that a particular radio source is going to turn out to be ET messaging us, the media will be all over it right away.” More rumors, more crazy press releases, maybe CNN reporters camped on the scientists’ doorsteps. Davies imagines there would be mayhem among the general public, too, with the observatory that made the discovery hounded by people, their computers besieged by hackers. “You could imagine police cordons and even riot police,” he said. Who knows how religious leaders would react? And the scientific community would pick apart any discovery, as they are now doing with the arsenic paper.

Scientists in a series of workshops in the early 1990s attempted to determine the social implications of a SETI discovery. “It depends” seems to be their ultimate answer. But people would likely fall into one of two camps, as they have done in the past and do now. The catastrophists predict that the discovery of alien life will result in the end of humanity as we know it, or at least the end of our current culture. But for the “millennial enthusiasts,” as the group named them, “the gloom of the doomsayers is more than offset by the rapture,” they wrote. They see revelations of how to cure cancer, solve the energy crisis or win world peace.

A lot of this would depend on the nature of any discovery, of course. Single-celled life on Mars certainly warrants a different reaction than a message from an intelligent extraterrestrial or a spaceship landing on the White House lawn. In any case, there would be some level of freaking out from the media and, possibly, the public, as the arsenic study has shown.

But for many of us, I think our response would be somewhere in the middle. The discovery of life outside of Earth, while interesting, would hardly negate the need to go to work and earn money, to visit with friends and family, to eat quality chocolate, to do all the things we do every day. That doesn’t mean that the search for extraterrestrial life isn’t important or won’t ever have some impact on the average person. But it won’t change us any more than we’re changing already.