Humans typically feel uneasy when they see a very realistic human-looking robot or computer avatar, a phenomenon called the “uncanny valley” response. According to a new study performed with monkeys, that reaction might have an evolutionary basis.
Researchers hypothesize that the response stems from almost realistic images that signal HUMAN! to us, but then fail to live up to the initial excitement. The uncanny valley response has been documented in humans since the 1970s, and has been blamed for the unpopularity of some CGI films with realistic characters [like The Polar Express and Final Fantasy], and it is touted as the reason Pixar stuck to characters with cartoonish features [New Scientist].
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The tender interactions between human mothers and their newborn babies may have deep evolutionary roots: a new study found that rhesus macaque monkey mothers engage in strikingly similar behavior with their infants.
The researchers found that the mothers would gaze intently at their newborns, sometimes even taking their baby’s face with their hands and gently pulling it towards them to get an even closer look. They would also engage in “lipsmacking” – an affectionate form of expression, where the macaques rapidly open and close their mouths [BBC News]. Several videos taken by the researchers show that just like human babies, the infant monkeys responded to their mothers by mimicking their facial expressions and returning their stares.
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Humanity has a new matriarch: a hominid named Ardi who lived in Ethiopia 4.4 million years ago. Anthropologists have unveiled the results of 17 years of research on a new species named Ardipithecus ramidus, presenting a rich trove of fossils including the partial skeleton of the small-brained, 110-pound female. Ardi is 1.2 million years older than the famed “Lucy,” of the species Australopithecus afarensis, and experts say the find fundamentally changes our understanding of human evolution.
Study coauthor Tim White says that Ardi provides clues to what the last common ancestor shared by humans and chimps might have looked like before their lineages diverged about 7 million years ago…. But despite being “so close to the split,” says White, the surprising thing is that she bears little resemblance to chimpanzees, our closest living primate relatives [Time].
Ardi’s pelvis, leg, and feet bones indicated that she walked upright on two feet, but her opposable big toes suggest that she was also comfortable climbing trees. Her hand, arm, and shoulder bones indicate that she didn’t often swing through the trees, though; instead she probably walked on her palms along tree branches like some extinct apes. Based on Ardi’s anatomy, it appears that chimpanzees may actually have evolved more than humans — in the scientific sense of having changed more over the past 7 million years or so [Time].
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For two squirrel monkeys nicknamed Dalton and Sam, life has gotten a lot more colorful. Researchers used gene therapy to correct the color blindness of the two adult monkeys, giving them the ability to distinguish between red and green for the first time. The fascinating accomplishment suggests that scientists may someday be able to cure other kinds of blindness in humans. And because the treated monkeys were “middle aged”, it challenges the assumption that gene therapies cannot work in adults because their brain connections are too set in their ways to change beneficially [New Scientist].
The field of gene therapy, in which a malfunctioning gene in a patient’s body is replaced with a functional one, fell into disarray one decade ago following the death of an 18-year-old in a clinical trial. But since then scientists have regrouped, using animal studies to probe the technique’s safety. Last year, researchers progressed to the point of safety trials in humans for the treatment of one rare eye condition called Leber congenital amaurosis, and were able to dramatically improve the patients’ sight. Those results were stunning, but they were also achieved in children, whose still-growing brains can rewire themselves on the fly in response to new sources of visual stimuli [Wired.com].
In the new study, published in Nature, the researchers used a type of squirrel monkey in which the males lack a visual pigment called L-opsin. Its absence renders the monkeys color-blind, unable to distinguish reds and green. Most of the females, on the other hand, see in full color. So the scientists got to wondering: what would happen if they gave a boy squirrel monkey the same opsin that girls have [Scientific American]. They used a harmless virus to ferry in the gene that makes opsin, injecting the virus behind the monkeys’ retinas.
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Yawning is so contagious that even chimpanzees who watched animations of cartoon chimps yawning couldn’t resist the impulse, according to a new study in Proceedings of the Royal Society B. Study coauthor Matthew Campbell doesn’t think the chimps were “fooled” by the animations into thinking they were looking at real chimps, he explained that there was evidence that chimpanzees “process animated faces the same way they process photographs of faces”. He said: “It’s not a real chimpanzee, but it kind of looks like a chimpanzee, and they’re responding to that” [BBC News].
The chimps were tested by first showing them animated chimps making a variety of facial expressions, and then another set of cartoons with yawning chimps. Only the latter cartoons elicited the yawning response. Campbell says the findings could assist in the future study of empathy…. “We’re interested in using animation for presenting stimuli to animals, because we can control all the features of what we show them” [BBC News].
As for why yawns are so contagious, Campbell suggests that the phenomenon may have evolved to allow some animals “to coordinate activity better, resting when other individuals are resting” in order that they “can travel when it’s time to travel, eat when it’s time to eat” [Discovery News].
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Image: J. Devyn Carter. Still frames from the animated yawning.
As anyone who has a favorite (and least-favorite) musical artist knows, music can affect our moods. Now it seems it can do the same for cotton-top tamarin monkeys, but only when the music is composed specifically for them, according to a study published in the journal Biology Letters.
Except for one anomaly (they liked Metallica), the monkeys didn’t respond to samples of human music–but the tamarins did respond to cello music that was reminiscent of their natural calls. Cellist and composer David Teie studied recordings of both happy and upset tamarins, and used them as the bases for two different kinds of monkey music. “Basically I took those elements and patterned them the way we do normally with music,” he says. “You repeat them, take them up a [musical] third — you know, using the same kind of compositional techniques we use in human music.” He played the compositions on his cello and then electronically boosted them up three octaves, to a pitch that matched the monkeys’ voices [NPR].
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Imitation may be the sincerest form of flattery not just for humans, but for many primates. In human social interactions, people have an instinctive tendency to copy each other’s body language and mannerisms, and previous studies have shown that such imitation gives rise to friendly feelings. Now a new study has found that capuchin monkeys respond to imitation in the same way, suggesting that the behavior may date back to early in our evolutionary history. The subtle aping may promote the formation of social groups—building cooperation, reducing conflict, and aiding the survival of each individual [Scientific American].
To study the behavior in capuchin monkeys, which live in highly social groups of 30 or 40 individuals, the researchers gave each monkey a Wiffle ball — a lightweight plastic ball with holes in it. Monkeys typically poked the ball with their fingers, put it in their mouths or used it to pound on something. Each monkey was paired up with two human researchers, one that copied their ball-handling skills, and one that did not. When the balls were put away, the monkeys appeared to prefer the company of the like-minded ball handler [Reuters].
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Using the first known animal instruments, orangutans use leaves to make their voices sound deeper, perhaps thereby tricking predators into thinking the apes are bigger than they really are, according to a study published in the journal Proceedings of the Royal Society B.
Orangutans produce a noise known as “kiss squeaks” to let predators like snakes and leopards know that they’ve been spotted, and can use their lips and fingers or folded leaves to make the sound. To find out more about why the animals produce the noise, researchers recorded kiss squeaks between 2003 and 2005 near a research station … on the island of Borneo. The team noted whether the sounds had been made with hands, leaves, or lips alone [National Geographic News]. They found that squeaks made using only the lips had a higher pitch than those produced using hands, and that leaf-produced pitches had the lowest frequency and therefore the deepest sound.
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Researchers have determined how malaria first came to afflict humanity, and have laid the blame on our closest relative, the chimpanzee. Researchers have long known that chimps get infected with a malaria parasite of their own, called Plasmodium reichenowi, which is closely related to the human malaria parasite, Plasmodium falciparum, but they believed that the two parasites evolved from a common ancestor many millions of years ago and then developed on parallel tracks. Now a new genetic comparison indicates that the human version more likely developed from the chimpanzee type [AP].
“Current wisdom that P. falciparum has been in humans for millions and millions of years is wrong,” said study co-author Nathan Wolfe, director of the Global Viral Forecasting Initiative…. “We now know that there was a point in time when this was primarily a disease in chimpanzees that jumped and took hold in humans” [National Geographic News]. Malaria probably came to our species when mosquitoes that had previously fed on infected chimpanzees bit humans, Wolfe says, and the transmission may have happened as recently as 10,000 years ago.
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In the first known case of its kind, scientists have identified a strain of HIV that can be traced to gorillas, not chimpanzees, according to a report in Nature Medicine. The new strain was detected in a Cameroonian woman living in France.
Previous strains of HIV virus type 1, the main type of the disease, have been shown to have arisen from chimpanzees, and researchers found that the new virus is dissimilar enough from previously known strains that it cannot be detected by standard HIV tests. After genetic analysis, scientists also found that the infection is closely related to gorilla simian immunodeficincy virus, or SIVgor, the gorilla version of HIV. Genetic analysis of the woman’s virus shows that it is so closely related to SIVgor that “the most likely explanation for its emergence is gorilla-to-human transmission” [Bloomberg], says co-author Jean-Christopher Plantier.
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The oldest known tree-dwelling vertebrate lived 30 million years before the dinosaurs, scientists have found. The animal, known as Suminia getmanovi, had opposable thumbs and long hands, which would have allowed it to live in trees, according to a study published in the journal Proceedings of the Royal Society B.
A team of researchers found that Suminia, which lived about 260 million years ago, had disproportionately long arms and slender, curved fingers that were well-adapted to grabbing tree branches. But perhaps most importantly, one finger on each hand and foot was “opposed” to the rest, much like a thumb. “It’s the first time in the fossil record that we’ve seen evidence of an opposable thumb,” [said lead researcher Jorg Frobisch], adding that the creature was an early ancestor of mammals [BBC News]. The 12 well-preserved Suminia skeletons the scientists analyzed, which were found in Russia the 1990s, predate by 100 million years what was previously thought to be the earliest tree-dwelling animal.
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It may seem as though orangutans’ 180-pound bodies would be unwieldy when it comes to swinging from delicate tree branches in the rainforests of Indonesia and Malaysia. But the animals have figured out a variety of ways to navigate treetops, allowing them to avoid a potentially deadly fall, according to a study published in the Proceedings of the National Academy of Sciences.
When scientists observed wild orangutans in the Sumatran rainforest, they found that the animals traversed the delicate branches by moving their bodies with a rhythm that counters the vibrations of the trees. At the highest treetops in the forest, tree branches are thin and begin to wobble as animals climb on them, much as a suspension footbridge vibrates as people walk over it. Too much vibration and an orangutan can be thrown off altogether. From high in the trees, such a fall would be deadly [Time]. But because orangutans move with an irregular beat, they avoid compounding the already-shaking branches with the motion of their own bodies. Also increasing their stability, the animals also have the habit of grasping more than one branch at once–in fact, nearly one-third of the time, orangutans held on to more than four branches simultaneously.
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Scientists have long known that chimpanzees and other nonhuman primates can become infected with simian immunodeficiency virus, or SIV, a variant of HIV. It was thought, however, that only Asian macaque monkeys could die from the infection. But a new study published in Nature contradicts this assumption by finding that the virus can also be deadly to chimpanzees, humans’ closest relatives.
Some wild primates appear to have developed a way to keep SIV from becoming deadly, and scientists had hoped that studying chimpanzees could reveal how this mechanism works, possibly opening to the door to a human remedy. The new results suggest that it will not be possible to find the key to HIV immunity in the chimpanzee genome, as scientists had hoped. However, the study… sets the stage for researchers to gain insight into how HIV and SIV cause disease in their hosts by studying the responses of different primates to the viruses [Nature News].
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It’s been a big week on the longevity front: First, scientists found that an immunosuppresant drug called rapamycin extended the lifespan of mice. Now, a 20-year-long study reported in the journal Science shows that a diet 30 percent lower in calories than normal decreased the incidence of age-related diseases in macaque monkeys as the animals got older.
Half the monkeys were fed a low-calorie diet, and the other half a standard diet. All were closely monitored, with researchers regularly measuring their body composition, blood chemistry, endocrine function, and heart and brain function. When monkeys died, they were necropsied and the causes of death established [Wired.com]. Researchers found that monkeys on a calorie-restricted, nutrient-rich diet (on the left in photo) were three times less likely than monkeys on a full-calorie diet (on the right) to die from age-related diseases like cancer, diabetes, and heart disease. Scientists have hypothesized that calorie restriction triggers mechanisms that evolved to help organisms survive in times when food was scarce, but the exact process is still mysterious.
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A landowner in Indonesia may soon find it more profitable to sell carbon credits from untouched forest than to clear the land for agriculture, according to new research. As a case study, the researchers looked at 8.2 million acres that are slated to become plantations in Kalimantan, the Indonesian region of the island of Borneo. The researchers found that paying to conserve the forest was more valuable than plantations as long as poorer nations could earn between $10 and $33 for each tonne of CO2 saved. Currently a credit representing a tonne of CO2 sells for about $20 in the European Union, which has the world’s largest greenhouse gas trading system [The New York Times].
Since forests act like sponges for carbon dioxide, the principal greenhouse gas driving global warming, they can play a role in carbon credit markets that are used in international climate treaties. Industries that can’t cut their emissions enough pay landowners to leave their forests standing, so the trees can suck up carbon and offset the industrial emissions. What’s more, researchers say that such systems could also be a roundabout way to protect endangered species. The 800 proposed plantations that were studied contain 40 of the region’s 46 threatened mammals including orangutans and pygmy elephants [AP].
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