Blogs / 80beats

The so-called “love hormone” oxytocin, which is linked to a mother’s tender feelings for her child and long-term devotion between mates, may play a more general role in promoting the social cohesion of a group. In a small new study, researchers found that volunteers who got an oxytocin boost were better able to recognize faces they had seen the day before than people who got a placebo, but were no better at recognizing landscapes and and sculptures that they’d previously viewed.

The results are “striking,” says psychologist Thomas Insel, director of the National Institute of Mental Health in Bethesda, Maryland. Insel and colleagues have [previously] shown that oxytocin improves the ability of mice to recognize other mice, … but he notes that this is the first time such a specific effect has been seen in humans. The research “supports the notion that social memory is a unique form of memory, biologically distinct from general object memory,” he says [ScienceNOW Daily News].

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In a remarkable experiment, researchers found that a man who was rendered completely blind by several strokes could deftly navigate an obstacle course unaided, easily avoiding boxes and sidling around pieces of office equipment. The patient, known only as TN, was left blind after damage to the visual (striate) cortex in both hemispheres of the brain following consecutive strokes. His eyes are normal but his brain cannot process the information they send in, rendering him totally blind [BBC News]. Researchers say TN’s successful performance was an example of the phenomenon “blindsight,” and say it suggests that some small amount of information is being transmitted from his undamaged eyes to a more primitive part of his brain, which operates beneath the level of consciousness.

TN usually walks with a cane, but researcher Beatrice de Gelder convinced him to put it aside and to try to navigate the obstacle course without its help. He was able to do so flawlessly, despite being unable to consciously see any of the obstacles. Head down and hands loose by his side, he twisted his body to slalom slowly but surely between a camera tripod and a swingbin, and neatly stepped around a random series of smaller items. “At first he was nervous,” says de Gelder. “He said he wouldn’t be able to do it because he was blind.” The scientists broke into spontaneous cheers when he succeeded [Nature News].

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Researchers have discovered that it’s simple to trigger the illusion of body swapping: All it takes are some goggles, live-streaming video, and a bit of a belly rub. Spooky as it sounds, neuroscientists … were able to use simple camera trickery to fool volunteers into perceiving the bodies of both mannequins and other people as their own [New Scientist].

In an article published in the journal PLoS ONE researchers describe an experiment in which the volunteer put on a pair of high-tech goggles and was told to look down. At the same time, video was beamed into the glasses’ displays from a camera attached to the head of a mannequin. In short, the study participant was looking in the direction of his or her own stomach, but actually seeing the stomach of the mannequin. At that moment, the person conducting the experiment would rub both the stomach of the mannequin and of the research subject. Subjects reported that they felt as if they were feeling the touch on the mannequin [Wired News]. What’s more, when the mannequin’s belly was threatened with a knife, electrodes on the test subject’s skin showed a physiological stress response.

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Researchers have determined the mechanism by which the world’s simplest vision system works. A team of biologists spent a decade studying the larvae of the marine rag-worm Platynereis, a tiny creature with just two cells that respond to light and direct the worm to swim towards it. The rag-worm and other zooplankton like krill drift in the ocean’s water columns, swimming up from the depths towards the light in order to graze on marine plants called phytoplankton near the surface. This movement, called phototaxis, is the biggest biomass displacement in the world [AFP].

The rag-worm has two cells that work together as “proto-eyes”: one pigment cell and one light-sensitive cell. First, the pigment cell absorbs light and casts a shadow over the photoreceptor cell. The shape of the shadow varies according to the position of the light source. The photoreceptor cell then converts this light signal into electricity, sending it in a signal along a nerve that connects to a band of cells endowed with thin hairs, called cilia, that beat to displace water [AFP]. So although the worm sees no images, it can sense the difference between light and dark and swim in the right direction.

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Researchers have used a CT scanner to peer inside the hollow, fossilized skulls of a group of meat-eating dinosaurs that dominated the Jurassic Period, and found that the Tyrannosaurus rex had another advantage besides its size, speed, and pointy teeth–it also had an excellent sense of smell. Study coauthor Darla Zelenitsky says the scans show the impressions left on the skull by different brain regions, and says the T. rex had the biggest olfactory bulb, which regulates the sense of smell.

Zelenitsky says the findings suggest that the T. rex relied on smell extensively. “It’s probably fairly significant, because the sense of smell was likely used for foraging or searching for food,” Zelenitsky said. “And as well, it could have been used for patrolling relatively large home ranges. So, in that respect, it would have been a significant part of the biology and daily activities of the animal” [Calgary Herald].

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Tennis referees are far more likely to make wrong “out” calls than wrong “in” calls, according to a new study. A quirk of our visual perception system, which helps us anticipate the motion of an object, seems to bias our perception of where a speeding tennis ball stops moving. “This is not a problem with referees,” says study co-author David Whitney…. “It’s a consequence of human visual processing … a visual illusion caused by a mechanism that allows the system to localize a moving object” [Scientific American].

The idea to study this visual illusion in a real-world context came to Whitney during a Wimbledon match as he watched a player challenge and overturn a referee’s call. For the study, published in Current Biology [subscription required], the researchers used Hawk-Eye technology, a system of high-speed cameras that is often used for contested calls in tennis matches. Three scientists independently reviewed video and instant replay of 4,457 randomly selected points from the 2007 Wimbledon championships. Of the 83 calls that the video and instant replay showed were wrong, 70 were “out” calls [Scientific American]. Without the visual bias, there should have been the same number of wrong “out” calls as “in” calls.

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Volunteers who held a warm cup of coffee in their hands were more likely to rate other people as warm, generous, and sociable, a new study has found, in contrast to those subjects who cradled a cup of ice coffee. In a second experiment, people who held a heating pad were more likely to give a small reward to a friend than keep it for themselves, in contrast to those who held an icepack. In other words, researchers concluded, holding something warm makes you feel more generous toward others; holding something cold makes you, well, cold and selfish [Scientific American].

The findings offer a neat reversal of another recent study, which also studied the phenomenon of the unconscious “priming” of thoughts; in that earlier study, volunteers who experienced social rejection were found to prefer a hot beverage to a cold one, presumably as a way to restore their good spirits. The message of both studies is that very subtle cues from our environment can significantly influence behavior and feelings, said lead researcher Dr. Lawrence Williams…. Physical and psychological concepts “are much more closely aligned in the mind than we have previously appreciated,” said Williams [AP].

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An electronic sniffer can not only determine when plants are under stress, it can also differentiate between those that have been damaged by caterpillars, mites, mildew, or by humans armed with a hole-puncher. In a new study, researcher Nigel Paul showed that an electronic nose can detect the subtle volatile organic compounds given off by plants that are under attack.

In previous experiments with artificial noses, researchers have found that they can tell the difference between champagne and other white wines, can find minuscule gas leaks in the space shuttle, and may even be able to detect the chemical compounds given off by cancer cells. But the new study, published in Environmental Science and Technology [subscription required], is the first to apply the technology to agriculture. Paul says that a number of electronic noses could be dotted around a glasshouse, checking the air for the early signs of pest attack. Portable electronic noses – about the size of a four-pack of beer – could be used to precisely locate infected plants [New Scientist].

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People who feel that they lack control while participating in lab experiments are more likely to see patterns where none exist, researchers say, in a finding that helps explain persistent beliefs in superstitions and conspiracy theories. In a new study, researchers manipulated volunteers’ perception of control and then watched the insecure subjects find connections where none existed in an apparent attempt to restore a sense of order to the world.

In one experiment, researchers gave half the volunteers a feeling of powerlessness and confusion by randomly scoring them right and wrong (and mostly wrong) on a series of questions. Then the volunteers had to find patterns. In one task, they were asked to find faint images in grainy patterns of dots. Half of the pictures had images and the others were random dots. While people in both groups correctly spotted the images, the group that felt they lacked control from a previous part of the experiment also “saw” images in 43 percent of pictures that were not there [Reuters].

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In a development that may pave the way for the invention of an “artificial nose,” researchers have found a way to mass-produce the odor receptors found in human nostrils. An artificial nose could have military applications: DARPA has taken an interest in the research, which it believes could lead to the development of tools to replace drug- and bomb-sniffing dogs [io9]. But the technology could eventually be used in medical diagnostics as well, as diseases like skin and bladder cancer have distinctive odors.

Many researchers worldwide are working on “E-noses”, which detect the same molecules that make up the scents we recognise…. However, while many rely on sensors constructed from artificial materials, the US researchers are working on a sensor with the biology of the human nose at its centre [BBC News].

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In Africa’s Lake Victoria, researchers believe they’ve caught a fish population in the act of splitting into two distinct species. Researchers say this example of evolution-in-action is remarkable because the two sub-populations of fish aren’t geographically isolated and could theoretically interbreed, but adaptations to their vision are causing them to diverge.

Lead researcher Norihiro Okada and his colleagues had previously shown that cichlid fish in Lake Victoria’s shallow waters are bathed in bluer light, while the turbid water of the lake predominantly lets redder light filter down to fish living in deeper water. The researchers showed that the fish’s eyes have adapted to this difference so that fish that live in deeper water have a pigment in their eyes that is more sensitive to red light, while shallow-water fish have a pigment that’s sensitive to blue [Science News]. Okada’s new study, published in Nature [subscription required], shows that those eye adaptations have also affected mating patterns.

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In a promising result for gene therapy, researchers have dramatically improved the vision of several patients with a rare, inherited eye condition called Leber congenital amaurosis. The early study was intended to simply test the safety of the treatment, but the patients displayed such significant improvement that researchers decided to publicize the results.

Gene therapy works on a simple principle - to replace a malfunctioning gene, and restore function to a part of the body affected by a genetic disorder. In practice, however, it has proved very difficult to find ways to introduce the new gene copies in the correct tissues, and experiments in animals have had mixed results [BBC News].

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A new psychological study has found that social exclusion made test subjects feel literally cold, and increased their preference for warm beverages and soup. It’s the latest finding from the field of embodied cognition, in which researchers have shown that the language of metaphor can activate physical sensations, and vice versa…. “We know that being excluded is psychologically painful,” said the lead author, Chen-Bo Zhong… “and here we found that it feels just like it’s described in metaphors,” like icy stare and frosty reception [The New York Times].

Researchers conducted two experiments in the study, which was published in the journal Psychological Science [article not yet online]. In the first, they divided 65 students into two groups. They asked the first group to recall a time when others left them out. The second group recalled a time when they were included by others. In the middle of this, purportedly in response to maintenance staff, they were asked to estimate the temperature of the room [WebMD]. They found that the students who had been remembering an emotionally painful moment of rejection estimated that the room was much colder than the other students.

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In a match-up between an annoyed human brandishing a fly swatter and a buzzing fly, who wins? As most people know from frustrating experience, all too often the fly easily evades the human’s swat, and buzzes merrily into another region of the room. Now, using a high-speed camera, scientists have determined just how the fly makes its astoundingly effective escape.

Biologist Michael Dickinson used a video camera that shoots 5400 frames per second to record a fly’s precise motions when threatened with a swatting. The video showed that as a threatening object moved towards the fly from one direction, it shuffled its feat and positioned itself to take off in the opposite direction–all within 200 millisecionds. “They perform an elegant little ballet with their legs,” says Dickinson. “They move their legs around to reposition their bodies so that when they do jump, they will push themselves away from the looming threat” [NPR].

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Scientists have produced the cells that make up delicate inner ear hairs in mouse embryos, a step that could point the way to reversing hearing loss and curing congenital deafness. Sensory hair cells inside the cochlea, the auditory portion of the inner ear, convert sound waves into electrical impulses that are delivered to the brain. The loss of these minute hairs, or the nerves that control them, is the most common cause of hearing impairment and so-called nerve deafness [ABC Science].

Researchers used gene therapy to create the crucial cells: They used a virus to introduce a gene into the mice embryos, which caused non-sensory cells to turn into cochlear hair cells. While this preliminary experiment was done on normal-hearing mice, the discovery that the engineered cochlear cells functioned as well as natural cells was an important step. Says lead researcher John Brigande: “One approach to restore auditory function is to replace defective cells with healthy new cells…. Our work shows that it is possible to produce functional auditory hair cells in the mammalian cochlea” [Reuters].

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