Chapter 15. Language and Our Divided Brain
Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.
By NICHOLAS BAKALAR Concussions are not as common in Major League Baseball as they are in professional football, but they happen often enough, with players getting hit by pitches, running into walls or catching a knee in the head sliding into a base. Catchers are particularly at risk — a foul tip off the mask will snap the neck back and give the brain a solid rattle. Collisions at the plate take a toll, too. Now, a study published in the American Journal of Sports Medicine suggests that position players in the majors who sustain concussions do not hit as effectively in their first weeks back after their injury. Under Major League Baseball rules, players can return after a concussion if they pass the concussion protocol — a series of interviews and tests of physical and mental functioning. But the new study found that even after passing the tests and having no apparent symptoms, hitters showed an initial decline when they returned to action. The study identified 66 position players who had concussions between 2007 and 2013, including some who never went on the disabled list. The study then compared their performance in the weeks before and after the injury. The gap was noticeable. In the two weeks before their injuries, the players hit .249 with a .315 on base percentage and a .393 slugging average. For the two weeks after the injury, their line was .227/.287/.347. Baseball instituted a seven-day disabled list in 2011, specifically to let players recover from concussions while allowing the team to maintain a full roster. But there is no set time that a player must stay out after a concussion. If he passes the protocol, he is cleared to play. © 2015 The New York Times Company
Keyword: Brain Injury/Concussion
Link ID: 20715 - Posted: 03.24.2015
By Nicholas Weiler Where did the thief go? You might get a more accurate answer if you ask the question in German. How did she get away? Now you might want to switch to English. Speakers of the two languages put different emphasis on actions and their consequences, influencing the way they think about the world, according to a new study. The work also finds that bilinguals may get the best of both worldviews, as their thinking can be more flexible. Cognitive scientists have debated whether your native language shapes how you think since the 1940s. The idea has seen a revival in recent decades, as a growing number of studies suggested that language can prompt speakers to pay attention to certain features of the world. Russian speakers are faster to distinguish shades of blue than English speakers, for example. And Japanese speakers tend to group objects by material rather than shape, whereas Koreans focus on how tightly objects fit together. Still, skeptics argue that such results are laboratory artifacts, or at best reflect cultural differences between speakers that are unrelated to language. In the new study, researchers turned to people who speak multiple languages. By studying bilinguals, “we’re taking that classic debate and turning it on its head,” says psycholinguist Panos Athanasopoulos of Lancaster University in the United Kingdom. Rather than ask whether speakers of different languages have different minds, he says, “we ask, ‘Can two different minds exist within one person?’ ” Athanasopoulos and colleagues were interested in a particular difference in how English and German speakers treat events. © 2015 American Association for the Advancement of Science
By Matthew J.X. Malady One hour and seven minutes into the decidedly hit-or-miss 1996 comedy Black Sheep, the wiseass sidekick character played by David Spade finds himself at an unusually pronounced loss for words. While riding in a car driven by Chris Farley’s character, he glances at a fold-up map and realizes he somehow has become unfamiliar with the name for paved driving surfaces. “Robes? Rouges? Rudes?” Nothing seems right. Even when informed by Farley that the word he’s looking for is roads, Spade’s character continues to struggle: “Rowds. Row-ads.” By this point, he’s become transfixed. “That’s a total weird word,” he says, “isn’t it?” Now, it’s perhaps necessary to mention that, in the context of the film, Spade’s character is high off nitrous oxide that has leaked from the car’s engine boosters. But never mind that. Row-ad-type word wig outs similar to the one portrayed in that movie are things that actually happen, in real life, to people with full and total control over their mental capacities. These wordnesias sneak up on us at odd times when we’re writing or reading text. I was in a full-on wordnesiac state. On one of my spelling attempts, I think I even threw a K into the mix. It was bad. Here’s how they work: Every now and again, for no good or apparent reason, you peer at a standard, uncomplicated word in a section of text and, well, go all row-ads on it. If you’re typing, that means inexplicably blanking on how to spell something easy like cake or design. The reading version of wordnesia occurs when a common, correctly spelled word either seems as though it can’t possibly be spelled correctly, or like it’s some bizarre combination of letters you’ve never before seen—a grouping that, in some cases, you can’t even imagine being the proper way to compose the relevant term. © 2014 The Slate Group LLC.
Link ID: 20688 - Posted: 03.14.2015
By Gretchen Reynolds An easy, two-minute vision test administered on the sidelines after a young athlete has hit his or her head can help to reliably determine whether the athlete has sustained a concussion, according to a new study of student athletes, some as young as 5. The test is so simple and inexpensive that any coach or parent potentially could administer it, the study’s authors believe, and any league afford to provide it as a way to help evaluate and safeguard players. Those of us who coach or care for young athletes know by now that an athlete who falls or collides with something during play or seems dazed, dizzy, loses consciousness or complains of head pain should be tested for a concussion, which occurs when the brain is physically jostled within the skull. But most of us are clueless about how to test young athletes. The most commonly recommended sideline test is the Standardized Assessment of Concussion, a multipart examination during which athletes are asked to name the date, describe how they feel, memorize and recall lists of words, and do jumping jacks and other tests of coordination. Ideally, this assessment should be administered and evaluated by a medical professional. But while the sidelines of college and professional games are crowded with doctors and certified athletic trainers, few high schools and youth leagues have those resources. Most of the time, concussion testing in youth sports falls to volunteer coaches or parents with little if any medical experience. That situation prompted researchers at New York University’s Langone Concussion Center to begin wondering recently whether there might be other, easier diagnostic tools to check young players for concussions. Their thoughts soon turned to vision. “About 50 percent of the brain’s pathways are tied in some to way to vision and visual processing,” said Dr. Steven Galetta, chairman of neurology at N.Y.U. Langone Medical Center and senior author of the study, which was published in The Journal of Neuro-Ophthalmology. © 2015 The New York Times Company
Keyword: Brain Injury/Concussion
Link ID: 20680 - Posted: 03.12.2015
By Nicholas Bakalar Sleeping more than eight hours a day is associated with a higher risk for stroke, a new study has found. Researchers studied 9,692 people, ages 42 to 81, who had never had a stroke. The study tracked how many hours a night the people slept at the beginning of the study and how much nightly sleep they were getting four years later. Over the 10-year study, 346 of the study subjects suffered strokes. After controlling for more than a dozen other health and behavioral variables, the researchers found that people who slept more than eight hours a day were 46 percent more likely to have had a stroke than those who slept six to eight hours. The study, published online last week in Neurology, also found that the risk of stroke was higher among people who reported that their need for sleep had increased over the study period. The authors caution that the data on sleep duration depended on self-reports, which can be unreliable. In addition, the study identified an association between sleep and stroke risk, rather than cause and effect. Sleeping more may be an early symptom of disease that leads to stroke, rather than a cause. “It could be that there’s already something happening in the brain that precedes the stroke risk and of which excessive sleep is an early sign,” said the lead author, Yue Leng, a doctoral candidate at the University of Cambridge. In any case, she added, “we don’t have enough evidence to apply this in clinical settings. We don’t want people to think if they sleep longer it will necessarily lead to stroke.” © 2015 The New York Times Company
Helen Shen Repeated head injuries in American football have been linked to a degenerative brain disorder later in life. Dave Duerson suspected that something was wrong with his brain. By 2011, 18 years after the former American football player had retired from the Phoenix Cardinals, he experienced frequent headaches, memory problems and an increasingly short temper. Before he killed himself, he asked that his brain be donated for study. Researchers who examined it found signs of chronic traumatic encephalopathy (CTE), a degenerative condition linked to repeated head injuries. At least 69 cases have been reported in the literature since 2000, many in former boxers and American football players (P. H. Montenigro et al. Alz. Res. Ther. 6, 68; 2014) — heightening public concern about concussions during contact sports. Yet much about CTE is unknown, from its frequency to its precise risk factors and even whether its pathology is unique. Researchers now hope to take a major step towards answering those questions. At Boston University in Massachusetts on 25–27 February, neuroscientists will convene to examine the characteristics of CTE in brain tissue from post-mortem examinations. They hope to agree on a set of diagnostic criteria for the disease, and to assess whether it is distinct from other brain disorders, such as Alzheimer’s disease. The effort is sorely needed, says Walter Koroshetz, acting director of the US National Institute of Neurological Disorders and Stroke in Bethesda, Maryland, which is organizing the meeting. “The definition is the important piece that lets you do the rest of the research,” he says. And the stakes are high. CTE is associated with memory loss, irritability, depression and explosive anger, which are thought to appear and worsen years after repeated head trauma. © 2015 Nature Publishing Group
Keyword: Brain Injury/Concussion
Link ID: 20613 - Posted: 02.25.2015
By Tia Ghose A woman who had persistent headaches found there was a strange culprit for her pain: a Pilates class that caused her brain fluid to leak, according to a new case report. The brain fluid leak led to a persistent, worsening headache that was only alleviated when the 42-year-old British woman laid down, according to the report that was published in December in the Journal of Medical Case Reports. Though doctors never identified the exact location of the leak, the patient improved after a few weeks of bed rest and pain relievers. [The 16 Oddest Medical Cases] Cerebrospinal fluid is a clear liquid that flows between the brain and its outer covering, and between the spinal cord and its outer covering. Both of these structures' outer coverings are called the dura. This fluid cushions the brain and spinal cord and helps clear metabolic waste from the brain. However, sometimes holes can emerge in the dura, said Dr. Amber Luong, an otolaryngologist at the University of Texas Health Sciences Center in Houston. "The most common cause [of such leaks is] trauma, like a car accident," Luong told Live Science. Often, cerebrospinal fluid leaks out of a person's nose because there is a crack in the base of the skull and a tear in the dura lining the brain. One telltale sign of a cerebrospinal leak is that there is clear, metallic-tasting fluid coming out of just one nostril, Luong said. (The woman in this case did not experience this symptom because her tear was around the spinal cord, not the brain.)
Keyword: Brain Injury/Concussion
Link ID: 20579 - Posted: 02.16.2015
Ewen Callaway A mysterious group of humans from the east stormed western Europe 4,500 years ago — bringing with them technologies such as the wheel, as well as a language that is the forebear of many modern tongues, suggests one of the largest studies of ancient DNA yet conducted. Vestiges of these eastern émigrés exist in the genomes of nearly all contemporary Europeans, according to the authors, who analysed genome data from nearly 100 ancient Europeans1. The first Homo sapiens to colonize Europe were hunter-gatherers who arrived from Africa, by way of the Middle East, around 45,000 years ago. (Neanderthals and other archaic human species had begun roaming the continent much earlier.) Archaeology and ancient DNA suggest that farmers from the Middle East started streaming in around 8,000 years ago, replacing the hunter-gatherers in some areas and mixing with them in others. But last year, a study of the genomes of ancient and contemporary Europeans found echoes not only of these two waves from the Middle East, but also of an enigmatic third group that they said could be from farther east2 (see 'Ancient European genomes reveal jumbled ancestry'). Ancient genes To further pin down the origins of this ghost lineage, a team led by David Reich, an evolutionary and population geneticist at Harvard Medical School in Boston, Massachusetts, analysed nuclear DNA from the bodies of 69 individuals who lived across Europe between 8,000 and 3,000 years ago. They also examined previously published genome data from another 25 ancient Europeans, including Ötzi, the 5,300-year-old 'ice man' who was discovered on the Italian-Austrian border. © 2015 Nature Publishing Group
Link ID: 20571 - Posted: 02.13.2015
by Andy Coghlan Apple's the word. Chimpanzees can learn to grunt "apple" in two chimp languages – a finding that questions how unique our own language abilities are. Researchers have kept records of vocalisations of a group of adult chimps from the Netherlands before and after the move to Edinburgh zoo. Three years later, recordings show, the Dutch chimps had picked up the pronunciation of their Scottish hosts. The finding challenges the prevailing theory that chimp words for objects are fixed because they result from excited, involuntary outbursts. Humans can easily learn foreign words that refer to a specific object, and it was assumed that chimps and other animals could not, perhaps owing to their different brain structure. This has long been argued to be one of the talents making humans unique. The assumption has been that animals do not have control over the sounds they make, whereas we socially learn the labels for things – which is what separates us from animals, says Katie Slocombe of the University of York, UK. But this may be wrong, it seems. "The important thing we've now shown is that with the food calls, they changed the structure to fit in with their new group members, so the Dutch calls for 'apple' changed to the Edinburgh ones," says Slocombe. "It's the first time call structure has been dissociated from emotional outbursts." © Copyright Reed Business Information Ltd.
By Virginia Morell To prevent their hives from being attacked by invaders, wasps must quickly distinguish friend from foe. They typically do this by sniffing out foreigners, as outsiders tend to have a different scent than the home colony. Now researchers have discovered that, like a few other wasp species, a tiny social wasp (Liostenogaster flavolineata) from Malaysia employs an additional security measure: facial recognition. The wasps’ nests are typically found in large aggregations with as many as 150 built close together, and each colony faces persistent landing attempts by outsiders from these other nests. To find out why and how these wasps employ both vision and scent to determine if an incoming wasp is a comrade, scientists carried out a series of experiments on 50 colonies (see photo above) in the wild. Close to the nests, the researchers dangled lures made of captured and killed wasps. The lures had been given different treatments. For instance, some lures made from nest mates were coated with a foe’s scent, whereas outsiders were painted with the colony’s odor. The wasps, it turns out, pay more attention to facial markings than to scent when faced with a possible intruder, the team reports online today in the Proceedings of the Royal Society B. Indeed, in tests where the wasps could assess both an intruder’s face and scent, they relied solely on facial recognition and immediately attacked those whose faces they didn’t know, ignoring their odor. That’s the safest strategy, the scientists note, because the wasps can recognize another’s face at a distance, but need to actually touch another wasp to detect her scent—not a bad ploy for a tiny-brained insect. © 2015 American Association for the Advancement of Science
Link ID: 20547 - Posted: 02.05.2015
By ERICA GOODE A study suggests that newborn chicks map numbers spatially, associating low numerical values with space to their left. Credit Rosa Rugani/University of Padova Asked to picture the numbers from one to 10, most people will imagine a straight line with one at the left end and 10 at the right. This “mental number line,” as researchers have termed it, is so pervasive that some scientists have argued that the spatial representation of numbers is hard-wired into the brain, part of a primitive number system that underlies humans’ capacity for higher mathematics. Now a team of Italian researchers has found that newborn chicks, like humans, appear to map numbers spatially, associating smaller amounts with the left side and larger amounts with the right side. The chicks, trained to seek out mealworms behind white plastic panels printed with varying numbers of identical red squares, repeatedly demonstrated a preference for the left when the number of squares was small and for the right when the number was larger. The research, led by Rosa Rugani, a psychologist who at the time was at the University of Padova, will appear in Friday’s issue of the journal Science. Researchers demonstrated that chickens naturally order numbers left to right. When the number five is in the middle, chickens naturally go left for lower numbers and to the right for higher numbers. Publish Date January 29, 2015. In their report, the researchers said the findings supported the idea that the left-right orientation for numbers is innate rather than determined by culture or education — a possibility that was raised by some studies that found that in Arabic-speaking countries where letters and numbers are read right to left, the mental number scale was reversed. But the new research, Dr. Rugani and her colleagues wrote, indicates that orienting numbers in space may represent “a universal cognitive strategy available soon after birth.” Tyler Marghetis, a doctoral candidate in psychology at the University of California, San Diego, who has published research on the spatial association of numbers, called the researcher’s studies “very cool.” © 2015 The New York Times Company
By KEN BELSON A new study of N.F.L. retirees found that those who began playing tackle football when they were younger than 12 years old had a higher risk of developing memory and thinking problems later in life. The study, published in the medical journal Neurology by researchers at the Boston University School of Medicine, was based on tests given to 42 former N.F.L. players, ages 41 to 65, who had experienced cognitive problems for at least six months. Half the players started playing tackle football before age 12, and the other half began at 12 or older. Those former N.F.L. players who started playing before 12 years old performed “significantly worse” on every test measure after accounting for the total number of years played and the age of the players when they took the tests. Those players recalled fewer words from a list they had learned 15 minutes earlier, and their mental flexibility was diminished compared with players who began playing tackle football at 12 or older. The age of 12 was chosen as a benchmark because it is roughly the point by which brains in young boys are thought to have already undergone key periods of development. Research has shown that boys younger than 12 who injure their brains can take longer to recover and have poor cognition in childhood. The findings are likely to fuel an already fierce debate about when it is safe to allow children to begin playing tackle football and other contact sports. Youth leagues are under scrutiny for putting children at risk with head injuries. Pop Warner and many other youth leagues have added training protocols, have limited contact in practice and have adjusted weight and age limits to try to reduce head injuries and the risks associated with them. But some leagues continue to allow children as young as 5 to play tackle football. © 2015 The New York Times Company
By Ling Xin For many, the hardest part of learning to speak Chinese is mastering its complex tonal variations. Now, new research suggests a surprising explanation for how those tones arose: a humid climate. By examining the correlation between humidity and the role of tone in more than 3700 languages, scientists found that tonal languages are remarkably rare in arid regions like Central Europe, whereas languages with complex tone pitches are prevalent in relatively humid regions such as the tropics, subtropical Asia, and Central Africa. Humidity keeps the voice box moist and elastic, allowing it to produce correct and complex tones, the scientists explain online this month in the Proceedings of the National Academy of Sciences. “If the United Kingdom had been a humid jungle, English may also have developed into a tonal language,” they claim. So, next time you go to your Chinese class, don’t forget to wet your whistle! © 2015 American Association for the Advancement of Science.
Link ID: 20517 - Posted: 01.26.2015
By Amy Ellis Nutt Scientists have discovered what a traumatic brain injury, or TBI, suffered by a quarter-million combat veterans of Iraq and Afghanistan looks like, and it’s unlike anything they’ve seen before: a honeycomb pattern of broken connections, primarily in the frontal lobes, our emotional control center and the seat of our personality. “In some ways it’s a 100-year-old problem,” said Vassilis Koliatsos, a Johns Hopkins pathologist and neuropsychiatrist. He was referring to the shell-shock victims of World War I, tens of thousands of soldiers who returned home physically sound but mentally wounded, haunted by their experiences and unable to fully resume their lives. “When we started shelling each other on the Western Front of World War I, it created a lot of sick people . . . . [In a way,] we’ve gone back to the Western Front and created veterans who come back and do poorly, and we’re back to the Battle of the Somme,” he said. “They have mood changes, commit suicide, substance abuse, just like in World War I, and they really do poorly and can’t function. It’s a huge problem.” Many of the lingering symptoms of shell shock, or what today is known as neurotrauma, are the same as they were a century ago. Only the nature of the blast has changed, from artillery to improvised explosive devices. Koliatsos and colleagues, who published their findings in the journal Acta Neuropathologica Communications in November, examined the brains of five recent U.S. combat veterans, all of whom suffered a traumatic brain injury from an IED but died of unrelated causes back home. Their controls included the brains of people with a history of auto accidents and of those with no history of auto accidents or TBI. Koliatsos says he was prompted to do this study because he is both a pathologist and a neuropsychiatrist, and he sees many TBI cases, both in veterans and in young people with sports concussions.
// by Jennifer Viegas Researchers eavesdropping on wild chimpanzees determined that the primates communicate about at least two things: their favorite yummy fruits, and the trees where these fruits can be found. Of particular interest to the chimps is the size of trees bearing the fruits that they relish most, such that the chimps yell out that information, according to a new study published in the journal Animal Behaviour. The study is the first to find that information about tree size and available fruit amounts are included in chimp calls, in addition to assessments about food quality. "Chimpanzees definitely have a very complex communication system that includes a variety of vocalizations, but also facial expressions and gestures," project leader Ammie Kalan of the Max Planck Institute for Evolutionary Anthropology told Discovery News. "How much it resembles human language is still a matter of debate," she added, "but at the very least, research shows that chimpanzees use vocalizations in a sophisticated manner, taking into account their social and environmental surroundings." Kalan and colleagues Roger Mundry and Christophe Boesch spent over 750 hours observing chimps and analyzing their food calls in the Ivory Coast's Taï Forest. The Wild Chimpanzee Foundation in West Africa is working hard to try and protect this population of chimps, which is one of the last wild populations of our primate cousins. © 2015 Discovery Communications, LLC
by Ashley Yeager The brain's got its own set of pipes for flushing waste. The plumbing is delicate, however — a finding that may complicate scientists' attempts to create a blood test to diagnose traumatic brain injuries. Bumps to the head can knock proteins out of brain cells. The brain's plumbing system is supposed to wash these proteins away from the damaged area and eventually into the blood. But new research in mice shows that slight alterations to the brain's self-cleaning system, even from treating head injuries, can change the levels of proteins flushed into the blood. As a result, the proteins are unreliable markers of injury, researchers report January 14 in the Journal of Neuroscience. © Society for Science & the Public 2000 - 2015.
By Michael Balter If there’s one thing that distinguishes humans from other animals, it’s our ability to use language. But when and why did this trait evolve? A new study concludes that the art of conversation may have arisen early in human evolution, because it made it easier for our ancestors to teach each other how to make stone tools—a skill that was crucial for the spectacular success of our lineage. Researchers have long debated when humans starting talking to each other. Estimates range wildly, from as late as 50,000 years ago to as early as the beginning of the human genus more than 2 million years ago. But words leave no traces in the archaeological record. So researchers have used proxy indicators for symbolic abilities, such as early art or sophisticated toolmaking skills. Yet these indirect approaches have failed to resolve arguments about language origins. Now, a team led by Thomas Morgan, a psychologist at the University of California, Berkeley, has attacked the problem in a very different way. Rather than considering toolmaking as a proxy for language ability, he and his colleagues explored the way that language may helps modern humans learn to make such tools. The researchers recruited 184 students from the University of St. Andrews in the United Kingdom, where some members of the team were based, and organized them into five groups. The first person in each group was taught by archaeologists how to make artifacts called Oldowan tools, which include fairly simple stone flakes that were manufactured by early humans beginning about 2.5 million years ago. This technology, named after the famous Olduvai Gorge in Tanzania where archaeologists Louis and Mary Leakey discovered the implements in the 1930s, consists of hitting a stone “core” with a stone “hammer” in such a way that a flake sharp enough to butcher an animal is struck off. Producing a useful flake requires hitting the core at just the right place and angle. © 2015 American Association for the Advancement of Science.
|By Matthew H. Schneps Many of the etchings by artist M. C. Escher appeal because they depict scenes that defy logic. His famous “Waterfall” shows a waterwheel powered by a cascade pouring down from a brick flume. Water turns the wheel and is redirected uphill back to the mouth of the flume, where it can once again pour over the wheel in an endless cycle. The drawing shows us an impossible situation that violates nearly every law of physics. In 2003 a team of psychologists led by Catya von Károlyi of the University of Wisconsin–Eau Claire made a discovery using such images. When the researchers asked people to pick out impossible figures from similarly drawn illustrations, they found that participants with dyslexia were among the fastest at this task. Dyslexia is often called a learning disability. And it can indeed present learning challenges. Although its effects vary widely, some children with dyslexia read so slowly that it would typically take them months to read the same number of words that their peers read in a day. Therefore, the fact that people with this difficulty were so adept at rapidly picking out the impossible figures puzzled von Károlyi. The researchers had stumbled on a potential upside to dyslexia, one that investigators have just begun to understand. Scientists had long suspected dyslexia might be linked to creativity, but laboratory evidence for this was rare. In the years to follow, sociologist Julie Logan of Cass Business School in London showed that there is a higher incidence of dyslexia among entrepreneurs than in the general population. Meanwhile cognitive scientist Gadi Geiger of the Massachusetts Institute of Technology found that people with dyslexia could attend to multiple auditory inputs at once. © 2015 Scientific American
by Clare Wilson Could a lopsided gap help set us apart from our primate cousins? Our brains and chimps' are built differently in the areas that give us our social skills and language. The human brain has a 4.5-centimetre-long groove running deeper along the right side than the left. Chimp brains lack this asymmetry, as François Leroy of the French National Institute of Health and Medical Research in Saclay, and colleagues, have discovered. The groove's function is unknown, but its location suggests it played a role in the evolution of our communication abilities. "One day this will help us understand what makes us tick," says Colin Renfrew of the University of Cambridge, who was not involved in the study. Although our brain is about three times the size of a chimp's, anatomical features that only the human brain possesses are surprisingly hard to find. One known difference is in a region called Broca's area, which is also involved in speech and is larger in humans than chimps. The asymmetrical groove in humans was also known, but the new study, in which 177 people and 73 chimps had brain scans, revealed it is almost completely absent in the other primates. In humans, the deeper groove in the right brain lies in the region that controls voice and face recognition and working out what other people are thinking – our so-called theory of mind. The shallower groove on the left is at the heart of the areas associated with language. The lack of symmetry could signify that tissue layers in the right brain have been reorganised, says Leroy. © Copyright Reed Business Information Ltd.
By DOUGLAS QUENQUA A sparrow’s song may sound simple, consisting of little more than whistles and trills. But to the sparrows, those few noises can take on vastly different meanings depending on small variations in context and repetition, researchers have found. In humans, the ability to extract nearly endless meanings from a finite number of sounds, known as partial phonemic overlapping, was key to the development of language. To see whether sparrows shared this ability, researchers at Duke University recorded and analyzed the songs of more than 200 Pennsylvania swamp sparrows. They found that the sparrows’ whistles could be divided into three lengths: short, intermediate and long. The researchers then played the sparrows two versions of the songs — the original and a slightly altered one. They found that replacing a single short whistle with an intermediate one, for example, could significantly alter a bird’s reaction, but only if it came at the right moment in the song. “Identical sounds seemed to belong to a different category depending on the context,” said Robert F. Lachlan, a biologist now with Queen Mary University of London and the lead author of the study. The findings, which were published in Proceedings of the National Academy of Sciences, are part of a larger effort to better understand how human language evolved. If even birds rely on phonemic overlapping to communicate, Dr. Lachlan said, it could indicate that such features “developed independently of higher aspects of language.” © 2015 The New York Times Company