Use It or Lose It: Why Language Changes over Time

Use It or Lose It: Why Language Changes over Time

More commonly used words are the least likely to evolve

CONSTANTLY EVOLVING: Two new studies show the words in a language that are used infrequently are subject to change rapidly over time.

The words used the most in everyday language are the ones evolving at the slowest rate, say two new studies published in Nature.

In one paper, researchers at Harvard University focused on the evolution of English verb conjugations over a 1,200-year period. In a separate study, a team at the University of Reading in England reviewed cognates (similar sounding words in different languages for the same object or meaning, such as "water" and the German "wasser") to determine how all Indo-European tongues progressed from a common ancestor that existed between 6,000 and 10,000 years ago.

"What our frequency effect allows us to do is identify…ultraconserved linguistic elements," says Mark Pagel, an evolutionary biology professor at Reading, about his research. "Namely, they're the words we use all the time."

In their search for cognates, Pagel and his team examined some 200 words in 87 Indo-European languages, including those for "water," "two," "to die" and "where." The number of distinct classes of cognates for each word ranged from one (indicating all the words sound similar) for frequently used concepts such as numbers to as many as 46 different basic sounds to describe a single entity such as a bird. The word for the number three in all Indo-European languages, for instance, is similar to the English version: from tres in Spanish to drei in German to the Hindi theen. In contrast, the word for bird has several different sounds associated with it like pajaro in Spanish and oiseau in French.

The researchers then narrowed their focus to the frequency of use of each of the words in just four Indo-European languages—English, Spanish, Greek and Russian. Pagel says the team found that they were used at similar rates across the board even if the words with the same meaning were not cognates. "The high frequency words in Spanish are the same as the high frequency English," he says. "That [indicated] that we could come up with a kind of Indo-European frequency of use."

By combining their data, the researchers determined that it would take as little as 750 years to replace less-used words and up to 10,000 years for new words to evolve in place of the most frequently used ones.

The Harvard researchers specifically studied the roots of English, tracing verb conjugations in the language from the time of Beowulf 1,200 years ago through Shakespeare in the 16th century to its current form. Over the years, several past tense forms of verbs have died out in English and now only one persists as a rule: adding "-ed" to the end of verbs. (Verbs that end in "-ed" in their past tense form "regular verbs" in modern English.)

Researchers scoured grammatical texts dating back to the days of Old English, cataloguing all the irregular verbs they came across. Among them: the still irregular "sing" / "sang," "go" / "went" as well as the since-regularized "smite" which once was "smote" in Old English but since has become "smited," and "slink," which is now "slinked" but 1,200 years ago was "slunk." They located 177 verbs that were irregular in Old English and 145 that were still irregular in Middle English; today, only 98 of the 177 verbs have not been "regularized.'"

After calculating the frequency of use of each of the 177 irregular Old English verbs, researchers determined that the words that evolved most quickly into regular conjugational forms were used significantly less than those that went unchanged over time. In fact, their statistical analysis determined that given two verbs, if one was used 100 times less frequently than the other, it would evolve 10 times faster than the verb employed more often. They predict the next verb to fall into line will be wed, the past tense of which will regularize from wed to wedded.

By being more frequent, a verb is more stable," says study co-author Erez Lieberman, a graduate student in applied mathematics at Harvard University. He adds that both the Harvard and Reading papers lay out a case for a version of natural selection that acts on linguistic evolution and mirrors biological evolution. "Both studies," he says, "illustrate this profound effect that frequency has in the survival of a word."

Partha Niyogi, author of the book The Computational Nature of Language Learning and Evolution and a professor of computer science and statistics at the University of Chicago, says these empirical findings are consistent with theoretical models on the lexical evolution. "Languages are constantly changing," he notes. "In biological evolution that fact has been given a lot of attention, but the fact is that in languages this is happening all the time, [as well]. Darwin in [The Descent of Man] commented that languages were evolving over time, and it was just like speciation." 

Are You a Liar? Ask Your Brain

Are You a Liar? Ask Your Brain

Researchers use fMRIs to track blood flow in the brain to determine if someone is fibbing 

 
FULL OF IT?: An fMRI scanner detects changes in the magnetic properties in blood, particularly hemoglobin molecules in red blood cells that exhibit different magnetic properties depending on the amount of oxygen they contain.
Courtesy of the University of Sheffield

The mere thought of being interrogated—by a parent, boss or significant other—is enough to make one's blood pressure rise and pulse and breathing rates race. But contrary to popular belief, these signs of anxiety are not reliable indicators of a person's honesty. Instead, researchers are looking into the brain to separate liars from truth tellers.

The act of lying or suppressing the truth triggers activities in the brain that send blood to the prefrontal cortex (located just above the eye sockets), which controls several psychological processes, including the one that takes place when a person crafts a new rather than a known response to something. "Lying is an example of this type of executive response, because it involves withholding a truthful response," says Sean Spence, a professor of general adult psychiatry at the University of Sheffield in England. "When you know the answer to a question, the answer is automatic; but to avoid telling me the true answer requires something more."

Spence and colleagues use functional Magnetic Resonance Imaging (fMRI) technology to determine whether someone is fibbing by tracing blood flow to certain areas of the brain, which indicates changes in neuronal activity at the synapses (gaps between the neurons). "If you're using fMRI, the scanner is detecting a change in the magnetic properties in the blood," he says. More specifically, hemoglobin molecules in red blood cells exhibit different magnetic properties depending on the amount of oxygen they contain. The most active brain regions use—and thereby contain—the most oxygen.

An fMRI is a full body scanner—"rather like being in a long cigar box," Spence says. The subject is completely immersed by the machine, which contains microphones, speakers and a keyboard that enable him or her to communicate with researchers. Researchers compare images taken of the subjects at rest with those snapped after they had been asked to respond to a series of questions.

Polygraph, or lie detector, tests are the most well-known method of discerning fact from fiction, but researchers say they are not reliable because they measure anxiety based on a subject's pulse or breathing rate, which can easily be misread. "They're not detecting deception but rather the anxiety of being…[accused of deception]," Spence says. "It's known that psychopaths have a reduced level of anxiety," that would allow them to fool a polygraph. The fMRI, he says, images the actual processes involved in deception.

Spence's research faced its greatest test in June during a demonstration of the technology on an episode of a three-part English reality TV show called Lie Lab, which studied the truthfulness of a man accused of being a terrorist, a woman who claimed to have been abused as a child, and a woman convicted of poisoning a child in her care. Spence and his team used an fMRI to study Susan Hamilton of Edinburgh, Scotland, who in 2003 was convicted of poisoning with salt a girl diagnosed with a terminal metabolic condition. Hamilton, who was in charge of feeding the child via a feeding tube that led directly into her stomach, was arrested after the girl was admitted to the hospital with massive blood sodium levels. The police testified that a syringe full of salt was found in Hamilton's kitchen, but she denies any knowledge of it. The woman was released from prison last year and has continued to search for ways to publicly prove her professed innocence.

This provided a stage for Spence to extend his research, which until then had only been conducted on young, healthy university students. In most of Spence's tests he and his team asked subjects questions twice, which they would answer first honestly then dishonestly. In Hamilton's case, there were specific events in dispute and she was answering queries about them under duress.

The researchers scanned Hamilton, 42, four times; during each scan they grilled her about the poisoning. With the fMRI, Spence was able to see that she activated extensive regions of her frontal brain lobes and also took significantly longer to respond when agreeing with the cops' account. The results did not prove her innocent, Spence says, but suggested that her brain was responding as if she were innocent.

Spence acknowledges that the results might have been more accurate if he had first done a baseline study that included asking her more general questions unrelated to the charges. Unfortunately, TV is show biz and his time with her was limited. "Being able to study this lady pointed out problems with the technique," he notes. "There are a number of control studies we want to do."

Spence says the technology is not ready to be widely used in criminal investigations, noting that there is a big difference between determining deception in innocuous instances (such as whether someone had a cup of coffee that morning) and in serious crimes. But it hasn't stopped scores of inmates from contacting him in the hope that his technique might help prove their innocence.

Companies have already begun to market fMRI tests as accurate lie detectors, even though Spence says the results achieved during controlled studies are rarely duplicated during far less predictable police probes. Cephos Corporation in Pepperell, Mass., last year began to offer what it calls "commercially available fMRI-based deception detection services," following a 2005 study of 61 individuals that claimed to be able to determine deception with more than 90 percent accuracy. No Lie MRI, Inc., in Tarzana, Calif., offers similar services.

But Spence warns that more research is needed before fMRIs can be accurately used to determine someone's guilt or innocence in a criminal case. He is currently preparing to apply for grants to study the technology on volunteers from different economic backgrounds as well as those with a history of personality problems and depression who are more likely to find themselves in legal hot water.

Tomorrow's Space Telescopes: Bigger and Better

Tomorrow's Space Telescopes: Bigger and Better

Astronomers always want bigger, better telescopes and spacecraft to get the best information they can about the universe.

And despite federal pocketbook pinching—level funding devalued by rising inflation—new and relatively affordable technologies to squeeze the most out of spacecraft are just around the corner, said Dennis Ebbets, a spokesperson for Ball Aerospace in Boulder, Colo., here at the Space Telescope Science Institute's Astrophysics 2020 meeting at Johns Hopkins University this week.

Although the bill for the still-in-development James Webb Space Telescope (JWST) may top more than $1 billion, Ebbets noted the observatory is a proof-of-concept for the future. Engineers intend to squeeze the final 21-foot (6.5-meter) diameter observatory into an Ariane 5 rocket payload space, which tops out in diameter at less than 18 feet (5.4 meters).

"It's very impressive," Ebbets said of the JWST prototype's ability to fold up into a tight space. "The technologies exist or can exist for getting bigger [telescope] apertures into modest launch vehicles."

Speedier space downloads

As bigger telescopes with more sensitive light-gathering sensors launch into space, Ebbets said, they'll have to handle beaming that data back to Earth more efficiently.

"We're not getting every pixel of data back from telescopes right now," he said of most space observatories' on-board data processing systems.

The idea is similar to converting a large-image format to a smaller file size by a factor of 10. During the compression process, some of the image data is inevitably lost.

Sending telescope data back to astronomers on the ground at about 2.5 Gigabits per second—a DVD-worth of data in a few seconds—is now possible, Ebbets said, using laser-based communication technology called LaserCom. Such a speed could cut spacecraft weight, make real-time observations possible and circumvent compression problems as telescope data would not need to be processed into smaller packages before shipment to Earth.

"I can imagine having Mars missions or other deep-space missions sending data back to Earth in very large data packages," he said.

Automated exploration

Ebbets also noted that automating spacecraft repair, refueling and other tasks will help squeeze the value out of unmanned missions by eliminating the expense of humans in space.

One way to do that is with instruments that grant better "machine vision" for automated yet delicate on-orbit tasks such as docking.

"These things actually do exist," Ebbets said of new light detection and ranging (LIDAR) systems his company has designed. The device's 3-D laser technology helps a spacecraft gauge its distance from another object such as an asteroid or other probe—precise within under an inch (2 centimeters).

"These allow for autonomous rendezvous and docking in space, and allow two spacecraft to operate in close proximity to each other," he said. "LIDAR could also be used for hazard avoidance during lunar or Mars missions."

As such technologies such as LaserCom and LIDAR mature and make their way onto new spacecraft, Ebbets said, making the most of increasingly tight funding will continue to push the development of spaceflight technologies.

"We all want to get the most and best science out of the budgets we have available," Ebbets said. "We're now seeing less costly things could be made much more capable."

When Milky Way and Andromeda Collide, Earth Could Find Itself Far From Home

When Milky Way and Andromeda Collide, Earth Could Find Itself Far From Home

Galactic "Brangelina" combo could knock our solar system out of the Milky Way

 

A COSMIC COLLISION such as this one between spiral galaxies NGC 2207 and IC 2163 will befall the Milky Way and Andromeda galaxies within the sun's lifetime, according to a new simulation.
NASA/HUBBLE HERITAGE TEAM (STScI)

If Homo sapiens can stick it out on Earth for another two billion years, our descendants may witness quite a show in the night sky. Researchers estimate that the Milky Way will collide with its nearest neighbor, the Andromeda galaxy, at around that time—well before the sun collapses into a white dwarf, perhaps destroying the Earth in the process.

This close encounter of the galactic kind could easily kick our solar system to the farthest reaches of the galaxy, and there is a small chance we might even take up residence in Andromeda, according to astronomers T. J. Cox and Abraham Loeb of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

The pair simulated the collision by estimating the relative speed between the two galaxies and the amount of gas and dark matter in the intervening space, which exerts a drag on their motions.

Andromeda is currently 2.3 million light-years from our galaxy. Researchers know that the two neighbors are approaching each other at 120 kilometers per second, but they are far less certain of Andromeda's sideways speed. If moving fast enough to the side, it would miss us entirely.

"I think it's very likely they will come together," Loeb says. "The issue is, will it be [in] three billion years, five billion years or 10 billion years?"

Taking their cue from the latest models of the galaxies' structures, Cox and Loeb assumed a relatively small sideways motion. Based on this assumption, Andromeda would first graze the Milky Way two billion years from now, they report in a paper submitted to the Monthly Notices of the Royal Astronomical Society. The two galactic cores would orbit each other for another three billion years before merging.

During that time, the stars making up the two spiral galaxies would slowly coalesce into a more elliptical combo galaxy, "Milkomeda" (or the Andromedy Way, if you prefer). Although most of the stars would be too sparsely spaced to bump together, one galaxy's gravity would jostle the other's stars.

The fate of the sun, which is expected to last at least until the simulated merger, would depend on where it was in its 24,000 light-year-wide orbit around the galactic core. The researchers estimate that by the time the cores had fused, the solar system would have a 50 percent chance of being swept to a wispy tail extending from Milkomeda, three times further out from galactic center than it is now.

Cox and Loeb also find a 3 percent chance of the sun being nudged into orbit around Andromeda when the two galaxies first collide. Of course, they note, different assumptions for the simulation would likely result in different outcomes.

"What's cool about this," says astronomer Gregory Laughlin of the University of California in Santa Cruz, "is they track a reasonable orbit for the sun … and sort of give a plausible range of scenarios for what the solar system might encounter. … It's fun to speculate on this stuff."

Diabetes drug to warn of risk to heart

Diabetes drug to warn of risk to heart

The government slapped a prominent, though confusing, warning on the popular diabetes drug Avandia on Wednesday — telling patients that it may, or may not, increase the risk of heart attacks.

The move is less stringent than steps Canada took last week to restrict the drug's use to hard-to-treat diabetics.

But the U.S. Food and Drug Administration concluded that studies are too contradictory to tell if Avandia really is riskier than other treatments for Type 2 diabetes.

So the FDA described the controversy in a black box on Avandia's label — the most severe type of warning the agency can require — pending further research. Unlike most black-box warnings that urge strong caution, Avandia's says, "The available data on the risk ... are inconclusive."

"It's still an open question," said Dr. John Jenkins, FDA's drug chief. Still, he said, "We want to make sure health care providers and patients are aware this signal of risk has been identified."

Patients may need a medical dictionary to interpret the new warning. It says Avandia may be associated with "myocardial ischemic events such as angina or myocardial infarction."

In layman's terms, that's chest pain or a heart attack. Manufacturer GlaxoSmithKline PLC is to develop a pamphlet that will come with each bottle putting the warning in easier-to-understand language.

Glaxo also agreed to FDA's demand for a major study directly comparing Avandia and its competitors' heart effects. The study will begin by next November and won't end until 2014, but the FDA will order interim checks to see how patients are faring and if it's possible to settle the issue any sooner.

"It isn't as if we're going to be clueless until 2014," said Dr. Janet Woodcock, FDA's chief medical officer.

For now, Type 2 diabetics who also have heart disease or are at especially high risk for it should talk with their doctor about Avandia's potential heart effects as they decide among treatment options, FDA advised.

In contrast, Canada's drug regulators last week withdrew approval of Avandia as a stand-alone therapy except for patients who can't tolerate older competitors. Health Canada announced that Avandia should be used only in combination with certain other drugs for hard-to-control blood sugar.

Dr. Steven Nissen of the Cleveland Clinic, who first brought the heart attack issue to public attention, said he preferred Canada's approach — but that Wednesday's warning is important, if imprecise.

"It is a black-box warning, and no matter what the language says, it's telling you something," Nissen said. "A black-box warning is telling you there's enough evidence here that physicians and patients ought to be concerned."

What should Avandia users do?

"The easy answer is talk to your doctor, but that doesn't help much because the doctors are just as much in the dark as the patient," said Dr. Thomas Pickering, a cardiovascular disease expert at Columbia University Medical Center and an FDA adviser. While he isn't convinced of the heart attack risk, he advises trying other drugs first, and adding Avandia if they're not enough.

It is not the first warning about Avandia's heart effects. In August, the FDA ordered a black-box warning for both Avandia and a competitor, Actos, that they may cause or worsen heart failure, a different cardiac problem.

About 1 million Americans with Type 2 diabetes use Avandia. It helps control blood sugar by increasing the body's sensitivity to insulin.

Diabetics already are at increased risk of heart disease. Type 2 diabetes, the most common form, is linked to obesity, which in turn harms the heart. Plus, high blood sugar over time damages blood vessels. Lowering glucose prevents many diabetes complications, such as blindness and kidney failure.

The hope is that intensive treatment also will lower the risk of a heart attack.

But on Wednesday, the FDA also said Avandia's competitors must change their own labels — to say none has been proven to reduce diabetics' risk of heart disease. That includes the treatment mainstay metformin, a family of medicines called sulfonylureas, and Actos.

The Avandia question, however, is whether it might actually increase heart attacks.

Last May, Nissen and colleagues published an analysis that found Avandia users had a 43 percent higher risk of heart attack than other diabetics. The analysis added 42 different studies that included 14,000 patients, most that compared Avandia users with diabetics given a dummy pill and tracked them for six months.

But three other studies together tracked the same number of patients for a few years — and neither confirmed nor refuted the heart attack risk, FDA found. Those studies mostly compared Avandia to other diabetes medications, and some suggested Avandia might even help diabetics live longer, Jenkins said.

Last summer, FDA's independent scientific advisers ruled the heart risk probably was real but that Avandia should stay on the market with warnings. In further debate, FDA's own employees sharply split on how to address Avandia, although Woodcock said a majority wanted it kept on the market.

A scientist works in GlaxoSmithKline's plant in Singapore, December 16, 2005. The U.S. Food and...