科学美国人

Recession: Just What the Doctor Ordered?

A study in the Canadian Medical Association Journal finds that recessions in wealthy countries can lead to better health habits, as people spend less on alcohol, tobacco and rich food. Adam Hinterthuer reports

It sounds paradoxical, but in wealthy countries, there's nothing like a recession to boost the population's health. According to a report in the September 1st Canadian Medical Association Journal, when our paychecks get lighter, we do more than tighten our purse strings—we also cinch our belts, kick bad habits and manage to lower our mortality rates.

Economic growth is usually associated with increased life spans, but the report says that’s only true for very poor countries. Researchers looked at data from dozens of 20th century international health studies and found that, once per-capita income passed $5,000, recessions actually helped health. During lean times, people in relatively wealthy countries drink and smoke less and stop overeating. They also go out less, which means fewer trips in the car. It all adds up to fewer deaths from things like lung cancer, liver disease, heart attacks and car crashes.

The researchers say that fewer hours in the office can also mean more time with family and friends. These close social interactions lead to less stress and better health. Of course, some people may find more family time to be like a lot of good medicine—hard to swallow.

—Adam Hinterthuer

September 2, 2009 | 2 comments

Making Music for Monkey Minds

A study in the journal Biology Letters finds that music based on monkey's own calls has similar effects on them that human music has on us. Cynthia Graber reports Music is known to make us happy, or calm, or sad. But do other animals respond to dulcet tones, as well? In studies, our primate cousins prefer silence to our music. But maybe we were playing the wrong tune.

Psychologist Charles Snowdon and musician David Teie teamed up to show that South American monkeys called cotton-top tamarins do respond to music: their own. The study was published in the journal Biology Letters.

With actual monkey calls in mind (MONKEY SOUNDS) Teie composed monkey music. (THREAT MUSIC) That tune was based on calls signifying anxiety. This one represents a happy, safe condition. (CALMING MUSIC) Snowdon played the compositions to tamarins. They became agitated hearing the threat song. And the more upbeat music put them in a mellow mood.

Much of what we communicate does depend on tone, not just words. This study suggests that what Snowdon calls the musical elements of speech has a deep evolutionary history. Just goes to show that music can “soothe a savage breast”—as long as it’s species appropriate. —Cynthia Graber

September 3, 2009 | 0 comments

Whistle While You Wing

A study in the Proceedings of the Royal Society B finds that pigeon wing-flapping produces distinct whistles, which can warn flock-mates, when merely taking off or when actively escaping predators. Karen Hopkin reports

When crested pigeons spot a predator, they give a little whistle. But the sound doesn’t come from their beaks. And according to a study published by The Royal Society, that whistle warns the rest of the flock to flee.

There’s safety in numbers, and a flock offers protection in part because it has so many eyes watching for danger. But it’s not clear how an individual sounds the alarm when it spots a predator. Maybe anytime one or two birds fly off, they all do. Just in case. Of course that kind of knee-jerk reaction could produce a lot of false alarms. So how can birds tell when their flockmates are seriously headed for the hills?

Scientists recorded the sounds made by the wings of crested pigeons during a routine liftoff (wing sound 1). And the noise their wings make during an emergency takeoff (wing sound 2). And they found that the sound make by wings flapped in terror includes a distinctive sort of whistle.

That noise alone will scatter a flock of feeding pigeons just as quick as the shadow of a passing hawk. And gives a whole new meaning to the expression, “on a wing and a prayer.” —Karen Hopkin

September 4, 2009 | 10 comments

Freeing the Mind to Forget

Young brains can forget painful memories, but old ones tend not to. An animal study in the journal Science finds that it may be possible to restore the old brain to its younger, more pliable state. Karen Hopkin reports

Some things are hard to remember. Others are hard to forget—especially things that are traumatic. But kids, it turns out, are better than adults at forgetting the bad stuff. Now scientists think they know why. According to an animal study in the September 4th issue of the journal Science, the brains of adults erect physical barriers that keep painful memories intact.

As adults, events that emotionally disturb us tend to get seared into our brains. And those memories can resurface, causing anxiety, fear and even post-traumatic stress disorder. But young brains are much more resilient—and can even erase unpleasant memories.

To get a better handle on this youthful forgetting, scientists studied the brains of young and old rats. They found that in adult brains, a physical net forms around certain cells in the amygdala, a structure associated with emotional memories. Adults that had been trained to associate a mild foot shock with a specific sound would flinch when they just heard the sound. But using a drug to dissolve this barrier restored the older rats’ ability to extinguish fearful memories. So rats that got the net-busting treatment stayed calm when they heard the sound.

One of the few instances where a net loss is a real gain.

September 7, 2009 | 0 comments

Tuning In to the Insect Philharmonic

Allison Beall of the Marshlands Conservancy in Rye, N.Y., led a twilight walk on September 5th to tune in to the insect sounds of the evening. Become more aware of the nocturnal symphony and, in the New York metropolitan area, help scientists count the insects during the \"Cricket Crawl\" on September 11th. Steve Mirsky reports

“Can you hear the end of the daytime insect? That’s the cicada. But I’m hearing crickets in the background, too. And just listen for a second, listen to how many different sounds you can hear.” That’s Allison Beall of the Marshlands Conservancy, a wildlife sanctuary in Rye, New York. She led a twilight walk through the preserve on September 5th.

“There’s a wonderful event that’s about to take place, on September 11th. There’s going to be a 'Cricket Crawl,' where people are going to go out and listen for the sounds of seven crickets and katydids, angle-winged katydids, and coneheads and various other night insects that are singing. And you can go to a Web site, and you can go out into your own backyard and listen for the sounds and actually be part of this scientific count. So all of the sounds are on the Internet, you can listen, you can see the insect close-up, and you can hear the sounds, and then you can send in the data from your own backyard.” The Web site is www.discoverlife.org/cricket or just google “Cricket Crawl.” The official count is taking place in the New York City metropolitan area, but anyone can get a new appreciation for the tiny wildlife producing nature’s nocturne.

“Okay, so we are just about at the end of this walk, and I want to tell you something. It has not anything to do with this walk, this is called a crepuscular walk. It was just a trick, it was a trick to get you to go outside in your own habitat and to listen for the same things that have been in your backyard or in your neighborhood all along and you just haven’t paid any attention to them. So here’s what I recommend. You go out and you get a flashlight, and at eight o’clock go out and follow the sounds that you’ve heard here tonight.

Do you realize how many different species of crickets and katydids and grasshoppers there are? And your job is to find them.” —Steve Mirsky

September 8, 2009 | 4 comments

Lie Detection with Handwriting

A study in the Journal of Applied Cognitive Psychology shows that handwriting tests could give polygraphs a challenge for lie detection. Cynthia Graber reports

When we lie, our brains work hard to make sure we get the story right and come off as truthful. Law enforcement officials try to tap into that effort, for example with polygraphs, to find out if a suspect is telling the truth. But such stress tests are beatable and not admissible in court. Now comes a report that handwriting tests could be a competitor to the familiar, but unreliable lie detector. The study appears in the Journal of Applied Cognitive Psychology.

Researchers at Israel’s Haifa University worked with 34 volunteers, who wrote truthful and false paragraphs on paper using a wireless electronic pen and a pressure sensitive tip. A computerized system measured pressure and stroke duration, both on the paper and in the air. Spatial measures, such as stroke length, height and width were also tracked. And the scientists found significant differences in pressure and spatial measures in deceptive statements compared with the truth.

The investigators say they need to validate this initial result and compare the technique with polygraphs and other lie detection tools. But perhaps in the future even a written claim of innocence could turn out to be a de facto confession. —Cynthia Graber

September 9, 2009 | 4 comments

On-the-Job Chimps Use Multiple Tools

A study in the American Journal of Primatology found that chimps wield different tools, each with a specific purpose, when attempting to catch tasty ants. Karen Hopkin reports

To do a job right, you need the right tools. Even a chimp knows that. According to a study in the American Journal of Primatology, chimps in the Congo use multiple tools to capture army ants.

You’ve probably seen footage of chimps using sticks to harvest honey or trap termites. But when it comes to collecting ants, the apes are all over the place—sometimes using tools, other times going in barehanded. To investigate these different techniques, a research team spent almost 10 years in the Congo, filming chimpanzees and collecting more than 1000 ant-fishing tools. And they found that the nastier the ant, the more likely the ape is to pick up a stick.

Chimps that tear open a nest with their hands risk getting bitten, and driving the insects away. Instead, many chimps use a series of tools: one to poke a hole in the nest, and another to dip in to gather a few tasty specimens. They even pick up tools left behind by other chimps.

Now, would an infinite number of chimpanzees using an infinite number of tools produce a Louis-the-Fourteenth-style table and chairs? It’s doubtful. But they’d probably catch an infinite number of ants. —Karen Hopkin

September 10, 2009 | 2 comments

Expedition Finds World War II Navy Wreck

A National Oceanic & Atmospheric Administration expedition has located a naval vessel lost off North Carolina during World War II's Battle of the Atlantic. Steve Mirsky reports The National Oceanic & Atmospheric Administration [NOAA], spends most of its time trying to understand and predict changes in the environment, along with conserving and managing coastal and marine resources. But its scientific expertise also just made it possible to locate the remains of a U.S. Navy patrol boat sunk by a German submarine in World War II.

The ship is the YP-3, which went down about 20 miles off the coast of Cape Hatteras, North Carolina, on June 19, 1942. Six sailors were killed in the attack. The wreck was found in 300 feet of water, in an area called the Graveyard of the Atlantic. That region is the final resting place for more than 80 American, British and German vessels lost in the Battle of the Atlantic.

The discovery was made during a summer archaeological expedition to research and document historically significant World War II shipwrecks. The remains will be surveyed, photographed and documented non-invasively, as the lost boats and ships are considered war graves. The researchers will also survey the marine life that has found a home among the ruins. —Steve Mirsky

September 11, 2009 | 0 comments

Prehistoric Human-Fashioned Fibers Found

A report in the journal Science announces the finding of the oldest known

human-fashioned threads, left in a cave by the Caucasus mountains about 34,000 years ago. Cynthia Graber reports

We humans love to decorate things. We wear flashy clothes, tie ribbons to suitcases and personalize the cases for our iPhones. And apparently we’ve had this tendency for a long, long time. More than thirty-four thousand years, to be exact.

Harvard researchers, together with Israeli and Georgian scientists, recently discovered the oldest known fibers used by humans, in a cave by the foothills of Georgia’s Caucasus Mountains. The researchers weren’t searching for thread. They were looking for tree pollen samples that would reveal how environmental and temperature fluctuations influenced people’s lives. But they knew they’d found something historic when they saw the colored thread.

The fibers were made from wild flax. Some were twisted, indicating rope, while others were knotted. They might have been used to sew pieces of clothing to keep these ancient people warm. Or maybe they tied together packs that would allow the group to be more mobile. The strings could also have served as handles for stone tools.

The fibers were colored black, grey, turquoise and pink. So in addition to cave paintings, we now have evidence of cave fashion, the first tentative steps on the way to the cover of Vogue.

—Cynthia Graber

September 14, 2009 | 13 comments

Tree Electricity Runs Nano-Gadget

A report in the journal IEEE Transactions on Nanotechnology shows that maple trees generate a small, but measurable amount of electricity, which can power tiny devices. Karen Hopkin reports

If scientists have their way, we may someday be tapping maples—not for pancake fixin’s, but for power. Because researchers from the University of Washington in Seattle have found there’s enough electricity flowing in trees to run an electronic circuit.

If you’ve ever made a potato battery, you know that plant material can generate current. But the energy in trees is something else entirely. The potato experiment uses electrodes of two different metals to set up a charge difference that gets local electrons flowing.

But in the current study, researchers use electrodes made of the same material. Sticking one electrode into a tree and another in the soil, they found that big leaf maples generate a steady voltage of up to a few hundred millivolts. That’s way less than the volt-and-a-half provided by a standard AA battery. So the scientists designed a gadget so small, with parts just 130 nanometers in size, that it can run on tree power alone. Their results appear in the journal IEEE Transactions on Nanotechnology.

If you’re nuts for renewable energy, you probably can’t get much greener than a forest full of electrici-tree. —Karen Hopkin

If scientists have their way, we may someday be tapping maples—not for pancake fixin’s, but for power. Because researchers from the University of Washington in Seattle have found there’s enough electricity flowing in trees to run an electronic circuit.

If you’ve ever made a potato battery, you know that plant material can generate current. But the energy in trees is something else entirely. The potato experiment uses electrodes of two different metals to set up a charge difference that gets local electrons flowing.

But in the current study, researchers use electrodes made of the same material. Sticking one electrode into a tree and another in the soil, they found that big leaf maples generate a steady voltage of up to a few hundred millivolts. That’s way less than the volt-and-a-half provided by a standard AA battery. So the scientists designed a gadget so small, with parts just 130 nanometers in size, that it can run on tree power alone. Their results appear in the journal IEEE Transactions on Nanotechnology.

If you’re nuts for renewable energy, you probably can’t get much greener than a forest full of electrici-tree. —Karen Hopkin

If you’ve ever been to a hairdresser, chances are you’ve found yourself scrambling for things to talk about as your locks are expertly coiffed. One common topic of discussion, at least for older Americans, is their health. Which leads social scientists to conclude that hairstylists may be in a unique position to encourage their clients to seek medical attention.

Keith Anderson, a professor of social work at The Ohio State University, started to study seniors’ relationships with their stylists after hearing such sessions referred to as “salon therapy.” He conducted a survey of hairdressers near the campus and found that clients often unburden themselves to stylists who offer a sympathetic ear along with a trim and highlights. More than 80 percent of salon workers surveyed said that their older clients share their problems during appointments, results published in the Journal of Applied Gerontology.

The problem, of course, is that hairdressers aren’t equipped to offer medical advice, although two thirds say they’d be willing to refer clients to someone who can help. Given that medieval barbers were also surgeons, getting stylists back into primary care should be pretty cut-and-dried. —Karen Hopkin

September 16, 2009 | 5 comments

Gene Therapy Cures Color-Blind Monkeys

In a study in the journal Nature, researchers report that they have used gene therapy to cure a form of color-blindess in adult squirrel monkeys that lack a visual pigment. Karen Hopkin reports

Now, here’s something you don’t see every day: scientists cure color-blind monkeys. According to a report published online in the journal Nature, researchers have used gene therapy to allow color-blind squirrel monkeys to look at their fruit in a whole new light.

In one type of squirrel monkey, 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.

Using a harmless virus, the scientists introduced the pigment gene into the eyes of color-blind adults. Lo and behold, about a month later, the monkeys with the new L-opsin gene were able to see hues they’d never seen before.

The research doesn’t mean we’ll soon be trying the same thing in humans. Because we’re not yet ready to monkey with our own selves that way. But the fact that a fellow primate was able to make and use the new pigments, even though they received the genes as adults, was a real eye-opener. —Karen Hopkin

September 17, 2009 | 3 comments

Salty Origins for Early Earth Biomolecules

In a study presented at the European Planetary Science Conference in Potsdam, researchers proposed that salt deposits on the early Earth's volcanic coasts enabled the conversion of amino acids into other important molecules for the start of life. Cynthia Graber reports

The early Earth’s oceans were home to a lot of interesting chemistry. Now scientists have found that amino acids thought to be present way back when could have been cooked into other compounds vital for life—an idea you should take with a grain of salt. Four billion years ago, the planet was probably covered by a salty ocean, dotted with volcanic islands and short lived continents. German researchers recently mimicked some of the chemistry taking place along the coasts of the volcanic islands. They created an approximation of primordial seawater. Then they evaporated it, to simulate what went on at those volcanic coasts. They baked the residue, creating salt crusts.

At those high temperatures, amino acids interacted with metal ions in the salt crusts and were converted into other important biological molecules, such as pyrroles—which are part of the structures of chlorophyll in plants and hemoglobin in animals. The scientists presented their findings September 17th at the European Planetary Science Conference in Potsdam.

Over hundreds of thousands of years, these novel compounds could have built up along the volcanic coasts, creating materials for the first living cells. Which were really worth their salt. —Cynthia Graber

September 18, 2009 | 11 comments

Mini T. Rex Recovered

In a study in the journal Science, researchers announce the discovery of a dinosaur 125 million years older and one ninetieth the size of T. Rex, but having virtually the same body plan as the giant dino. Cynthia Graber reports

Ask any young dinosaur fanatic about the mighty Tyrannosaurus rex and you’ll probably get a fairly accurate description: huge reptile, big head, powerful jaws, tiny little arms. Scientists had thought that the animal evolved its bizarre proportions as it grew to its gargantuan stature. But in this week’s issue of the journal Science, paleontologist Paul Sereno describes a newly discovered miniature tyrannosaurid that evolved millions of years earlier—and has all the attributes of the larger one.

The tiny dino had been excavated in Mongolia illegally and sold to a private collector. He contacted Sereno to evaluate the preserved tyrannosaurid. Sereno agreed to do so if the dinosaur was donated to science, and eventually returned to China.

The dinosaur is about nine feet long and had an estimated weight of only 150 pounds. But it’s all there—the tiny arms, the huge head, the large teeth and muscular jaw. A

hundred-twenty-five million years later, that animal’s descendants had ballooned into an almost exact replica more than 90 times larger. Sereno and his colleagues say the body plan must have been a successful structure for hunting prey—and ultimately thrilling dinosaur lovers everywhere. —Cynthia Graber

September 21, 2009 | 14 comments

Torture Interferes with Memory

In the journal Trends in Cognitive Sciences, psychologist Share O'Mara notes that torture can interfere with the brain's memory retrieval apparatus, making it counterproductive to the aim of producing useful information. Karen Hopkin reports

You’ve heard of waterboarding used as a means to get suspected terrorists to talk. Some people object to such methods on the grounds that they amount to torture. But in the journal Trends in Cognitive Sciences, psychologist Shane O’Mara of Trinity College in Dublin raises another objection: torture's not likely to work.

Proponents claim that waterboarding's effective because prisoners will tell the truth to make the interrogation stop. But O’Mara says that’s not supported by scientific evidence. Harsh interrogation doesn’t motivate prisoners to tell the truth. It motivates them to talk. Because while they’re talking they’re not being waterboarded. But that doesn’t mean that what they say is true.

What’s more, prolonged extreme stress impairs memory retrieval. American Special Ops soldiers have been shown to have trouble recalling things they’d learned before being subjected to food- or sleep-deprivation as part of their training. That’s because stress hormones can compromise brain activity, especially in regions involved in memory.

O’Mara notes that mildly stressful events actually facilitate recall. So simply capturing, moving and then questioning prisoners, he says, should be stressful enough to get the information flowing.

September 22, 2009 | 4 comments

Scary Music Scarier with Eyes Shut

In the journal Public Library of Science ONE, researchers report that listening to scary music with eyes shut may intensify the emotional experience. Cynthia Graber reports Scary music plays a key role in ramping up the fear factor in movies. The soundtrack has such an effect that I put my hands over my ears during the most frightening moments. Now researchers at Tel Aviv University report that scary music is even scarier if you shut your eyes.

In research published in the Public Library of Science ONE, they say this effect may lead to new ways to treat neurological diseases. Volunteers listened to Hitchcock-style music twice: once eyes open and once eyes shut. With eyes closed, their amygdalas lit up. That’s the region of our brains that processes emotions. Volunteers said they also felt the emotional effects of the music much more in the dark.

Scientists say shutting our eyes might synch up different brain activities, allowing our brains to “better integrate the highs and lows of the emotional experience.” The researchers hope that these findings could lead to music-based therapies for conditions like depression and schizophrenia.

As for me, during some of those scary movie scenes, music does sneak through my hands into my ears—good thing I leave my eyes open. —Cynthia Graber

September 23, 2009 | 7 comments

Drink Now, Pay Later

A study with animals in the Proceedings of the National Academy of Sciences shows that alcohol abuse in adolescence leads to a lifetime of poor decision-making skills. Karen Hopkin reports

We all know that drinking can cloud judgment. That’s why you should never e-mail an ex after you’ve had a few. But for teenagers, doing dumb things now because of alcohol may be just the start. Because research with animals suggests that drinking during adolescence can set you up for a whole lifetime of bad decisions. The study is in the Proceedings of the National Academy of Sciences.

People who abuse alcohol when they’re young don’t always make good choices as adults. But it’s been unclear whether the drink gives them the stupids, or whether folks prone to poor choices are predisposed to drink.

One way to tackle the question is by studying alcohol intake in animals, like rats. But rats don’t like to drink. So to make the alcohol more palatable, scientists infused it into a tasty “gel matrix”. Yes, the researchers gave teenage rats Jello shots. And the animals’ decision-making ability stayed impaired well into adulthood…as measured by their tendency to chase after rewards with associated high risk rather than taking a sure thing. So, young party animals, remember the words of Faber’s Dean Wormer: “Drunk and stupid is no way to go through life, son.” —Karen Hopkin

September 24, 2009 | 3 comments

Water on the Moon

Studies in the journal Science report that instruments on three different spacecraft have found evidence for widespread trace amounts of water on the moon. Karen Hopkin reports

For all you space buffs who like to keep track of where the water is, it looks like you can add our very own moon to your list. Because according to a trio of papers appearing in the journal Science, the lunar surface is wetter than we realized.

Forty years ago, Apollo astronauts brought a bunch of moon rocks back home. For the most part those samples showed no traces of water whatsoever. Those that seemed even the slightest bit moist were thought to have been contaminated by water from Earth—because the containers they were stored in turned out to be leaky.

But now scientists say they’ve spotted water right on the moon’s surface. Using instruments on three different spacecraft, the scientists detected the chemical signature of good old H2O. And they think the water springs from the moon itself. The lunar soil is nearly 50 percent oxygen, and the scientists think that hydrogen comes from the solar wind that pounds the moon’s surface.

Put the two together and you get wet. Not too wet, of course. There’s probably only about a quart of water in every ton of lunar soil. That’s dryer than the Sahara. But wetter than we thought. —Karen Hopkin

September 25, 2009 | 5 comments

Antennae Key to Butterfly Navigation

A study in the journal Science shows that monarch butterflies' sun-related directional sensing is governed by antennae, not the brain. Cynthia Graber reports

Every year, millions of monarch butterflies fly thousands of miles to alight in one specific forest in Mexico. How do they know what direction to flutter? Scientists had thought that an insect GPS system in their brains steered them in the right direction. Now, a new study published in the journal Science overturns that idea. Because sun-related directional sensing actually resides in the butterfly’s antennae, say scientists at the University of Massachusetts Medical School.

The researchers remembered a half-century old study that noted that if butterflies lost their antennae mid-flight, they became disoriented. So they put butterflies in a flight simulator and tried to convince them to fly south. Those with their antennae intact had no problem orienting and flying south. But those without their antennae just couldn’t do it. Next they painted some butterflies’ antennae black, blocking light sensing. Those insects couldn’t orient themselves. But when researchers covered antennae in clear paint, the butterflies could once again fly in the correct direction.

Butterfly antennae were already known to sense odor, wind, even sound. Now it seems that they’re also vital for getting lonely Lepidopterans back to Mexico to mingle—and make the next generation of monarchs. —Cynthia Graber

September 28, 2009 | 18 comments

Teen Inventors Fight Tinnitus

Irish teenagers Eimear O'Carroll and Rhona Togher have developed a treatment they hope will help people with tinnitus, an unpleasant ringing in the ears. Cynthia Graber reports

Ever get a ringing in your ears after a loud blast of music on your iPod? That’s one example of the usually temporary condition called tinnitus, the sensation of sound even when no sound is being produced. But a new invention—created by high school students—may help.

The cochlea in the ear converts sound waves to electrical impulses that the brain processes as sound. Thousands of tiny hairs in the cochlea bend when exposed to the original sound vibrations. But those hairs can get stuck in a bent position. Which is why we hear the sound even when it’s gone.

Two young women in Ireland were studying the problem in physics class. They thought that a low hum might straighten out those bent cochlear hairs. So they developed a minute-long therapy using the hum and tested it on 250 subjects.

Ninety-nine percent of the tinnitus sufferers said the treatment got rid of the disturbing phantom sound. The two 18-year-olds and their physics teacher have now launched a company called Restored Hearing. Good news for the iPod generation from two of their own, who fought fire with fire. Or rather, sound with sound. —Cynthia Graber