Inkfish

Baseball Players Make Worse and Worse Decisions as the Season Goes On

2013-06-14T09:46:00.000-05:00

If their goal were to frustrate fans, they couldn't plan it any better. Major-league baseball players reach a low point in their decision making in September, just in time for playoffs. Across all teams, batters swing at more and more pitches they shouldn't as the season goes on.

They may just need a nap.

"Consistently getting too little sleep—even if it's just [by] one hour a night—can lead to a state of chronic sleep deprivation that can compromise performance," says Vanderbilt University neurologist Scott Kutscher. "Specifically, things like judgment and reaction time."

Judgment and reaction time are just what a baseball player needs when a ball is hurtling toward his body at 90 miles an hour: he has to decide whether to swing, then react quickly enough to actually get it done. And sleep deprivation is familiar to pro ball players, who have a packed schedule and frequently travel back and forth across the country.

To see whether baseball players suffer the effects of sleep loss as the season drags on (or skips along for six non-tedious months, depending on your inclinations), Kutscher and his colleagues looked at data from 2011 back to 2006, after the MLB cracked down on steroid use. For each team, they tracked how often players swung at pitches outside the strike zone.

Over the course of the season, the researchers saw a steady increase in how many out-of-the-strike-zone pitches players swung at. These badly judged swings went up by about six-tenths of a percent each month.

Then Kutscher and his colleagues tested that model on the data from the 2012 season. When the numbers from all the MLB teams were pooled together, the model was a tight fit. Out of 30 teams, 24 were swinging at more balls in September than in April. Kutscher presented the findings at a recent conference on sleep.

Other factors aside from sleepiness may be at work. Pitchers might be throwing better curveballs as the months pass, for example. But Kutscher says pitchers threw pretty much the same ratio of balls and strikes throughout the season; if they were improving a lot, you'd expect to see them throwing more strikes. (Not to mention that batters, too, are practicing and honing their skills during the season.)

Since the researchers looked at whole teams rather than individuals, it's also possible that a change in the roster during the season—say, the addition of less experienced players who are called up from the minors—has an effect. Kutscher doesn't think this could account for all the deterioration he witnessed, though.

"I am hesitant to argue that fatigue is 100% of the story," Kutscher says. "But we have findings that are consistent with what we know about fatigue and chronic sleep loss."

Pro ball players, and other athletes, might see their performance improve if they could avoid sleep deprivation. So stop shouting at that guy on your screen who just struck out—he needs to go home and get some rest.

Image: Ed Gaillard (via Flickr)

Moths Wait until Bats Lock On, Then Jam Their Sonar

2013-06-11T09:23:00.001-05:00

If you are a human reader, you've probably never seen your lunch put up an invisibility shield and perform an evasive maneuver just as you reached for it. But spare a thought for the bats. If your peanut-butter sandwich were anything like a tiger moth, you'd have a hard time finding a meal.

Several kinds of insects are able to detect the echolocation calls of a bat that's approaching like an enemy submarine. Moths may fly in another direction if they hear a bat nearby, or even drop into an escape spiral. Some species of tiger moth, while making their dramatic maneuvers, also make clicking sounds that jam a bat's sonar.

"Jamming is the most effective defense against bats ever documented," says Aaron Corcoran, a postdoc who studies echolocation at the University of Maryland. The moths generate "bursts of ultrasonic clicks" like machine-gun fire—as many as 4,500 clicks a second—and those clicks mix with the echoes from the moth's body that the bat is listening for. "This distorts the echo signature, effectively blurring the acoustic image in the bat's brain," Corcoran says.

In a study published in PLOS ONE, Corcoran and his coauthors examined the timing of that jamming signal: how does a tiger moth decide when to start clicking? If it throws around its sound effects too freely, the moth risks drawing attention to itself (usually a bad idea for a prey species).

The researchers secured Bertholdia trigona tiger moths in dark chambers and played recordings of echolocating bats, observing which bat signals triggered clicking from the moths. Then they went into the woods and hung the moths on tethers from a device not unlike a giant fishing pole. (After each moth was "hoisted into the air," the paper explains, "the pole was shaken periodically by the experimenter to add motion to the tethered moth and to keep the moth flying.") Also hanging from the pole was a tiny microphone, which let the researchers record the sounds of approaching bats--as well as bats snagging nearby, non-tethered moths.

In a bat's hunt, there are three main phases: the search, when the bat scans the area with sonar; the approach, once the bat has found a target and begins sending faster, more intense sound pulses at it; and the "terminal buzz" as it homes in to make the kill.

The researchers found that tiger moths, dangling from their fishing poles, liked to start their sonar-jamming clicks early in the approach phase. "This allows the moth the maximum amount of time to jam the bat," Corcoran says. It also lets the moth make sure the bat's sonar is aimed at itself, and not at a nearby, less fortunate insect. Corcoran says, "The interesting part to me is that the moths appear very well adapted for determining precisely when they have been targeted by a bat."

Once a moth takes action, the approaching bat is in trouble, Corcoran says. A tiger moth sending out a jamming signal is about 10 times more likely to escape its pursuer than it would be otherwise. In his study, moths that sent out jamming clicks and simultaneously made an escape dive "got away every time." It's enough to make a hungry bat wish it had packed a sandwich.

Corcoran, A., Wagner, R., & Conner, W. (2013). Optimal Predator Risk Assessment by the Sonar-Jamming Arctiine Moth Bertholdia trigona PLoS ONE, 8 (5) DOI: 10.1371/journal.pone.0063609

Image: by Aaron Corcoran. You can find more photos, videos, and other tidbits at his website.

Now Available: A Chastity Belt for Your Mouth

2013-06-07T10:35:00.000-05:00

Is your main problem with dieting that you have a whorish mouth? Instead of saving itself for the truly worthy suitors—the poached lean proteins and steamed vegetables with dressing on the side—does it open up for every corn chip and chicken wing that passes by?

Good news, tramp-trap! For only $2,000 plus airfare to Los Angeles, you can have a patch of spiky plastic mesh stitched onto your tongue.

Doctor Paul Chugay promises the procedure is quick and easy. You’ll be back at work the next day. And instead of snacking at your desk, you’ll be sipping a new all-liquid diet, because your lingual chastity garment makes it too painful to consume solid foods.

Patients can expect to lose 20 to 30 pounds in a month on his 800-calorie-a-day “liquid beverage plan,” Chugay says in a video* on his site, or as much as 50 pounds in two months. After that, according to a Time article, the patch will have to be removed; otherwise it may be absorbed into the flesh permanently. That tongue just can’t control itself.

Image: www.drchugay.com

*Website NSFW, thanks to perky plastic-surgery “after” photos everywhere.

Better IQ Testing for Animals: There's an App for That

2013-06-05T09:22:00.001-05:00

It's 2013, and laboratory pigeons are demanding an upgrade. Well, maybe they aren't demanding so much as continuing to do whatever tasks get them their pigeon pellets. Nevertheless, switching from analog to digital testing could mean more rigorous studies, better statistics, and a chance for previously ignored animals to try their paws at cognition research.

One of the classic cognitive tests that psychologists like to give animals involves two or more strings. At the far end of one string, there's a treat. The animal has to figure out that tugging on the near end of this string will gradually bring the reward close enough to eat.

How classic is the string test? In a recent Animal Cognition paper, Edward Wasserman of the University of Iowa and his coauthors list 74 different papers involving this experiment. Animals subjected to string-pulling tasks have includes apes, monkeys, birds, cats, rats, and Asian elephants. The experiments have been limited, though, to animals that can grasp and pull on a string or rope. Another constraint is the time it takes an experimenter to physically set up the strings and refill the food dishes over and over again.

Wasserman and his colleagues used a pigeon focus group to try out a new kind of string test with no string at all. The whole thing took place on a touchscreen, which you can see above. When pigeons pecked at the square on the near end of a "string," the "dish" on the other end moved a little closer. One dish was an empty black box; the other was a photo of pigeon feed. When a pigeon reeled the food dish all the way in, a tasty (non-virtual) pellet dropped out of a dispenser.

The four pigeons in the study quickly got the gist of things, learning to peck the end of the string attached to the food. They started off with simple tasks, in which the strings were short and didn't cross over each other. Then the strings got longer, appeared at various angles, and eventually crossed. These tasks were increasingly challenging to the pigeons. But even for the hardest tasks, the first string they pecked was usually the correct one.

Unlike in a real string test, there was no pulling—no physical weight of food to focus on dragging closer. Still, Wasserman thinks the touchscreen experiment is an accurate substitute for the real thing. In videos like this one, you can see the pigeons bobbing their heads along the strings as they work, seeming to understand the logic of the puzzle. The authors compare the experiment to a game of Angry Birds, which also simulates real physics (albeit with slingshotted cartoon animals).

Also unlike a real string test, the researchers were able to instantly change the length or placement of the strings. They put their pigeons through tens of thousands of trials without much trouble. All of this means better statistical analyses and more reliable results are possible. Using a touchscreen "allows us to conduct experiments with much greater rigor than would otherwise be the case," Wasserman says.

The new method could also let researchers try this kind of testing on any animal that can work a touchscreen, Wasserman says—"even those without dextrous appendages." For example, fish. He also suggests mammals such as dogs, horses, or cows, as well as birds that can't use their claws like hands. One aquarium has already demonstrated that its penguins can play an iPad game. From the aquarium's video, though, it's unclear whether the penguin is truly enjoying the app for cats, or if trying to nab an onscreen mouse is turning it into an Angry Bird.

Wasserman, E., Nagasaka, Y., Castro, L., & Brzykcy, S. (2013). Pigeons learn virtual patterned-string problems in a computerized touch screen environment Animal Cognition DOI: 10.1007/s10071-013-0608-0

Image: Wasserman et al.

How Science Education Changes Your Drawing Style

2013-05-31T09:38:00.001-05:00

Take a look at these neurons. Ignore the fact that several of the brain cells look like snowflakes and at least one looks like an avocado. Can you pick out the drawings done by experienced, professional neuroscientists? What about the ones made by undergraduate science students?

Researchers at King's College London gave a simple task to 232 people: "Draw a neuron." (Actually, being British, they said "Please draw a neuron.") Some of the subjects were undergraduates in a neurobiology lecture. A small group were experienced neuroscientists who led their own research labs at the college. And a third, in-between group included graduate students and postdocs.

The researchers saw marked differences in how the three groups drew their brain cells. To confirm what they saw, they also pooled the drawings together and asked a new batch of subjects to sort the drawings into categories. These subjects agreed: the drawings clustered into distinct styles. The results are in the journal Science Education.

Did you pick out the pictures in the top row as examples from undergrads? Student sketches had lots of detail and were often labeled. In fact, they mostly resembled this classic textbook drawing from 1899, which the authors describe as the "archetype" of brain cells.

Sketches made by lab leaders are on the bottom row. These highly experienced scientists were more likely to make abstract or stylized drawings. Instead of imitating a textbook picture, they drew from their own personal understanding of what a neuron is. (Or possibly, for the scientist on the bottom left, what a martini glass is.)

The graduate students and postdocs, whose drawings are in the middle row, seemed to fall somewhere in between. They didn't label their drawings like undergrads did, and they didn't include quite so much detail. Their neurons were more likely to bend, and the nuclei of the cells were often hidden—in other words, the cells looked more like they would under a microscope, rather than on a textbook page. But they weren't quite as simplified and abstracted as the lab leaders'.

Lead author David Hay says that the three drawing styles represent "different cultures." Undergraduate students spit out textbook images; scientists in training draw on their own observations; and more experienced scientists make "highly conceptual" drawings that represent their personal judgment.

This matters because "learning to reproduce the textbook images is NOT learning science," Hay says. Even postdoctoral researchers didn't seem to have internalized the concept as much as the lab leaders had. However, Hay thinks there are ways that experienced scientists can help students gain perspective.

One way might be by physically acting out scientific ideas. After Hay and his coauthors had students try a couple such exercises—for example, walking on different paths through a laboratory to mimic how neurons grow—the students produced drawings that were more creative and less like the textbook.

Hay thinks students need to internalize scientific concepts before they can play around with them and make their own hypotheses. "Scientists do not simply know information," he says; "they put information to work to discover something new." Failing that, they can create formidable Pictionary teams.

HAY, D., WILLIAMS, D., STAHL, D., & WINGATE, R. (2013). Using Drawings of the Brain Cell to Exhibit Expertise in Neuroscience: Exploring the Boundaries of Experimental Culture Science Education, 97 (3), 468-491 DOI: 10.1002/sce.21055

Images: Hay et al.

Everyone Underestimates Fast-Food Calories (But Especially at Subway)

2013-05-28T09:12:00.003-05:00

At a McDonald's shareholder meeting last week, a nine-year-old girl accused CEO Don Thompson of sneaky advertising. Stop "tricking kids into eating your food," she demanded, saying that McDonald's ads tell kids to "keep bugging their parents" until they get that Happy Meal. In the world of fast-food chains, though, the golden arches may not be the sneakiest purveyor of excess calories. Diners in all kinds of fast-food restaurants underestimate the calories they're taking in—and the most dramatic underestimation happens at Subway.

Thompson may not have been swayed, but Jason Block of Harvard Medical School and a group of other researchers writing in BMJ do care what consumers think about their fast food. Specifically, they care how many calories people think they're eating. To find out, they went into the trenches: 80 fast-food restaurants in New England cities.

Researchers stood outside their chosen dining establishments (which included McDonald's, Burger King, Subway, Wendy's, KFC, and Dunkin' Donuts) in 2010 and 2011. They asked customers on their way in whether they'd be willing to save their receipts and answer a few questions when they came back out. (Only a few restaurants kicked the researchers off the premises.) At dinnertime, they targeted adults, either eating on their own or with kids. At lunchtime and after school let out, they went to fast-food places within a mile of a school and talked to adolescents.

In all, more than 3,000 people participated. Across all the restaurant chains, the average dinnertime meal for adults was 836 calories, and the average afternoon meal for adolescents was 756 calories. Yet when asked how many calories they thought their meals held, people consistently guessed too low. And the bigger their meals were, the more severely they underestimated.

The researchers also asked subjects whether they'd noticed any calorie information indoors. "All of [the chains] provide information in some way," says Block—"on a wall poster, on napkins/cups, on sandwich wrappers and tray liners, and on 'special menus' that might present items that are below a certain number of calories."

Yet less than a quarter of adults said they'd even noticed this information. Those people didn't do any better at estimating their calories than others. Did they use the information to help them make menu choices? Only five percent of all adults said yes. Of adolescents, two percent.

Block says it's easy for diners to miss the calorie information provided by fast-food chains today. But soon, as part of the Affordable Care Act, all chain restaurants with more than 20 locations will have to post calorie information in a standard format. "The menu labeling regulation will require the calories to be up front and highly recognizable," Block says.

Even this kind of prominent labeling has had mixed results in past studies. However, Block adds, the new law will also require menus to post an "anchoring statement" pointing out that people only need about 2000 calories a day. This might make, say, the 970 calories in a Wendy's Baconator more meaningful to a customer.

Anchoring was effective in at least one small study, Block says. Other studies have looked at "traffic light" labeling (in red, yellow, or green), or listing calories in terms of how much exercise you'd need to burn them back off. "We'll be in a position to know much more after the federal law is implemented," Block says. His group is collecting data this year and next year to see how well the new labeling works.

If people do start noticing how many calories their favorite chains are offering, they may be surprised. When researchers broke down their results by restaurant chain, they found that people underestimated their calories more dramatically at some restaurants than others. At McDonald's, adults guessed too low by an average of 100 calories, and adolescents by a little more than 200. The guesses were off by a bit more, on average, at Burger King and Wendy's. At Subway, the errors were most extreme: adults underestimated their calories by an average of about 350, adolescents by close to 500.

Five hundred calories is equivalent to all the bread in a 12-inch sub (or, if you opt for multigrain, all the bread plus four American-cheese triangles). It's a lot not to know you're eating. This mistake, the authors write, may happen because people view Subway with a "health halo." After seeing TV ads featuring fresh vegetables, smiling Olympians, and Jared's old pants, consumers may think they're making a healthier choice than they are.

The new calorie labeling could help most in places like this. A fast-food chain that brands itself as healthy is even sneakier than someplace like McDonald's, which even little girls know is bad for you.

Image: by Jeremy Brooks (via Flickr)

Block, J., Condon, S., Kleinman, K., Mullen, J., Linakis, S., Rifas-Shiman, S., & Gillman, M. (2013). Consumers' estimation of calorie content at fast food restaurants: cross sectional observational study BMJ, 346 (may23 3) DOI: 10.1136/bmj.f2907

Ants Reveal How to Build a Tunnel You Can't Fall Down

2013-05-24T09:01:00.000-05:00

It's hard to keep your footing in a steep tunnel made of loose dirt while others are scrambling around and over your body. Harder still in pitch blackness. That's why fire ants build tunnels that will catch them when they fall—a strategy human engineers might want to steal.

"Slips and missteps are likely a constant, recurring feature of life underground," says Nick Gravish, a graduate student in Daniel Goldman's rheology and biomechanics lab at Georgia Tech. Yet ants have to traverse their tunnels quickly, especially when there's a colony emergency like a flood or destruction by a gardener's spade.

To study how ants engineer their tunnels, Gravish brought the fire ant Solenopsis invicta into the lab. Invasive to countries around the world and packing a nasty sting, these South American ants deal out plenty of hardship. But Gravish was interested in how they handle adversity themselves.

First, the ants were put into "laboratory soil" (actually tiny glass balls) to dig. Researchers took x-ray CT scans of the resulting tunnels and found that no matter the moisture of the "soil" or the size of the glass beads, ants dug circular tunnels of approximately the same diameter. That diameter was just a little bit more than the length of their bodies, not counting legs or antennae.

This suggested that the diameter of the tunnel was crucial to the fire ants. To see how well the ants moved within these tunnels, the researchers recorded video of them climbing as fast as they could. ("We startled them into climbing at high speed by exhaling gently into the nest," Gravish says.) They saw that ants were able to navigate their tunnels quickly, reaching speeds of more than 9 body lengths per second. They also saw that sometimes the ants slipped and had to recover their footing.

In addition to their tunnels, the researchers recorded ants climbing in vertical glass tubes. To get a better idea of how ants corrected their falls, the scientists jolted the tubes to knock the ants off the walls while they were climbing. (If you enjoy videos in the falling-bugs genre, this study generated several new additions. Here's one video of several ants falling and stopping themselves.)

Now the reason ants build tunnels so close in diameter to their own body length became clear. Ants responded to a fall by spreading all their appendages wide and waiting until they jammed to a stop. "One of the coolest things we found was that fire ants used their antennae to brace themselves," Gravish says. While falling, the ants turned these delicate sensors into extra load-bearing limbs.

When the glass tube width increased to 1.3 times the ants' body length, the strategy began to fail. The tunnels ants built themselves had an average diameter of just 1.06 times their body length, the authors report in PNAS. It seems fire ants put most of the responsibility for stopping falls on the tunnels themselves. After that, all a plummeting insect has to do is stretch out its limbs.

Gravish likens this strategy to the way humans build stairs. Steps are engineered to fit our bodies. If they're too tall or short, we struggle to use them (or maybe just fall down them). But with the right design, our environment works with us to get us where we're going.

This strategy could inspire how we design robots for confined spaces such as search-and-rescue zones, Gravish says. For instance, "falling is usually considered a failure mode for a robot." But fire ants seem to use little falls to descend more quickly through their tunnels. If engineers knew the size of the cracks and crevices in a disaster area, they might be able to send in many inexpensive robots designed to tumble through those spaces—rather than one very expensive robot built to keep its footing.

What about humans ourselves: would we benefit from building tunnels that were only as wide as our head-plus-torso length, like the ants? Gravish points out that fire ants often fall many body lengths before catching themselves, making this not such a great strategy for people. "Ants have a robust exoskeleton," he says. "We humans are quite soft in comparison."

Images: ant in tunnel by Laura Danielle Wagner; ants falling by Gravish et al.

Gravish, N., Monaenkova, D., Goodisman, M., & Goldman, D. (2013). Climbing, falling, and jamming during ant locomotion in confined environments Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1302428110

Even People Without Synesthesia Find Colors in Music

2013-05-21T10:40:00.000-05:00

It’s time to stop scoffing at the synesthetes: linking music to colors is totally normal. It’s not really about the notes, though. Researchers say the colors we find in music are actually the colors of the emotions the music makes us feel.

Synesthetes are people whose sensory experiences overlap; they most often link letters or numbers to certain colors. Music-color synesthesia, in which hearing music triggers the colors, is rarer. In fact, when Stephen Palmer and Karen Schloss at the University of California, Berkeley, set out to do a pilot study of music-color synesthetes, they couldn’t find any. So instead they began looking at the connections between music and colors in everybody else.

As part of a larger study called the Berkeley Color Project, Palmer and Schloss included questions about music. Participants saw a grid of colors while listening to 18 brief clips of classical pieces, and chose the colors that were “most consistent” and "least consistent" with each selection.

The researchers suspected that a connection between music and color, if there was one, might be emotional. So they separately asked their 48 subjects how happy, sad, angry, calm, strong, weak, lively and dreary each piece of music was. Subjects answered the same emotional questions about each color. (If you’re the kind of person who hates attributing personality traits to color swatches, you would not have enjoyed this study.)

There were 18 music samples, representing every possible combination of 3 composers (Bach, Mozart, Brahms), 3 tempi (fast, medium, slow), and 2 modes (major or minor). The Andante movement of Bach's Brandenburg concerto in F major, for example, was Bach/major/slow.

What emerged from this sea of lively Mozart and sad burnt-orange was a clear pattern. People linked uptempo and major-key music to colors that were warmer (yellower), lighter, and more vivid. Pieces with a slower tempo or in a minor key provoked the opposite colors: cooler (bluer), darker, and less saturated.

Additionally, music that was both slow and in a major key tended to be greener. And although there wasn’t a difference between Mozart and Bach, Brahms—a Romantic composer who wrote the most recently of the three—leaned more to the slow and minor colors.

To learn whether this consistency was strictly cultural, Palmer and Schloss found a collaborator at the University of Guadalajara who wanted to repeat the experiments with Mexican subjects.

The researcher, Lilia Prada-León, “initially complained that she didn’t want to study classical music because her Mexican participants don’t listen to that music much,” Parker recalls. “She wanted to do it with mariachi bands, which we may still do sometime later.”

Despite Prada-León's hesitation, the results from her Mexican subjects fit snugly with the results from Americans. “The pattern of results for tempo, mode, and composer were remarkably similar,” the authors write.

Also similar were the emotional ratings that Mexican and American subjects gave the musical selections, as well as the colors themselves. The emotions linked to each piece of music matched the emotions linked to that music's colors. This suggests that music itself doesn't make most people think of color. Instead, music triggers emotion—and that emotion is linked to a certain set of colors in the mind. The results are published in PNAS.

Out of the eight emotions in the original list, only four were needed to explain the results: happy, sad, strong and weak. Happier and stronger colors were associated with upbeat, major-key tunes, while weaker and sadder colors were tied to slower, minor-key pieces.

So what does all this tell us about actual synesthesia?

Palmer says his group has now repeated a version of their experiments with real music-color synesthetes (after finally rounding some up). The results looked different. While non-synesthetes chose different colors depending on the tempo of a piece of music—even if it was the same musical line artificially sped up or slowed down—synesthetes didn't.

"My current opinion is that synesthetes’ color experiences arise from direct mappings from sound to color," Palmer says. In their minds, emotions don't act as the middleman. However, "non-synesthetes’ color associations are indirect and do involve emotional mediation."

But when researchers asked synesthetes to choose the colors that were most "emotionally consistent" with the music, rather than the colors they experienced in their minds, the synesthetes picked out the same colors as everyone else. Additionally, when researchers altered melodies just enough to change them from minor to major, synesthetes—like everyone else—"chose happier colors," Palmer says.

There may be some common ground after all between synesthetes and others. The two groups probably won't agree, though, on the color of the mariachi music playing there.

Images: top by tanakawho (via Flickr); bottom Palmer et al.

Palmer, S., Schloss, K., Xu, Z., & Prado-Leon, L. (2013). Music-color associations are mediated by emotion Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1212562110

"Fool Me Twice, Shame on ME," Says Sea Slug

2013-05-16T10:14:00.000-05:00

"Simple" is often a compliment in the human world, used to describe low-fuss dinners or closet solutions. When scientists use "simple" to describe an animal, they mean something more like, "That sac of goo has no business acting clever." An especially simple creature—a sea slug—recently demonstrated that despite its humble resources, it can learn from experience and form new hunting strategies. Smaller goo sacs, beware.

Despite its squishy stature, the sea slug Pleurobranchaea californica is a killer. It roams the sea and swallows whatever appealing morsels are in its way. Being blind, it can't tell how tasty its prey looks—or doesn't.

It can't see, for example, the flashy coloration of the "Spanish shawl" nudibranch (Flabellina iodinea). If it could, it might guess that those bright pink and orange hues are a warning: Flabellina is not nice to eat. It steals stinging cells from its own prey (such as corals and anemones) and stores those stingers in its bristles.

Rhanor Gillette, a neuroscientist at the University of Illinois, Urbana-Champaign, observed that not only do Pleurobranchaea slugs spit out Spanish shawls, but they seem to remember and avoid the animals in the future. To study how well the predatory sea slugs learn their lesson after tasting Flabellina, he and graduate student Vanessa Noboa set up a meet-and-greet between the two species.

In tanks, the large, hungry sea slugs encountered the smaller nudibranchs. Researchers recorded how long it took for Pleurobranchaea to take a taste, then waited for the slugs to change their minds and turn away from their potential prey. (Here's a great video of a Pleurobranchaea attempting to Hoover up a Flabellina, then spitting the animal back out. While the big slug pivots away in disgust, the little one does its "Don't eat me" dance like nobody's watching, which is true.)

On the first day, this interaction happened five times. By the end, most of the Pleurobranchaea slugs were much slower to take a taste of the Spanish shawls, or were ignoring them altogether. Twenty-four hours later, the sea slugs were still reluctant to approach Flabellina. Even after 72 hours, they remembered what they'd learned. Gillette and Noboa report their results in the Journal of Experimental Biology.

Since the predatory slugs seem to sniff something in the water that makes them turn away, the researchers think the noxious Spanish shawls give off a distinctive warning odor.

Gillette says the sea slugs have a decent memory, considering their elementary nervous system. "In these experiments their memory is strong at 48 hours," he says, "and in unpublished work we've seen savings up to a week, so it's not bad." (Oddly, some slugs had to be removed from the experiment because they didn't mind the taste of the stinging Flabellina at all. They sucked it up just like any other food.)

Learning from an unpleasant taste experience, then using that memory to change one's hunting strategy, is "a real cognitive trait," Gillette says—in other words, a "goal-directed use of knowledge." The Pleurobranchaea slugs learned to avoid the smell of Flabellina, although they continued to eat a related, non-stinging species without hesitation.

Being able to change their feeding strategy is a good thing, since these slugs are generalists. Everything in the path of their oozing is a potential meal. "More specialized animals, say sea-slugs that may munch on a particular kind of sponge, may not need to employ such learning abilities," Gillette says. For a hunter like Pleurobranchaea, the decisions aren't so simple.

Noboa, V., & Gillette, R. (2013). Selective prey avoidance learning in the predatory sea-slug Pleurobranchaea californica Journal of Experimental Biology DOI: 10.1242/jeb.079384

Image: Rhanor Gillette.

How to Convince People WiFi Is Making Them Sick

2013-05-13T10:05:00.000-05:00

All it takes is an antenna on a headband. If you've got a breathless video report on the dangers of wireless internet connections, that will help your case. It doesn't take much, though, to turn an ominous hint into a real headache.

Some people consider themselves sensitive to electromagnetic fields. They report symptoms such as burning skin, tingling, nausea, dizziness, or chest pain, and they blame their malaise on nearby power lines, cell phones, or WiFi networks. A recent Slate article described such people moving to a remote West Virginia town where radio-frequency signals are banned. (The town is within the U.S. National Radio Quiet Zone, an area that's enforced to keep signals from interfering with radio telescopes there—telescopes that work because they receive the radio-frequency signals constantly hitting our planet from space.)

There's no known scientific reason why a wireless signal might cause physical harm. And studies have found that even people who claim to be sensitive to electromagnetic fields can't actually sense them. Their symptoms are more likely due to nocebo, the evil twin of the placebo effect. The power of our expectation can cause real physical illness. In clinical drug trials, for example, subjects who take sugar pills report side effects ranging from an upset stomach to sexual dysfunction.

Psychologists Michael Witthöft and G. James Rubin of King's College London explored whether frightening TV reports can encourage a nocebo effect. They recruited a group of subjects and showed half of them a clip from a BBC documentary about the potential dangers of wireless internet. (The BBC later acknowledged that the 2007 program was "misleading.") The remaining subjects watched a video about the security of data transmissions over mobile phones.

After watching the videos, subjects put on headband-mounted antennas. They were told that the researchers were testing a "new kind of WiFi," and that once the signal started they should carefully monitor any symptoms in their bodies. Then the researchers left the room. For 15 minutes, the subjects watched a WiFi symbol flash on a laptop screen.

In reality, there was no WiFi switched on during the experiment, and the headband antenna was a sham. Yet 82 of the 147 subjects—more than half—reported symptoms. Two even asked for the experiment to be stopped early because the effects were too severe to stand.

Witthöft says he expected to see a greater effect in people who had watched the frightening documentary. This wasn't the case overall. Instead, the movie mainly increased symptoms in subjects who described themselves beforehand as more anxious.

"It suggests that sensational media reports especially in combination with personality factors (in this case anxiety) increase the likelihood for symptom reports," Witthöft says.

Plenty of symptoms were reported without the sensationalist TV show, though. The antenna on the head, the researchers' allusion to a "new kind of WiFi," and the instructions to monitor their bodies closely were enough to trigger symptoms in many people who watched the other video.

Witthöft points out that his study would have been stronger if there were a third group of subjects who didn't wear the "WiFi" headband at all, but were simply told to pay attention to their bodies for 15 minutes. This kind of attentiveness might trigger symptoms on its own.

Still, Witthöft says, "I think the high percentage of symptom reports nicely shows how powerful nocebo effects are."

Though the researchers set out to show how irresponsible reports in the media can trigger a nocebo effect, they ended up showing how easy it is to make a person feel sick with just a a prop and a few choice words. Even a National Radio Quiet Zone can't protect against that.

Witthöft, M., & Rubin, G. (2013). Are media warnings about the adverse health effects of modern life self-fulfilling? An experimental study on idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) Journal of Psychosomatic Research, 74 (3), 206-212 DOI: 10.1016/j.jpsychores.2012.12.002

Image: Scott Beale/Laughing Squid (via Flickr)

Happy Blogday! Help Me Rename This Site

2013-05-09T09:34:00.001-05:00

Inkfish is three years old today!

One great thing about blogs that doesn't apply to real three-year-olds is that you can change their name and appearance at will. I'm getting tired of "Inkfish"—too mysterious, too many creepy arms. Too much guilt about mistakenly calling octopus arms "tentacles" on occasion.

So I'd like to give the blog a new name and a new look. Below are several directions I'm considering. I hope that you, readers, will weigh in.

**********

Welcome! You Probably Got Here by Googling Your Juice Cleanse Symptoms
Tagline: Or Searching for Ionic Foot Detox Reviews
Alternate tagline: I Write About Other Stuff Too. Check It Out When You're Less Hazy
Banner art: a weeping woman with her feet in a small tub of brown water. Foregrounded, a glass of kale juice with a party umbrella.
Inspiration: juice cleanses, foot detox, everything else.

Why I Couldn't Hang Out Last Night
Banner art: a blogger on a couch in a dark room, gently lit by the glow of the laptop screen.
Inspiration: purely fictional.

Every Study About Penguins
Banner art: penguins.
Alternate art: not penguins. Irony could increase my readership among hipsters.
Inspiration: penguins, penguins, penguins, penguins, penguins.

The Loom
Banner art: portrait of Carl Zimmer.
Inspiration: trying to lure Bing users who are searching for Carl Zimmer's blog, The Loom.
Potential complication: lawsuit.

Animals with Things on Their Heads
Banner art would be a rotating selection of photos: crabs wearing GPS devices, pigeons carrying cameras, penguins with earmuffs, and this seal.

Inspiration: animal stalking, pigeons.

Girl That Poops Flowers
Alternate title: Most Inconvenient Moments to Have Narcolepsy
Banner art: a mouse that's quiet—too quiet.
Inspiration: unusual internet searches addressed at the help desk.

Adventures in Bodily Fluids: An Ongoing Quest to Make My Grandmother Admit She Doesn't Love Everything I Write
Banner art: the empty vanilla ice cream bowl I considered using to illustrate a story about sperm-eating flies.
Inspiration: see above.

**********

Please leave your votes in the comments (or just say hello). Thanks for your help, and thanks as always for reading!

What's the Point of Making This Face When We're Scared?

2013-05-07T09:52:00.002-05:00

If cartoonists ever pause in their sketching to ponder human evolution, they must feel grateful to the forces that shaped our fear expression. All it takes is a pair of extra-wide eyes to show that a character is freaking out. There may be a point to this expression beyond making artists' lives easier: widening our eyes expands our peripheral vision, and might even help other people spot the cause of our alarm.

"Our lab is interested in the evolutionary origins of emotional expressions," says Daniel Lee, a graduate student in psychology at the University of Toronto—in other words, "why they look the way they do." When we feel afraid, for example, is there a point to stretching out our eyelids and raising our eyebrows to the ceiling?

To explore this question, Lee and his coauthors first asked whether widening our eyes helps us see better. They had 28 volunteers look at a fixed spot on a computer screen while holding their eyes in a neutral expression, an expression of fear, or one of disgust. (Subjects acted out these expressions rather than, say, having a chair pulled out from under them before each trial. Lee points out that emotions themselves may also change our perception, but he wanted to study the effects of widened eyes separate from any psychological effects of fear on the brain. "We coached each participant on how to make fear and disgust expressions based on the Facial Action Coding System," he says.)

Subjects were tested with flashing images on the screen in their peripheral vision. Lee found that people making a disgusted expression—with the eyelids narrowed as in "Ew, get that out of my face"—scored the worst. People making a wide-eyed fear expression scored the best, with a useful field of vision 9% larger than that of people with a neutral expression.

Being afraid, then, may help us gather more visual information about whatever's threatening us in our environment. But does it also help us communicate that threat to our companions?

The researchers next used pictures of models' eyes expressing different emotions to create simplified, graphic eye images. (They didn't use real eyes because those might have conveyed extra emotional information, instead of only varying in wideness.) Subjects saw these eye images flash briefly on a screen, looking toward the right or left by varying degrees. Lee found that when the eyes were wider, subjects had an easier time telling which way they were looking. The results are reported in Psychological Science.

"We believe the widening eyes of fear...[are] a functional response for vigilance toward threat," Lee says. When we're scared, he thinks, widening our eyes helps us to see threats and to communicate their location to our group.

The researchers point out that human eyes are uniquely suited for this kind of communication: we're the only primate with a white sclera (the area outside the iris). In other apes and monkeys, this part of the eye is dark. It's yet another factor that cartoonists, no doubt, appreciate.

Lee, D., Susskind, J., & Anderson, A. (2013). Social Transmission of the Sensory Benefits of Eye Widening in Fear Expressions Psychological Science DOI: 10.1177/0956797612464500

Image: by Tom Check (via Flickr)

Tone-Deaf Birds Disrupt Society, Are Easier to Get into Bed

2013-05-03T10:11:00.000-05:00

While male birds are singing elaborate arias and flashing their feathers, it's easy to imagine their female counterparts are unimportant actors. Duller and quieter, all a lady bird has to do is hold still and let one of these frantic performers mate with her. Yet in brown-headed cowbirds, at least, the quiet female keeps the whole society in order. Scientists discovered this by targeting a tiny portion of the female brain and frying it.

Males of the species Molothrus ater use their songs to compete with each other and to woo females. Once a a mating pair forms, they stay faithful to each other for the whole mating season, the male guarding his partner from rivals.

Near the top of the bird brain, a region called nucleus HVC controls females' choosiness toward their potential mates. Scientists at the University of Pennsylvania and Wilfrid Laurier University performed brain surgery on female cowbirds, carefully destroying only this region. Then they put their lobotomized females back into the dating arena to see what would happen.

First, the ladies listened to recordings of male songs. The researchers played tunes sung by a variety of males and observed the females' responses. (When they like what they hear, female cowbirds show it by crouching down in a copulation-ready pose.)

Normal females were choosy, only responding to the highest-quality male songs. Females who'd had brain surgery, though, responded positively to every song.

The researchers wanted to see what effect the females' new, lax attitude would have in cowbird society. So they put post-surgery females, normal females, and males in one big group together. Then they watched.

At first, it looked like nothing was different. Females missing their HVC seemed to act the same as females with intact brains; once they were all together in the aviary, there was no clear difference in how often females approached male birds or in how they "chattered" back at males to encourage their singing.

Nevertheless, something had changed. The other birds in the aviary treated post-surgery females differently. For one thing, females missing their HVC were serenaded by a greater variety of males, even once they'd chosen a mate. Normally, a female who's bonded with a male hears his song almost exclusively. This is a measure of how strong the bond between partners is, says study author David White. Now, with more males bending a female's ear, her pair bond was weaker.

There were other changes too. With the altered females introduced into the group, female birds competed more for mates. And the whole hierarchy of male birds, which is established before the breeding season starts, was disrupted. Male cowbirds sing at each other to show who's dominant. After the HVC-less females came to live with them, the rules about which males were dominant singers shifted significantly.

"The result in this paper turned everything around for us," White says.

Previously, it had seemed to be the male cowbird's responsibility to create a strong bond with his partner. Females appeared to be passive agents in the group. "They don't sing, they don't fight," White says. "They don't, to our eye, do much of anything." Yet when the choosiness was erased from females' brains, the whole group dynamic changed. "Now we could see that it was the female that was playing a much more active role in pair-bonding, and in all sorts of other roles within the social network," White says. Everything depended on her song preferences.

Incidentally, it's not clear why female cowbirds bond with males at all.

Females have likely evolved to pick mates whose songs demonstrate—somehow—that they have the best genes. Then the males keep singing to the females throughout the breeding season, strengthening the bond between them.

Usually, White says, bird couples only form strong bonds when both parents will need to care for the young. But cowbirds "are very bad parents overall" who abandon their eggs in the nests of other birds. The powerful bond between cowbird partners "really makes no sense," White says.

Yet once they're bonded, males direct almost all their singing to their partner and never try to mate with other birds. "They follow each other around, they eat together, he comes when she calls him," White says. If a female dies or disappears, he adds, "her pairmate just becomes a wreck. We call it the widowed male phenomenon."

After the loss of his mate, the male gives up for the season. "He flies around looking for her," White says. To him, at least, the quiet female never seemed unimportant.

Maguire, S., Schmidt, M., & White, D. (2013). Social Brains in Context: Lesions Targeted to the Song Control System in Female Cowbirds Affect Their Social Network PLoS ONE, 8 (5) DOI: 10.1371/journal.pone.0063239

Image: female brown-headed cowbird by JanetandPhil (via Flickr)

Whale Turns Down Its Hearing When Expecting Loud Sounds

2013-04-30T10:50:00.001-05:00

We can knit sweaters for oiled penguins, but it's harder to protect whales and dolphins from the harm of having us as neighbors. Loud underwater sounds from activities like sonar and drilling may damage these animals' hearing and even lead to mass strandings. Though we can't chase cetaceans around with homemade earmuffs, we might be able to teach them to tune us out.

Like squinting or letting one's pupil shrink in bright light, some animals can adjust how sensitive their ears are. When we're making loud noises, humans reflexively squeeze the muscles of the middle ear to dampen our hearing. Some bats do the same thing while echolocating.

"Generally speaking, mammals have evolved mechanisms to protect their auditory systems from self-produced intense sounds," write Paul Nachtigall of the University of Hawaii and Alexander Supin of the Russian Academy of Sciences. In 2008, the pair showed that a false killer whale (Pseudorca crassidens) could adjust its hearing while it echolocated. So they set out to see whether the species could also dial down its hearing in response to sounds made by someone else.

They taught their whale (a female, originally caught in the wild and now thought to be 30 or 40 years old) that hearing a quiet warning sound meant a louder sound was coming soon. The subject wore suction-cup electrodes on her head during the experiment. Waiting at an underwater listening station, she first heard a series of tones while the electrodes measured which ones her ears responded to. Then, a variable amount of time later, she heard a sudden loud sound (170 decibels).

Over hundreds of trials,* the researchers saw that the whale learned to anticipate the loud sound. If it came within 35 seconds of the warning sound starting, the whale was able to desensitize her ears before it played. (With a longer delay, her response wasn't as strong.) The authors report their results in the Journal of Experimental Biology.

Nachtigall can't say how a whale turns down its hearing. "No one knows for sure how the cetacean middle ear works," he says. Whales don't have eardrums like humans or other land animals, he says, because the sounds they hear must travel through tissue instead of air. So his whale subject probably doesn't squeeze her ear muscles to dampen sound, as a human or bat would. He speculates that it's more likely a top-down control from the brain.

However she does it, the whale can make her ears less sensitive when she knows a loud sound is coming soon. The biggest decrease in her hearing sensitivity was about 13 decibels. That's "about what your hearing changes if you stick your fingers in your ears," Nachtigall says. If you—or the whale—are trying to protect your hearing from a loud noise, he says, "That helps. This would help."

When humans must make a racket underwater, it's possible that we could help whales and other animals by making quieter warning sounds beforehand. This could teach the animals to anticipate the sound and "plug" their ears.

Since he's only studied one animal so far, Nachtigall doesn't know how the abilities of other marine mammals to desensitize their ears compare. "To ask whether [warning sounds] would prevent whale hearing damage is sort of like asking whether ear plugs would prevent deafness in people who work next to jet engines," he says. "I believe the possibility is great, but there are more questions to be answered."

Image: by MichiKimmig (Flickr)

Nachtigall, P., & Supin, A. (2013). A false killer whale reduces its hearing sensitivity when a loud sound is preceded by a warning Journal of Experimental Biology DOI: 10.1242/jeb.085068

*If you're wondering how one convinces a whale to participate in so many trials, the answer is "fish reinforcement."

The Shambulance: Reflexology and Other Stories

2013-04-26T10:03:00.000-05:00

The Shambulance is an occasional series in which I try to find the truth about bogus or overhyped health products. Helping me keep the Shambulance on course are Steven Swoap and Daniel Lynch, both biology professors at Williams College.

Sticking a Q-tip up one’s nose is not the source of many great insights. Yet it’s how an American doctor in the early 20th century developed the theory that became modern reflexology. He would be proud—though maybe a little confused—to see people today flocking to reflexology spas, where practitioners treat all their problems via the soles of their feet.

The American doctor in question was William H. Fitzgerald, an ear, nose and throat specialist. In a 1917 book, he explained the genesis of his big idea:

Six years ago I accidentally discovered that pressure with a cotton tipped probe on the muco-cutinous margin (where the skin joins the mucous membrane) of the nose gave an anesthetic result as though a cocaine solution had been applied . . . Also, that pressure exerted over any bony eminence of the hands, feet or over the joints, produces the same characteristic results in pain relief . . . This led to my ‘mapping out’ these various areas and their associated connections and also to noting the conditions influenced through them. This science I have named "Zone Therapy."

Chapter titles from Zone Therapy include "Zone Therapy for Women" (tongue depressor into the back of the throat for menstrual cramps), "Painless Childbirth" (rubber bands around the toes, among other interventions) and "Curing Lumbago with a Comb."

A nurse and physical therapist named Eunice D. Ingham extended the idea of zone therapy in the 1930s and 1940s, eventually mapping the entire body onto the soles of the feet. She called each important point on the foot a “reflex” because it reflected back to a certain organ or body part. Ingham wrote two books on the subject, now called reflexology: Stories the Feet Can Tell and Stories the Feet Have Told.

Today, the International Institute of Reflexology describes its practice as as “a science which deals with the principle that there are reflex areas in the feet and hands which correspond to all of the glands, organs and parts of the body.” Stimulating these points “can help many health problems in a natural way.” The site insists, “Reflexology…should not be confused with massage.”

There has been some confusion and blending, though, between Western reflexology and traditional Chinese medicine. Ingham and Fitzgerald's idea of "zones" is similar to the Chinese principle of "meridians." In traditional Chinese medicine, meridians are paths that carry qi through the body and connect the acupuncture points. Reflexology groups like to say that Fitzgerald "rediscovered" the science from more ancient roots. They even claim that ancient Egyptians practiced it, based on tomb paintings showing people holding each other's feet.

Whoever thought it up first, the idea that the soles of your feet hold a miniature map of the entire rest of your body defies a scientific explanation.

“The problem is communication,” says physiologist Steven Swoap. “How does the foot talk to the pancreas?”

The foot is full of sensory nerves, Swoap explains. These can detect temperature, pain or position and send that information to the spinal cord. If the signal is something urgent—say, you stepped on a nail—the spinal cord will send a quick command back to the foot (“STOP!”). If the signal from the foot is a non-painful one (“Hey, I’m walking on grass”), it will travel all the way up the spinal cord to the brain.

“But in no instance do those sensory nerves bypass either the spinal cord or the brain and go directly to the liver, or the kidney, or the colon,” Swoap says. This means your foot can’t communicate directly with any other body part except your spinal cord or brain. Whatever stories the feet have told, they’ve had a limited audience.

Daniel Lynch, a biochemist, points out that sex organs are missing from some reflexology maps. “Why aren’t the gonads on there?” he asks. Other maps label a "testes and ovaries" region around the middle of the heel, but there's variation from one chart to the next.

Setting aside the map itself, Lynch says, “Where is the evidence that it actually works?”

The evidence is slimmer than a stiletto heel. In a 2011 review paper, complementary medicine researchers at the Universities of Exeter and Plymouth dug up every scientific study of reflexology they could find. Out of 23 randomized clinical trials, only 8 “suggested positive effects.”

The quality of the studies was “variable,” the authors write, “but, in most cases, it was poor.” Only four studies that found a positive effect used a placebo control—that is, did massaging the feet without regard to “zones” give patients the same symptom relief? In general, studies tended to use small groups of subjects and not to be replicated by other researchers.

Reflexology has been tested on conditions including asthma, premenstrual syndrome, irritable bowel syndrome, multiple sclerosis, and back pain. If reflexology does have a benefit, “The most promising evidence seems to be in the realm of cancer palliation,” or making patients more comfortable, the authors write. Overall, though, they found no convincing evidence that reflexology has power beyond the placebo.

Not that we should thumb our Q-tip-free noses at the placebo effect. The body has an impressive power to make itself feel better based on our expectations. A foot rub from a professional may very well ease a person’s pain. If that professional says anything about zones, though, it’s only a story.

Image: Foot reflexology chart by Stacy Simone (Wikipedia)

Ernst, E., Posadzki, P., & Lee, M. (2011). Reflexology: An update of a systematic review of randomised clinical trials Maturitas, 68 (2), 116-120 DOI: 10.1016/j.maturitas.2010.10.011

Scientists Unsure Why Female Flies Expel Sperm and Eat It

2013-04-23T13:26:00.000-05:00

She's apparently a picky mater but not a picky eater. The female of a certain fly species, after mating with a male, dumps his ejaculate back out of her body and onto the ground. Then she gobbles it up. Despite new hints that this behavior may help the female choose which partner fertilizes her eggs, or keep her healthy in times of famine, scientists are still a little perplexed by it.

Various female insects, spiders, and birds are known to expel the male ejaculate from their bodies after the deed is done. In some cases, it seems to let them decide which male's sperm reaches their eggs. Females don't always choose who mates with them, but that doesn't mean they have no choice in their progeny's fatherhood. (This kind of female choosiness about sperm can lead to evolutionary arms races between males and females. The "copulatory plug" is a popular tool among male insects, spiders, reptiles, and even some mammals.)

Eating the ejaculate, as Euxesta bilimeki does, is less popular. This fly lives on agave plants and mates pretty much all the time. "Females can be observed escaping male advances in chases that can last more than an hour," write Christian Luis Rodriguez-Enriquez and his coauthors from the Instituto de Ecología in Veracruz, Mexico. Using videocameras and careful meal planning, they tried to divine a reason for the female flies' behavior.

Out of 74 females that the researchers recorded mating, every one expelled and ate the ejaculate afterward. The researchers then killed the females and pulled them apart with tweezers to look for sperm inside their various storage locations. They found that three-quarters of the females had kept some sperm from their male partner, while one-quarter had expelled it all.

There was no obvious rule to which sperm the females kept. There were some patterns, though. For example, females that mated with larger males, then waited longer before expelling the sperm, were more likely to keep some. Since the female's behavior doesn't seem random—and since it's possible for her to keep no sperm at all—the authors think she may be choosing between mates after the fact.

This could explain why the female expels the sperm, but not why she eats it. In another experiment, researchers fed female flies various diets and measured whether supplementing those diets with ejaculate made them healthier. When female flies were starved entirely, the extra snack did help them live longer—but under normal circumstances there was no difference. The authors report their results in Behavioral Ecology and Sociobiology.

"Our study appears to have raised more questions than provided answers," the authors admit. They expected there would be some clear nutritional benefit to justify the females' tastes.

Rodriguez-Enriquez and his coauthors speculate that the ejaculate-as-meal habit may have evolved as a "nuptial gift." This is an edible present that male insects sometimes give to females as part of their courtship. Usually it's nutritious—a nicely wrapped dead bug, say—but in some cases it's just an empty sac. The ejaculate may be, like these gifts, just an edible empty gesture.

(The above is a video of Euxesta bilimeki flies mating. It doesn't look any different from what you're imagining, but the soundtrack is a nice twist.)

Rodriguez-Enriquez, C., Tadeo, E., & Rull, J. (2013). Elucidating the function of ejaculate expulsion and consumption after copulation by female Euxesta bilimeki Behavioral Ecology and Sociobiology DOI: 10.1007/s00265-013-1518-5

Image and video: Rodriguez-Enriquez et al.

Google Promises We'll Feel Better in the Summer

2013-04-19T12:15:00.000-05:00

Shakespeare wasn't kidding about the "winter of our discontent." In the colder and darker months, people do more internet searches for mental health terms, from anxiety and ADHD all the way to suicide. Search patterns also promise that like a refreshed browser window, better times are due to arrive soon.

John Ayers, of the Center for Behavioral Epidemiology and Community Health in San Diego, and other researchers dove into Google Trends to explore whether certain searches vary by season. "Seasonal affective disorder is one of the most studied phenomena in mental health," Ayers says, "with many individuals suffering mood changes from summer to winter due to changes in solar intensity." He wanted to find out whether any other mental health complaints changed with the seasons, as some studies had hinted.

Since Google Trends breaks down searches by category, the researchers started in the "mental health" section. Looking at all mental health searches in the United States between 2006 and 2011, they saw a consistent cycle with peaks in the winter and troughs in the summer. (If you do this search yourself, you'll see that there's also a dip around the December holidays—but the curve reliably bottoms out in July of each year.)

The team did some statistical smoothing and found that mental health searches overall were about 14% higher in the winter than in the summer. To confirm that the difference was due to the season, they ran the same analysis on data from Australia. Searches cycled in the same way—about 11% higher in winter than summer—but the peaks in the southern-hemisphere country were almost exactly 6 months out of sync with the United States.

When the scientists broke down searches by specific symptoms or illnesses, the seasonal cycle remained—and in some cases got much stronger. "We were very surprised" to see this, Ayers says. Searches including the terms ADHD, anxiety, bipolar, depression, anorexia or bulimia, OCD, schizophrenia, and suicide all rose in the winter and fell in the summer.

One of the most dramatically cycling search terms was schizophrenia, at 37% higher in the winter. Eating disorder terms varied just as strongly. (The smallest seasonal difference was for anxiety, which was just 7% higher in the winter in the United States, and 15% in Australia.)

Some of this seasonality might be due to the schedule of the school year, Ayers points out. Referrals for kids with ADHD and eating disorders may come from their schools.

Other explanations involve winter itself. The effect of shorter days on our circadian rhythms and hormone levels might be a factor, the authors write, as in seasonal affective disorder. They speculate that a lack of vitamin D (which we make using sunlight) in the winter might contribute. Even omega 3 fatty acids might matter: we consume less of them in winter, and omega 3 deficiency has been linked to some mental illnesses.

There's also the question of what we're doing all season. People hunkered indoors during the colder months may have fewer chances for socializing, which is "a well-known health emollient," the authors write. The same goes for physical activity.

"There is a lot more we need to learn about mental health and seasonality," Ayers says. "For instance, is there a universal mechanism that impacts our mental health?"

Of course, sometimes our malaise isn't about the season.

Whatever portion of mental health is predictable, though, doctors would love to know about it and use that information to help.

This study doesn't reveal much about low-income or elderly populations who aren't online. And knowing what people are searching for isn't exactly the same as knowing what symptoms they're experiencing. "We are actively working to address these limitations," Ayers says. Working with Google.org, the charitable branch of Google, he hopes to develop systems similar to Google Flu Trends that can track a population's mental health.

"Intuition suggests that these results are reflective of an important link between the seasons and mental health," Ayers says. For now, we have the reassurance of computer algorithms that skies will be clearer soon.

Ayers, J., Althouse, B., Allem, J., Rosenquist, J., & Ford, D. (2013). Seasonality in Seeking Mental Health Information on Google American Journal of Preventive Medicine, 44 (5), 520-525 DOI: 10.1016/j.amepre.2013.01.012

Image: Skaneateles, NY, by me.

Homing Pigeons Never Stop Learning Ways to Get Home

2013-04-16T09:31:00.000-05:00

A young homing pigeon must learn quickly how to find its way home from the strange neighborhoods where humans insist on leaving it. At first the bird does this by relying on its crudest instincts, returning to its roost along a route full of youthful zigzags. Over time, though, it refines its methods. A mature pigeon takes a much simpler route, because it has drawn itself a more complex map.

Homing pigeons have been subjected to all kinds of research. The latest study used GPS devices, which the birds carried in little Teflon backpacks. Ingo Schiffner of the Queensland Brain Institute and Roswitha Wiltschko of Goethe-Universität Frankfurt studied pigeons at three different ages: juveniles (6 to 7 months old), yearlings (the same pigeons in their second year of life, after going through a training program), and older trained birds (at least two years of age).

Wearing their tracking harnesses, the birds were released from various sites that ranged from 3.2 to 23.5 kilometers away from their home loft in Frankfurt, Germany. Here are the routes some of the birds took when returning to their home (the square) from a release site 6.8 kilometers away (the triangle):

You'll notice that some pigeons traveled by more, shall we say, scenic routes than others. The researchers calculated each bird's "efficiency" and found that the youngest group of pigeons were the least direct fliers. On average, they traveled more than three times the distance of a straight-line trip between the two points. (The pigeon researchers, in a bit of a mixed-species metapor, refer to this ideal trip as a "beeline.")

The two older groups of birds were much more efficient, flying no more than 25 percent farther than they needed to. Since their youthful zigzagging days, they had gone through a training program that had them practicing as far as 40 kilometers from their home roost. Now more familiar with the features of the landscape around their home, they could navigate it easily.

But that didn't mean the pigeons stopped refining their internal maps after their first year. Schiffner and Wiltschko also calculated something called the "correlational dimension," which is the number of factors that seem to be contributing to a system—in this case, pigeon navigation.

Previous research has suggested that homing pigeons have multiple tools in their navigational toolkit. In various experiments, "pigeons have been deprived of visual cues, magnetic cues, olfactory cues, infrasound cues, and their gravitational sense," Schiffner says, "yet pigeons are still able to find their way home." Rather than relying on just one tool at a time, they seem to use several.

The correlation dimension is meant to count how many tools each pigeon uses to complete a trip. The youngest pigeons usually hovered close to 2. But year-old pigeons had a somewhat higher score, and the oldest pigeons were closer to 3. In his previous research, Schiffner says, pigeons have seemed to use as many as 4 types of navigational cues simultaneously.

This suggests that pigeons keep refining their mental maps as they age, adding new elements—visual landmarks, say, or the smell of a local factory—to others such as sunlight and magnetic fields. "I cannot say yet which factors pigeons are using," Schiffner says, but he believes the factors add up with age. He and Wiltschko report their results in the Journal of Experimental Biology. Schiffner adds, "I assume that pigeons continue to learn and integrate new information into their navigational map as they grow older."

Attaching GPS devices to animals is currently trendy; there's a whole new journal dedicated to the subject. But humans have a long history of rigging our technologies to pigeons. At the start of the 20th century, German apothecary Julius Neubronner designed and patented a little camera on a harness for homing pigeons to carry (he had previously used the birds to ferry prescriptions and drugs for his patients).

The German military toyed with using Neubronner's pigeon-camera technology for reconnaissance during World War I. With the cameras hooked to timers, the birds could take pictures above enemy lines and carry them back home. These days we're attaching our instruments to the accommodating birds not for the sake of spying on our enemies, but to decode the secrets of the pigeons themselves.

Images: Homing pigeons by Amanda Dague (via Flickr); figure from Schiffner and Wiltschko; pigeon cameras by Julius Neubronner (via Wikimedia Commons).

Schiffner, I., & Wiltschko, R. (2013). Development of the navigational system in homing pigeons: increase in complexity of the navigational map Journal of Experimental Biology DOI: 10.1242/jeb.085662

Rubber Hand Experiment Shows Kids Have More Flexible Body Boundaries

2013-04-11T09:39:00.001-05:00

Close your eyes. Do you know where all your fingers and toes are? Can you pinpoint the exact edges of your body in space?

You may think your knowledge of your body is unshakeable, but a simple trick with a rubber limb can sway you. In kids, the effect is even more extreme—a finding that gives intriguing hints about how our body sense develops.

The new research relies on the "rubber hand illusion," first published in 1998. To produce this illusion, an experimenter sits across a table from a subject. The subject rests one hand, let's say the left, flat on the table and keeps the other hand in his lap. A little wall blocks the left hand from the subject's sight. But the subject can see a rubber hand, also a left hand, sitting on the table just inside the wall.

Actually, hold on, I'll draw you a picture.

OK. The experimenter (or, oval with glasses) holds two paintbrushes and uses them to stroke the backs of the real hand and the rubber one simultaneously. The subject watches these paintbrush strokes that seem to match the ones he's feeling, and eventually the brain takes a shortcut: it decides the seen hand and the felt hand are one and the same. This gives the subject the eerie impression that the rubber hand is part of his body. (I wrote about trying the rubber hand experiment for my eighth-grade science fair—and someone else's kooky version of the illusion that uses entire bodies instead of hands—here.)

University of London psychologist Dorothy Cowie and her colleagues tested the rubber hand illusion on kids of varying ages to see how their response compared to adults. Like researchers before them, they measured the effect in two ways. The first was a questionnaire about whether the rubber hand felt like the subject's own (for kids, the scale went from "definitely not" to "lots and lots").

For the second measurement, subjects closed their eyes and slid the index finger of their right hand under the edge of the table until they believed it was aligned with the index finger of their left hand. After experiencing this illusion, subjects tend to get skewed in the direction of the rubber hand.

The researchers tested adults as well as 90 kids between the ages of 4 and 9. They saw that in the sliding-finger measurement, kids in all age groups drifted farther toward the rubber hand than adults did. The results are reported in Psychological Science.

To explain this, Cowie suggests that people rely on two different methods to figure out where their body parts are. One combines vision and touch: do the cues I'm feeling match what I see? The illusion worked best for adults when the paintbrush strokes on both hands were perfectly in sync.

But for kids, the illusion stayed strong even when the paintbrush strokes they saw were out of sync with the ones they felt. This suggests that a second system of perception simply asks whether something that looks like our arm appears in roughly the place we expect it. Kids overuse this system, Cowie says. "Seeing a 'hand-like thing' in front of them on the table was enough to sway their perception of where their own hands were." By adulthood, Cowie thinks, we learn to pay more attention to tactical cues. "Adults rely less on the visual stuff than kids."

The fact that the illusion works at all demonstrates that "we don't just rely on muscle info to tell us where our body is," Cowie says, whether we're kids or adults. "In fact vision is really important!" Her research group is conducting further studies to find out how perception changes with age. "The results are absolutely always that kids are more susceptible than adults" to the illusion, she says.

If you're feeling worried that you don't know your body very well, consider taking on a more childlike attitude. Cowie says the kids in her experiment enjoyed being tricked by the illusion. One kid reacted with "You seem to have painted my hand!" They were eager to check where their hands really were when the test was over.

"Kids are actually open to weird stuff more than adults are," she says.

Cowie, D., Makin, T., & Bremner, A. (2013). Children's Responses to the Rubber-Hand Illusion Reveal Dissociable Pathways in Body Representation Psychological Science DOI: 10.1177/0956797612462902

Images: St0rmz (via Flickr); me (via Post-It note).

Squid's Daily Rhythms Are Controlled by Glowing Symbiotic Bacteria

2013-04-08T10:19:00.003-05:00

At nightfall, the Hawaiian bobtail squid digs itself out of the sand and rises into the ocean water like a spaceship taking off. It switches on its cloaking device: glowing bacteria inside its body light up, disguising the squid's silhouette against the moonlight for any predators swimming below. As sleek a vehicle as it appears, though, the bobtail may not totally outrank its microscopic crewmembers. The bacteria seem to power a clock inside the squid's body that can't function without them.

Hiding during the day and hunting at night in shallow Pacific waters, Euprymna scolopes clearly has a working circadian clock. Researchers had noticed, though, that the squid's light organ—the specialized pocket inside its body that houses its bacterial helpers—seemed to have a rhythm of its own. The Vibrio fischeri bacteria give off fluctuating amounts of light throughout the day, for one thing. And the bacteria have their own daily rhythm of gene expression (when various genes are turned on or off), explains Margaret McFall-Ngai, a microbiologist at the University of Wisconsin, Madison.

McFall-Ngai and her coauthors looked for genes linked to circadian rhythms within the squid. They found two types of "cry" genes, which are known to control internal clocks throughout the animal and plant kingdoms. One gene had a daily cycle of activity in the squid's head—which is what you'd expect, since animals' main circadian clocks are in our brains. Other clocks can be elsewhere in the body, though, and this is what researchers found with the second cry gene. It was cycling only within the light organ.

Baby squid, which hadn't yet collected bacterial friends in their light organs, didn't show the same cycling. So it seemed that the bacteria themselves were driving the daily rhythms in the light organ. When the researchers let squid fill their light organs with defective, non-glowing bacteria, the cry gene still didn't cycle properly. This suggested that the glow of the bacteria was the crucial ingredient.

To test this idea, the scientists shone a blue light on the squid holding defective bacteria. Now they expressed just as much cry as the original squid.

McFall-Ngai explains that cryptochromes, the proteins made by cry genes, respond to blue light. Based on the light signals the cryptochromes receive, they turn other genes on or off. Cryptochromes in the squid's head respond to light from the sun to drive its daily rhythms, as in other animals and plants. Those in its light organ, though, respond to the light of its glowing bacterial companions.

The role of the bacterial clock isn't clear yet. "We don't know if the light organ rhythms control any other rhythms in the body," says McFall-Ngai. "But they certainly seem to be involved in controlling the rhythms of the organ itself." The squid controls the daily schedule of the bacteria, too: it jettisons most of its bacteria in the morning, and seems to keep them dimmed during the day by restricting their oxygen supply. At night, it gives the bacteria enough resources to glow at full strength—and that glow drives the clock within the light organ. "There seems to be a tit for tat," McFall-Ngai says. "The host and symbiont 'talk' to one another, controlling one another's biology."

The idea that bacteria can drive circadian rhythms inside their hosts is exciting to humans because we, too, are animals packed full of bacteria. Ours don't glow, but they do line our guts and participate in digesting our food. McFall-Ngai points out that scientists have found "profound circadian rhythms" within our gut tissues, both in their activity and in what genes they express.

Even though we're land-bound, non-glowing vertebrates, our bacteria could be powering circadian rhythms within our bodies just like the squid's. "We think it might be a very general phenomenon," McFall-Ngai says. Our microscopic passengers, that is, might be helping to steer the spaceship.

Heath-Heckman, E., Peyer, S., Whistler, C., Apicella, M., Goldman, W., & McFall-Ngai, M. (2013). Bacterial Bioluminescence Regulates Expression of a Host Cryptochrome Gene in the Squid-Vibrio Symbiosis mBio, 4 (2) DOI: 10.1128/mBio.00167-13

Image: Margaret McFall-Ngai

New Journal Celebrates Animal Stalking

2013-04-05T09:46:00.000-05:00

Christmas arrived early this year for people who love animals carrying transmitters around. A new open-access journal called Animal Biotelemetry launched this week, and it promises to bring new tales of mind-blowing bird migrations and seals that study climate change (without exactly having volunteered for the job). Also, sharks.

Published by BioMed Central, the journal will include all kinds of research having to do with biological data gathered by instruments attached to animals. This is a field that's been expanding as the technologies themselves shrink. A few decades ago, scientists were limited to studying the movements of giant land animals such as bears or elk—because transmitters and battery packs were too bulky to comfortably attach to other creatures. Now, miniaturized electronics (aided by GPS satellites) mean that even lightweight birds can carry tracking devices.

Editor A. Peter Klimley describes the history of the field in an introduction to the journal. Klimley himself is a professor and shark guy at the University of California, Davis. His biography claims that he "is known to have held his breath while diving up to 100m deep in order to hand-tag hammerhead sharks with a dart gun." In case "biotelemetry" didn't sound exciting to you.

To mark the occasion, here are some earlier posts involving animals carrying transmitters around, since I am one of the aforementioned people who love them.

Monitoring from Space Shows Even This Giant Crab Can Navigate Better than You

Climate-Studying Seals Bring Back Happy News

This Penguin: An Unexpected Journey

Klimley, A. (2013). Why publish Animal Biotelemetry? Animal Biotelemetry, 1 (1) DOI: 10.1186/2050-3385-1-1

Image: by MEOP Norway North

Kids Learn Better When Teachers Wave Their Hands

2013-04-04T12:58:00.000-05:00

Maybe it's no mistake that we talk about "grasping" new ideas. When we find our hands moving wildly as we try to explain something, maybe we shouldn't feel ridiculous. Research in math classrooms has found that kids learned better when a teacher used gestures—and their grip on the new material improved even more after the lesson ended.

Teachers who gesture more or less while they speak can have other differences too, of course: they might use different intonation or vocabulary, or have more or less energy. University of Iowa psychologist Susan Wagner Cook and her coauthors, though, were only interested in the effect of teachers' hand motions. To isolate this factor, they created a series of videos.

In the videos, aimed at elementary schoolers, a teacher taught a single scripted lesson. The subject of the lesson was equivalence, the idea that what's on one side of an "=" must be equal to the other side.

In one set of videos, the teacher used her hand to indicate "one side" and "the other side" of an equation. A second set of videos showed the same teacher reading the same script, but she kept her hands at her sides. The researchers made several recordings and chose the ones in which the teacher's intonation was the most consistent, ensuring that the only difference between the lessons was her hands.

The kids who watched the videos were 184 boys and girls from 22 classrooms in central Michigan schools. Most were in second or third grade, and a few were in fourth. The kids had taken a pretest to make sure they weren't already familiar with this mathematical idea.

Each classroom watched a videotaped lesson, either the one with hand gestures or the one without. Immediately afterward, they took a test with questions such as:

7 + 2 + 4 = 7 + __

Kids who had understood the lesson would answer "6."

A day later, the kids had a second set of test questions spring on them. First they answered the same type of questions that they had the day before. Then they saw a second set of questions designed to make them "transfer" the rules they'd learned to new situations. For second graders, this meant trickier addition problems such as:

6 + 4 + 2 = __ + 3

in which none of the numbers on the right side matched the left. Third and fourth graders had to transfer their new skills to multiplication problems such as:

5 x 2 x 3 = __ x 3

Kids who had seen the lesson with gestures did significantly better than the no-gesture kids on the first test. A day later, they again outperformed the hands-free group—and beat their own test scores from the day before. Their understanding of the lesson seemed to have gotten even better in the 24 intervening hours. (This wasn't true of kids who watched the hands-free lesson.) Finally, the gesture group did better on the test of transferred skills.

A couple factors could explain why students learned better from a gesturing teacher, the authors write. Hand movements might help them pay better attention to the teacher, for example. And seeing a repeated hand motion across different problems might reinforce how those problems are similar.

That doesn't answer the question of why students continued to improve over the next 24 hours. Susan Wagner Cook explains that shortly after we form new memories, those memories are stabilized or "consolidated" in our minds. Consolidation can make new memories even stronger.

"We do know that motor memory is often consolidated during sleep," Cook says. Seeing another person's hands moving may have built motor (movement) memories in kids' minds, as if they were pointing and waving their own hands. "One possibility is that memories encoded with gesture are more likely to be consolidated during sleep," Cook says. "We are trying to figure this out!"

Although being able to point to the two sides of an equation seems like a clear advantage in this particular lesson, Cook says the benefit of gesturing goes beyond arithmetic—or even math. Other studies have shown that hand motions help kids learn in a wide range of subjects.

What's new is the idea that gestures help in the future, not only the present. Cook points out that even though some kids learned the lesson just fine without gestures, they didn't show the same improvement over time that the other kids did. Instead of only clarifying, gestures may help kids grasp their new knowledge more tightly. (Please imagine a fist-closing gesture to drive home this idea.)

Image: sleepinyourhat (via Flickr)

Cook, S., Duffy, R., & Fenn, K. (2013). Consolidation and Transfer of Learning After Observing Hand Gesture Child Development DOI: 10.1111/cdev.12097

Why Fish Raise Foster Kids (and Give Up Their Own)

2013-04-01T10:26:00.001-05:00

A fish swims along a sandy lake bottom, carrying one of its babies in its mouth. It approaches the nesting cave of another family of fish. With a furtive "ptooey," it leaves the baby behind for adoption. For certain fish, this seems to be a common scene: giving up your young and taking on others' may be the best way to ensure your offspring grow past snack size.

The fish in question is Neolamprologus caudopunctatus, a type of cichlid (pronounced like a compliment for someone's hat).* Just a couple of inches long, the diminutive fish lives only in East Africa's Lake Tanganyika. Males and females form monogamous pairs. They raise their young in burrows under rocks; carrying sand in their mouths, they pile it up around the rocks to build narrow entrances.

For the first 40 days or so in the lives of the young fish (called fry), both parents work to protect them from predators. They guard the nest and attack any other fish that come by looking for a meal. Cichlids can also protect their young by carrying them inside their mouths.

As the fry grow older and start swimming on their own, they may wander away from their parents' nests and into nearby ones. However, cichlids have also been spotted carrying young in their mouths and leaving them at other nests. Scientists at the Konrad Lorenz Institute of Ethology in Vienna set out to see how much of the baby swapping among N. caudopunctatus is intentional.

Researchers scuba dived down to the home of the cichlids, mapped the locations of their nests, and collected DNA samples. Back on land, like the crew of a daytime talk show for African lake bottoms, they analyzed the DNA to find out just how these fish were related.

Out of 32 nests, more than half held adopted fry, the authors report in Behavioral Ecology. Within nests that housed adopted fish, those outsiders made up anywhere from 10% to 77% of the nest.

The researchers took their DNA analysis a step further for a dozen adopted fry, hunting down their biological parents. They found that while some fry had been adopted from nearby nests, others were a very long way from home—as far as 40 meters or more. "It is virtually inconceivable that they swam there alone," says senior author Richard Wagner. The lake is packed with hungry predators. It would be, he says, "like a toddler walking across a busy city without mishap." It's more likely that parents deliberately carried these young fish in their mouths from one nest to the other.

There was another piece of evidence that adoptions happened on purpose. Adopted fish were on average larger (which is to say older) than non-adopted fish across the whole sample. But within each nest, the size difference wasn't significant. This suggests that when cichlid parents give up their young, they select nests with fry that are close in size to their own. Such a strategy might make the adopted fish less conspicuous to predators.

Parents who leave their fry at other nests may be hedging their bets, making sure that at least some of their offspring survive if their own nest is wiped out by a predator. As for adoptive parents, they could just kick out the freeloading fry. But keeping adopted fish around means that when predators attack, there's a smaller chance of your own offspring ending up in another fish's mouth.

"Our paper adds evidence that adoption is an adaptive strategy," Wagner says, rather than simply the result of wandering babies. We humans aren't the only animals that regularly choose to raise others' young. One hopes, though, that human foster parents aren't in it for the reduced predation.

Schaedelin, F., van Dongen, W., & Wagner, R. (2012). Nonrandom brood mixing suggests adoption in a colonial cichlid Behavioral Ecology, 24 (2), 540-546 DOI: 10.1093/beheco/ars195

Image: N. caudopunctatus by Varmer (via Flickr)

*"Sick lid!"

NOTE: It's been pointed out to me by an astute reader (my mother) that the hat compliment could also be "chic lid." Fair point, Mom.

The Composer and the Cassowary: An Appreciation of Mistakes

2013-03-29T11:09:00.000-05:00

High in a church balcony last weekend, waiting to perform a solo for Palm Sunday and trying not to panic, I thought about cars being hit with hammers. I'm not sure this is the kind of visualization recommended for singers. But sometimes genetics asserts itself.

A college biology professor once told my class that genetic mutation is like whacking a car with a hammer. You will almost never improve your car this way. More often, you'll damage it. If you're lucky the damage will be only superficial: a change in the silent portion of your genome, or maybe a few funny feathers.

The piece my choir was getting ready to sing, Gregorio Allegri's Miserere, has experienced some mutations in its own DNA over the centuries. Allegri composed the piece way back in the early 1600s, and after that it was sung exclusively during Holy Week at the Sistine Chapel. Even though people had to attend a 3 AM service in Rome to hear it, the Miserere became famous. The Vatican, wanting to keep the piece to itself, threatened excommunication for anyone who copied down the score.

As secrets and life forms tend to do, though, the music leaked out. In the late 18th century, a certain precocious teenager with the last name of Mozart spent Holy Week in Rome with his father. After hearing the Miserere at the Sistine Chapel, young Wolfgang sat down and transcribed the whole thing from memory. He returned for a second performance to double-check his work. From there, the score got into the hands of a music historian who published it.

If the music had really been genetic material, Mozart would have been DNA polymerase, a molecular machine that copies DNA. The polymerase molecule grasps a DNA strand and crawls along, letter by letter, building a matching strand as it goes.

Like Mozart, the enzyme is good at what it does. It proofreads. But sometimes it slips up: A single letter of DNA might be swapped for another one. A section of the code might be flipped backward. One or more letters might be inserted or deleted. (Even one letter lost or gained can cause a major change, since the DNA code is read in three-letter words. In English, imagine losing a letter from the sentence "SHE ATE THE RED BUG" and ending up with "SEA TET HER EDB UG." Some words are still there, but the meaning of the sentence is destroyed.)

Even if DNA polymerase is performing well, damage to the genome can come from outside sources such as UV radiation. But a large fraction of your DNA seems to do nothing at all. If a mutation happens here, you won't know the difference. If a slip-up creates a synonymous change in a gene—the code allows for some words to be spelled in multiple ways—you'll also be fine. And if the mutation does something horrible, it will remove you from the gene pool.

Evolution doesn't care much about any of this. It only notices the rare constructive strokes of the hammer, and it only sees them if they happen in the cells that will become your sperm and eggs (called the "germ line"). If you have DNA damage in the skin of your back from too much tanning, you can't pass it on to your children.

Back when Allegri's Miserere was being sung in the Sistine Chapel, the choirs were made up of men and boys. In choirs like mine, women sing the alto and soprano parts. But that's only a superficial mutation; we singers are the flesh of the piece.

The germ line mutation came in the 19th century. Someone who copied the piece apparently made a mistake, shifting a whole repeated section up by a fourth. What started out as a normal soprano solo now rocketed all the way to a high C, a preposterous note that humans are almost never asked to sing.*

Natural selection didn't weed out this mutation. Once the change had happened and been passed to new generations of the musical score, it stayed in place—even after the error was discovered. We continue to sing the mutated piece because, simply, it's awesome this way. Here's a video. You'll know when the boy soprano hits the high C: it's the note you hear through the bones of your spine instead of your ears.

It's not an overstatement to say that what happened to Allegri's music represents the whole history of life on Earth. Every new development has come from a mistake, small or egregious, that was allowed to stick around for one reason or another. Life started as tiny blobs, then whoops—heads! Legs! Oops again—tulips! Uncorrected errors became tree bark, snail shells, lungs, fur, resistance to antibiotics. Inching along mistake by mistake, life forms developed the machinery to make blood, slime, deadly venom, and spider silk.

Some living things have come together so elegantly that they bring an audience to its feet. There are racing cheetahs, swooping owls, orchids that mimic bees. But even the giant, gut-colored flower that stinks like a corpse to attract flies is a success in its family line. The cassowary is a bird that made so many mistakes, it traded the ability to fly for tree-trunk legs and a head with a sail on top. Even the cassowary, though, is doing something right. Errors become the high notes.

Postscript: My choir director turns out to have a son who, at age three, actually took a hammer to the family car while it was in the garage. The car was not improved.

Images: Top, cassowary from The New Student's Reference Work and Gregorio Allegri, both via Wikimedia Commons. Bottom, cassowary by Peter Nijenhuis via Flickr.

*Plot clarification, in case anybody is worrying about me up there in the loft: this is not the part I sang.

Good Coot Parents Let Kids Starve, Make It Up to Them Later

2013-03-26T10:28:00.000-05:00

Too many mouths to feed? Just make your babies fight each other to the death! That's a strategy some bird parents have been using since even before The Hunger Games was popular. It means the strongest chicks get stronger while the weakest ones conveniently stop showing up to the table.

One type of bird takes this family drama a step further: after letting the biggest chicks bully their siblings for a while, parents suddenly decide the runts are their favorites and begin beating up the older chicks themselves. Authors looking for the next dystopian mega-hit, take note.

"Many species of birds show 'hatching asynchrony,'" says Daizaburo Shizuka of the University of Nebraska, Lincoln. This means they stagger the hatching of the eggs within a nest. When some chicks emerge from their eggs days later than others, the younger birds are doomed to be outweighed and outcompeted by their older siblings. Blue-footed boobies, for example, produce two mismatched chicks; one may peck the other to death or shove it out of the nest. (If you think that's horrifying, you haven't heard about sand tiger sharks, which eat each other inside their mother's womb.)

The polite way to say "letting half your babies die" is "brood reduction." Why hatch a runty egg at all? Parents may allow more siblings to live if food is plentiful. Or a second egg might be a kind of insurance in case the first doesn't hatch.

American coots are waterbirds that lay large clutches of eggs and may space out their hatching over a week or more. This means some siblings end up much heftier than others. At first, young coots follow their parents around, relying on their parents to feed them insects and plant material they find by diving. Siblings don't physically attack each other, but older birds easily out-jostle smaller ones for food. Half of all chicks die of starvation.

Over several years, Shizuka and Bruce Lyon, an ecologist at the University of California, Santa Cruz, monitored 75 American coot families on a lake in British Columbia. They snuck every new chick away as it hatched to give it a color-coded tag. Spying on these families while their chicks ate or starved, the researchers discovered a highly unusual system at work.

During the first 10 days after hatching, younger coot chicks often died of starvation. But any runty chicks who survived this period saw their luck turn around. Parents suddenly started playing favorites. Each coot parent picked one preferred chick out of those who'd hatched last, and gave that chick the most food. Heightening the drama, moms and dads each chose a different favorite.

To discourage bigger siblings from asking for so much food, the parents spent more time "tousling" these birds. In humans this means "affectionately messing up someone's hair," but in birds it means "grabbing your baby by the head and shaking it." As you might imagine, it's pretty convincing. The beefy siblings backed off.

Once parents switched to spoiling the runts and beating up the bigger kids, late hatchers became just as likely to survive as their siblings. The youngest chicks even grew slightly larger than their older brothers and sisters.

This system may be a way "for parents to try to get the best of both worlds," Shizuka says. First, coot parents allow brood reduction to happen, watching their chicks compete to the death. Once the family reaches its optimal size, he says, "parents can take matters into their own hands to make sure that the youngest chicks that are still surviving end up getting enough."

Don't throw out your parenting books yet. Although this method seems to work for the coots, scientists still aren't sure why so many birds have evolved elaborate strategies that require siblings to murder each other—or why chicks go along with it. Shizuka says, "It's safe to say the matter is not resolved."

Shizuka, D., & Lyon, B. (2013). Family dynamics through time: brood reduction followed by parental compensation with aggression and favouritism Ecology Letters, 16 (3), 315-322 DOI: 10.1111/ele.12040

Image: Bruce E. Lyon