Field of Science


Play the Oldest New-World Game of Pictionary

Take a good look, because this may be the oldest piece of art in the Americas. Archaeologists say it's also our earliest drawing of a human. Of course, when your Pictionary partner has been dead for been ten millennia, no one can tell you you're wrong.

In eastern Brazil, the cave of Lapa do Santo is a deep toy box for anthropologists. It's a long, sloping space that sheltered groups of humans intermittently over 11,000 years of history. The ground is made of wood ash, from human hearths, packed as deep as 13 feet. It's full of graves.

On one of the final days of their expedition, having dug to the very bottom of that ashy floor, a group of Brazilian researchers led by Walter Neves discovered the stickman you see above. He's about a foot tall, chipped out of the rock. I say "he" because that projection on the lower right is, according to the experts, a phallus.

Radiocarbon dating of charcoal on the wall showed it to be more than 10,000 years old. And the carving was buried even farther down in the layers of ash than a hearth known to be about the same age. This means the figure can be "confidently" placed at 10,500 years old, Neves writes, and may be as ancient as 12,000 years.

Personally, "human male" would not have been the first thing I thought when I saw this piece of cave art. Why not a tree ( roots)? Some kind of flowering plant? A map of the cave's fire exits? Assuming it is a picture of a person, maybe it's a cave person's patent application: "After extending the arms and opening the mouth, step two is to squeeze your companion. I'm calling it a hug."

What makes researchers see a human, though, is the style of other rock art findings in Brazil. The Lapa do Santo art is similar to regional carvings such as these:

The fellows above have the same C-shaped head, and indeterminate number of lower appendages, as the Lapa do Santo stick figure. (The tall hats or hair must not have caught on everywhere.)

Is that a pregnant cave woman with a baby flying out of her?

Maybe this culture just hadn't invented any numbers bigger than 3, and therefore couldn't pin down how many limbs are on the average human.

OK fine, now I see the phalluses. That's actually pretty disturbing.

If you look closely, you can see some stick people along with stick deer in the cave wall above (and at least one stick plant).

Earliest recorded zombie attack.

As sketchy as he is, the Lapa do Santo petroglyph has now claimed the title of the oldest known rock art in the Americas. In 8000 BC, or maybe before, someone was determinedly chipping that stick figure and all of his extra limbs into a rock wall in Brazil.

The similarity of cave art styles across different regions of Brazil suggests to researchers that these far-flung cultures were connected somehow. Caves a thousand miles apart show the same gape-mouthed, extra-manly drawings. This suggests, Neves writes, that Brazil was inhabited gradually rather than all at once. As human groups grew and traveled, they carried their symbolism with them.

If you have more solutions to suggest for this prehistoric Pictionary game, please share them below. But be mindful of the cave children.

Neves, W., Araujo, A., Bernardo, D., Kipnis, R., & Feathers, J. (2012). Rock Art at the Pleistocene/Holocene Boundary in Eastern South America PLoS ONE, 7 (2) DOI: 10.1371/journal.pone.0032228

Images: First two from Neves et al. Others from A. Prous and G. Martin, found in figure S3 of Neves et al.

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Your Sunscreen Makes Fish Anorexic

Infinitesimal particles inside our cosmetics, drugs, and processed foods are making their way into streams and oceans. There, they become a whole new food group for fish and other aquatic life. Although we treat them as harmless, the nanoparticles added to fish's diets may put them off their lunch altogether.

Manmade nanoparticles--bits of material built to be 300 microns across or smaller--have been booming over the last 10 to 15 years. In pharmaceuticals, they carry tiny doses of drugs into our bodies. In sunscreen, they protect our skin without creating an opaque white coating. Eddie Bauer uses them to make stain-repellent "Nano-Care" khakis.

But once these products have passed through our bodies or been washed off our skin, nanoparticles can journey out into the world, perhaps to be ingested by other organisms. And they don't travel alone. Like staticky socks, nanoparticles collect a coating of hangers-on as they pass through the hallways of an animal's body. Instead of dust and hair, though, they like to gather proteins. For example, several types of nanoparticles are known to trap molecules called apolipoproteins. These proteins are crucial to animals: they help us process the fat that we eat.

Researchers in Sweden set out to discover whether nanoparticles in a fish's environment would affect its metabolism. Would nanoparticles travel up the food chain and into the bodies of predatory fish? And after they'd ingested nanoparticles, would fish have trouble breaking down fats?

Inside the lab, the scientists set up a simple food chain. On the first day of their study, they added plastic nanoparticles to bottles of growing green algae. After 24 hours, they filtered out the algae and fed it to speck-sized crustaceans called daphnia, or water fleas. After another 24 hours, these tiny animals were removed and rinsed off. (The filtering and rinsing steps ensured that only nanoparticles that had actually been consumed would travel up the food chain.)

On the third day, the daphnia were fed to tanks of carp. The researchers observed the fish's feeding behavior, and timed how long it took the fish to gobble up 95% of the hapless water fleas. Then the cycle started over: new nanoparticles were given to new algae, which was fed to new daphnia, which were fed to the same tanks of carp. This went on for 30 days, with the fish fed every 3 days and weighed periodically.

The effects of the fish's new diet didn't show up right away. But after a couple weeks of eating water fleas infused with plastic nanoparticles--and accumulating those nanoparticles inside their own bodies--the carp behaved strangely.

Fish fed a nanoparticle-free diet consistently munched through their food in about five minutes. But the nanoparticle-eating fish slowed way, way down. It took these fish more than twice as long as the others to eat their meal. They moved sluggishly, not actively hunting for the tiny food animals that had been freed in their tank. Bizarrely, the researchers write, "test fish let daphnia swim in and out of their mouth without trying to eat them."

Because they expected nanoparticles to screw up the fish's fat processing, the researchers intentionally gave the fish too little to eat. This made all the fish lose weight as they began to burn up their fat reserves, just like any animal on a diet.

But as time went on, the nanoparticle-fed fish stopped losing weight. By the end of the month, they'd even gained a little.

The authors think that because nanoparticles had sucked up more and more of the carp's apolipoproteins as they ate the contaminated food, the fish couldn't use those proteins to process fat. When starved, they were unable to burn up their stored fat. And somewhere in the complex system of feedback loops that control eating and energy, the fish actually stopped losing weight--even as they lost nearly all interest in their food.

The plastic nanoparticles used in this study are a type that's handy for research, but not especially common outside of the lab. The nanoparticles in sunscreen, for example, are made of zinc oxide or titanium dioxide. Nanoparticles can have various shapes and surface charges, which determine what proteins they'll cling to as they pass through the world. But previous research has shown that the types of metal nanoparticles found in sunscreen can bind to lipoproteins, just as the plastic particles in this study did.

The authors don't address how the concentration of nanoparticles used in their study compares to the concentration that might be found in, say, a contaminated pond--or in your body. But it wouldn't hurt to  look into how nanoparticles affect our own metabolisms. And the effect on the fish in this study intensified over time, as nanoparticles seemed to accumulate in their systems.

Every bit of nanoparticle-containing material we add to the waterways, then, might be contributing to some effect on fish. Maybe in the future we'll have to medicate them with nanodrugs.

Cedervall, T., Hansson, L., Lard, M., Frohm, B., & Linse, S. (2012). Food Chain Transport of Nanoparticles Affects Behaviour and Fat Metabolism in Fish PLoS ONE, 7 (2) DOI: 10.1371/journal.pone.0032254 

Photo: Benson Kua/Flickr

Thanks to Michael Shuler at Cornell University for talking to me about nanoparticles. He published a paper earlier this month on the effect of dietary nanoparticles on chickens.

Seeds from 30,000-Year-Old Squirrel Cache Flower Again

Confession: As a nerdlet of nine or ten, I decided to help flowers get fertilized. I loved seeing the glossy seeds hidden inside the fat green ovaries of dead flowers when I split them open with my thumbnail. I must have watched one of those nature specials where the scientists climb up to the top of the Alps and dust pollen onto endangered flowers with a paintbrush, because I started going around roadside fields with cotton balls and gathering pollen. Partway through my project I realized that these particular plants were doing fine without human intervention, and abandoned them.

Now, a group of Russian scientists has given some help to plants that were, unlike my backyard buttercups, definitely not going anywhere on their own. The seeds and fruits of Silene stenophylla were buried 12 stories deep in the Siberian permafrost. They'd been cached there by a ground squirrel some 30,000 years ago. After digging up these long-frozen specimens, a team led by Svetlana Yashina managed to resurrect the ancient organism. They grew healthy plants that flowered and produced their own new, fertile seeds.

When the team excavated this ground squirrel's hoard, they could tell from the ice structures around it that the spot hadn't been touched--or thawed--since it was first interred 30 millennia ago. Though the industrious squirrel had stored a variety of seeds and fruits, previous studies had shown that the seeds of S. stenophylla had a little more liveliness left in them than the others.

From unripe fruits of S. stenophylla, the researchers extracted placental tissue. (Yes, flowering plants have placentas; it's the place where each seed attaches to the ovary. This was news to me too.) They grew this tissue on its own, coaxing it to develop into actual plant shoots. These shoots were fed and grown up into real, potted, flowering plants.

Alongside the ancient and reconstituted plants, the researchers also grew modern plants of the same species. The ancient plants produced up to twice as many flower buds, as if excited to be alive again.

Once the plants had become flowering adults, there were notable differences between the ancient and modern versions. The ancient plants' flower petals, for instance, had a narrower and more shallowly bisected shape. (You can see one of the modern flowers below, and an ancient flower at the top of this page.) The plant was like a snapshot from an earlier stage of its evolution.

Not only did the plants grow and flower--thirty-six of them!--but they were fertile. Scientists demonstrated this by artificially pollinating the plants with each other's pollen (like me with my cotton balls, sort of). Eight or nine weeks later, the plants produced seeds. When scientists gathered these seeds for germination, 100% of them successfully sprouted into new plants. As adults, they grew the same unusual, ancient flower petals that their parents had.

No one has brought a plant this ancient back to life before. The oldest viable seeds ever found are from the first century BC. Yashina writes that the rapid, deep, and permanent freezing of this squirrel's pantry effectively preserved the plant tissues inside. A similar strategy is employed today at the Svalbard Global Seed Vault in Norway, where samples of seeds from around the world are held in an under-ice bunker. If the world's other seed banks are someday destroyed or abandoned, the Svalbard stock can be used to reestablish our crops.

As for seeds that have been unintentionally frozen, there are countless more under the world's icy regions. Permafrost covers a fifth of the planet's surface. If scientists can find other viable plant tissues preserved beneath it, they may discover more species that, like S. stenophylla, have changed since they were frozen--or they could reanimate plants that are now completely extinct.

There's another potential reanimation to consider. Under the permafrost is a rich community of microorganisms, frozen and preserved like the fruits of S. stenophylla. But unlike the flowering plant, which required plenty of manipulation to bring back to life, these organisms are built to last. David Gilichinsky, the senior scientist on this study, has resurrected permafrost bacteria that were frozen for millions of years.

"They are very tough little guys, especially if they are capable of forming spores," McGill microbiologist Lyle Whyte told me. Whyte was not involved in the plant regeneration study, but researches microbes in the Arctic permafrost. He adds that bacteria in, say, million-year-old permafrost may not be quite that old themselves--there's evidence that these frozen communities actually grow and reproduce very slowly while trapped under the ice.

As climate change begins to thaw the permafrost, will some of these frozen microorganisms be awoken and released into the above-ground world? Whether they've been in suspended animation for thousands of years, or quietly reproducing for millions, these microbes would represent strains that modern-day species have never been exposed to. Ancient bacteria--or perhaps viruses or fungi--might discover that the modern world is fertile ground. Humans might discover the Neanderthal flu.

Sadly, David Gilichinsky himself passed away just two days before the publication of his remarkable plant regeneration discovery. "David was at the same time a great expert [on] microorganisms isolated from the cold permafrost and a warm-hearted friend," a colleague wrote on a memorial page. Although Gilichinsky will be greatly missed by his scientific community, he leaves behind him the message that even something unthinkably long gone can be brought back to flowering life.

Svetlana Yashina, Stanislav Gubin, Stanislav Maksimovich, Alexandra Yashina, Edith Gakhova, & David Gilichinsky (2012). Regeneration of whole fertile plants from 30,000-y-old fruit tissue buried in Siberian permafrost. PNAS : 10.1073/pnas.1118386109

Photos: Yashina et al.

To Kill Parasites, Flies Self-Medicate with Booze

Everyone negotiates hazards in their lives. Your food is poisonous, say. Everything wants to eat you. Parasitic wasps are laying eggs in your body that will eventually hatch and chew their way out. To balance the difficulties of invertebrate existence, fruit flies have developed a grim strategy. Baby flies that are infected with parasites turn to alcohol, aiming to ingest just enough to kill their invaders without also offing themselves.

Drosophila melanogaster is the fruit fly species familiar to biologists and people who don't empty their fruit bowls fast enough. It prefers to eat--and lay its eggs inside--rotting produce. Fermenting fruit holds ethanol, which is toxic. But fruit flies have evolved to be relatively resistant to ethanol, allowing them to survive where other insects wouldn't be able to.

For example, parasitic wasps. Though these insects don't have the fruit fly's resistance to alcohol, some parasitic wasps are attracted to the smell of rotting fruit because it tells them where to find new victims. The wasps attack fly larvae, laying their eggs inside the hapless maggots. The wasp parent also injects venom that prevents the young fly's immune system from attacking their eggs. Inside the larva, the wasp eggs hatch into young that proceed to eat the fly from the inside out.

Researchers at Emory University wanted to know how young flies' consumption of toxic, ethanol-containing food affects their parasitic squatters. Is alcohol a weapon in the fight between fly and wasp?

They first confirmed that ethanol is more toxic to parasitic wasps than to fruit flies. This tolerance testing took place in petri dishes holding fly food with various concentrations of ethanol. Adult flies and wasps were placed in the dishes to breathe in the alcohol fumes. Then the insects were observed to see how long it took before they "could no longer stay upright on their feet," says researcher Todd Schlenke.

So living on more-alcoholic food discourages parasitic wasps from hanging around and laying eggs inside you. But what about fly larvae that are already infected--can they use alcoholic food to their advantage?

The researchers allowed wasps to attack their fly larvae. Then they put the larvae, now carrying a cargo of wasp eggs, on alcoholic or nonalcoholic food. Three days later, they checked up on the flies and wasps. More wasp larvae had died inside the flies eating alcoholic food. Additionally, the still-living wasp larvae inside those flies were often grossly malformed.

The crucial question, though, is whether the fly larvae choose to eat alcoholic, relatively toxic food when they have parasites inside them. Do flies self-medicate?

To test this, the researchers put fly larvae in petri dishes divided in half: one side held nonalcoholic food, and the other alcoholic. A day later, larvae that started on the dry side were more likely to have hit the liquor if they were infected with parasites. Infected larvae on the ethanol-containing side tended to initially crawl away--this food is toxic, after all--but returned later. Overall, flies that held baby wasps inside them preferred the alcoholic side of the dish. They also were more likely to survive to adulthood than their infected-but-sober peers.

It may seem incredible enough that tiny maggots can recognize and respond to a parasitic infection by carefully dosing themselves with toxic food. But the story has a final twist.

All along, the researchers were actually studying two species of parasitic wasp. One is a "specialist"--it only infects D. melanogaster and its close relatives. The other is a "generalist," laying its eggs in whatever species of fruit fly is nearest. The specialist parasite also has some resistance to ethanol, though not as much as the fruit flies. Presumably, it's evolved to tolerate the environment where its prey live. But the generalist has lower ethanol tolerance.

The specialist also has greater tolerance of fly hosts that eat alcoholic food. While this behavior killed off a large number of generalist parasites, it was less effective on the specialists. As if they knew this, fly larvae infected with these hardier parasites were less likely to opt for alcoholic food.

It's possible, Todd Schlenke says, that the fly larvae can tell which type of wasp is living inside them and adjust their behavior accordingly. They might identify a unique antigen from the wasp's eggs or venom. There's a second, more sinister possibility: The specialist wasps might be influencing the flies' behavior, making them less interested in consuming alcohol.

This kind of mind control is very possible for parasites. There are fungi that make their ant hosts carry them to a high place, then shoot spores out of the ants' heads. There's a parasitic worm that gets grasshoppers to drown themselves. A certain fluke convinces fish to flag down passing birds, thrashing and displaying their bellies in the water, because the parasite needs to be swallowed by a bird before it can lay its eggs.

Not all fruit flies living on decaying fruit. Some prefer poisonous mushrooms, or toxic rotting cactuses. It's possible that these flies self-medicate against parasites in a similar way. And who knows what other species might be using alcohol, or different toxins in their environment, to fight off invaders? Even humans could have evolved such a trick without knowing it. If scientists can't prove it, at least it'll be an excuse for your midweek drinking that your friends haven't heard before.

Neil F. Milan, Balint Z. Kacsoh, & Todd A. Schlenke (2012). Alcohol Consumption As Self-Medication Against Blood-Borne Parasites In The Fruitfly Current Biology

Photo: Peter Clark/Flickr

Your Sharkskin Speedo Makes Sharks Scoff

"Inspired by the sleek, hydrodynamic properties of sharkskin," Speedo claims, its Fastskin FSII swimwear mimics the texture of a shark to reduce drag and make you faster. But the material might work better if you wore it inside-out. And a closer look at the shark itself reveals engineering features that put our technology to shame.

Calling the suit--or the shark--"sleek" is a little misleading. A shark's skin is covered in miniature teeth called denticles (in case you thought sharks weren't toothy enough). The denticles themselves have ridges that run parallel to the line of the shark's body. To see what these tiny ridged teeth are or aren't doing, researchers at Harvard assembled some robotic sharkskin sandwiches.

Johannes Oeffner and George V. Lauder tested fresh pieces of skin from two kinds of sharks, the porbeagle and shortfin mako; a ribbed silicone material; and Speedo's Fastskin FSII fabric. They glued pairs of sharkskin pieces together sandwich-style to make flat rectangles of skin. With the silicone and Speedo pieces, they made both normal and inside-out sandwiches (with the textured surface on the inside).

These rectangles of skin, rubber, or swimsuit were tested with a kind of robotic swimming machine. The device dangles a rectangle of material in a current of water, waving it back and forth like an undulating 2D fish. Outside the water tank, the device floats on something "rather like an expensive air hockey table," George Lauder explains. This lets the robot propel itself: It may outswim the current, fall behind, or keep up like a person on a treadmill. It also lets the researchers see just how fast each material can swim on its own.

The sharkskin rectangles propelled themselves through the water significantly more quickly when they were intact than when they had their denticles scraped off, suggesting that the little teeth do aid in swimming speed. The rectangles made of ribbed silicone also swam faster when they were right-side-out than smooth-side-out.

But the Speedo Fastskin sandwiches were not so fast. They actually propelled themselves more quickly through the water when they were turned inside-out. That highly engineered fabric surface made the robot swim "quite a bit slower," Lauder says.

When viewed at a microscopic level, it's pretty clear why the Speedo performed differently from the real sharkskin.
Each of the shark's denticles (left) has three pronounced ridges. The imitation of this ridged pattern is presumably what helped the ribbed silicone rectangles swim faster, even though the sharkskin as a whole doesn't really have a ridged pattern. The Speedo fabric (right) doesn't have pronounced ridges at all, but does have occasional grooves--you can see these as the darker stripes in the material. 

When it comes to lessening drag, it seems Speedo's sharkskin impression is a bust. But the shark is only getting started. Those tiny teeth have another speed-enhancing trick besides reducing drag: They actually increase thrust, helping to propel the shark forward through the water.

Oeffner and Lauder discovered this by tracking the flow of water around their flapping robot. What they saw was a vortex--a little whirlpool of water--forming near the leading edge of the flapping sharkskin. "Insects and birds form these on their wings in flight," Lauder says. Comparing the intact sharkskin to the skin that had its denticles sanded off, the researchers saw that the toothed skin enhanced this vortex and held it closer. The low-pressure vortex helps to suck the sharkskin forward through the water.

(To make sure the flapping of the sharkskin wasn't too exaggerated compared to the motion of a real shark swimming, the researchers observed live sharks called spiny dogfish. These sharks had been trained to swim steadily in a flow tank, like a human in one of those Endless Pools. The sharkskin sandwiches, according to their measurements, did curve back and forth comparably to a real shark.)

Even though the Speedo Fastskin FSII material didn't show any signs of inherent fastness (and seemed to actually increase drag, compared to when it was turned smooth-side-out), that doesn't discount the Speedo swimsuit as a whole. Fastskin suits compress an athlete's body, making it more streamlined. Panels of material squeeze the body into a shape that's, according to the company, more efficient for swimming. And the newest designs, which use a different fabric than the one tested here, even come with a corresponding Fastkin swim cap "designed using global head scanning data."

There's one more crucial ingredient to the Speedo: psychology. "Comfort allows focus and inspires confidence," the company's website says. "And with confidence comes peak performance." 

The mental game may be just as important to athletes as the physical one. And when it comes to confidence, a swimsuit that's marketed to make you feel like a top predator can't hurt. (The sharks themselves, one assumes, don't need any such ego boost.)

Oeffner, J., & Lauder, G. (2012). The hydrodynamic function of shark skin and two biomimetic applications Journal of Experimental Biology, 215 (5), 785-795 DOI: 10.1242/jeb.063040

Photo: Shortfin mako shark jidanchaomian/Flickr; swimsuit; ESEM images Oeffner and Lauder.

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Dogs Understand Us Better than Our Closest Relatives

Does your dog understand you when you point at something? If so, this may be one of the few pop intelligence quizzes on which it can outscore a chimpanzee.

Previous studies had shown that dogs can pass a test in which a human points to a container and the dog must look inside it to find food. Human one-year-olds can pass this kind of test too. But chimpanzees have a hard time with it. Researchers at the Max Planck Institute for Evolutionary Anthropology in Germany wondered if these previous tests were unfair to chimpanzees. Would changing the setup of the experiment prove that chimps really do understand our gesturing?

In previous versions of the experiment, chimpanzees had been seated behind a barrier, while dogs were in the same room as the humans. Additionally, the objects that the animals were asked to choose between usually sat between the human experimenter and the chimpanzee--so the human didn't actually need the chimps' help to lift a container and get the food underneath. Perhaps the chimpanzees understood just fine when the human experimenter pointed to a cup, but thought, "Get it yourself, big-brain."

So the German researchers leveled the playing field between the two non-human species. They added a barrier between human and dog to make their setup more like the chimps'. They put the objects they were pointing to on the far side of their animal subjects, so the humans really couldn't reach the objects themselves. They also replaced containers and hidden food with boring, inedible objects, such as a rope or a sponge. Then they gathered 32 dogs and 20 chimps. ("For practical reasons," the authors write, "the studies of the chimpanzees and the dogs were conducted separately.")

First came a warm-up phase in which the experimenter encouraged the animal to fetch a single object (in exchange for a treat) by saying "Give it to me!" This taught the animals to associate the voice command with retrieving an object. But the experimenter didn't point or look at the object she wanted.

For the experiment itself, there were two objects in the room instead of one. The experimenter pointed to the one she wanted and repeated the "Give it to me!" command, moving her eyes between the animal and the desired object to make her point clearer. The dog or chimp had to turn around, retrieve the correct object, and bring it back to the experimenter to get a treat.

The chimpanzees flunked the test. While they consistently picked up one of the two objects and brought it back to the researcher, they only picked the correct object half the time. But the dogs, as a group, performed significantly better than if they were guessing. (And they did even better when the barrier between them and the human experimenter was removed.)

It's not that chimpanzees don't follow other animals' gazes. Previous studies found that great apes will look where a human is looking to check for anything of interest. But they don't seem to understand that gaze as a form of communication. And pointing with a finger--which is really just an exaggerated way to show where you're looking--doesn't help them.

Dogs, on the other hand, have evolved to be highly attuned to what humans want. As long as they pee outside and perform the duties we assign them (sheep herding, duck retrieving, company keeping) we give them food and warm place to stay.

Of course, dogs' understanding of human gestures will depend somewhat on their personal experiences with their owners. In this study, many of the individual dogs did not perform any better than chance. But earlier studies have shown that young puppies can understand human finger-pointing, while young wolves don't understand it as well.

The fact that chimps don't understand pointing as a form of communication suggests this isn't a universal ape gesture. They can follow a gaze and understand that other individuals have different perspectives; and the captive chimps in this study should have been especially used to communicating with people. But, fittingly enough, the gesture that says "go and fetch that thing for me" seems to be specifically human.

Kirchhofer, K., Zimmermann, F., Kaminski, J., & Tomasello, M. (2012). Dogs (Canis familiaris), but Not Chimpanzees (Pan troglodytes), Understand Imperative Pointing PLoS ONE, 7 (2) DOI: 10.1371/journal.pone.0030913

Photo: by me.

When We Talk about Snow

"Excuse me," the man next to me on the train said mildly, turning in his seat. "Do you remember what you did in the snow?"


"They say it was exactly this day last year that we had all that snow," he said. "So I was wondering, what did you do? Were you working? Did you go home early?" The man was middle-aged, with pale eyes that weren't quite right. He clutched a dirty bag in his lap with both hands.

"Um. They sent us home early, yeah."

"I wish I had a better memory," he said, smiling regretfully.

"You don't remember what you did?"

"About nine o'clock at night," he said, "I remember, I went to go check out the snow. I walked a block or two down the street, but then I saw all those big, huge snow drifts. And I thought, well...if something happened, there was no one around to pull me out, you know?"

Chicagoans called that February 2011 storm the Snowpocalypse. The snow came down furiously all evening. Muffled cracks of thunder sounded from high inside the blizzard. On the highway that runs the city's length, the whiteout slowed traffic to a stop, then froze it in place. Commuters were stranded overnight and had to be rescued by firefighters.

"I wonder," the man on the red line continued, "if you could ask everyone what their ideal snow is, what they would say. Like maybe somebody says, I'd like half an inch of snow between nine and nine-thirty, and that's it!"

"I like a lot of snow," I offered. "But I don't have a car."

"I like a lot of snow, too," he said. We both looked out the window at the gray cityscape, snowless in a 40-degree February.

Chicago isn't the only place experiencing a weirdly temperate winter. Most of the United States has had a warm and dry couple of months. Meteorologist Jeff Masters says that an extremely out-of-the-ordinary jet stream is to blame. Warm air from the Southwest is being pushed across the rest of the Lower 48.

That's funny; I remember when forecasters were telling us this winter would be "another brutal one." But weather is chaotic and hard to predict. That's why climate change models can't tell us for sure whether this freakish year is our fault. Would this one warm streak have happened without our influence, or is it part of the larger pattern of global warming?

Our fault or not, it's hard to talk about this year's unwinter without thinking of climate change. It's not impossible, though. The L.A. Times ran a whole article about the warm weather ("If you looked at U.S. temperatures, you'd say, 'Wow, it was a warm winter,'" says a quoted expert) without once mentioning the climate.

The Wall Street Journal, rather than similarly ignoring climate change in the face of a balmy winter, published an opinion piece called "No Need to Panic about Global Warming." The letter was signed by "sixteen concerned scientists," including at least one (named Claude Allegre) who is also not panicked about asbestos causing cancer.

Previously, the Wall Street Journal had rejected a similar but opposite piece, on why we do need to be concerned about climate change, signed by 255 scientists. Science magazine published that letter, which you can read here. And the Wall Street Journal itself published a rebuttal to the original op-ed. (I won't rehash any of those arguments here, but you can check out my toolkit for talking to climate change deniers.) Unfortunately, when misinformation oozes into the mainstream, it's notoriously sticky to clean up. Rebuttals and corrections can't erase what people have already seen and believed.

You might notice that several signatories of the original Wall Street Journal piece are meteorologists. This is a group especially resistant to the idea of climate change: a 2010 study found that fewer than a third of TV weathercasters believe humans are causing global warming. It may be a problem of seeing the forest through the snow-covered trees. When broadcasters are doing their reporting from the middle of a blizzard, it must be hard to imagine that the world is getting hotter.

I chatted with a man in the Raleigh-Durham airport who looked to be around retirement age. He was an engineer traveling to Chicago for an enormous meeting of people in the heating and cooling businesses. I told him I edit a children's science magazine.

"So you write about the environment? Climate and stuff?" he asked.

"Sure we do," I said. I asked if global warming was a major topic at a conference like this one.

"Well," he said. "I don't know about that warming."

Then he described to me some of the big issues in his industry, such as benefits companies can receive by meeting certain energy standards. "Reducing the carbon footprint of buildings, that's huge," he said.

"If you're talking about reducing carbon footprints," I pointed out cautiously, "that's because of climate change."

"Oh. Sure, I guess," he said. The connection didn't seem to have occurred to him.

Maybe it's impossible right now to show everyone the big picture, the snowless woods behind those icy branches. In our country, climate change has been made into a political issue, rather than an issue of living on the planet. But if people are willing to accept smaller practicalities--tax credits, efficiency requirements, gas prices, different cars on the road--then it might not matter how they perceive the big picture. If the guy in the airport is lowering people's carbon emissions, it makes no difference to a polar bear that he's also reading the Wall Street Journal.

And once people notice the snow is gone, maybe then we'll be able to talk about it.

Photos: by me.

Why Super Bowl Advertisers Want a Close Game

While Americans gather around the nachos today to find out whether the Patriots beat the Giants and how much clothing Danica Patrick wears in her GoDaddy spot, advertisers will have their fingers crossed that their commercial makes a good impression. They've paid millions of dollars for each 30-second ad. That's because they assume this piece of TV real estate is the most valuable there is. But they should be crossing their fingers for a close game--with their ad aired at the very end.

A theory called excitation transfer says that your excitement from one event can overflow into the next thing that happens. So researchers from the University of Oregon decided to find out whether a hotly contested sports game makes the ads that interrupt it more exciting too. They also wanted to know if it mattered where in the game an ad was shown. And finally, did the commercial itself have to be exciting for the effect to work?

Colleen Bee and Robert Madrigal gathered 112 undergrads and 4 TV ads. In earlier testing, people had rated these ads as especially suspenseful or especially not suspenseful. (To prove it, the authors describe each ad in their paper. A suspenseful Nike ad: "International football (soccer) commercial featuring international players against monsters/demons in a dramatic match for the survival of football." An un-suspenseful ad: "Two women playing golf illustrating the frustrations and subsequent solution to bladder control issues." I'd argue that bladder control issues are pretty suspenseful, but apparently that urgency didn't carry over to the commercial.)

In small groups, subjects watched footage of basketball games involving their college team. The footage was edited into four different mini-games (each consisting of two four-minute halves). Subjects saw a close game that the home team lost; a close game the home team won; a win where their team had a wide lead the whole time; or a loss in which their team was always well behind.

Subjects also saw two ads at "halftime," and the other two after the game was over, making note of their reactions to each ad. The order of the four ads was shuffled between the different groups of subjects. From all this, the researchers found three things that make viewers see ads more positively:

A nail-biter
When they watched suspenseful games--that is, games where the score was close throughout--viewers reported having a more powerful emotional response to an ad. They also reported feeling more positive about the ad and the brand itself.

But wait, there's more! This effect was only found when there was also...

A conclusion
The ads that drew the best response from viewers were the ones shown immediately after the end of a suspenseful game. Not in the middle of the game; not a couple ad slots after the game ended; but right after the clock ticked down.

This fits with the theory that residual excitement about an event can spill over into the next event. It's interesting, though, that excitement during the middle of a game doesn't have the same effect. Maybe anxiety over the outcome takes away from people's positive feelings about the ads they're seeing.

Finally, the researchers found that it was necessary to have...

Added suspense
The ad itself must also be suspenseful for the effect to appear. No matter how exciting a sporting event is, that bladder control golf game is just not going to get anyone revved up. But suspenseful ads (like the Nike spot with the demonic soccer players) can get a boost by appearing at the very end of an exciting game.

Since subjects were watching their home basketball team compete, the researchers expected the outcome of the game to be important too. But in this case, they were surprised. Win or lose, the results were the same. Suspenseful ads immediately following a suspenseful game got the best response from viewers, whether or not their team won.

The outcomes of these basketball games, though, had been decided long before viewers saw the footage. Subjects might have felt more suspense--and been more swayed by a win or loss--if the games were taking place in real time. Additionally, the authors point out that pausing after every commercial to rank your emotional responses isn't exactly the normal way of watching TV. Viewers who aren't being forced to stop and reflect on their feelings might not have the same perception of ads as these subjects did.

This study doesn't address how someone's positive feelings about an advertisement might translate into recognizing a brand in the future, or buying that brand's products. That's, of course, the bottom line for advertisers. But it stands to reason that your positive feelings about a TV ad could become positive feelings the next time you see that brand--maybe on a store shelf.

The Super Bowl, too, is a special case. Some people look forward to the ads more than the game itself, and advertisers are pulling out all the stops. But if today's game is a close one--and if it's immediately followed by an exciting ad--we'll see whether critics are swayed to put that ad on their top-10 lists Monday morning.

Colleen C. Bee, & Robert Madrigal (2012). It's not whether you win or lose, it's how the game is played: The influence of suspenseful sports programming on advertising Journal of Advertising, 41 (1)

Image: Screenshot from Bud Light "Replay" commercial, my favorite.

Evolutionary Road: Runoff Breeds Super Salamanders

There's no comic-book hero I know of whose origin story begins, "I was lying in a swampy forest when suddenly, some dirty water trickled onto me."* But with roads and traffic crisscrossing their habitat--and runoff leaking into the pools where they breed and grow--salamanders have had to develop their own superpowers to survive.

Yale researcher Steven Brady recently studied spotted salamanders (Ambystoma maculatum) living in range of street runoff. Amphibians such as salamanders or frogs are vulnerable because they divide their time between land and water and can absorb pollutants through their skin. They also have a tendency to develop freakish mutations and alarm school groups. (Or, say, people who are just looking for a nice A. maculatum photo to illustrate a blog post, not a dozen pictures of a salamander with three arms coming out of one shoulder.) How is runoff affecting salamanders that breed in roadside ponds?

Brady set up a kind of house-swap among salamanders. First, in the woods of northeastern Connecticut, he located five ponds within 10 meters of paved roads. He paired each of these ponds with a similar pond that was safely away from any streets. As soon as the egg masses of salamanders began to appear in those ponds, Brady dug in. (A salamander egg mass, so you'll recognize it the next time you see one, is a cross between scrambled eggs and snot.)
From every pool, Brady plucked out a set of salamander eggs that would stay at home, and another set that would travel. He swapped the traveling eggs between their paired ponds. Then, with home and away eggs safely tucked into enclosures within each pond, Brady waited for the salamanders to hatch.

Two results became clear. The first was that if you're a salamander egg, a nearby road is not your friend. In the ponds deep in the woods, 87% of eggs survived and hatched successfully. In ponds next to a road, that number plummeted to 56%. 

The second result came from comparing the two kinds of eggs within those deadly roadside ponds. The survival rate wasn't the same for local versus visiting salamanders. The eggs that had started out in the roadside pond were, on average, 25% more likely to hatch there than eggs that came from ponds deeper in the woods. It seemed that the roadside salamanders were better adapted to hatch in poisonous ponds than their clean-living peers were.

But there was no complementary effect in the deep-woods ponds. The roadside eggs survived just as well there as the local eggs did. So this wasn't a question of salamanders in each location laying eggs that were better suited to their environment. Rather, the road-adjacent salamanders had apparently evolved extra protection against toxic waters.

What exactly was in those waters? Brady found that water in his roadside pools conducted electricity better, indicating that ions or metals were present. This is what you'd expect to find in runoff from roads. Chloride ions, from road salt being washed away in winter, are an especially likely culprit.

Brady notes that for four out of the five roadside ponds he studied, the roads adjacent to them were only built within the past 50 or 60 years. Within that brief time, the local salamanders have apparently evolved to better survive the polluted water. 

Spotted salamanders spend almost all their time on land, creeping under rocks and damp logs on the forest floor. But once a year, they return to their favorite local pond to mate and lay eggs.  These ponds are usually temporary ones that reappear with each spring's rain and snowmelt. 

Salamanders roam over a larger area during the non-breeding season, but other research suggests these animals are faithful to one breeding pond. Fidelity to a site that kills an extra one-third of your eggs must provide a powerful selective pressure. In each generation, those eggs that can't survive the toxic water get removed from the gene pool. The eggs that are resistant to runoff materials hatch and go on to parent the next generation.

Since these mutant salamanders aren't any more fit than regular salamanders in non-polluted ponds, it doesn't seem that their superpower gives them any advantage in the world outside their breeding pools. They're unlikely to grow large muscles, leave the woods and start fighting crime. They're just demonstrating how nature can make the best of a world sullied by super-villains.

*Correction: I've been informed by my dad that there is, in fact, such a superhero. Called Swamp Thing, he's a man transformed into a "humanoid mass of vegetable matter" by some swamp chemicals. Fittingly, he is a defender of the environment.

Brady, S. (2012). Road to evolution? Local adaptation to road adjacency in an amphibian (Ambystoma maculatum) Scientific Reports, 2 DOI: 10.1038/srep00235

Images: salamander, Wikimedia Commons/Camazine; egg mass, Flickr/dmills727