Have a great Labor Day weekend, everybody! But be careful not to enjoy yourself too much. (This post on the dangers of laughter first appeared in December 2013.)
Careful with the bedside banter, doctors. Before you put on your best Patch Adams impression, you might want to consider whether your attempts at humor will ease your patient’s discomfort or give him a protruding hernia.
That’s the conclusion of a review paper in the Christmas issue of BMJ that asks the jolly question of whether laughter can kill. The two authors, R. E. Ferner of the University of Birmingham and J. K. Aronson of Oxford University—no JK-ing, those are his real initials—take a tongue-in-cheek approach. They even give their research question an acronym: MIRTH (Methodical Investigation of Risibility, Therapeutic and Harmful).
Ferner and Aronson scoured medical literature for studies having to do with laughter. After “excluding papers on the Caribbean sponge Prosuberites laughlini and with authors called Laughing, Laughter, Laughton, or McLaughlin,” they were left with three categories of study. One had to do with the benefits of laughter, one with its dangers, and the third with medical conditions that have laughter as a symptom.
Let’s hear the bad news first. Read More
A bat’s voice is its livelihood. Chirping and squeaking at just the right frequencies lets it echolocate food and stay alive. Sounding pretty isn’t the point—except when it is. For the first time, scientists think they’ve found a bat species in which females choose mates based on their voices. Even if a lower-frequency squeak might be better for finding prey, males with the highest squeaks are the sexiest.
The horseshoe bats, or Rhinolophidae, are a family of nearly 80 species with bizarre noses. Often generously described as “leaf-shaped,” the nose looks more like a many-layered tree fungus growing out of the bat’s face. The bats live in Europe, Africa, Asia and Australia.
Throughout this family of bats, the larger species make lower-frequency echolocation calls. Think of a tall, barrel-chested bass singer in a choir compared to a smaller tenor (if the whole choir were singing above the range of human hearing, that is.) But one species, Rhinolophus mehelyi, breaks the pattern. Read More
Stalactites hold tight to the ceiling, the saying goes, and stalagmites might grow high enough to reach it. But the simple mnemonic doesn’t come close to covering the variety of weird, rocky shapes growing all over a cave. There are even, it turns out, rocks made from bacteria. They’re not putting the “tight” in “stalactite” so much as the “ack!”
Researchers found the microbe-made rocks in a cave in northern Sweden called Tjuv Antes. (It’s named for a fugitive thief who allegedly hid there in the 1800s.) Therese Sallstedt and Magnus Ivarsson of the University of Southern Denmark’s Nordic Center for Earth Evolution, along with colleagues from Sweden and Spain, saw many kinds of rocky formations in the cave. There were smooth crusts of stone. There were bubbly structures that looked like popcorn. There were structures with delicate fingers like coral (above).
The walls of Tjuv Antes Cave are made of granite. But the researchers only found the stony growths on the cave’s ceiling, which is made of dolerite. There were other things growing on the ceiling too. Read More
You’ve already picked a side in the bird wars, whether or not you know it. As humans carve up formerly empty expanses of the western United States with our roads, electrical towers, and power lines, we’re inadvertently giving a boost to ravens. Meanwhile, the birds of prey that once ruled the land are being left in the dust.
“The ecology of the sagebrush steppe is changing,” says Idaho State University biologist David Delehanty. He means a type of dry, scrubby grassland that’s found in the western part of the country. Raptors used to be the dominant predators here—specifically the buteos, a genus that includes certain hawks and buzzards (and is pronounced “beauty-ohs,” like a very lovely breakfast cereal). These birds have traditionally lorded over the big expanses of arid land.
But in recent decades, raptors have become rarer. Taking their place are common ravens. Read More
Researchers at Disney Research Zurich—who normally work on computer graphics, video manipulation, and animation—recently took a spin in the physical world instead. Along with researchers at the Swiss Federal Institute of Technology Zurich, they developed an algorithm that can take any solid 3D object and turn it into a top.
To understand the challenge, think of spinning a teapot on a single point. It’s round, sure—but between “here is my handle” and “here is my spout,” it’s unbalanced and won’t stay up.
Do you remember on Who Wants to Be a Millionaire—apparently this show is still on, but I’ll assume no one else has seen it this decade—how after contestants picked an answer, Regis Philbin sometimes asked, “How sure are you?” They’d pull a number seemingly out of the air: “Oh, eighty-five percent.” This trick of estimating our own confidence is a psychological phenomenon called metacognition. And if you ask in the right way, even kids as young as 5 can do it.
Adults aren’t randomly picking numbers when we say we’re 85% sure of something. We may be overconfident in ourselves, but in general we can sense when our knowledge is stronger or weaker. In kids, though, it’s been harder for psychologists to tell whether this is true. Results of metacognition tests in young subjects have been mixed.
“Verbal instructions can be difficult for young children to interpret and remember,” says Jessica Cantlon, a cognitive scientist at the University of Rochester. Read More
Evolution can seem like a slow way to get things done. It took more than a billion years for Earth’s life forms to try having more than one cell. In the famous March of Progress illustration showing an ape becoming an upright human, you can almost hear the stoop-shouldered cave guy in the middle groaning, “Hurry up already!” But all that is deceptive, because evolution is also fast. It took scientists only a few quick generations of butterflies to make a brown species turn violet. In doing so, they gained insights about color that they hope will last a little longer than their subjects’ dull wings.
Nature has two ways of making colors. There are pigments, like the green chlorophyll molecules within plant leaves and the brown melanin in humans. Then there’s structural color: nanoscale tricks of reflection that make surfaces appear different colors, depending on their microscopic shapes. Butterflies are masters of this. Read More
Here’s an experiment that’s easy to do on your own. Grab the nearest elementary- or middle-school-age kid, sit her down in a quiet place, and ask her to name everything she can think of that’s alive. The results might tell you a lot about your young subject’s life. The wilder the animals, the more domestic the kid.
The 5-to-14-year-olds in Andrea Taverna and Sandra Waxman’s version of this experiment lived in Argentina. (Taverna is a researcher at Argentina’s National Research Council; Waxman is a psychology professor at Northwestern University.) One group of subjects lived in a city and another group lived in a rural area. A third batch of kids were members of an indigenous group called the Wichí, who live in the forest and speak a native language instead of Spanish. Read More
It sounds like the setup to a bad joke told by zoologists: What do you get when you cross a bird that always flies to the west with one that always flies east? But the punch line is weirder than you’d guess. Birds’ migratory routes are partly coded into their DNA. A baby that inherits genes for two different routes doesn’t commit to either path. Instead it bounces between them and may take a wild zigzag straight through the middle—even if that route is perilous.
Laboratory tests in the past have hinted that this might be true. One study of captive warblers, for example, crossed a type that orients itself to the southwest when it’s ready to migrate with a type that orients southeast. The offspring pointed themselves directly south.
Kira Delmore and Darren Irwin, researchers at the University of British Columbia, wanted to put this idea to a tougher test. So they captured wild birds, attached geolocator tags to their backs, and sent the birds out into the world again. When the travelers returned, the researchers could see exactly where they’d chosen to fly. Read More
It may be time to leave “busy as a bee” with other dubious animal similes like “happy as a clam” and “drunk as a skunk.” That’s because some bees, it turns out, aren’t all that busy. A small group of hive members do the bulk of the foraging, while their sisters relax at home. But their lifestyles aren’t permanent. If the busy bees disappear suddenly, the lazier ones will step up to take their place.
Scientists figured this out—somewhat incredibly—by gluing tiny RFID tags to over a thousand honeybees. (An RFID tag is the same miniature transponder that a vet might inject into your dog, that’s replacing barcodes on some merchandise and library books, and that makes your public transit card work.) Each beehive in the experiment had a pair of laser scanners over a walkway at its entrance. As bees passed through, they were recorded like items in a checkout lane. Using two scanners let the scientists tell whether bees were coming or going. Read More