Even Kindergarteners Can Rate Their Own Confidence

By Elizabeth Preston | August 12, 2014 9:47 am

kid thinking

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

CATEGORIZED UNDER: brains, education, math, Uncategorized

It Only Takes Six Generations to Turn a Brown Butterfly Purple

By Elizabeth Preston | August 8, 2014 9:27 am

butterfly scales

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

Kids Name the Darnedest Animals

By Elizabeth Preston | August 5, 2014 9:51 am

chalk art

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

When Mom and Dad Have Different Migratory Routes, Kids Fly Right Down the Middle

By Elizabeth Preston | July 29, 2014 11:02 am

swainson's thrush

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

CATEGORIZED UNDER: birds, evolution, genes, navigation, top posts

Some Bees Are Busier Than Others

By Elizabeth Preston | July 25, 2014 8:45 am

bee hive

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

CATEGORIZED UNDER: bees, math, top posts
MORE ABOUT: Animals, Gadgets

How to Lose a Finger, and Other Things I Learned from Darwin’s Library

By Elizabeth Preston | July 23, 2014 8:59 am

old books

It’s always a good idea to bring reading material on your trips, whether you plan to have some airport downtime or you’re spending five years floating on the ocean. When Charles Darwin departed in 1831 for his trip around the world on the HMS Beagle, he had a well-stocked library. But the collection wasn’t saved, and neither was the catalogue listing the titles.

The team behind Darwin Online, led by John van Wyhe, has been working to recreate that library. They painstakingly worked backward from comments and citations in Darwin’s notebooks, which were sometimes brief and cryptic (“Ellis horse story,” read one). Now they’ve reconstructed the Beagle library as completely as possible. It’s an online collection of 404 volumes, which all of us in the 21st century can peruse from the comfort of solid ground.

The library is heavy on atlases and travel narratives and light on fiction (I hope you like Paradise Lost). Here are a few critical pieces of 19th-century knowledge I uncovered there: Read More

Baboons Trade Morning Favors for All-Day Payoffs

By Elizabeth Preston | July 18, 2014 10:01 am


Primates basically invented “You scratch my back and I’ll scratch yours.” Baboons, for example, trade grooming for favors from other troop members. Social relationships are important to the monkeys. But it seems they put more effort into certain relationships depending on the time of day: in the morning, lower-ranking baboons invest more energy in grooming animals who can make the rest of their day go smoothly.

Chacma baboons help each other out in several ways, says Claudia Sick, a biologist at the University of Copenhagen. They groom each other, which keeps them clean, relieves stress, and strengthens their social bonds. They also trade grooming for favors like access to infants (everyone in the troop enjoys hanging out with the babies), mating, and maybe even backup in fights. We can think of these favors like commodities that the monkeys exchange in a “biological market,” Sick says. Read More

CATEGORIZED UNDER: economics, top posts, Uncategorized

Here’s What Happens When You Put Camera Traps in Trees

By Elizabeth Preston | July 15, 2014 11:18 am


The world holds very few unexplored places between zero and six feet off the ground. If humans can walk right up to it and take a picture, we probably already have. But the tops of the trees, like the bottom of the ocean, are a different story.

“We know so much less about arboreal mammal activity than we do about terrestrial mammal activity,” says Tremaine Gregory, a research scientist at the Smithsonian Conservation Biology Institute. She thought camera-trapping, a common method for observing land animals, might also be useful for studying the ones hiding in the treetops. That’s why she hooked herself to a rope and started hoisting cameras into the towering Amazonian canopy. Read More


Say No to Nocebo: How Doctors Can Keep Patients’ Minds from Making Them Sicker

By Elizabeth Preston | July 9, 2014 10:19 am


“First, do no harm,” the saying goes, but that might be close to impossible. Just as our expectations can make us feel better, they can also make us feel much worse. This means that how doctors phrase their instructions or introduce new drugs may have a real impact on our health. But some doctors are trying to figure out how they can do less harm by harnessing the surprising power of their words.

“In the classical view that is still taught at medical school and in textbooks, drug actions are purely determined by the drug,” says Ulrike Bingel, a neurologist at the University of Duisburg-Essen in Germany. “But that is not true.” Read More

The Shambulance: 5 Reasons Not to “Cleanse” Your Colon

By Elizabeth Preston | July 4, 2014 9:22 am

Happy Independence Day! Here’s hoping all your fireworks are experienced externally. This post first appeared in October 2012.


The Shambulance is an occasional series in which I try to find the truth about bogus or overhyped health products. Physiologist Steven Swoap is with me at the helm.

If you’ve been tempted by promotions for “colon hydrotherapy”—that is, sessions in which you would pay someone to put a tube up your rectum and wash out your large intestine with water, like a dirty garage being hosed down in summer—then you’ve already overcome some impressive mental hurdles. Maybe you’re almost ready to enjoy the relaxation, renewed energy, and improved health that the procedure promises. Before you take the plunge, as it were, here are a few points to consider.

It’s not the 19th century.
People who offer colon hydrotherapy (also called a colonic) tell you the large intestine is full of “toxic waste and toxins.” It does, of course, carry waste out of your body. But is it a two-way street? Read More


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Like the wily and many-armed cephalopod, Inkfish reaches into the far corners of science news and brings you back surprises (and the occasional sea creature). The ink is virtual but the research is real.

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