Category: Science

The crayola-fication of the world: How we gave colors names, and it messed with our brains (part II)

Untitled (Cubes) by Scott Taylor

Update: This post was an Editor’s pick by Cristy Gelling at Science Seeker, and was included in Bora Zivkovic‘s top 10 science blog posts of the week.

Lately, I’ve got colors on the brain. In part I of this post I talked about the common roads that different cultures travel down as they name the colors in their world. And I came across the idea that color names are, in some sense, culturally universal. The way that languages carve up the visual spectrum isn’t arbitrary. Different cultures with independent histories often end up with the same colors in their vocabulary. Of course, the word that they use for red might be quite different – red, rouge, laal, whatever. Yet the concept of redness, that vivid region of the visual spectrum that we associate with fire, strawberries, blood or ketchup, is something that most cultures share.

So what? Does any of this really matter, when it comes to actually navigating the world? Shakespeare famously said that a rose by any other name smells just as sweet. So does red by another name look just as deep? And what if you didn’t have a name for red? Would it lose any of its luster? Would it be any harder to spot those red berries in the bush?

Rose coloured glasses by jan_clickr

This question goes back to an idea by the American linguist Benjamin Whorf, who suggested that our language determines how we perceive the world. In his own words,

We cut nature up, organize it into concepts, and ascribe significances as we do, largely because we are parties to an agreement to organize it in this way—an agreement that holds throughout our speech community and is codified in the patterns of our language […] all observers are not led by the same physical evidence to the same picture of the universe, unless their linguistic backgrounds are similar

This idea is known as linguistic relativity, and is commonly described by the blatantly false adage that Eskimos have a truckload of words to describe snow. (The number of Eskimo words for snow probably tells you more about gullibility and sloppy fact-checking than it does about language.)

Hyperbole aside, color actually provides a neat way to test Whorf’s hypothesis. A study in 1984 by Paul Kay and colleagues compared English speakers to members of the Tarahumara tribe of Northwest Mexico. The Tarahumara language falls into the Uto-Aztecan language family, a Native American language family spoken near the mountains of North America. And like most world languages, the Tarahumara language doesn’t distinguish blue from green.

The Tarahumara language falls among the southern Uto-Aztecan languages. Image credit: Wikimedia Commons

The researchers discovered that, compared to the Tarahumara, English speakers do indeed see blue and green as more distinct. Having a word for blue seems to make the color ‘pop’ a little more in our minds. But it was a fragile effect, and any verbal distraction would make it disappear. The implication is that language may affect how we see the world. Somehow, the linguistic distinction between blue and green may heighten the perceived difference between them. Smells like Whorf’s idea to me.

Do you see what I see? A young girl from the Tarahumara tribe, whose language doesn’t distinguish green from blue. Photo credit: Fano Quiriego

That was 1984. What have we learnt since? In 2006, a study led by Aubrey Gilbert made a rather surprising discovery. Imagine that you’re a subject in their experiment. You’re asked to stare at the cross in the middle of the screen. A circle of colored tiles appear. One of the tiles is different from the others. Sometimes it will be on the left, and other times on the right. Your task is to spot whether the odd-color-out is on the left or on the right. Keep your eyes on the cross.

That’s easy enough. What’s the catch?

Well, sometimes you’ll also get a picture that looks like this.

See the difference? In one case, English speakers have different words for the two colors, blue and green. So there’s a concept that builds a wall between them. But in other cases like above, the two colors are conceptually the same.

Here’s what the researchers wanted to know. If you have a word to distinguish two colors, does that make you any better at telling them apart? More generally, does the linguistic baggage that we carry effect how we perceive the world? This study was designed to address Whorf’s idea head on.

As it happens, Whorf was right. Or rather, he was half right.

Continue reading The crayola-fication of the world: How we gave colors names, and it messed with our brains (part II)

The crayola-fication of the world: How we gave colors names, and it messed with our brains (part I)

“Who in the rainbow can draw the line where the violet tint ends and the orange tint begins? Distinctly we see the difference of the colors, but where exactly does the one first blendingly enter into the other? So with sanity and insanity.”

—Herman Melville, Billy Budd

Spectral Rhythm. Screen Print by Scott Campbell.

This post was chosen as an Editor's Selection for ResearchBlogging.org

In Japan, people often refer to traffic lights as being blue in color. And this is a bit odd, because the traffic signal indicating ‘go’ in Japan is just as green as it is anywhere else in the world. So why is the color getting lost in translation? This visual conundrum has its roots in the history of language.

Blue and green are similar in hue. They sit next to each other in a rainbow, which means that, to our eyes, light can blend smoothly from blue to green or vice-versa, without going past any other color in between. Before the modern period, Japanese had just one word, Ao, for both blue and green. The wall that divides these colors hadn’t been erected as yet. As the language evolved, in the Heian period around the year 1000, something interesting happened. A new word popped into being – midori – and it described a sort of greenish end of blue. Midori was a shade of ao, it wasn’t really a new color in its own right.

One of the first fences in this color continuum came from an unlikely place – crayons. In 1917, the first crayons were imported into Japan, and they brought with them a way of dividing a seamless visual spread into neat, discrete chunks. There were different crayons for green (midori) and blue (ao), and children started to adopt these names. But the real change came during the Allied occupation of Japan after World War II, when new educational material started to circulate. In 1951, teaching guidelines for first grade teachers distinguished blue from green, and the word midori was shoehorned to fit this new purpose.

Reconstructing the rainbow. Stephanie, who blogs at 52 Kitchen Adventures, took a heat gun to a crayola set.

In modern Japanese, midori is the word for green, as distinct from blue. This divorce of blue and green was not without its scars. There are clues that remain in the language, that bear witness to this awkward separation. For example, in many languages the word for vegetable is synonymous with green (sabzi in Urdu literally means green-ness, and in English we say ‘eat your greens’). But in Japanese, vegetables are ao-mono, literally blue things. Green apples? They’re blue too. As the Viagra pill, it is also blue. As are the first leaves of spring, if you go by their Japanese name. In English, the term green is sometimes used to describe a novice, someone inexperienced. In Japanese, they’re ao-kusai, literally they ‘smell of blue’. It’s as if the borders that separate colors follow a slightly different route in Japan.

And it’s not just Japanese. There are plenty of other languages that blur the lines between what we call blue and green. Many languages don’t distinguish between the two colors at all. In Vietnamese the Thai language, khiaw means green except if it refers to the sky or the sea, in which case it’s blue.  The Korean word purueda could refer to either blue or green, and the same goes for the Chinese word qīng. It’s not just East Asian languages either, this is something you see across language families. In fact, Radiolab had a fascinating recent episode on color where they talked about how there was no blue in the original Hebrew Bible, nor in all of Homer’s Illiad or Odyssey!

(Update: Some clarifications here. Thanks, Ani Nguyen, for catching the mistake about Vietnamese. See her comment below about how the same phenomenon holds in Vietnamese. Also, the Chinese word qīng predates modern usage, and it mingles blues with greens. Modern Chinese does indeed distinguish blue from green. Thanks to Jenna Cody for pointing this out, and see her insightful and detailed comment below.)

I find this fascinating, because it highlights a powerful idea about how we might see the world. After all, what really is a color? Just like the crayons, we’re taking something that has no natural boundaries – the frequencies of visible light – and dividing into convenient packages that we give a name.

Imagine that you had a rainbow-colored piece of paper that smoothly blends from one color to the other. This will be our map of color space. Now just as you would on a real map, we draw boundaries on it. This bit here is pink, that part is orange, and that’s yellow. Here is what such a map might look like to a native English speaker.

A map of color for an English speaker. Results of the XKCD Color Survey. Randall Munroe.

But if you think about it, there’s a real puzzle here. Why should different cultures draw the same boundaries? If we speak different languages with largely independent histories, shouldn’t our ancestors have carved up the visual atlas rather differently?

This question was first addressed by Brent Berlin and Paul Kay in the late 1960s. They wanted to know if there are universal, guiding laws that govern how cultures arrive at their color atlas.

Continue reading The crayola-fication of the world: How we gave colors names, and it messed with our brains (part I)

How a new understanding of itch leads to better pain treatments


"Happiness is having a scratch for every itch" - Ogden Nash. (Image credit: doug88888)

It begins with an itch. That familiar irritating feeling, swiftly followed by the inevitable scratch. For most of us it ends here, in a fleeting moment of bliss. But then there are those tortured few for whom scratching provides little relief.

In 1660, the German physician Samuel Hafenreffer defined an itch as “an unpleasant sensation associated with the desire to scratch.” As an operational definition, it does the job. As far as we know, every animal with a backbone has a scratching reflex. It’s a useful instinct to rid yourself of fleas, mites, mosquitoes and other small insects that might carry infection. But this protective mechanism can also go awry.

In a masterful essay entitled The Itch, the surgeon Atul Gawande recounts the case of an HIV patient suffering from a severe chronic itch. The patient had recently been diagnosed with shingles, a disease whose symptoms often include extreme itchiness. After many sleepless nights of relentless scratching, she woke up one morning with a greenish fluid trickling down her face. Hours later, in the emergency room, her doctors informed her that she had managed to scratch through her skull, all the way to her brain.

Chronic itching is triggered by various diseases, such as eczema, shingles, HIV, chronic kidney problems, or even as a side effect from some medications. In most cases, it adversely affects quality of life, as patients are constantly tortured by their incessant need to scratch themselves. Standard medications often have no effect. These are people who are suffering from an itch that they can’t get rid of.

Imagine an itch that you couldn't scratch away. This is the plight of those suffering from a chronic itch. (Image credit: Gerald Slota)

The story of itch is inextricably woven with the story of pain. Starting from the discovery of morphine in the early 1800s, there has been steady progress in the medical understanding of pain. Researchers have mapped the circuitry that transmits pain, and have developed increasingly effective painkillers and anaesthetics. In contrast, an itch was not considered life threatening, and relatively little effort was spent trying to understand it. For a long time, it was simply thought to be a dull form of pain.

But this picture is changing fast. In the last decade, researchers have learned about receptors in the nerves under our skin that react specifically to itchy substances. When these receptors fire, they send a signal racing up our spinal cord, headed to our brain where it creates an urge to scratch. Scientists now have a basic map of the roads that an itch takes on its way to our brain. And they have even been able to block some of these roads in mice, essentially preventing them from feeling an itch.

"Scratching is one of nature's sweetest gratifications, and as ready at hand as any. But repentance follows too annoyingly close at its heels." - Montaigne. (Image credit: Stuart Oikawa)

Continue reading How a new understanding of itch leads to better pain treatments

Bacteria use slingshots to slice through slime

This post was chosen as an Editor's Selection for ResearchBlogging.orgBacteria have busy social lives. You might get a glimpse of this the next time you take a shower. The slimy discolored patches that form on bath tiles and on the inside of shower curtains are the mega-cities of the bacterial world. If you zoom into these patches of grime, you’ll find bustling microcosms that are teeming with life at a different scale.

That we can see these microbial communities with our naked eye is testament to the scale of their achievement. Perhaps the most spectacular examples are the giant mats of bacteria that lend life to the Grand Prismatic Spring in Yellowstone National Park. These macroscopic structures are just as impressive as our cities that are visible from outer space. Microbes have colonized practically all moist surfaces on earth, from the inside of our mouths (they’re responsible for dental plaque) to hot vents at the bottom of the ocean. And it all started from small beginnings.

Grand Prismatic Spring, Yellowstone National Park, USA. The people above give a sense of the scale. (Image credit: Leto-A)

The first wave of bacterial settlers that arrived on your shower curtain were few and far apart. They would try to hold on using the molecular adhesion between themselves and the shower curtain. Those that couldn’t get a grip were flushed down the drain plug.

Bacteria have an adaptation that serves them well in such tricky situations. It’s a sort of multi-purpose prong, technically known as a type IV pilus (plural: pili). These wonderful filament-like structures extend out from the bacteria, and grab on to the surface like a suction cup on a bathroom tile. What happens next is straight out of science fiction.

Once these settlers have their ‘feet’ firmly planted on the ground, the next step is to build a home. They begin to excrete a polymer substance, forming a grid that locks them into place. Many different microbes can co-inhabit these homes, from bacteria and archaea to protozoa, fungi and algae. Each species performs a specialized metabolic function, neatly occupying a niche in this city. Together these interlocked communities, or biofilms, are the beginnings of a thriving multicultural microbial civilization.

Continue reading Bacteria use slingshots to slice through slime

What it feels like for a sperm, or how to get around when you are really, really small

This post was chosen as an Editor's Selection for ResearchBlogging.orgWe don’t usually learn about the physics of squishy things. Physics textbooks are filled with solid objects such as incompressible blocks, inclined planes and inelastic strings. This is the rigid world that obeys Newton’s laws of motion. Here, squishiness is an exception and drag is routinely ignored. The only elastic object around is a spring, and it is perfectly elastic. It will never bend too far and lose its shape. But any child who has played vigorously with a Slinky has stretched past the limits of this Newtonian world.

Mr. Newton's not going to like that..

Whereas the rigid universe is notable for its strict adherence to a few basic principles, the squishy universe is a different beast altogether.

I was recently out paddling, and noticed that as you move the paddle through water, tiny whirlpools begin to develop along its sides. The whirlpools grow in size, become self-sustaining, and break off and float away. Eventually they die out, as they lose their energy to the fluid around them.

You could also watch the spirals and vortices created by rising smoke. Or notice the strange shapes made by the wind as it sweeps through the clouds. It’s as if fluids have a life of their own, often wondrous and beautiful, and other times surprising and counter-intuitive.

The brief and wondrous life of vortices

But the motion of fluids is notoriously hard to predict. It’s so difficult that if you can solve the equations of fluid flow, there are people willing to offer you a million dollars. The difficulty comes from a mathematical property of the equations known as non-linearity. Simply put, a non-linear system is one where a small change can lead to a large effect. The same thing that makes these equations difficult to solve is also what makes fluids surprising and interesting. It’s why the weather is so hard to predict – tiny changes in local temperatures and pressures can have a large effect.

At this point, most reasonable people would throw their arms up in despair. But physicists are an unreasonably persistent bunch, and when faced with an equation that they can’t solve, they try to get some insight by looking at what happens at extremes. For example, thick and syrupy fluids like glycerine behave in a surprisingly orderly fashion. Take a look at this video (watch through to the end, it’s worth it).

I bet you’ve never seen a fluid do that before. So what’s going on here? And what does this have to do with swimming sperm?

Continue reading What it feels like for a sperm, or how to get around when you are really, really small

Launch speed of the leaping sifaka

Update: Added discussion on launch angle at the end of the post.

Edit: The final numbers in this post went through a few rounds of revision. What is the world coming to, when you have to track down missing factors of 2 in your blog posts?!

This week, I’m looking at the strategies and mechanisms by which different animals solve the problem of getting around. I started off by writing about how birds and aquatic animals conserve energy on-the-go. This post is another spinoff on the theme of locomotion.

Here’s a clip from one of my favorite documentaries, David Attenborough’s Life of Mammals. It shows the incredible sifaka lemur of Madagascar, a primate that has a really remarkable way of getting around. (If the embed doesn’t work, you can watch it here)

As they launch out from the trees, they almost look like they’re defying gravity. And so, taking inspiration from Dot Physics, I thought it might be interesting to put physics to use and analyze the flight of the sifaka.

I loaded the above video into Tracker, a handy open source video analysis software. I can then use Tracker to plot the motion of the sifaka. I chose to analyze the jump at about 21 seconds in. I like this shot because it isn’t in slow motion (that messes up the physics), the camera is perfectly still (we expect no less from Attenborough’s crew), and the lemur is leaping in the plane of the camera (there are no skewed perspective issues that would be a pain to deal with). The whole jump lasts under a second, but at 30 frames per second, there should be plenty of data points.

This is what it looks like when you track the sifaka’s motion:

The red dots are the position of the sifaka at every frame. That’s the data. In order to analyze it, we need to set a scale on the video. I drew this yellow line as a reference for 1 unit of size (call it 1 sifaka long). And how big is that?

If we believe this picture that I found on the National Geographic website, then a sifaka is about half the size of this folded arms dude.

Now, to the physics..

Continue reading Launch speed of the leaping sifaka

A revealing photograph

While looking around on Flickr for images for the previous post, I came across this captivating photograph taken by Toni Frissell.

More than meets the eye?

It’s a gorgeous shot on aesthetic grounds. Perfect lighting and composition, a beautiful subject, and a strikingly dramatic moment. And seen another way, it’s a metaphor for what Empirical Zeal is all about: diving beneath the surface, and looking at things from a different point of view.

It turns out that this photograph is a neat illustration of two interesting physical phenomena. Can you guess what they are? And here’s another (admittedly odd) question. Can we use this photograph to work out the density of this woman?

(Answers below the fold)

Continue reading A revealing photograph

I made it to the 3QD finals!

I’m very excited to report that my post on blind cavefish made it to the list of finalists for the 3QuarksDaily Science Prize 2011. I’m in the company of some seriously excellent writers, all of whom I admire. A big thanks to everyone who voted me in and helped spread the word about this very young blog. You’re all incredible!

Here are the other finalists:

  1. Cosmic Variance: The Fine Structure Constant is Probably Constant
  2. Dr. Carin Bondar: Sacrifice on the Serengeti
  3. Highly Allochthonous: Levees and the Illusion of Flood Control
  4. Laelaps: The Pelican’s Beak – Success and Evolutionary Stasis
  5. Oh, For the Love of Science: Prehistoric Clues Provide Insight into Climate’s Future Impact on Oceans
  6. Opinionator: Morals Without God?
  7. Scientific American Guest Blog: Serotonin and Sexual Preference: Is It Really That Simple?
  8. Starts With A Bang: Where Is Everybody?

They’re all excellent posts, and it’s great to see science writing getting some love.

Vote for your favorite online science writing

Update: They’ve kept voting open till Friday, June 10. Please vote!
Update: Voting closes in one day – on Wednesday, June 8. Please vote!

The excellent blog 3quarksdaily has an annual science writing competition, where they reward the best posts on science over the last year. This year, it’s being judged by the particle physicist and cosmologist Lisa Randall.

There are lots of great nominations. You can check out the list here. It’s now open to online votes, and the top 20 entries will be passed to the editors for the next round of selection. So, get out there, and start reading! And don’t forget to vote. You’ll learn about some fascinating stuff, and you’ll be encouraging science writing.

2011 3QD science prize nominees

Flies alter their ejaculate to get the best bang for the buck

Smarter than you think..

Sex is war. It’s a battle for limited resources.

The source of sexual conflict is this: sperm is a relatively cheap resource for males to produce, whereas producing eggs and rearing offspring is a much larger investment on the part of the female. Darwin was the first to realize the implications of this. He reasoned that this imbalance should result in males competing with each other to fight for the limited resource, and females exerting a strong choice on who to mate with. Taken together, male competition and female choice were the two pillars of the theory that he called sexual selection.

The battle of the sexes is not a new idea, but it has changed with the times.

In the 1960s and 70s, the sexual revolution was eroding away conservative ideas about sex. This was the era of promiscuity. And this changing social fabric was being mirrored in science. The ‘free love’ era brought about an equally potent, but more silent, revolution within biology – one that completely shook up our old, prudish notions of reproduction. Research from these decades onwards taught us that in almost all animals, from insects to birds and mammals, females typically copulate with multiple males. We learned that promiscuity is not a freak event, it’s actually the norm. What this implies is that, like any modern war, the battle of the sexes is a messy and involved affair, often leading to surprising and unexpected consequences.

For one thing, it’s being fought on many fronts. In many species, competition between males for the egg doesn’t stop at intercourse. Even after the female is inseminated, the battle rages on inside her reproductive tract. In this alien battlefield, the sperm cells of different males compete with each other to fertilize the eggs. Meanwhile, the reproductive organs of the female can still exert control by choosing between the different sperm.

And just like the Greeks who sneaked into Troy, the soldiers in this battle use every trick at their disposal to gain an upper hand. Some males do the equivalent of taking their ladies out to a fancy restaurant – they present females with a nutritious meal in their sperm, at substantial cost to themselves (delightfully, biologists call this a prenuptial gift). Others resort to date rape  – their sperm includes a harmful cocktail of drugs that alter the females’ behavior in their favor. Even more chilling, there are species in which the males engage in traumatic insemination, where they essentially rape the females. Other males are just outright weird. Some leave their penis behind to plug the vagina from use by other males. Others have smelly sperm that repels other males. And others have spiky penises, that scrape the vagina clean of the sperm of competitors.

Not a pleasant lay. That thorny structure is the penis of a bean weevil.

Continue reading Flies alter their ejaculate to get the best bang for the buck