With just over two months until The Science of Kissing’s debut (publication date has moved up to Jan 5), my book’s been mentioned in the brand new issue of Scientific American MIND by Ferris Jabr:

No matter how old and experienced we get, sex and romance never fail to surprise and perplex us. Three new books explore the origins of human sexuality, whether we are capable of monogamy, and why we kiss.

__

In The Science of Kissing: What Our Lips Are Telling Us (Grand Central Publishing, 2011), biologist and science journalist Sheril Kirshenbaum explores all aspects of a lip lock. For instance, women usually require a kiss to feel intimate with another person, whereas men are more willing to forgo the first kiss and go straight for sex. Although scientists don’t know why we kiss, Kirshenbaum explores several possibilities, such as that kissing rekindles the intimacy we first experienced in infancy when breastfeeding.

It’s exciting as an author to see the first nod to a project that has taken years of research, experimentation, and composition. Feels surreal knowing SoK’s nearly available to share with readers! More coming soon…

(In the meantime, flip through the book’s brand new gallery website!)

A bountiful archaeological site in South Africa has given up another discovery showing humans becoming sophisticated tool users. According to a study out in the journal Science, 75,000-year-old artifacts in the Blombos Cave appear to show signs of pressure flaking, a process of finely shaping hard material. Before this, study author Paola Villa says, the oldest evidence of humans using the technique was dated to just 20,000 years ago.

Pressure flaking consists of trimming the edges of a finished tool by pressing with a bone point hard enough to remove thin slices of rock. This process creates the narrow, evenly spaced grooves found on flint tools from Europe’s 20,000-year-old Solutrean culture and prehistoric Native American groups. Wider, more irregular grooves characterize 36 pressure-flaked Blombos tools, which were made from silcrete, Villa says. This rock, a silica-rich material, is of lower quality than flint and requires heating to ready it for pressure flaking. [Science News]

It’s not easy to tell from these artifacts whether their makers simply hammered them into shape or used the more sophisticated flaking method to polish them off. So the team, led by Vincent Mourre, found silcrete around the cave site and tried to make their own.

Mourre himself then created replicas of the buried artifacts using two techniques: the earlier hammering method and the later method that used pressure flaking as a retouch after hammering. When Mourre and his colleagues compared the artifacts with the copies, almost three-fifths of the ancient tools showed marks of pressure flaking: They had thinner, straighter edges that could pierce deeper and last longer. [ScienceNOW]

Stone Age tool expert John Shea told Science News he didn’t necessarily agree that pressure flaking made these people’s tools that much better. It could have been more a signal of skill—a Stone Age “Hey, look what I can do.” But, he agreed with the study authors that humans were using creative techniques like pressure flaking much further back than they’d been getting credit for, and the method may even date back to 100,000 years ago.

“This finding is important because it shows that modern humans in South Africa had a sophisticated repertoire of toolmaking techniques at a very early time,” said Villa. The authors speculated that pressure flaking may have been invented in Africa and only later adopted in Europe, Australia and North America. [AFP]

That’s the key implication of studies like this one—that these kinds of skills emerged and diffused through early human cultures gradually, not all at once:

The finding fits with the idea that symbolic art, rituals and other forms of modern human behavior developed gradually over hundreds of thousands of years, not in a burst of cultural innovation marked by cave paintings and other creations that appeared after 50,000 years ago in Western Europe. [Science News]

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Image: Mourre et. al.; Science / AAAS

By now you may have heard the report that as many as 1/4 of all the sun-like stars in the Milky Way may have Earth-like worlds. Briefly, astronomers studied 166 stars within 80 light years of Earth, and did a survey of the planets they found orbiting them. What they found is that about 1.5% of the stars have Jupiter-mass planets, 6% have Neptune-mass ones, and about 12% have planets from 3 – 10 times the Earth’s mass.

This sample isn’t complete, and they cannot detect planets smaller than 3 times the Earth’s mass. But using some statistics, they can estimate from the trend that as many as 25% of sun-like stars have earth-mass planets orbiting them!

Like mass?

Now, there’s a very important caveat here: these are planets that have the same mass as Earth, but that doesn’t mean they are very earth-like. The planets the team could find were very close to their parent stars, so they’d be very hot, and uninhabitable. But the good news is that if that trend in mass they saw is correct, the Milky Way is littered with planets the mass of the Earth! If some of them are in the habitable zone of their star… well.

So a funny thing: I was thinking about this very problem a couple of days ago, but from a different angle. How many habitable planets are there in the Milky Way? Not just earth-mass, but also orbiting their star in the so-called Goldilocks Zone, where temperatures are right for liquid water?

There’s a way to estimate it. And it involves the planet recently announced, Gliese 581g. This planet is about 3 times the Earth’s mass, and it orbits its star in the right place. We don’t know what it’s made of, if it has an atmosphere, or really very much about it at all! But given its mass and temperature, it’s potentially habitable.

The distance to the Gliese 581 system is what gets me excited: it’s 20 light years away. That’s close, compared to the vast size of our galaxy. So let’s assume Gliese 581g is the closest potentially habitable planet to us. Given that assumption, we can estimate the number of potentially habitable planets in the entire Milky Way! And the math’s not even that hard.

The not-so-hard math

Extrapolating from our one example, let’s say that habitable planets are roughly 20 light years apart in the galaxy (as we’ll see, that number can be a lot bigger or smaller, and the end result is still cool). That means there’s one star per cube 20 light years on a side:

In the drawing, each box is centered on a star, and the two stars are 20 light years apart. That means the cubes are 20 light years on a side, right? If we assume stars with livable planets are distributed throughout the galaxy like this, then there is one star per 20 x 20 x 20 = 8000 cubic light years. That’s the density of habitable planets in the galaxy.

So how many cubic light years are there in the galaxy?

A lot. Let’s say the Milky Way is a stubby cylinder 100,000 light years across, and 2500 light years thick. The equation of volume of a cylinder is

volume = π x radius of disk² x height of disk

so

volume = π x 50,000² x 2500 = 2 x 10¹³ cubic light years

Holy wow! That’s 20 trillion cubic light years!

Now we just divide the volume of the galaxy by the density of stars with planets to get

2 x 10¹³ / 8000 = 2,500,000,000 planets

Oh my. Yeah, let that sink in for a second. That’s 2.5 billion planets that are potentially habitable!

What does this mean?

Well, that’s a whole lot of planets! That’s what it means.

What’s cool, too, is that this number isn’t all that far off from what you can estimate using the report from yesterday. Something like 25% of the stars in the galaxy are like the Sun (that’s a rough estimate, but close enough). That’s 50 billion stars. If 25% of those have earth-mass planets, that’s about 13 billion total, about five times the number I got. I’d call that pretty close! We made a lot of guesses here, so even a factor of ten isn’t so bad. And we’re not really comparing apples to apples, either, since they were looking for earth-mass planets, and I was looking for earth-like planets.

So think about it: 2.5 billion habitable planets is roughly enough for every man, woman, and child on Earth to each have a planet. You can see why I’m not too concerned with the exact math. Even if my numbers are way off, there could be as few as hundreds of millions of planets, or as many as maybe hundreds of billions in our galaxy alone that we could live on!

Again, the point being that mathematically speaking, there may be a lot of habitable planets out there. And who knows; some may be marginally habitable and we can terraform them. And then there are moons of worlds, too… I don’t think I’m speaking too far out of school if I were to speculate that for every perfect Terra Nova out there, there might be three or four more planets we could live on with some work.

Of course, I’m ignoring how we’d get there! But that’s an engineering problem, and given enough time — oh, say, a century or two — I imagine we can overcome a lot of those issues.

If, and when, we do, there will be a lot of real estate out there to poke around in.

Per ardua, ad astra!

“BACKGROUND: Individuals’ faces communicate a great deal of information about them. Although some of this information tends to be perceptually obvious (such as race and sex), much of it is perceptually ambiguous, without clear or obvious visual cues. METHODOLOGY/PRINCIPAL FINDINGS: Here we found that individuals’ political affiliations could be accurately discerned from their faces. In Study 1, perceivers were able to accurately distinguish whether U.S. Senate candidates were either Democrats or Republicans based on photos of their faces. Study 2 showed that these effects extended to Democrat and Republican college students, based on their senior yearbook photos. Study 3 then showed that these judgments were related to differences in perceived traits among the Democrat and Republican faces. Republicans were perceived as more powerful than Democrats. Moreover, as individual targets were perceived to be more powerful, they were more likely to be perceived as Republicans by others. Similarly, as individual targets were perceived to be warmer, they were more likely to be perceived as Democrats. CONCLUSIONS/SIGNIFICANCE: These data suggest that perceivers’ beliefs about who is a Democrat and Republican may be based on perceptions of traits stereotypically associated with the two political parties and that, indeed, the guidance of these stereotypes may lead to categorizations of others’ political affiliations at rates significantly more accurate than chance guessing.”

Photo: flickr/leoncillo sabino

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A couple of years or so ago, Jonathan Feng at UC Irvine, George Musser from Scientific American and I began discussions about an article for the magazine. This week, that article finally hit the newsstands in the November Issue.

Back in 2008, Jonathan and I had for quite a while been interested in the connections between particle physics and cosmology, and in particular how experiments at current, upcoming (the LHC at that point) and future colliders could inform and be informed by modern cosmology. In fact, I’d written about these connections a number of times here on the blog, discussing, for example, the nature of WIMP dark matter, and the origin of the matter-antimatter asymmetry of the universe. And these were the starting point for our interactions with George about a SciAm article.

The journey from these initial musings to a final article was a mostly enjoyable and interesting one, and for me it contrasted greatly with the vast majority of writing that I do, presenting my own current research for journals. In those efforts, the editorial input is generally small. One receives referee reports that are hopefully mostly positive, and can sometimes (although rarely, to be honest) contain excellent suggestions that improve the final version of the paper. The editorial role is mostly in the selection of referees by a scientist serving on the editorial board, and in general grammatical editing of the paper and verification of references as it nears the publication date.

But writing for a magazine is a different experience. From the beginning it was very much a collaborative effort, with Jonathan and I honing our ideas about what should appear in the article, and George pushing some ideas and downplaying others, to fit with his experience of the kind of article that most readers want. We were all searching for the right mix of background material, new directions in the field, and connections to work that Jonathan and I had been directly involved in, and so could comment on from direct experience. Although we didn’t always agree, it was definitely a constructive process, and the final content was a consensus in the best sense of the word, with what to emphasize and what couldn’t make it into the article for space reasons (which are very tight) the outcome of lengthy, but useful negotiations between us and George. That it took a couple of years from inception to publication is partly a reflection of the natural time it takes for a lot of back and forth between editor and authors who have busy day jobs, and partly because in the middle I moved institutions, putting me out of action for a while.

What we ended up focusing on is the intriguing possibility that the dark sector of cosmology might exhibit a considerably richer structure than our usual simple descriptions of a plain WIMP candidate for dark matter, and a cosmological constant, or sequestered dark energy component driving cosmic acceleration. Rather, it is possible that the dark sector contains it’s own set of new particles and forces, and that our detections, gravitationally based so far, have not yet been able to probe this underlying structure. We wrote about interesting possibilities for dark matter, some of which are related to work Jonathan has done, for much of the article, and at the end turned to the possibility of interactions with dark energy, which I’ve worked on and have occasionally written about here. As we concluded the article:

The only matter we know anything about, visible matter, comprises a rich spectrum of particles with multiple interactions determined by beautiful underlying symmetry principles. Nothing suggests that dark matter and dark energy should be any different. We may not encounter dark stars, planets and people, but just as we could hardly imagine the solar system without Neptune, Pluto and the swarm of objects that lie even farther out, one day we might not be able to conceive of a universe without an intricate and fascinating dark world.

The article isn’t perfect, of course. For example, there is a heading for one of the figures that reads “Experiments that claim to have detected dark matter”. We didn’t write that, but we should have caught it in proofs. It is wrong, of course, and should read something like “Experiments that are searching for dark matter”. Also, after being so close to the material for a while, there are some ambiguities that you don’t notice unless someone else reads them a different way and lets you know. But in all, I think Jonathan and I are pretty happy with the final article.

For me, it was an enjoyable experience, with several highlights. First and foremost, we had an engaged ad sympathetic editor who understood both the science and the target audience. Thanks George! Second, it is wonderful fun to receive some actual draft page proofs, after months of exchanging a visually unappealing text file, and to see the art work that has been designed to accompany the article. We had some very rough ideas regarding one or two of the figures, but most of the visual parts of the article were created with no initial input from us. We helped tweak at the end, and certainly helped with text in the figures, but the gorgeous graphics were essentially all the magazine’s work. And finally, George never even hinted to us, but when we received copies of the actual magazine a few days before it appeared, we were shocked and delighted to see that our article was the cover article. I can’t tell you how thrilled my mother will be!

Just like the newsstand version, the online version of the article costs money of course. But if you do read it, I hope you enjoy it.

There are many different kinds of intelligent. Are you book smart? Street smart? Good at school and test-taking smart? Good at schmoozing your way out of deadlines and into jobs smart? Better at writing or math?

One new intelligence test, put online today by New Scientist and the Discovery Channel, claims to be the best test of overall smarts. The test was designed by neuropsychologist Adrian Owen to test 12 different “pillars” of wisdom, and to work every part of your mind.

From Owen’s article about the test for New Scientist:

Like many researchers before us, we began by looking for the smallest number of tests that could cover the broadest range of cognitive skills that are believed to contribute to intelligence, from memory to planning.

But we went one step further. Thanks to recent work with brain scanners, we could make sure that the tests involved as much of the brain as possible – from the outer layers, responsible for higher thought, to deeper-lying structures such as the hippocampus, which is involved in memory.

As an intrepid blogger, I went ahead and took the test. Some of the exercises resembled classic games like “Memory” (to test paired associates learning, you’re asked to remember what items are hidden where) and “Simon” (to test working memory, you have to remember sequences). Others are more similar to cognitive psychology tests like the Stroop test (which tests focused attention), and there are also some puzzle-solving tests (to test your ability to plan for the future).

The 12 tests are designed to test 12 different aspects of working memory, reasoning, focus, and planning. I did the worst on the “verbal working memory” test, which was reading a string of numbers and typing it in from memory. This actually makes sense, because I’ve always known myself to be a physical learner, and highlight or write down everything I hear that I need to remember. I wonder if there is a correlation there?

You can only take the test once, so make sure to do some mental push-ups first before diving in. Then come back here and tell us what you thought! Also, visit http://www.cambridgebrainsciences.com to play additional games, to train your brain, and to test your 12 pillars.

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Image: Flickr/B Rosen

The universe abounds with Earth-sized planets. That hopeful notion has been reinforced by individual planets finds like possible Goldilocks planet Gliese 581g, by the hordes of planet candidates discovered by the Kepler mission, and now, by a census of a small space in the sky that tells us one in four sun-like stars should possess worlds that are close to the size of Earth.

Take a moment to think about that: One in four.

In Science, exoplanet hunters Geoffrey Marcy and Andrew Howard published their team’s census of 166 nearby stars like ours, of which they picked 22 at random to investigate for planets. They watched the stars’ doppler shifts to hunt for planets over the last five years, and used the results to extrapolate how common terrestrial planets must be far beyond just this set of stars.

In total, the astronomers detected 33 planets orbiting 22 stars, and the distribution of the planets showed they became more plentiful the lower their mass…. They estimate that 23% of sun-like stars are circled by an Earth-like planet, 12% are orbited by more massive “super-Earths” and around 1.6% are circled by planets similar to the gas giant, Jupiter. [The Guardian]

As is always the difficulty with planet hunting, “Earth-size” is not “Earth-like.” So just because there may be a glut of planets about as big as ours, that doesn’t mean they look anything like home (and, in fact, Marcy and Howard sampled planets that orbit their stars much closer than the Earth does to the sun).

Their observations and extrapolations say nothing about whether all these Earth-size planets will actually have the characteristics of Earth: its density, its just-right distance from the sun, the fact that it is a rocky structure rather than gaseous ball. But Marcy said that with so many Earth-size planets now expected to be orbiting distant suns – something on the order of 50,000,000,000,000,000,000,000 across the universe – the likelihood is high that many are in “habitable zones” where life can theoretically exist. [Washington Post]

Indeed, the astronomers are working with rough estimates—studying relatively few stars to estimate the planetary distribution of the universe. But just getting in the right ballpark for how many planets like ours are out there is hugely invigorating, Howard says:

“I wouldn’t be surprised if the true number [of stars hosting Earth-mass planets] is one in two, or one in eight — but I’m almost sure it’s not one in 100,” he said. “That’s a really big improvement on our knowledge.” [Wired.com]

Discovery News says MIT’s Brice-Olivier Demory is wary of such a major extrapolation this early, but soon this won’t be the only star census trying to coax out the terrestrial planet answer.

More information will be coming soon. A Geneva-based team of planet-hunters has made preliminary assessments that 30 percent to 50 percent of its surveyed stars have planets. And scientists using NASA’s Kepler space telescope, which is on the hunt for Earth-sized worlds, has yet to weigh in. [Discovery News]

It’s hard to stay patient with so many worlds waiting to be found. In February, the scientists behind the Kepler mission will unveil the data they’ve been studying in secret for months, trying to sort out which of the planetary candidates their telescope has spotted are truly new worlds and not statistical errors. Kepler’s early results turned up the same thing as Marcy and Howard’s survey, that terrestrial planets are far more common than gas giants. And the February data set should contain a major batch of new, small worlds.

While humanity’s first 15 years of turning up exoplanets has caught the low-hanging fruit—all those hot Jupiters and super-Earths—there are countless Earth-sized worlds on the cusp of discovery.

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Image: Keck Observatory

From Ed Yong:

Spotting mistakes is a crucial part of typing (and indeed, life) and according to Gordon Logan and Matthew Crump, it’s a more complicated business than it might first appear. Using some clever digital trickery, the duo from Vanderbilt University found that the brain has two different ways of detecting typos. One is based on the characters that appear on the screen, and the other depends on the strokes of our fingers, as they tap away at the keys.

Logan and Crump asked 22 good typists to type 600 words presented on a screen, one at a time. Their efforts appeared below the target word, but all was not as it seemed. Throughout the experiment, Logan and Crump occasionally took control to the display. Sometimes, they put up the correct word, regardless of what the recruits actually typed so that their mistakes never appeared. On other trials, they deliberately introduced mistakes, which the typists hadn’t actually made.

To see whether the typists realized they were being toyed with, check out the full post at DISCOVER blog Not Exactly Rocket Science.

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Photographer Kris Pannecoucke was part of a six-week scientific expedition along the Congo River, the first of its size since the 1960’s. Panneoucke: “Yangambi—situated along the river and once the largest research center for tropical agriculture in the world—is in a ruined condition. Boats travel the river with 50-year-old maps made during Belgian colonial times.”

Pannecoucke took this photograph of entomologist Patrick Grootaert along the Itimbiri river, a tributary of the Congo River: “Every night entomologist Patrick hung out a white sheet and lamp to attract insects. He had to protect his ears because on earlier occasions he had some bugs stuck in his ear. He always invited us to his ‘cinema.’ And with a big bottle of beer we all waited for the insects to come.”

Grootaert collected some 5,000 specimens, including a fly that may represent a previously unknown genus. In January 2011, the scientists will hold a press conference to announce the results together with an exhibition of images in three locations: the Royal Museum for Central Africa in Tervuren, the Royal Belgian Institute of Natural Sciences in Brussels, and the National Botanical gardens of Belgium.

Kris Pannecoucke/Aurora Photos

The retreat of the ice covering “Snowball Earth” 700 million years ago might have been the key to the Cambrian explosion that seeded our planet with diverse forms of life. But the trigger may not have been the changes to the climate, but rather the release of phosphorus into the ocean.

During this time period, called the Cryogenian or Snowball Earth stage, the entire planet was covered in snow and ice, and the oceans may even have been frozen. Many researchers believe that the ice receded twice during this freezing period, first around 700 million years ago and then again around 635 million years ago. In a paper published in Nature this week, a team of researchers propose that these receding sheets released phosphorus into the oceans.

In the scheme offered by [Noah] Planavsky and his colleagues, the snowball ice sheets would, as their modern counterparts do, grind up continental rock that would release phosphorus when the glaciers retreated. That phosphorus would wash into the ocean, where it would fertilize algal blooms that could drive a surge in the production of organic matter and oxygen. And the added organic matter that settled into the mud on the ocean bottom would leave additional oxygen behind, eventually boosting atmospheric and oceanic oxygen. [ScienceNOW]

Phosphorus isn’t usually present in the oceans in high concentrations, but it is essential, so it is often the piece missing from the algal growth equation. To figure out if phosphorus levels rose before the Cambrian explosion, the researchers, lead by Planavsky, studied marine core samples from around the world.

“Gathering samples for this study was a long endeavor,” recalled researcher Noah Planavsky, a biogeochemist at California-Riverside. “Cars will get stuck in mud, flat tires are unavoidable, and old maps can lead you wandering for hours. It is essential to accept that you could spend days traveling to sample some rocks, sometimes halfway across the world, and find nothing useful for your study.” [LiveScience]

What they got from this world-trudging was evidence for a spike in phosphorus levels in the oceans that occurred between 635 and 750 million years ago, about the time of the recession of Snowball Earth’s ice sheets.

“We have potentially found the smoking gun for the mechanism that drove the oxygen increase that ushered in the first animals,” said researcher Timothy Lyons, another biogeochemist at California-Riverside. “Our results may be the first to capture the nutrient driver that was behind this major step in the history of life, and that driver was ultimately tied to the extreme climate of the period.” [LiveScience]

Some researchers disagree with this model, because phosphorus has a limited lifetime in the ocean, and because some believe there was only a single thawing of Snowball Earth. In order to have a strong impact on ocean life, critics say, the levels of phosphorus in the ocean would need to be elevated for longer than could be attributed to a single thaw. But Planavsky argues that even if there was just one thawing event, ice sheets would have moved back and forth repeatedly during the warming, and phosphorus would have been released continually over millions of years. That would have kept the phosphorus levels high, he says, spurring life in the oceans.

Other researchers are interested, but not yet convinced.

A phosphorus link between glaciations and oxygen, and therefore evolution, “is a fascinating possibility,” says biogeochemist Donald Canfield of the University of Southern Denmark in Odense. “But they don’t yet have the continuous [geologic] record that would prove it. In principle, it’s a testable hypothesis; that’s the work’s value.” [ScienceNOW]

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Image: Wikimedia/neethis

I’m typing about typing. As my fingers flit over the keyboard, my brain is hard at work. It is accessing my knowledge of language, processing the information taken in through my eyes and fingers, and coordinating the movements of my fingers. And all the while, I’m looking for errors. Spotting mistakes is a crucial part of typing (and indeed, life) and according to Gordon Logan and Matthew Crump, it’s a more complicated business than it might first appear.

Using some clever digital trickery, the duo from Vanderbilt University found that the brain has two different ways of detecting typos. One is based on the characters that appear on the screen, and the other depends on the strokes of our fingers, as they tap away at the keys.

Logan and Crump asked 22 good typists to type 600 words presented on a screen, one at a time. Their efforts appeared below the target word, but all was not as it seemed. Throughout the experiment, Logan and Crump occasionally took control to the display. Sometimes, they put up the correct word, regardless of what the recruits actually typed so that their mistakes never appeared. On other trials, they deliberately introduced mistakes, which the typists hadn’t actually made.

When the volunteers made a genuine error, they slowed down afterwards. This drop in speed also happened when they made a mistake that was surreptitiously corrected, but not when a false mistake was inserted. So regardless of what the typists saw, the feedback from their fingers told them that they had slipped up and they acted accordingly. It looked as if the typists had resisted the illusion… but not quite.

After their test, Logan and Crump asked the recruits whether they noticed any shenanigans, first subtly (“Did you notice anything about the kind of errors you made?”) and then more directly (“Did you notice that on some proportion of the trials the computer may have correctly typed a word even though you made an error?”) .

The answers revealed that a substantial proportion of the volunteers had consciously fallen for the illusion and hadn’t noticed what had happened (even though their typing speed had changed accordingly). The vast majority took credit for the corrected errors and accepted the inserted ones as their own. Even when directly asked, around 20% didn’t spot anything unusual going on.

According to Logan and Crump, this “illusion of authorship” reflects the fact that typing involves two different groups of skills that spot mistakes in different ways. The “outer loop” involves the language centres of the brain and is involved in producing the words that we type. It detects errors by checking what appears on the screen and matching it to our original intentions. If what turns up looks right, the outer loop thinks all is well and if what appears is wrong, the outer loop raises the alarm. The outer loop falls for the illusion.

Meanwhile, the “inner loop” sets up the right sequence of hand movements that type out the words put forward by the outer loop. It detects errors by checking the feedback from the fingers and no matter what Logan and Crump do on the screen, it knows what the typist actually typed. The inner loop sees through the illusion but it operates at a largely unconscious level. It’s the one that slows down the typists’ fingers when they sense that the wrong keys were pressed.

The experiment suggests that the two loops do indeed have different ways of spotting errors. Logan and Crump confirmed that by putting 24 typists through a variant of their first experiment (image below, left). This time, they were asked to say whether they had typed each of the 600 words correctly, immediately after each trial. Once again, they still consciously fell for the illusion, taking the blame for around 70% of the inserted errors, and taking credit around 90% of the corrected errors. But as before, they slowed down when they had made a genuine mistake, even for trials where they had been apparently fooled.

A third experiment was even more blatant (image below, right). This time, Logan and Crump actually told their recruits about what they would do behind the scenes; their job was to tell the difference between what was right and wrong, real and fake. This time, they spotted the inserted errors well enough but amazingly, some of them still fell for the corrected ones. They were just as likely to notice the artificial correction as they were to miss it and take credit for the results.

These three experiments clearly show that two different processes prevent us from making mistakes as we type. The two loops depend on different types of feedback and they work independently; after all, it’s possible to fool one but not the other.

Logan and Crump think that a similar pair of systems may control all sorts of abilities, including playing music and speaking. An inner loop deals with all the details, such as hitting the right notes or making the right sounds. Meanwhile, an outer loop matches the result to our intentions, checking to see if we have performed the right song or communicated the right message.

Reference: Science http://dx.doi.org/10.1126/science.1190483
If the citation link isn’t working, read why here

A couple of days ago I recorded a video interview with the Fourcast podcast, where four people sit around and predict the future. It was a lot of fun — we talked about beaming energy, world governments, Firefly, colonizing the Moon, and BBQs. Seriously.

You can download the MP3 directly, and they posted the whole video to YouTube.

Or you can watch it right here from the comfort of your monitor:

A few notes:

1) I’m not sure I was correct about Tesla coils, but they do seem to be a bad way to transmit energy.

2) It’s true, I still haven’t seen "Avatar".

3) Here’s the exoplanet advance I mentioned. I also mentioned Kepler.

4) I didn’t want to get into specifics on the religion topic (at the 24 – 27 minute mark) because this wasn’t the place, but if you take a look over at the Middle East and still disagree with me, well, I can’t help ya.

5) Yes, that’s Stewie on my wall. My wife gave me that poster a couple of years ago. Victory is mine!

My thanks to the guys at Fourcast for letting me spew unfettered misinformation^* for an hour. It was fun!

A very special note: I endorse Christie Wilcox for 2010 Blogging Scholarship.

A map of human genome variation from population-scale sequencing. This paper is getting a lot of play. A taste of things to come from the 1000 Genomes Project. It’s OA, so check it out.

Difficulties in Defining Errors in Case Against Harvard Researcher. I think Marc Hauser will be an emeritus professor by the time the case involving his alleged misconduct is resolved.

Where did all these monkeys come from? – Fossil teeth may hint at an Asian origin for anthropoid primates. We were all Asians before we were all Africans! Before that perhaps were all Laurasians and/or Gondwanans. How about Pangaeans?

Sugar-Sweetened Beverages and Risk of Metabolic Syndrome and Type 2 Diabetes. “…individuals in the highest quantile of SSB intake (most often 1–2 servings/day) had a 26% greater risk of developing type 2 diabetes than those in the lowest quantile.” Genetic background probably matters in terms of the effect size.

The evolution of the marine phosphate reservoir. “We propose that these two factors are intimately linked; a glacially induced nutrient surplus could have led to an increase in atmospheric oxygen, paving the way for the rise of metazoan life.” Interesting stuff.

Paul Conroy sent me a link to a Dutch article which purports to illustrate what the average human male’s face looks like. From what I can gather this is a weighted average by population. Click through and tell me what you think. Seems plausible enough to me.

For Congress, I think that the breakdown will be:

Senate – 50 Republicans, 50 Democrats

House – 240 Republicans, 195 Democrats

My reasoning? I just took FiveThirtyEight’s numbers and shaded them a bit to the Republican side. There’s no point in making predictions unless you predict something novel and a bit off expectations. Additionally, since the readership here leans a little Left I am inclined to tweak you guys a bit and make the political Götterdämmerung even more terrifying, though I didn’t want to push my luck and give you an implausible value which you’d reject on the face of it.

Image Credit: Therealbs2002, Wikimedia Commons

The last 24 hours of the initial sample collection phase of the Dodecad Ancestry Project are upon us. So if you have raw 23andMe data, you got a day to send it in, if you’re of the following groups:

-Greeks (not necessarily from Greece: Cypriots, Pontic Greeks from the former USSR, North Epirotes, Griko speakers from Italy, -Muslim rumca speakers from Turkey, etc. are all accepted)
-People from the Balkans
-People from Anatolia
-People from the Caucasus
-Italians
-Non-Indo-European speakers from Europe (e.g., Finns, Hungarians, Basques)
-Scandinavians and Icelanders
-Iranians
-Armenians
-Jews from Italy, the Balkans, or Anatolia
-Assyrians
-Arabs

The point of the project is to get a better picture of genetic variation in Eurasia, especially in undersampled groups.

A reader pointed me to a second composite image of a “global human.” It is “a composite itself from four composite of Northwest European, South & West Asian, East Asian and African faces….” I was very taken aback by this face, because it was familiar: staring back at me is younger variant of the faces of my maternal uncles! I asked a friend who has met my family their impression of the photo without a preface, and they immediately wondered if it was a stylized representation of one of my mother’s male relatives.

The snowy, wind-blown Scottish archipelago of St. Kilda may be inhospitable, but because it is inhospitable, it is an ideal natural laboratory. The last people left this place behind nearly a century ago, but the sheep stayed. And the in absence of human interference in their breeding, the sheep of St. Kilda have shown scientists something peculiar.

It has to do with the relationship between the immune system and reproduction. Andrea Graham and colleagues have studied the islands’ Soay sheep for years and years, and found the average lifespan of the ewes to be about 6 years. However, there’s great variation in there: Some lived just a few years, and some as many as 15.

The short-lived ewes had lower concentrations of antibodies than the longer-lived ones, which suggested why their lives were so short. But why was natural selection not weeding them out? Dr. Graham said the researchers found this to be a puzzle: “What are all these sheep doing with low antibody concentrations?” [The New York Times]

It’s a good question. If you just looked at the conditions on St. Kilda, you’d think that weaker sheep eventually would be wiped out.

The Soay sheep may not have any natural predators, but they do have the elements to contend with: a lack of food, brutal weather that can kill off half the population at a time and parasitic worms that live inside their bodies and suppress their immune systems. [MSNBC]

The answer, they found, was that the sheep with the weakest immune systems were the most fertile, reproducing like crazy during their short lives. Meanwhile, the sheep with strong immunity had less reproductive success, but they also lived a lot longer, so the reproduction stats just about even out. Therefore the archipelago hosts a population where neither the strong immunity/weak fertility sheep nor the weak immunity/strong fertility sheep have died out.

Graham’s study is out in Science.

Related Content:
80beats: Like a Wool Sweater, Scottish Sheep Shrink As Climate Heats Up
80beats: Naturally Produced Hydrogen Peroxide Summons White Blood Cells to Wounds
80beats: How Male Antelopes Lie to Get More Sex: With False Alarm Calls

Image: Wikimedia Commons

In the post below on the genetic history of India, or earlier when discussing the revisions of European prehistory, one general trend that is cropping up is that the future seems more complex and muddled than we’d presumed. This introduces the real possibility that in the foreseeable future we won’t be able to opine with any credibility about the nature of the pre-literate past, because our tools are good enough to falsify simple models, but not powerful enough to distinguish between the set of more complex models. In contrast, ten years ago when it came to the expansion of farming in Europe on offer we had simple and clear dichotomies; demic diffusion of Anatolian farmers vs. cultural diffusion of farming techniques along trade routes. Ten years ago when it came to India we are mooting the possibilities between elite transmission of Indo-European language, versus demographically significant migrations into South Asia bringing the Indo-Aryan dialects.

I think that such models are wrong, because there are major parameters left out of the picture. Now in the world we see around us the possibility of really achieving plausible consensus around a positive truth has decreased significantly, because the causal possibilities are proliferating. A model then becomes synonymous with a story. But to admit that it may be that we can’t know is still a greater improvement on the delusion that we did know.

These are general observations. R. A. Fisher’s attempt to transform evolutionary biology into a deterministic set of laws as powerful as those of thermodynamics seems to have failed; at least beyond a trivial level. The importance of history and contingency, of specific detail, muddles the general insight which we can derive in evolutionary processes. But if there is no general insight to derive then we shouldn’t be deriving it, should we? False confidence in knowledge we think we have is a far greater sin than the admission of ignorance.

UPDATE:  SOLVED by El at 12:50 CDT

It’s Saturday already.  Have you ever noticed how some weeks seem to speed by so fast, you’re not sure what happened to the individual days?  People tell me it’s a sign of old age to gripe about how fast the days go by.

The riddle this week will require a touch of imagination from you, but nothing too radical.  Your answer is an iconic SciFi event.  Are you ready?  ONE for the money…
TWO for the show…
THREE to get ready… and
FOUR TO GO!

..
While today’s answer is an iconic SciFi event, you are aware of down-to-Earth versions of this event occurring all through history.

Quite simply, this must occur.

Everything follows from this.

Image by Dietrich Bartel, all rights reserved

..

When used as a SciFi theme or plot device, this iconic event strikes a deep chord.

Without this event, SciFi as we know it pretty much isn’t happening.

This event has been addressed by mainstream scientists as well as SciFi authors.

..
There we are; short ‘n sweet.  I’m thinking you don’t need too many clues for this one, so enjoy.  You know where I’m lurking.