Robert Spitzer has recanted his paper claiming homosexuality can be changed.

This is not the usual apology for a scientific error. “I believe I owe the gay community an apology for my study making unproven claims of the efficacy of reparative therapy,” Dr. Spitzer has written in a letter to the editor of the Archives of Sexual Behavior,  which published his paper in 2003 and may publish his retraction. He first expressed his regret last month to writer Gabriel Arana, who interviewed him in The American Prospect about problems with the study.

Many scientists, when admitting they have been wrong, express much narrower mea culpas. Hwang Woo Suk of Seoul National University, whose breakthroughs in stem cell cloning were shown to be fake in 2006, apologized to his nation and the world while blaming the problems on his collaborators. In 1998, Bruce Wachholtz, then a radiation scientist at the National Cancer Institute, told the U.S. Senate he was sorry for a 15-year delay in releasing results of a radiation health study, and said it was because no one had seemed interested in the research. (The data, from Cold War bomb tests, indicated the radiation was responsible for tens of thousands of cancer cases.) And 60 years after a U.S. scientist infected thousands of Guatemalans with syphilis to test various therapies, federal officials apologized while reassuring the public that times, and research standards, had changed for the better.

The psychologist Diederik Stapel, formerly of Tilburg University, was caught fabricating data in dozens of papers last year, and directed his regret to his colleagues in a statement (translated from the original Dutch by The New York Times) that said “I have failed as a scientist and a researcher.”

Dr. Spitzer, on the other hand, has a keen awareness of the larger effects of his work. His study was taken up by anti-homosexual activists and therapists who said they could “cure” patients of their sexual orientation. (Mr. Arana, the American Prospect journalist and a gay man, spent years in such therapy.) Dr. Spitzer also apologized to those patients. He said he did not start the study to show that homosexuality could be done away with. He did it, rather, to debunk the claim that “reparative therapy” was completely ineffective in changing sexual orientation.

But he did so with bad science. He interviewed 200 people who said they used to be gay, and asked them if therapy helped them make the switch. There was, he now says, no way to determine if they were telling the truth, and no comparison group of people who didn’t undergo therapy. And there was no replication of the study. It didn’t validate anti-gay therapy for most scientists, but it did give ammunition to anti-gay groups. So he asked Mr. Arana to print his retraction. Dr. Spitzer wants not only to set the research record straight, but correct a mistaken cultural idea.

Bad science then, but few could say a bad scientist now.

Figuring out whether someone committed plagiarism is usually straightforward. You compare the two texts to see how much of one appears verbatim in the other. Even if some words have been changed, there is often a pattern of similarities that can’t be coincidental. It’s not that hard.

Determining whether someone swiped an idea, or a set of ideas, is another beast entirely. In a review in the June 7 issue of The New York Review of Books, the possibility is raised that Terence W. Deacon, chairman of the anthropology department at the University of California at Berkeley, borrowed heavily and failed to credit core ideas in his book, Incomplete Nature: How Mind Emerged From Matter, from at least two scholars. Here’s what the NYRB reviewer, Colin McGinn, a professor of philosophy at the University of Miami, writes:

One would never think from reading Incomplete Nature that the author’s main contentions have already been systematically developed by others, and that there is in fact hardly an original idea in the book. Two works, in particular, stand out in the prior literature: Dynamics in Action by Alicia Juarrero and Mind in Life by Evan Thompson. Neither book is cited by Deacon, although they cover much the same ground as his—far more lucidly and insightfully.

McGinn goes on:

I have no way of knowing whether Deacon was aware of these books when he was writing his: if he was, he should have cited them; if he was not, a simple literature search would have easily turned them up.

There’s more to this story. In fact, a mini-controversy has been burbling for months. In a review published in Nature last December, Evan Thompson (mentioned above in McGinn’s review) wrote that Deacon “doesn’t discuss other theorists who have given similar accounts of life and mind,” mentioning his own book and Juarrero’s.

In an interview, Thompson, a professor of philosophy at the University of Toronto, said he believed that there was a “substantial overlap of ideas” and that Deacon was guilty of “significant scholarly oversight.” He stopped short of accusing Deacon of actually having cribbed.

An e-mail campaign of sorts has been carried out by Michael Lissack, executive director of the Institute for the Study of Coherence and Emergence, and a self-styled whistle-blower, to persuade Deacon and officials at Berkeley to take some kind of action. Lissack says he gave a copy of Juarrero’s book to Deacon a few years ago at a conference (Deacon says that’s not true).

Juarrero, a professor of philosophy at Prince George’s Community College, in Maryland, has compiled a detailed spreadsheet of apparent similarities between the structure of the arguments in the two books and the examples used to make those arguments.

And there do seem to be plenty of similarities. Deacon acknowledged those in an interview, but he said that they were superficial and that his argument and Juarrero’s were substantially different. Part of the reason she and others are upset, Deacon said, is that he is not a philosopher—his background is in biological anthropology. He is an outsider to the field, he argued, and so philosophers are circling their wagons. “I don’t give all the philosophers their due because I didn’t intend to write a book about philosophy,” he said.

Untangling all of this is tricky. Whether one person handed another person a book at a conference years ago is tough to prove, and wouldn’t necessarily matter even if it happened (how many unread books are on your shelf?). Plus the topics in the books are, for nonphilosophers, a bit esoteric: the nature of causation, the evolution of human consciousness, dynamic systems theory. Deacon’s book is about how mind emerged from matter. Juarrero wants to discover the difference between “a wink and a blink.”

I called McGinn, who wrote the review. He doesn’t know any of the people involved, though he did receive an e-mail from Juarerro stating her case. So he read her book, Thompson’s book, and Deacon’s book. “I was a little outraged when I realized the degree of overlap,” he said. That overlap, according to McGinn, “is not superficial at all.” Discovering that other researchers had already proposed more or less the same ideas would have required, he contended, just a few minutes on Google.

Deacon conceded that his citations “don’t go deep enough” and said he takes “responsibility for that.” He insisted, though, that he hadn’t read either book when he wrote his, and that any failure to give credit was unintentional. “Should I apologize to everyone I didn’t cite?” he asked. “I don’t think so.”

But what’s truly amazing here are the patients, doing what you see in this photo: A woman named Cathy, who hasn’t been able to move anything below her neck for 15 years, is drinking coffee from a bottle she lifted to her lips, with a computerized arm that is wired into her brain. The connection, a plug in the top of her head, is called BrainGate, and it was developed by the Brown University neuroscientist John Donoghue and his team. What BrainGate and Cathy have done, along with similar feats by another paralyzed patient named Bob, are described in detached scientific prose in today’s issue of Nature. (Cathy is patient “S3″ and Bob is “T2.”)

But even dry language can’t hide this: These otherwise frozen people have an image of their arm and how it moves mapped onto a group of brain cells—that’s the phantom—and the device is able to read it. When Cathy thinks “grab,” the robot does what her real arm used to do.

When I first wrote about linking mind and machine several years ago for National Geographic, BrainGate got only a few sentences because it was facing some trouble. Matt Nagle, one of the earliest paralyzed patients in this study, had learned to move a cursor around a computer screen but then had his plug removed so he could take advantage of some therapy. (He subsequently passed away.) And Cyberkinetics Neurotechnology Systems, the private company Donoghue formed to supervise the clinical trial, went under in 2009. “It closed because of the 2008 financial crisis,” Donoghue says.

So another technology, helping amputees by connecting robotic arms to the severed nerves of their stumps, took center stage. I drank several cups of coffee with a woman named Amanda Kitts, who lifted a cup and angled it into her mouth just as if she were using her real arm. And in a sense she was: Her phantom limb still existed in her brain, and she just thought about natural movements and they happened.

At the Rehabilitation Institute of Chicago, which pioneered this work, scientists were able to conjure up the phantom on a computer screen, by attaching electrodes to Amanda’s stump to read the nerve signals. We watched the arm on the screen twist and grab, although Amanda’s flesh arm ended above her elbow.

But now “my hat is off to John Donoghue,” says Todd Kuiken, a physician and biomedical engineer at the institute who figured out how to link real nerves and artificial arms. “I let the brain and the nerves process these signals, and then I hijack them,” he says. By the time signals make it to the stump, they are refined and a lot of extraneous noise is removed naturally. “But John is reading activity directly from the brain, and extracting meaningful signals,” Kuiken says. “He’s right at the source.”

Indeed, the BrainGate plug is an array of 96 electrodes attached to the top of the skull and extending into the motor cortex, a brain region that controls body movements. “We’re focused on a little collection of cells, really just a few dozen neurons,” Donoghue says. A computer takes their electrical activity, finds signatures when Cathy and Bob are thinking “reach forward” and “bend the elbow,” and turns them into commands that move motors in the robot arm.

To make this happen after Cyberkinetics went under, Donoghue says, “we brought [the trial] back into the academic setting.” Brown University, Massachusetts General Hospital (an affiliate of Harvard Medical School), and Providence VA Hospital formed a collaboration, with Mass General administering the clinical trial. Stanford University recently joined the group. The academics, unlike the private company, found it easier to get financing from federal agencies.

And what they’ve been able to show is that paralyzed patients, after years of immobility, maintain a sophisticated phantom that can move in three dimensions, in the real world rather than just the flat two dimensions of a computer screen. BrainGate—a device inserted through the skull, tethering a patient to a computer with wires—is proof of feasibility, not therapy itself. (Kuiken’s arms, in contrast, have left the lab and gone home with dozens of patients.) But what BrainGate illuminates is a path along which the patients, through their phantoms, may be able to reach out in reality.

To learn more about Cathy’s journey along this path, you can read her biography, The Electric Mind, written by Jessica Benko and available today from The Atavist, an online publisher of short books, for iPads and Kindles.

[Photo credit: Braingate2.org]

Jonah Lehrer

Last Sunday a harsh review of Jonah Lehrer’s new book on the science of creativity, Imagine, appeared in The New York Times. That was followed by a lengthy response from Lehrer and an even lengthier response to that response by the author of the review, Christopher Chabris.

In one sense this is just a spat between an author and a reviewer. But it’s worth looking at closely because it’s also about how science gets communicated and translated, summarized and (possibly) dumbed-down.

Here’s a brief dissection of the back-and-forth (the quotes are from Chabris’s review):

• “Visual information from the left eye does not go only to the brain’s right hemisphere; information from the left visual field does.”

Chabris points out an error. Lehrer acknowledges it. Point Chabris.

• “The different electrodes in an EEG don’t record brain waves of different frequencies; they record from different locations on the scalp.”

Another error that Lehrer admits. Point Chabris.

• “And the enzyme COMT is not involved in producing dopamine; it breaks it down.”

I could find only a single reference to COMT in Imagine, and it’s in a footnote. Lehrer describes it as a gene that “underlies dopamine production.” This seems like unfortunate wording. He’s talking about how DNA-coding differences can lead to “variations in attentional abilities,” and presumably it still holds that variations in COMT (which does indeed break down dopamine, according to multiple sources) would play a role in these variations. Is that a flub worthy of a vigorous lashing in a high-profile review? Nah. Point Lehrer.

• “He uncritically accepts studies whose results support his argument, rarely bothering to discuss whether or how often they have been replicated. On the basis of one experiment, for instance, he claims that ‘being surrounded by blue walls makes us more creative.’”

I e-mailed one of the authors of the study in question, Ravi P. Mehta. Here is what he said:

Note that part of our research is indeed replications of past research on the effect of color on performance. In addition, in this paper, we also tried to use different tasks across various studies to theoretically replicate our results. Of course, like any new findings, replication and extension of our research in future endeavors are much needed and will enrich our understanding of how our contexts, such as color, can affect the way our mind works. That being said, you cannot negate importance of new findings.

I read the Lehrer section in question and Mehta’s paper. It seemed like a fair summary to me, and Mehta thinks extrapolating the effect to include wall color is not unreasonable. Point Lehrer.

Christopher Chabris

I could go on and on because, in his response to Lehrer’s response, Chabris points to more supposed errors. Are they nitpicky? Maybe. But there’s value in someone like Chabris, a serious researcher who also co-wrote the popular book The Invisible Gorilla, scrutinizing a book like Imagine. He’s right that details matter. And Lehrer wouldn’t deny that (in fact, he acknowledges as much in his response).

The heart of Chabris’s critique, though, is that Lehrer doesn’t sufficiently acknowledge the provisional nature of science, that for effect (blue walls make you creative!) he breezes past dull notions like replication. Lehrer’s defense is that he is fully aware that, as he puts it, “our current science is very much a first draft,” but that you can’t weigh down every example with a page full of caveats and expect a normal person to read it on an airplane. This is a perennial tension between scientists and science writers, and a debate takes place every time someone like Lehrer or Malcolm Gladwell publishes a blockbuster.

Speaking of Gladwell, probably the biggest problem with Lehrer’s book isn’t something Lehrer wrote. Instead, it’s a blurb from Gladwell that says Lehrer “knows more about science than a lot of scientists.” That’s a ridiculous thing to say, even by blurb standards, and I can’t imagine Lehrer concurs. It’s the kind of hubris that could get a science writer into real trouble.

You’ve probably heard of Kickstarter, which allows would-be documentarians, video-game designers, and atheist cobblers to solicit money for their projects. A new company, called Petri Dish, gives that tool to scientists who want to finance their research projects. It’s already received significant attention considering that it has been around only since March and has raised tens of thousands of dollars.

As on Kickstarter, many Petri Dish participants offer rewards for donations. For instance, if you give $25 to Gerald Carter’s project to understand how animals “can enforce and stabilize cooperation in a complex society,” you will receive three photos of one of the vampire bats he’s studying. If you give $10 to Ashlee Lillis’s project to record audio of deep-sea habitats, you will get a five-minute compilation of the most interesting stuff she’s recorded.

If you’re willing to go big, though, and donate five grand to a project to track ancient dog populations, then the researchers, the brothers Adam and Ryan Boyko, will bring you back a puppy from Africa (you will have to prove you can provide a good home). And if you’re willing to go really big and donate $12,000 to Justin Yeager’s research to understand and save poisonous frogs, he will tattoo your name on his body. And not just any part of his body—he notes that it will be somewhere “visible.”

Could this way of financing science be more than a novelty? Rewards aside, several of the projects are intriguing and being carried out by researchers with the backgrounds to pull them off. The research they feature does so far tend to be animal-heavy, which makes sense if you’re trying to appeal to the public (it’s harder to imagine crowd-financing a project on particle physics, but who knows?). And it’s hard to evaluate, if you’re not familiar with a certain field, whether a research project is properly framed, hasn’t been done before, etc.

But in general Petri Dish seems like a great idea, and it’s already taking off. At the very least, it encourages researchers to explain what they’re doing, in layman’s language, and to make an argument about why it matters to the rest of us—something they’re not always very good at. And perhaps by donating $25, people will feel connected to science, rather than thinking of it as something happening in some far-off lab with no connection to their lives. Puppies or no puppies.

But it’s not just one state. Polls show that fewer than half of Americans accept evolution. Most of us still don’t buy it. As the comedian Louis C.K. asked in a bit about people who insist that they can’t possibly be related to monkeys: “Why are you fighting this?”

Dan McAdams offers one possible, rarely discussed reason: Maybe evolution is a lousy story. Actually, McAdams, a professor of psychology at Northwestern University, doesn’t think evolution is a story at all. There is no protagonist, no motivation, no purpose—all crucial elements in a narrative, whether it’s Frog and Toad Are Friends or Fifty Shades of Grey.

He mentioned this idea recently during a presentation at the Consilience Conference, which also drew researchers from biology, economics, and literary studies. Afterward, a seemingly annoyed audience member questioned McAdams’s apparent criticism of evolution, countering that it’s in fact a wonderful, elegant explanation of life. McAdams agreed that it’s wonderful and elegant. He just doesn’t think it’s a story.

McAdams’s research focus is narrative psychology—specifically, the development of a “life-story model of human identity.” As he writes in his book The Redemptive Self, “People create stories to make sense of their lives.” When you think about it, we tell stories to make sense of pretty much everything. The problem is that evolution doesn’t fit neatly into the narrative box. As McAdams puts it: “You can’t really feel anything for this character—natural selection.”

The biblical story of creation, in contrast, couldn’t be richer. Talk about drama! Characters who want things, surprising reversals, heroes, villains, nudity. There’s a reason it outsells On the Origin of Species, and it may be why scientists haven’t had more success at moving the needle of public opinion.

Jerry Coyne is one scientist who’s been trying. Coyne, an evolutionary biologist who writes the blog Why Evolution Is True, doesn’t put much stock in McAdams’s idea, adding that it’s one he’s never heard anyone else venture. In a forthcoming paper in the journal Evolution, Coyne explores why the resistance to evolution in the United States is “uniquely high among First World countries.” He looks at the data and convicts the No. 1 suspect: religion.

He cites polls like one that found that almost two-thirds of Americans say they would continue to believe what their faith teaches even if it runs counter to scientific findings. Another poll found that just 14 percent of respondents said a lack of evidence was keeping them from joining Darwin’s camp. Instead they said it’s God or Jesus or religion in general. In light of that, Coyne doesn’t think evolution’s failure as a thriller is the real issue. The only person who could conclude that, Coyne says, is “someone who hasn’t looked at the facts about why evolution is rejected.”

At the very least, though, evolution’s weakness as a story creates a PR opportunity for creationists. For example, one Christian Web site tries to fit evolution into a standard fairy-tale narrative, telling the intentionally absurd tale of an amoeba’s transformation from salamander to monkey to man, all thanks to a character called Mutation who waves a magic wand. It doesn’t read like it was written by someone with a background in biology, but it’s hard to disagree with the conclusion that evolution is a “strange story.”

Jonathan Gottschall thinks McAdams might be onto something. Gottschall is among the best-known proponents of Literary Darwinism, and in his latest book, The Storytelling Animal, he sets out to prove that the human brain is wired for story and to figure out why that might be useful. “If evolution is a story, it is a story without agency,” he writes in an e-mail. “It lacks the universal grammar of storytelling.” Stories are about a character finding a solution to a problem. Evolution has problems and solutions but no character. As a result, according to Gottschall, “it doesn’t connect as well—especially at the emotional level.”

So what to do? Coyne thinks belief in evolution will only rise when belief in God declines. McAdams isn’t sure, but he does think it’s an uphill battle regardless: “You can try to make some of these scientific theories into stories, but it is not easy to do, and science does not depend on your doing it.”

The first approach mimics what squids do: The animals’ cells have pigment sacs that squeeze and expand to create large blotches of color. The Bristol scientists created polymer bands that squeeze in the same way when triggered by an electric current, seen in the first part of the video.

Zebrafish use a different tactic for disguise. They pump pigment out to their skin from a central holding tank. Again scientists used electricity-driven polymers, but this time—as shown in the second video segment—they constructed one pump that squirts out a mixture of black ink and water, and another that squirts a clear substance to reverse the process.

It all happens very quickly. The researchers say the materials can be made larger, and they envision skintight “smart” clothing that can change colors or patterns in a few moments. They describe their work today in the journal Bioinspiration and Biomimetics.

The cells, in the most primitive brain region, the stem, “encode the direction, intensity, and polarity of the Earth’s magnetic field,” one of those scientists, David Dickman, a neuroscientist at the Baylor College of Medicine, told me. “These cells have the key ingredients to form maps of spatial directional heading and location, similar to the GPS in your car or cellphone.” He and his colleague Le-Qing Wu published their findings in Friday’s issue of the journal Science.

In an elegant experiment, the researchers created an artificial magnetic field around pigeons and learned that specific cells got active when the field pointed in one direction, and others got active when the field pointed elsewhere. Still other cells responded to changes in strength or angle. The cells are in nerve pathways linked to the inner ear, and Mr. Dickman says that he and Mr. Wu have found, in work that’s still unpublished, cells in the ear with tiny iron particles, which could be sensitive to magnetism. That is how birds pick up magnetic signals and send them on to the brain, they suggest.

But other suggestions like that have been knocked down very recently. Just two weeks ago, Mr. Keays published a paper in Nature showing that magnetically sensitive nerve cells were not located—as others had claimed—in bird beaks. “What still remains unknown is how pigeons detect the magnetic field in the first place,” he told me.

Mr. Dickman agrees that his case isn’t ironclad; the hunt is still on, he says. Something needs to capture signals from the outside world and transmit them to the brain—as the retina in the eye does for light. The inner-ear cells identified by the Baylor team are a new candidate, joining cells found in the noses of trout, and other cells in birds’ eyes. Ear, eye, nose—in which direction will the compass needle swing next?

[Photo courtesy Lea Miller under Creative Commons]

The geneticist Sarah Tishkoff, 5 feet 4¾ inches tall, stands at the center of a group of Pygmies in Cameroon, in West Africa.

From the outside, evolution sometimes seems fairly obvious: Finch beaks got bigger to crack harder nuts, dolphins and sharks developed shapes that let them move smoothly through the water. A peek under the skin and into the genes, however, can yield surprises. Pygmies have just gotten such a close look. And being short–their most obvious feature–may actually be a sort of evolutionary side effect: What they really needed were genes that confer resistance to disease, and those same genes happened to disrupt growth.

“When I think about natural selection, diseases will kill them off much faster than being tall,” says Sarah A. Tishkoff, a professor of genetics at the University of Pennsylvania.

Ms. Tishkoff has led a new genetic analysis of Pygmies in Cameroon—a group with an average height of 4 feet 11 inches—that has identified a “master gene” for immune response that is much more common in Pygmies than in their taller neighbors, the Bantu. In Thursday’s PLoS Genetics, she and Joseph P. Jarvis, a senior research scientist at the independent Coriell Institute for Medical Research, in Camden, N.J., and several other colleagues point out that this same gene can disrupt growth-hormone pathways.

“I can’t say for sure this is what’s going on,” Ms. Tishkoff says. “But in our bodies there is such intricate cross-talk among different systems that I’d be surprised if one gene didn’t alter different traits.”

Anthropologists who have studied Pygmies for decades—and puzzled over their stature—are not giving up on competing theories but agree that genetics is adding valuable new tools to their field. “We’ve been trying to link Pygmy height to something in their environment, and we haven’t been able to do that. That’s a knock on my discipline,” says Edward H. Hagen, an associate professor of anthropology at Washington State University at Vancouver who has studied Aka Pygmies in the Central African Republic. “Sarah’s paper doesn’t give us an answer, but it gives us a lot of new clues. It’s a different way of thinking about the problem.”

Pygmies have drawn the attention of scientists because they are such a clear example of human variation—they are under five feet while the rest of the world is well over it, on average—and they are all over the place. In addition to Africa, there are Pygmies in Asia and South America. Plus there is fossil evidence. The celebrated “hobbit” fossils of Indonesia date from 18,000 years ago and are about 3 feet 4 inches tall, says Geroge W. Perry, an assistant professor of anthropology and biology at Pennsylvania State University. There are even pygmy animals, such as elephants and mammoths, whose remains have been found on islands.

Scientists have offered a long list of explanations for shortness. Food limits are one, says Mr. Perry, who is studying the population genetics of a Pygmy group called the Bataa in Uganda. Pygmies live in dense rain forests where food is hard to obtain, and less body requires fewer calories to keep it going; however, today’s hunter-gatherers don’t search constantly for food, indicating they get enough. Then there is heat regulation: Small bodies generate less heat during exercise. But that idea also has a counterargument, Mr. Perry says. Some of the shortest populations live in cooler or drier areas.

In 2007 scientists proposed yet another theory: Pygmies in the Philippines usually die by their mid-20s, so they must put their metabolic energy into reaching reproductive age quickly rather than growing tall. That one got criticized because recent cultural changes among those Pygmies—which the researchers used for their calculations of energy use—probably didn’t represent their historical state.

Ms. Tishkoff and Mr. Jarvis and their team thought genetics might provide a better answer. They examined 67 Pygmies, and for comparison used 58 Bantu “because they literally lived right next door” but were 6 inches taller, on average, Ms. Tishkoff says. The populations do mix and marry, so the researchers first identified genes that were predominantly Pygmy and those that came from Bantu. “The more Pygmy ancestry, the shorter the people were, and that supported this as a genetic trait,” Ms. Tishkoff says.

Then they looked for regions of the genome that seemed highly selected for, which they did by finding stretches of DNA that were much more common in Pygmies than in Bantu or Masai comparison groups. They found one, a short piece of Chromosome 3. And one of the genes on it was called DOCK3, which affects height among Europeans. That gave the scientists confidence they were looking in the right place. “And right next to it was this other gene, CISH, which is a master regulator of immune response,” Ms. Tishkoff says. It is associated with resistance to tuberculosis, malaria, and bacteremia.

Mr. Jarvis, looking at genetic databases, found that CISH does something else extremely intriguing. It interrupts growth hormones in the body. Mice with overactive versions of this gene are exceptionally small. Furthermore, CISH was part of an entire network of genes and hormones that affect body size in people, part of a growth hormone pathway called insulin growth factor 1. Again, this package of genes cropped up most often in the shortest people, even within the Pygmy groups.

“It was like a bunch of giant arrows, all pointing in the same direction,” Ms. Tishkoff says.

And they pointed to disease and height. Pygmies in Cameroon carry a lot of parasites, so they need a strong immune system. There are also a lot of potent viruses in the region; HIV is theorized to have come from this area. So Ms. Tishkoff says that genes like CISH could have been very important, and very active, in this population. And their activity, as an offshoot, could have slowed down other genes responsible for body growth.

The next step is to test the function of these genes, to see if CISH is really hyperactive in Pygmies, and if it does interfere with growth-factor genes. Until someone demonstrates that, genetics doesn’t knock out any competing notions.

The idea is fascinating, Mr. Perry says, and actually could include the environmental explanations. There could have been various ecological pressures on Pygmy body size, some pushing for more height, some pushing less. And then the need for disease resistance arose, and tipped the balance towards the short end of the scale.

[Photo courtesy Alain Froment]

But take heart, unjuiced undergrads—there may be a solution on the way, albeit one that sounds dubious, even dangerous, at first. It’s called transcranial direct current stimulation (or tDCS), and it involves running a weak electrical current through your brain. While tDCS has been around for decades, in the last couple of years it’s been getting a lot of attention, thanks to research suggesting that it speeds up learning for certain kinds of tasks.

Here’s an example: In a study published in January, researchers tested subjects to see how well they could detect concealed threats in a series of still images, like a bomb disguised by roadside trash—the sort of deadly surprise a soldier in Afghanistan might encounter (the images were taken from a video simulation, called DARWARS Ambush!, that’s used to train soldiers). The subjects had electrodes placed on their heads through which researchers ran varying levels of low-voltage current.

Those given higher levels of current learned to detect threats faster than those given lower levels of current, and both groups performed better with current than without. When they were tested again, an hour later, minus the current, those who had previously been given higher levels of current still performed better even when they weren’t getting zapped. Throughout the experiments, researchers used fMRI neuroimaging to figure out where to place the electrodes and to determine which areas of the brain were experiencing increased blood flow.

As the researchers point out, being able to recognize threats, particularly in war but in other settings too, is a crucial ability, and tDCS seems to “reduce the time required to learn this skill.” Similar results were obtained in a follow-up, double-blind study.

Exactly how and why hooking your brain up to a battery makes learning easier isn’t entirely understood. It seems that the low-level current stimulates neurons, making them more likely to fire, thereby putting the brain in a state where it’s more likely to form connections. Earlier studies have indicated that tDCS appears to improve working memory, and may help in the treatment of depression and Parkinson’s.

This isn’t electroshock therapy, also known as electroconvulsive therapy, which is sometimes used as a last-ditch treatment for severe depression. During ECT, patients are anesthetized and given doses of current high enough to induce seizures. Unlike tDCS, which promotes memory formation, ECT can cause memory loss.

I first heard about tDCS at a conference last year called Narrative Networks, sponsored by Darpa. From the examples above, you can see why the military might be more than a little interested. In a brief presentation, Michael Weisend of the Mind Research Network, an Albuquerque-based nonprofit dedicated to neuroscience investigation, explained how the use of electrical brain stimulation had the potential to “enhance perception, memory, and cognition, whether in healthy individuals or in patients as a remedy for disorders.” I wrote the words “thinking cap” in my notes.

So should we be plugging ourselves in the way we plug in our laptops? A few people are already trying it. Go to YouTube, and you’ll find some daredevils electrifying their brains, or discussing their plans to do so, like this George Mason student. One Web site promises to sell you a kit so you can make your own, though the amateurish promotional video doesn’t inspire confidence.

I called Weisend recently to see what he thought of people experimenting with tDCS. “In the DIY crowd they don’t have the neuroimaging to start the process and know where to place the electrodes,” he told me. “Their success and their safety are going to be limited.” In the laboratory, subjects go through two or three sessions of tDCS over a week. What happens long term if you do more than that? Nobody knows. And the equipment you order from some random person online may not be as reliable as what’s used in a laboratory.

That said, Weisend believes tDCS can be done safely, and he thinks it might be used to prevent memory loss in the elderly or to help patients recover from traumatic brain injuries. He’s tried tDCS on his own brain hundreds of time and hasn’t suffered any deleterious effects—with the notable exception of a few skin burns that were severe enough to leave scars. “You get attached to your work, I guess,” he says.