It’s easy to wonder to what degree humans are still subject to natural selection; from the perspective of someone living in an industrialized western nation, it can look like everyone gets to live long enough to reproduce and can successfully raise their offspring to adulthood. Of course, in some parts of the world, that’s much less certain than in others, and furthermore, evolution is complicated. A new study, using data from the Framingham Heart Study, has found that natural selection does still seem to be at work on us.

Researchers used data from the 60-year Framingham study on more than 2,000 post-menopausal North American women. They examined the relationship between roughly half a dozen health-related traits and the number of children a women had, adjusting for things like income and education and assessing the way the traits might affect one another. The result indicates that humans are still evolving; as best I can gather, the idea is that certain heritable traits are likely to appear in greater numbers in future generations. On the basis of this information, several predictions can be made about the way natural selection is shaping the future of the human species (the female half of it, anyway).

To me, the interesting thing about this is the demonstration that we’re an evolving animal just like all the other evolving animals on the planet. The senior author of the study says we’re “kind of average” in the speed with which we evolve. It might not sound like a big deal, but the idea that current humans are not an end product but rather a snapshot in a long process goes against some deeply ingrained cultural assumptions. Even if you totally accept the truth of evolution and understand at some level how it works, it can be hard to really understand that the concept of “human” (or any other species) is provisional and time-dependent. (I thought of this when I saw the Ardipithecus show on Discovery last weekend, in particular regarding the idea that “humans evolved from chimps” versus the more precise statement that both evolved from a common ancestor, and the question of how exactly to categorize each group of animals during that process of evolution.)

This story from Medical News Today and this one from Science Daily have more information. The work is reported as Natural Selection in a Contemporary Human Population, by S.G. Byars et al. Proceedings of the National Academy of Sciences 107(suppl1), 1787–1792, 2010. doi: 10.1073_pnas.0906199106.

Fans of the surreal, take heart. Recent research suggests that reading stories involving bizarre events that don’t necessarily make sense can temporarily enhance your ability to identify patterns that help you learn new material. Researchers did two studies to investigate the effects of exposure to a “meaning threat,” something that didn’t make sense or that upset typical notions.

In the first study, subjects read either a Kafka short story (The Country Doctor) pretty much as he wrote it, with its strange and inexplicable series of events, or a tidied-up version that was edited into a more conventional story line. In the second study, people were asked to think about aspects of their own past behavior that are contradictory—in other words, to consider the ways that identity is not as unified as we typically assume it is. After this, participants in both studies were shown strings of letters arranged in a strict but subtle pattern. Then they were given new letter strings and asked to identify the ones that conformed to the pattern.

In both cases, the people who were exposed to the meaning threat (the original Kafka story, the idea of a somewhat fragmented identity) not only selected more strings as adhering to the pattern, but were also correct more often than the respective control group. The researchers explain this by suggesting that it’s uncomfortable to have our common-sense expectations violated, and to compensate when that happens, people are more motivated to make sense of what’s going on around them.

It would be interesting to know if this extends to other media such as music or visual art. It’s also kind of interesting to me that one of the problems with the human cognitive apparatus is that we often make connections too easily, through various cognitive biases such as confirmation bias. Finding associations between seemingly unrelated things or events is a source of creativity, and uniting disparate phenomena under a single comprehensive explanation is often a goal of science. On the other hand, finding patterns where none exist (the supposed face on Mars is a classic example) is a less agreeable manifestation of our hunger for meaning. Like so many things about human thought, perhaps pattern-seeking deserves a “Handle with care” label. Goo goo g’joob.

This article from ScienceDaily describes the research in more detail. Or you can look up the paper: Connections From Kafka: Exposure to Meaning Threats Improves Implicit Learning of an Artificial Grammar, Travis Proulx and Steven J. Heine. Psychological Science, 20 (9), 1125–1131.

I went to an interesting talk today, one of Indiana University’s themester activities. Steven Gaulin of UC Santa Barbara spoke about work he has done with William Lassek on the relationship between human brain size and sex differences in fat distribution. It’s a fascinating story. We women are fattier overall than men, and we tend to carry our fat in different places. One thing the sexes have in common, however, is that fat is vital to the brain, the dry weight of which is mostly fat. Could the differences and the similarity be linked?

Gaulin presented several lines of evidence suggesting that fat deposited on women’s hips and thighs provides the material needed to build the unusually big brains (as primate brains go) of their offspring. He also suggested that a link between lower-body fat and cognitive ability in one’s offspring might have driven male preference and thus sexual selection for a low waist-hip ratio (WHR, i.e., a smaller waist and larger hips).

Among the things he discussed is something called maternal depletion, evident in hunter-gatherers but also more subtly observable in American women, in which the amount of hip/thigh fat decreases as women bear more children. Another factor is a link between WHR in women and cognitive ability (the data they used showed a link between lower WHR—i.e., more lower-body fat—and higher cognitive abilities in their offspring). Menarche (the onset of menstruation in young girls) appears to be related not to the amount of body fat but to its distribution (specifically, a greater amount of it on the hips).

Other lines of evidence include the fact that hip/thigh fat is very hard to get rid of; the body seriously taps into it only during the last trimester of pregnancy and during lactation. Also, hip/thigh fat and abdominal fat (the kind men are more prone to carry around) have opposite effects on the body’s supply of two long-chain polyunsaturated fatty acids that are crucial to brain development, docosahexaenoic acid (DHA) and arachidonic acid (AA). As best I could understand it—I’m not a biochemist, so I’m speaking fairly broadly here—the former promotes and the latter hinders the synthesis of these two fats.

I can’t possibly do justice to the entire talk here. In a nutshell, the shape of women’s bodies could be intimately connected, in interesting ways, with the need to nurture the development in babies of these unusually large brains we have. You can check out Gaulin’s web page for more information, including links to papers about the maternal depletion and menarche research.

The World Science Festival, held in New York earlier this summer, has produced a couple of enjoyable videos that illustrate the power of music.

Here, Bobby McFerrin illustrates how deeply embedded the pentatonic scale is in the human mind and harnesses an audience’s instinctive awareness of it to generate a bit of a cappella music. His comment at the end about how audiences around the world seem to share this grasp of the pentatonic scale is particularly interesting.

But music reaches even further, occasionally binding disparate species. This video of a dancing cockatoo is a lot of fun, particularly the sight of a panel of distinguished neuroscientists getting up (or getting down) and dancing with the bird. One of the most touching parts of the movie The Wild Parrots of Telegraph Hill was a quiet moment when Mark Bittner was playing the blues and a bird called Mingus bobbed his head along with the music. This is similar, but bigger.

If you have time to view the entire “Avian Einsteins” panel discussion about avian and human brains and the links between language and movement, I highly recommend it.

So here I am back on the blog again. To jump back in with both feet, how about I write about climate change?

Recently I ran across this press release about the work of a couple of scientists who have suggested that human influence on global climate might go back much further than the Industrial Revolution. The press release covers a recent paper that follows up on earlier work suggesting that early agriculture was so much more land-intensive than current agriculture that its slash-and-burn practices might well have had an impact on the global climate. Today’s farming methods are much more efficient, so the amount of land under cultivation has dropped, allowing some reforestation (on the other hand, of course, Big Agriculture is also a big user of fossil fuels). Bottom line is that we may have been tweaking the atmosphere long before we started burning coal and so forth.

Our general effect on the environment, in fact, probably goes back even further. This story from Weekend Edition on NPR covers some of the intended and unintended consequences of the activities of groups of early hunter-gatherers. Although part of the message is that we’ve been ingenious enough to make our lives easier and help ourselves survive and thrive in ever greater numbers, the other part is that we sometimes caused big messes even back then.

Finally, an editorial from Cosmos Magazine recently discussed whether certain aspects of human nature work against vigorous action to address climate change. The argument is that our evolutionary history and culturally based beliefs and practices combine to make it difficult for us to work together to solve a large, complex long-term problem. I am a little leery of any argument that involves a set view of human nature based on evolution, for a number of reasons, but however we got to be this way, it certainly is common (although certainly not universal) for us to put self-interest ahead of the greater good and to ignore the long term in favor of right now. The author offers some suggestions for how to work around these problems in addressing climate change. Some of them seem like good ideas to me, and I’m all for using rationality over instinct and tradition, but I’m not sure how much time we have to learn about “our genetic makeup and why we feel powerless to act” before we have to somehow just gather up our ingenuity and actually take strong, concerted, collective action.

If you could translate your brain waves into music, what would it sound like? Would the sounds indicate anything meaningful to you? Some recent work published in PLoS One explores the characteristics of brain songs based on EEGs, and suggests that these songs do, in some circumstances, provide audible clues to brain activity.

Researchers in China translated data from EEGs into sequences of musical notes played on the piano. (Very roughly speaking, the amplitude of the brain waves was translated to pitch, the period to duration of the notes, and the average power to the intensity of the sound.) They processed EEGs taken during REM sleep (a sleep phase characterized by rapid eye movements and loss of muscle tone during which most vivid dreams occur) and during slow-wave or deep sleep. They found that volunteers who didn’t know which was which consistently attributed appropriate moods to the resulting musical sequences. The article (linked below) includes sound clips so you can listen for yourself.

I don’t grasp all the details of the conversion process, but thought it was fascinating to be able to listen to brain waves translated into piano music of a sort. The suggestion that such translated brain waves might someday be the basis of neurofeedback therapy was intriguing. (It seems like it would be wonderful to hear what my brain was doing and also hear how that activity changed according to my efforts. Could hearing brain waves really make it any easier to change your brain’s music from one song to another?) This bit of speculation toward the end is also quite interesting:

“We focus in particular on scale-free phenomena, which exist widely in nature and include those of neural activity, EEG, and human behavior. Therefore, the scale-free or equivalent power-law phenomenon may be an essential mechanism of the brain. In addition, this study also addresses an old question: why do people like music? A possible answer is that the brain and music both follow the same dynamic principle, the power-law, which may provide the most efficient method for humans to interact with the environment.

Scale-free music of the brain, Dan Wu, Chao-Yi Li, and De-Zhong Yao. PLoS ONE 4(6): e5915. doi:10.1371/journal.pone.0005915 (Published June 15, 2009)

It’s been awhile since I read it, but I seem to remember that Tolstoy’s novel Anna Karenina includes two strikingly different descriptions of journeys: an exuberant Levin going someplace just after Kitty has accepted his proposal of marriage, and a distraught Anna’s trip somewhere, perhaps to the train station where she killed herself. The details are hazy, but I remember clearly appreciating how well Tolstoy portrayed the world as seen, very differently, through the eyes of the ecstatic Levin and the despairing Anna.

Some recent research has examined the ways people’s view of the world changes, quite literally, depending on the mood they’re in. People who were primed with a happy-making image took a more expansive view of a second image, processing more of the details surrounding the image’s focal point, whereas those who were primed with a downer of an image focused more tightly on the central element of the second image and didn’t attend to the details in the background. This article from PhysOrg has more information, and points out that each level of attention—the broad and the narrow—has its uses, depending on circumstances.

The full citation is: Opposing Influences of Affective State Valence on Visual Cortical Encoding, by Taylor W. Schmitz, Eve De Rosa, and Adam K. Anderson. Journal of Neuroscience, June 3, 2009, 29(22):7199–7207.

The very idea of a mind wandering suggests that the wandering mind is off course, aimless, or somehow gone astray. However, it might be more accurate to suppose that the mind is looking the other way while loosening the reins to allow more productive interaction between areas typically seen as having opposing actions. Recent research has shown that when the brain shifts its attention from a routine task and wanders, or daydreams, the so-called executive network, which is important for complex higher-level processing and problem solving, is activated. Earlier research had shown activity in the default network during daydreaming; the default mode seems to be what our brain slips into when it’s not attending to anything in particular.

The recent study suggests that when the mind wanders, these two networks, hitherto seen as opposed, are able to work together, perhaps allowing the solution of knotty problems. The study used fMRI to examine the brains of people who were carrying out a rote task; their level of attention was evaluated based on their performance on the task, their own reports of how attentive they were, and their brain activity. This press release on EurekAlert has more details.

This might explain some of the mysterious workings by which the mind can come up with an answer by going at a problem sideways, while ostensibly working on something else. For example, every Sunday morning I listen to the Sunday puzzle with Will Shortz on NPR. Shortz leaves listeners with a puzzle to solve during the week; the solution often comes to me later in the day when I’m in the shower or folding laundry. And one reason that I enjoy jigsaw puzzles, long walks, and cross-stitch is that these seemingly mindless activities can give me a break from considering some troublesome situation and, at least sometimes, allow me to come up with an answer or an approach to try. (Try as I might, though, I still can’t justify having a bad Freecell habit.)

The paper will be in the Proceedings of the National Academy of Sciences: Experience sampling during fMRI reveals default network and executive system contributions to mind wandering, by Kalina Christoff, Alan M. Gordon, Jonathan Smallwood, Rachelle Smith, and Jonathan W. Schooler. Published online before print May 11, 2009, doi: 10.1073/pnas.0900234106.

I’ve been thinking a lot about creativity lately, in particular about how it works and what it feels like to create something. A couple of recent news articles, while not directly about creativity, do seem to shed some light.

An article from the Boston Globe discusses some of the capabilities of the infant mind and how they differ from those of the adult mind. The skills our brains are born with are useful in gaining mastery over the world; as we grow and use this initial tool kit, the result is a greater capacity for focused consciousness and time-saving familiarity with the world we live in. As in so many things, though, it’s not all gain. Some of those early-life attributes, such as greater flexibility and the capacity for noticing many more details of a situation or scene, would be kind of handy to regain from time to time. The article gives some interesting tidbits about how the brain develops from its early state into something more sophisticated but in some ways narrower and less rich.

Creativity comes into the story, it seems to me, because part of what it means to be creative is to be able to see things freshly, not only appreciating the familiar as if it were new but being able to present stories, colors, shapes, or sounds in new ways, as if seeing them from a new angle. I wonder if creativity is enhanced in any way by spending time with very young people and borrowing their sense of wonder and their capacity for absorbing situations (not knowing what they should pay attention to, the idea is that they try to pay attention to it all). One thing I’ve run across several times in advice about how to keep your brain fit and healthy as you age is to try new things: learn a new language or a new physical skill, read up on some subject or place that’s foreign to you. Maybe what’s going on there is that by immersing yourself in a world that you don’t know, you have to re-acquire some of that ability to notice everything and put it all together. It certainly seems like that might also be a boon to those who want to create; I’ve always had the feeling that doing new things, even if they weren’t related to the writing I wanted to do, was helpful somehow.

An article from The Economist, on the other hand, covers some new research into subconscious thought. A new study has used EEGs to examine brain activity while people were solving a particular type of problem; it turns out that brain activity can be used to predict, by up to 8 seconds, whether someone is going to get the answer to a puzzle. In other words, subconscious brain activity (specifically, an increase in high-frequency gamma waves in the right frontal cortex) reliably signals a forthcoming conscious moment of insight.

It’s always been fascinating to read about the many ways our subconscious minds seem to go on about their business without letting our conscious minds in on what’s going on until necessary. It’s like there’s some committee in the back room discussing the options unbeknownst to me (although “me” is a slippery pronoun in this context) until suddenly my conscious mind is announcing some decision to myself and to the world, just as confidently as if it had thought of it by itself. I’m sure this behind-the-scenes activity makes my cognitive processing much more efficient, but sometimes I’d really like to know what’s going on in there. The whole thing is even more peculiar when you’re coming up with ideas for some creative project or another, and you suddenly see a way to put together the pieces you’ve been mentally pushing around but you’re not sure where the insight came from, or you think you know what road you’re going to take in your writing that day but wind up finding yourself far from home with not much of an idea how you got there. Funny old things, brains.