The Thinking Meat Project

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)

The question of whether the language we use shapes the way we think is an old one that has been answered emphatically in both the positive and the negative down through the years. Over at Edge.org, Lera Boroditsky has written this essay describing some of the research done in her labs that shows interesting links between the language a person is using and the way he or she thinks. I was particularly intrigued by the parts about how the gender of a noun influences the way speakers of a language describe the object named by the noun. People more often come up with typically feminine attributes to describe bridges or keys, for example, if their language assigns a feminine gender to the noun, and are more likely to use typically masculine attributes if the language assigns a masculine gender. Although the essay describes the assignment of gender in the first place as being essentially a quirk (one with far-reaching cognitive consequences), I wonder if, in some cases where no obvious gender assignment exists, some nouns are masculine or feminine as a result of long-lost, very early metaphors.

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.

Anxiety disorders and depression often strike together, and the latter has been associated with decreased survival rates for newly born neurons in the hippocampus, a part of the brain important in regulating the emotions. New research has investigated a chemical called fibroblast growth factor 2 (FGF2), which is crucial to brain development and brain repair after an injury, in terms of its relationship with anxiety. Using rats that have been bred for either high or low anxiety, researchers (led by Javier Perez at the University of Michigan) confirmed the earlier finding that FGF2 levels are lower in the rats bred for high anxiety. The study also identified two things that made these rats behave less anxiously and increased their FGF2 levels: treatment with FGF2 alone, and also giving them new toys (with no FGF2 treatment). Furthermore, both of these treatments enhanced the survival of new neurons in the hippocampus.

Assuming these results are applicable to humans, they offer two potential new treatments for anxiety, and perhaps depression: FGF2 therapy, and environmental enrichment. While it’s not clear what the human equivalent of new toys might be, it seems like we already know that finding new activities that can spark a renewed interest in life is a good thing to try. (This also, to my mind, suggests a link between boredom and depression, although like most such links, there’s a certain chicken-and-egg aspect to it.) This is purely speculation, and I’m sure any application in humans is a long way off, but I’m wondering if FGF2 therapy might turn out to be a useful first step, to get seriously depressed or anxious people to the point where they can even take an interest in something new.

This article from EurekAlert summarizes the work, which will be published in the May 13, 2009, issue of the Journal of Neuroscience.

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.

This 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.

This article from The Economist, on the other hand, covers some new research into unconscious 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, brain unconscious 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.

Yesterday I heard an excellent talk on the evolution of skin color by Nina Jablonski of Penn State. She started by describing how little work there was on the subject when she was asked to give a talk about it in the early 1990s; although it’s an interesting topic, the subject of skin color and race was such a hot potato that people were reluctant to pick it up. Dr. Jablonski described herself as an optimist who believes that we’re socially mature enough to deal with discussions of skin color. Her talk didn’t directly refute the ideologies involved in racism, but was an excellent example of how to sidestep ideology entirely and present the evolution behind skin color variation in humans as a fascinating story of science and history, with an abiding biochemical tension at the heart of it.

The tension has to do with the human body’s love-hate relationship with ultraviolet radiation. In general, UV is deleterious to us (and to many other living things); in particular, it destroys the essential B vitamin folate and causes various sorts of tissue damage and DNA damage. However, certain wavelengths of UVB radiation are essential to the formation in the skin of vitamin D, which helps our bodies absorb calcium and can be very difficult to get enough of from dietary sources. Thus, we mostly could do very well without UV radiation, except that we need vitamin D, not only for bone health but for a host of other reasons.

(A side note on our current take on this problem: For years dermatologists have focused on the bad side of UV radiation, urging the use of sunscreen; also, the lifestyle, in industrialized countries in particular, has tended toward more time spent indoors and less out in the sun, resulting in lower UV exposure. I’ve recently read a bit on vitamin D and depression, mostly because I’m being treated for a severe vitamin D deficiency. I’ve been contemplating whether to continue protecting my skin at all times from UV (especially important because I grew up in a sunny climate at a time when sunscreen was not anywhere near as ubiquitous as it is today) or to let at least a little of the sunshine in so as to boost my vitamin D levels. Jablonski says she advises people to follow the advice of dermatologists to protect their skin and consider dietary supplementation to meet their vitamin D needs; some dermatologists, she reported, are now recommending prudent sun exposure, which means exposing only parts of the body that normally don’t get much sun. One dermatologist asked her to please encourage people to sun their buttocks.)

Exposure to UV radiation is the single most important factor in explaining human skin color, the story of which is based on the presence in our bodies of varying levels of melanin. This nifty chemical produces skin pigmentation and protects against the negative effects of UV radiation. The earliest members of genus Homo were darkly pigmented, living in an area with abundant UVR, but then, in time, we moved to areas with different levels of UV radiation. UVR is generally most abundant at the equator and tapers off at higher latitudes, with several variations. In areas of higher altitude, like the Himalayas and the Andes, UV exposure is higher because there is less protective atmosphere between the earth and the sun. Also, equatorial areas that typically have a lot of cloud cover get less UVR than noncloudy equatorial regions.

As the human habitat has expanded out of Africa and over virtually the entire globe, humans have moved to a variety of UV regimes, and we have evolved accordingly. There’s no single optimal skin color; in a given region, the optimum level of pigmentation depends on the balance between keeping UVR-related damage and mortality to a minimum while maximizing vitamin D production in the skin. Jablonski made two key points: 1) Skin color is not a good indicator of race or genetic grouping because both light and dark pigmentation have evolved independently multiple times (light pigmentation evolved at least twice in humans, for example, and once in Neanderthals; dark pigmentation also likely evolved multiple times). 2) Skin color is an excellent subject for teaching people about evolution, being one of the best examples of evolution in humans, and easily visible to all as a part of everyday life.

The story is full of fascinating little quirks; for example, Tibetans, although they live at high altitude, are not as darkly pigmented as you would expect for the amount of UVR there, because humans moved into that part of the world relatively recently (I think she said it was within the last three or four thousand years), and they came with heavy clothes and structures that protected them from the sun. As a result, they don’t actually get a huge amount of UV exposure, and need to stay relatively pale to get their vitamin D. Another interesting tidbit is that in most human populations (if not all, my notes are unclear on this point, sorry), the women tend to be more lightly pigmented than the men. This may be related to women’s childbearing role; for example, a successful pregnancy requires quite a lot of calcium. However, sexual selection may also play a role in areas where men preferentially choose lighter-skinned women, exaggerating a difference originally caused by natural selection.

Jablonski also explained why some people tan more easily than others. It turns out that some populations, e.g., some of those that live around the Mediterranean, have developed the facility to regulate the melanin content of their skin relatively easily in response to environmental conditions; i.e., they tan easily. She also addressed the question of why the Inuit are as highly pigmented as they are, despite living at such high latitudes. They are exposed to a great deal of reflected UVR bouncing off the snow, so they need the protection from UV, and they also consume some of the most vitamin D-rich foods on the planet, namely, the blubber of marine mammals, so they can afford to miss out on some of the vitamin D production in the skin that lighter pigmentation would allow.

The questions after the talk were all good, in particular one about why there’s (almost always) a broader range of hair colors associated with lighter skin pigmentation than with darker. The reason has to do with the variety of genetic differences that can combine to create light skin color; lighter skin color can be associated with a variety of genetic combinations and thus hair colors. In areas where dark skin is advantageous, however, dark hair is also often advantageous, so the two traits tend to be linked. Jablonski described how we learned that dark hair can be advantageous in a sunny climate from studying thermoregulation in birds. The black feathers of crows, for example, are good at dissipating heat. This is counterintuitive to anyone who has ever had a car with a dark vinyl interior, but heat penetrates white plumage (and I’m guessing is then transmitted readily to the bird), whereas black plumage traps the heat and then dissipates it when a breeze blows or when the bird puffs up its feathers, as crows evidently do in hot weather.

It’s stories like this that make the natural world such a rewarding and engaging object of study, and I wholeheartedly endorse Jablonski’s recommendation that the story of skin color be used as an educational tool for anyone who is teaching about evolution. I think she was addressing mostly professional scholars and educators, but anyone, especially parents and others involved in the care and tending of young minds, can learn more and share this story. Some online resources include a recent NPR story, a National Geographic article, and a story from Discover Magazine. Jablonski has also written a book, Skin: A Natural History, which has some information on skin color. I leave it to you to decide whether to sun your buttocks, but if you want to teach young people, or any people, about human evolution, I highly recommend that you consider using the story of skin color as a wonderful, accessible teaching story.

A recent EurekAlert article describes some work that examined the effect of positive and negative emotions on a person’s level of adherence to typical cultural values. The study looked at Asians and Europeans; each culture, broadly speaking, has a different attitude toward individuality versus fitting into the group, and these attitudes were examined in individual participants. Then the researchers manipulated the moods of the participants, cheering some up and lowering others slightly into the dumps. The jazzed or bummed participants then were given some things to do that were designed to reveal the degree to which they acted in accordance with their attitudes. The happier ones were more likely to behave in ways that were off their own personal beaten path (Europeans taking more of a group view, Asians acting more independently), indicating that being in a more cheerful frame of mind might predispose people to be more exploratory and open to different ways of being. Mild misery had the opposite effect, reinforcing existing attitudes and behaviors.

It’s a fascinating look into how fluctuations in mood can change something that on the face of it might seem fairly set. Identity is not a static thing. (Incidentally, it’s also a nice story for those of us who like to answer questions about personality—or other topics—with “It depends.”)

(The full article is in the March 2009 issue of Psychological Science: Who I Am Depends on How I Feel: The Role of Affect in the Expression of Culture, Claire E. Ashton-James, William W. Maddux, Adam D. Galinsky, and Tanya L. Chartrand. Psychological Science 20:3, 340-346.)

Of course, the down side of the contingent nature of our behavior is that, as we already know, anxious, fearful people are not always at their best. Maybe that’s why it’s important to keep finding something to laugh at or otherwise feel good about even in trying circumstances. Coincidentally, I also happened across this article from the Association for Psychological Science about the value of positive emotions. The article describes the “broaden and build” model of psychologist Barbara Fredrickson, who has a new book out on the benefits of positivity. The idea is that contentment, playfulness, and serenity appear to help open up the mind to novel ideas (as with the recent experiment into cultural stereotypes), and over time, such moments of broadening add up to a greater sense of purpose, better social connections, and other beneficial outcomes. The article opens with a wonderful anecdote about patas monkeys, who in their youth chase each other around and, in the process, throw themselves onto flexible young trees, which bend and then fling them off in another direction. The monkeys drop this kind of horseplay as they get older, except when they’re being chased by a predator, when they will use a sapling as a slingshot to try to escape death. Evidently those monkeys look like they’re goofing off while they’re actually learning a survival skill.

One of the most endearing things about humans and other animals, it seems to me, is the sense of play, of spontaneous joy in some goofy activity or another, preferably shared. If there’s some cumulative long-term benefit, so much the better. I’m glad psychologists are looking into this kind of thing, and I’m also glad that thinkers before this have examined the question. Edward Abbey, for example, in Desert Solitaire, had this to say about the croaking of frogs in a brief wet spell in the desert:

“Why do they sing? What do they have to sing about? Somewhat apart from one another, separated by roughly equal distances, facing outward from the water, they clank and croak all through the night with tireless perseverance. To human ears their music has a bleak, dismal, tragic quality, dirgelike rather than jubilant. It may nevertheless be the case that these small beings are singing not only to claim their stake in the pond, not only to attract a mate, but also out of spontaneous love and joy, a contrapuntal choral celebration of the coolness and wetness after weeks of desert fire, for love of their own existence, however brief it may be, and for joy in the common life.

Has joy any survival value in the operations of evolution? I suspect that it does; I suspect that the morose and fearful are doomed to quick extinction. Where there is no joy there can be no courage; and without courage all other virtues are useless.”

I can’t do much better than leave you with the words of Cactus Ed. Right now I’m going out on my back patio to joyfully celebrate warmth and sunshine after weeks of midwest ice. (I won’t sing, though, because despite my best efforts I might sound remarkably like the frogs.)

Wisdom is one of those difficult concepts: you know it when you see it, but it might be hard to describe succinctly. Perhaps that’s because it’s not a single entity, but a combination of traits. That’s the approach taken by a couple of researchers at the University of California at San Diego, who have mined existing research looking for studies on six characteristics that are common in definitions of wisdom. Looking mostly at neuroimaging studies, they identified brain areas associated with certain facets of wisdom, and also found that some brain regions seem to be involved in several of its components. The thing that really caught my interest is that, based on this very preliminary work on the neurobiology of wisdom, it seems that balance is important: wisdom may be best described as a balancing act between various faculties (e.g., rationality and emotion). That concept of the brain achieving wisdom by integrating multiple capabilities into a balanced whole makes a lot of sense to me.

This article from Science Daily describes the work, and Scientific American Mind has a blog post.

The full citation for the work is: Thomas W. Meeks; Dilip V. Jeste. Neurobiology of Wisdom: A Literature Overview. Archives of General Psychiatry, 2009; 66 (4): 355 DOI: 10.1001/archgenpsychiatry.2009.8

We’re in the middle of 100 Hours of Astronomy, part of the International Year of Astronomy. One of the 100 Hours activities is a 24-hour live webcast tour of some of the world’s big telescopes, Around the World in 80 Telescopes, which started this morning at 5:00 Eastern Daylight Time (9:00 UT). (The video can be a little flaky, but you can browse pre-recorded segments if the live video gets bogged down.) The visit to each observatory often includes canned clips showing off the scopes and the images from them, along with live interviews with astronomers and live views of the scopes. Why am I posting this here? The connection to Thinking Meat lies in this quote from a video about the Canada-France-Hawaii Telescope on Mauna Kea written and illustrated by David Gillette. Describing his arrival at the top of Mauna Kea with all its telescope domes, he said:

“For me, these buildings represent the best characteristics of our species: curiosity, collaboration, and the patient accumulation of knowledge.”

That’s exactly how I feel about observatories too, and those words make me feel especially happy to be thinking meat.

And while I’m on the subject, what do you think the best characteristics of our species are?

P.S. The entire webcast, nicely broken down into segments for each observatory, is archived at the 100 Hours of Astronomy channel on UStream. The UStream site is a little hard to navigate, in my opinion, but if you scroll down a bit, you’ll find the “video clips” section. Browse the links there, or click the RSS feed icon (orange) there to see an easy-to-scan list of all the observatories.

It’s a wise life form that knows enough to take good care of its environment. Does Homo sapiens fill the bill? The jury is still out. This weekend, cast your vote for taking care of Earth by participating in Earth Hour: between 8:30 and 9:30 P.M. on Saturday, March 28, turn the lights off. (In fact, I’d say to consider ramping down your power use as much as possible: shut down the TV, the stove, other appliances, your computer…shoot, don’t even read this blog—just for that one hour anyway.) It’s a symbolic action to call attention to the need to address global climate change. Our species is good at attaching meaning to symbols, and this particular symbol could speak volumes to elected officials. Learn more and sign up at the Earth Hour web site. (I’m happy that Indiana University Bloomington is a flagship campus for this year’s Earth Hour and will be taking action to reduce the university’s power usage during that hour; I hope that’s the start of long-term energy reduction measures on campus.)

You’ve probably heard about research into the universality of facial expressions, which has revealed that some emotions are associated with particular facial expressions that are recognizable around the world. It turns out that music evidently has some of that same universal ability to express emotions. Twenty-one members of a Cameroonian ethnic group, the Mafa, were able to identify happiness, sadness, and fear in Western music on their first exposure to it. Furthermore, the clues they used to identify the emotions were similar to those used by Westerners: temporal patterns and musical mode. I’ve long been curious about what makes music sound happy or sad, not to mention how it expresses a host of subtle emotional hues and shades, so it’s interesting to see that whatever it is that makes Western music expressive, it may be something about people in general, not just about people who were raised on this music. This article from Science Daily has the details.

A recent experiment at Ohio State, described in this story from Science Daily, looked at how depressed and non-depressed people view positive and negative things in their environment. To examine how people form positive or negative attitudes, researchers used a computer game that neatly sidesteps any possible confusion from pre-existing attitudes about particular topics. The game introduces players to a variety of beans with different appearances. They can accept or reject each bean as it appears on the screen; some beans are good beans, adding points to a player’s score, while others are bad beans, resulting in points being lost. The goodness or badness of a bean is reliably indicated by its appearance, and players have to learn to identify beans based on their experience with the game.

In this particular experiment with the bean game, depressed and nondepressed people were equally good at identifying the bad beans. However, depressed people didn’t do as well as the non-depressed at identifying the good beans. This seems to me to present an interesting chicken-and-egg question: Are people slower to spot the good things because they are depressed, or are they depressed because they’re slower to spot the good things? (I suspect the answer might be “Yes”; i.e., both are true.) The Science Daily article seems to come down on the latter side; it concludes by suggesting that therapists who are treating depressed people might try to make them more aware of the good things in their lives. This is probably excellent advice, but I think there’s more to it than that.

It seems to me—based, I hasten to note, on nothing more than my own experiences with depression—that maybe the crucial missing piece in a depressed person’s experience of the game is that to a depressed person, good things don’t reliably feel good. The word “anhedonia” describes the lack of pleasure in normally enjoyable activities that forms, for me, the core experience of depression, and I think it may be what’s at work in the depressed people’s poorer performance in recognizing the good beans. They just don’t always feel whatever it is that identifies experiences as being positive, pleasurable, or worthwhile. Reminding myself of the many blessings in my life is always a good thing to do, but sometimes it seems like an intellectual exercise that doesn’t really do much to bring back the normal feeling of enjoying those blessings. I wish I knew better what it is that brings that feeling of enjoyment back, or makes it go away, but I’d bet that its absence is at the heart of the difference in performance on the bean game.

Characters in novels, movies, and other fictions can seem quite real (we root for one and boo another, for example, and cry sometimes when one of them dies). Yet for all that, we can easily distinguish them from real people, people that we know personally. But how do you know that your mother is real, for example, but Scarlett O’Hara is not?

An ingenious recent fMRI study compared brain activity in cases where people contemplated scenarios involving fictional characters, famous people that they didn’t know personally, and friends or family members. Participants had to determine the plausibility of actions like dreaming about a fictional character (possible), talking with a fictional character (impossible) or having dinner with a real person (possible).

Two brain areas appeared to be involved in the activity of distinguishing flesh-and-blood people from the purely mental constructs that are fictional characters: the anterior medial prefrontal cortex and the posterior cingulate cortex. These are parts of the brain’s default network, which kicks in when we’re not doing anything in particular and our minds go wandering over an internal landscape; both areas are believed to be important in self-referential thought and the recall of autobiographical memories. These brain areas were most active in the tasks involving friends and family, moderately active in tasks involving famous people who were not personally known, and least active in tasks involving a fictional character. The idea is that perhaps you know your mother is real because your brain codes her as being more personally relevant to you than a fictional character is.

The paper is available on PLoS ONE: Reality = Relevance? Insights from Spontaneous Modulations of the Brain’s Default Network when Telling Apart Reality from Fiction, Anne Abraham and D. Yves von Craman. It’s got lots of interesting background, and some fascinating material on the possible relevance of this work and ways it could be extended. I’d love to know, for example, how particularly well-known and loved fictional characters fall on the spectrum of brain activity, and also what an writer’s brain looks like when it’s contemplating characters it has created. Meanwhile, it’s time for me to immerse myself in a fictional world and a hot bath.

It appears that musical training will do more than enhance your understanding and perception of music. In a study at Northwestern, musicians were better than non-musicians at detecting emotion in the sound of a baby’s cry. An examination of brain activity revealed that musician’s brains appear to be better able to focus on the more complicated part of the sound, which conveys the emotional meaning, while giving less attention to the simpler, less emotion-laden part. This article from PhysOrg.com gives some details. (The article, by Dana Strait et al., will appear in the European Journal of Neuroscience.) I remember hearing a relatively young Joshua Bell play Mendelssohn’s Violin Concerto with what seemed to me an emotional depth and richness beyond his years; I wonder if his years of musical training had anything to do with his sensitivity to emotional nuance.

The next time a particularly memory-laden song from your teen years comes across your iPod playlist and you suddenly start remembering people and places from long ago, thank your medial pre-frontal cortex. A recent fMRI study at UC Davis indicates that this area links our autobiographical memories and our emotional response to the music associated with them. Because this area is one of the last to be affected by Alzheimer’s disease, the findings could explain why people with Alzheimer’s still recognize and respond to music even after other memories are gone. This press release from EurekAlert gives an overview; the complete article is also available online, at least at the moment. (The Neural Architecture of Music-Evoked Autobiographical Memories, Petr Janata. Cerebral Cortex, Advance Access published online Feb. 24, 2009)

A couple of months ago I mentioned that New Scientist was looking for people to take part in a study about whether or not personality traits are reflected in facial appearance. This article describes the results of the study. Volunteers completed a brief personality questionnaire and sent in a photo; composite images were made using photos of people at either end of the spectrum for various personality traits. Then other volunteers rated the composites on the degree to which they appeared to possess the related trait. It appears that some personality characteristics can be accurately judged from how a person’s face looks–not all, but enough to be intriguing. The article presents several hypotheses for why this should be so. It’s an interesting read, with links to a number of relevant research articles. You can also go to the Face Experiment page and see for yourself whether you can tell which personality trait is associated with which composite face.

I’ve always been fascinated by the idea of synesthesia, and in fact a little envious of those who experience this unusual blending of sensory modes. The first hour of Performance Today for February 16 explored musical/color synesthesia. A synesthesia page is available on the Performance Today web site, featuring interviews with composer (and synesthete) Michael Torke and neuroscientist (and music lover) Oliver Sacks and links to more information. And for the next week, you can listen to the show by following the link on this page.

Happy Darwin Day, everyone! Here are links to several stories on how humans have reacted to the discoveries of evolutionary biology:

This essay in The Economist outlines some of the cultural ramifications of evolutionary thought (including a mention of that depressing chart that shows the US near the bottom of a list of around 20 nations in the percentage of people who believe in evolution). Stephen Jay Gould proposed that if the evolutionary sequence on earth could be somehow rewound and replayed, it might turn out differently, because evolution is not in any sense directed; some biologists today suggest that it would be at least broadly similar, not because it is directed but because it is constrained to some degree by physics and chemistry. If this is true, would it make the universe seem any less random or meaningless to those who perceive it so and blame evolution for the emptiness? I kind of doubt it, but it certainly would be interesting to know how flexible the process of evolution is.

This article from the New York Times emphasizes the magnitude of Darwin’s achievement and also covers the social impact of his thought. Another NYT article takes a look at the human role in the evolution of other species.

If you’re curious about how Darwin’s ideas looked to a biologist of his own day, Powells.com has republished this review of On the Origin of Species, originally published in the Atlantic Monthly in July 1960 and written by noted American botanist Asa Gray. (Origin was first published in 1859.)

February 12, 2009, is the 200th anniversary of the birth of Charles Darwin. In celebration of Darwin Day, science educators around the world are organizing evolution-themed lectures, parties, and other events. You can learn more and search for events in your area at the Darwin Day Celebration web site.