Wednesday Round Up #156

David Dobbs writes in National Geographic on Teenage Brains. His article covers the growing consensus that human brains take much longer to develop than previously thought (into our 20s), and that this developmental process (“a massive reorganization” between 12 and 25) has significant effects on teenage behavior (get the references over at Dobbs’ blog). Dobbs argues for an “adaptive adolescence” view, which “casts the teen less as a rough work than as an exquisitely sensitive, highly adaptive creature wired almost perfectly for the job of moving from the safety of home into the complicated world outside.” However, the anthropologist in me knows that with the incredible change in maturation rates (earlier development) in industrial, what exactly is “natural” in this story isn’t all that clear. Indeed, one could argue that there is an ever-clearer lack of synchrony between physical and sexual development (so early now) and brain and mental development (further delayed, with so much emphasis on complex mental learning, rather than tasks like farming or foraging). Adolescence as a life phase in the industrial world exists in the extremes of these two developmental processes. That said, Dobbs does a good job debunking several myths about adolescence, and highlighting what we know about adolescent brain development in the United States and other industrial countries.

The life of the mind is not in the brain. That is our post-modern trope, a seeming certainty as so much around us changes. The mind is a cultural product too, and nothing better to remind us of that than a book on intellectual history. Stephen Greenblatt’s The Swerve: How the World Became Modern tells us the story of Lucretius, his book On the Nature of Things, and its rediscovery in the Renaissance. NPR offers a delightful review.

Over at Ethnografix, Ryan Anderson brings together a lot of recent writing and blogging on open-access publishing (including the lack thereof) in anthropology. This is one stop shopping in his post Anthropology: Open Access & Academic Publishing Reading List. Ryan is also blogging now for Savage Minds; his latest post is Hipstamatic, Authentic, and (maybe) True.

Last week I highlighted new longitudinal research linking fatherhood with drops in testosterone. Two informed commentaries place this work in anthropological context. Jason Anstrosio writes on Testosterone Anthropology over at Living Anthropologically, interpreting the mainstream media coverage done by the New York Times. At Context and Variation, now on Scientific American Blogs (congrats, Kate!), Kate Clancy tells us that Parenting is not just for the ladies: on testosterone, fatherhood, and why lower hormones are good for you. Kate provides a parenting story, the bio anthro context for this research, and then a great interview with Peter Gray, one of the leaders in this field.

Barbara King, anthropologist and primatologist, is now blogging for NPR’s science blog 13.7 Cosmos and Culture. Her first post is Human and Other Animals: A Voice from Anthropology. Here’s just a taste:

We know now that the nonhuman great apes — chimpanzees, bonobos, the gorillas of Africa, the orangutans of Asia — are hotbeds of political intrigue, technology aided problem solving and an all-too-familiar mix of compassion and cruelty.

Over at Nature News, Mo Costandi writes on research arguing that Video game studies have serious flaws, in particular research showing cognitive benefits from video game playing. Bradley Voytek provides some informed commentary in Thank you Mario! But your methods are in another field!, arguing for a return to basic research design and statistics. But I take this as the sign of a maturing field, which is now moving towards a clinical studies trial model. Given the vast difference highlighted in spatial attention among gamers in Brad’s piece, I’m confident these types of results will continue to play out even as research moves from a cross-sectional approach to a longitudinal approach with greater controls.

SBS in Australia has put together a very good and very risqué documentary Sex: An Unnatural History. And Greg hasn’t done enough to toot his own horn about this, as he is one of the intellectuals who give great informed discussion about humans and sexuality, interspersed with um, well, the first time I was definitely shocked, so used to American standards, but the nudity combined with the sense of humor is perhaps a needed combination when really talking about, thinking about, and researching our sexual lives. The series is up to six episodes now, and Greg appears in #1, #5, and #6. Here is the link to the YouTube video of Episode One – Sex: An Unnatural History. Greg appears in the section that starts at 19:48. Complete with a horse!

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3 Responses to Wednesday Round Up #156

  1. David Dobbs says:

    Thanks for highlighting my adaptive adolescence article, Daniel. Your point on possible cultural effects on the scan results showing extended period of brain development is well taken. Vincent Tijms ,lodged the same caveat over at The Matter of the Mind. I’ve no doubt that the US researchers who did this longitudinal structural MRI studies (the scanned hundreds of kids as they grew up, from around age 5 well into their 20s) would love to do similar studies on diverse populations all over the globe. Two things make me suspect they’d find roughly similar long arcs of development. One is a huge anthropological study done by Alice Schlegel, (, which looked at over 200 cultures around the world, including some of pre-industrial nature, and found that all had significant cultural recognitions of adolescence as a unique period, with, among other things, a sort of gap between sexual maturity and motivation to be independent and the ability or privilege to do so. (That’s a sweeping summary of the findings, but hits at its essence. One huge caveat, e.g.: This often applied much more to males the females, which is why girls are sometimes married off at puberty to boys who went through puberty several years before.) So almost all cultures recognize this combination of heightened novelty-seeking and risk-taking (and same-age peer affiliation) at a time when the adolescent isn’t granted full privileges as an adult (presumably b/c it’s thought he or she is not ready.

    This argues that adolescence — a developmental phenotype if you will — is not cultural, though the form and expression it takes can vary hugely by culture.

    The other thing that makes me suspect we’d find roughly similar developmental arcs shown in cross-cultural scan studies is the stepped nature of those developmental arcs. Work by Giedd and others, some still unpublished, is showing that these long developmental arcs are really created by many smaller developmental arcs triggered by distinctive gene-expression patterns. Some of those patterns seem to be responsive to environment (stress in the home, for instance), while others seem to be tied mainly to time or the completion of other developmental arcs and associated surges in gene expression; and some happen in parallel, as it were, while others appear to need to happen in sequence.

    That’s early work and hardly conclusive, but atop everything, make me (and most of the researchers I talked to) suspect the arcs would be of similar shape and roughly similar duration in other cultures — not proven, but defensible reason for leaning that way.

    That said, those arcs might be shorter in cultures that don’t ask their youth to wait so long to be declared adults. One of the many passages on the cutting room floor was one in which BJ Casey wondered if the developmental arc that now (mostly) ends in the mid-20s might have ended significantly earlier in a time (or in cultures now) in which adulthood was granted earlier. Would be a hell of a cool study to do.

    Could it get done? Giedd and BJ Casey and I were discussing this before the NPR program yesterday (, and Jay described talking with an adolescent researcher in such a culture — one in which girls/women are married before their second menarche to boys/men of 15 or 16 — and saying he’d love to scan those kids. The researcher said, in effect, That’d be a great study; but if I had a thousand dollars to scan each of these kids, I’d use it to get them basic medical care.

    Tricky stuff.

    Thanks again for raising these issues — essential caveats and checks of the sort it’s very hard to get into a story of limited word length in a glossy. (If you could see all the stuff that didn’t make it …) One more reason to be grateful for blogs.

    • daniel.lende says:

      David, thanks for the great comment. And in large part I agree with what you say, that there is a fairly identifiable period across human societies that we call “adolescence,” and that doing neuroimaging studies cross-culturally of developing brains will lead to much greater insight. Even more than the cultural neuroscience, I think the neuroconstructivism approach coming out of developmental neurobiology will be key to understanding how these dynamics play out cross-culturally.

      My point isn’t so much a cultural anthropology one, however, as it is a biological anthropology one, with a focus on the development and maturation of biological systems over the lifespan. I am thinking of works like Barry Bogin’s recent overview chapter, Evolution of Human Growth; Carol Worthman’s Epidemiology of Human Development, an important and often overlooked chapter; and even Mel Konner’s latest book, The Evolution of Childhood.

      In industrial societies, with high levels of available energy and low levels of infectious diseases, it makes adaptive sense for children to develop as quickly as possible, to enter into reproductive state sooner. Hence the secular trend towards very early maturation among humans living in this high resource, low morbidity situations. And that early maturation unleashes a cascade of hormonal and neuronal processes that can have important organizational impacts on the brain. At the same time, we are pushing longer periods of study and complex learning, which take longer to master (and thus longer to put the neuronal processes together) and involve complex circuit and regional interactions in the brain. Thus, my point is that some of the complexity and the patterning that the neuroscientists are seeing comes from the dynamics of growth in a complex society,with earlier physical and sexual maturation due to biological development, and longer reorganization and neuroconstruction in those brain areas that undergird the complex behaviors, systems of knowledge, and social relationships we manage in industrial societies.

      In societies where physical and sexual maturation happens later, and/or where complex education isn’t the main route to societal success, I’m quite willing to bet that there will be a different pattern of neuronal development. In one sense, the biological systems will be more in sync in the overall lifespan, particularly as physical and sexual maturation happens over a longer timeframe and in tighter conjunction with other neuronal developmental processes. Carol Worthman’s research on physical and cultural development among Kikuyu adolescents offers a model for thinking about some of these things.

      I am also quite open to the idea that brain development, and even physical development, can continue to occur even later than the 25 year cut-off that seems to be imposed now (any coincidence that it is related to when we see children as finally, really becoming adults?). My friend John Wood who has worked with the pastoral Gabra in east Africa once told me how they viewed maturation among men there as a much longer process, with men reaching full maturity and physical size in their 30s. I’d be intrigued to see how brain development also happens in such a society. And the Gabra are also a wonderful example of how the lifespan can be quite different than we imagine. In their late lives, Gabra men become women, switching societal roles, behavior, and daily activities in dramatic fashion. John has an illuminating book, When Men Are Women: Manhood among the Gabra Nomads of East Africa.

  2. Erin Finley says:

    Wonderful to see this dialogue in the comments! My thanks to both of you for thoughtfully engaging on such a fascinating topic.

    Also, Daniel, I really love the new round-up format.

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