It’s the bane of manly existence everywhere: to be a cuckold. Or so the story goes. It seems to be taken for granted, in both evolutionary biology and post-Neolithic societies, that one of the worst possible things is for a man to be married to a woman who cheats. Why? Because the man might end [...]... Read more »
Beverly I. Strassmann, Nikhil T. Kurapati, Brendan F. Hug, Erin E. Burke, Brenda W. Gillespie, Tatiana M. Karafet, & Michael F. Hammer. (2012) Religion as a Means to Assure Paternity. PNAS, 109(25), 9781-9785. info:/10.1073/pnas.111044210
According to Dick Lewontin (evolutionary biologist, geneticist and social commentator) there is no way to know the evolution of cognition. He argued that we should ‘give up the childish notion that everything that is interesting about nature can be understood. [..] It might be interesting to know how cognition (whatever that is) arose and spread and changed, but we cannot know. Tough luck.’ (Lewontin, 1998:130)... Read more »
Honing, H., & Ploeger, A. (2012) Cognition and the Evolution of Music: Pitfalls and Prospects. Topics in Cognitive Science. DOI: 10.1111/j.1756-8765.2012.01210.x
Humans specialise in being smart. It wasn’t our sharp teeth that allowed us to rise to dominance chain but our brains. It provides us with the intelligence needed to build a metaphorical ladder to the top of the food chain. Yet what is it about our brains that makes us so smart? Is there something … Continue reading »... Read more »
Suzana Herculano-Houzel, Christine E. Collins, Peiyan Wong, Jon H. Kaas. (2007) Cellular scaling rules for primate brains. Proceedings of the National Academy of Sciences, 104(9), 3562-3567. DOI: 10.1073/pnas.0611396104
Suzana Herculano-Houzel. (2012) The remarkable, yet not extraordinary, human brain as a scaled-up primate brain and its associated cost. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.1201895109
What happened when the world's most no-nonsense psychologist took a Rorschach test?A fun little paper reports on B. F. Skinner's Rorschach results. He agreed to be tested as part of a 1953 project psychoanalysing various eminent scientists. The scientists were anonymous at the time but now Norwegians Cato Grønnerød et al have dug them out of the archives (Skinner has been dead since 1990).Skinner was the world's leading exponent of behaviourism, a school of thought that held roughly that it's impossible to know anything about "inner" mental states or thoughts, and that they might not even exist, so all we could do was look at and try to predict behaviour.It was never an especially convincing idea to be honest and behaviourism is now pretty much dead although many of the techniques pioneered by Skinner live on in the form of tests on lab animals to determine the addictiveness of drugs and so forth.But in the mid-20th century it was very popular and Skinner was a well-known figure, the Jonah Lehrer of his day in many ways although rather more controversial.Anyway. Grønnerød et al report that when Skinner was asked to describe those famous inkblots -The most evident feature of the protocol is the huge number of responses, showing a highly productive and creative person. But complexity is sacrificed for quantity... No perceptual distortions are evident, and reality testing and ability to function neutrally are in place. We found no signs of cognitive distortions, although some responses have an idiosyncratic twist... He might be an assertive person with a tendency to view relations as generally competitive and an area for the expression of his own needs, rather than an area of mutual support and belonging. Although he shows an interest in others, the balance between real and whole humans and other human representation suggests that perception of self and others is based more on fantasies and wishes than on real-life perceptions... “Necrotic looking,” “wounded animal,” and “sheep pushing the two wolves away” might reflect projected aggression. These processes point to more primitive defense mechanisms...Which is exactly the kind of speculation that Skinner spent his career trying to put a stop to. Still, it's an interesting paper, although I think it tells you more about the Rorschach than about Skinner.Grønnerød C, Overskeid G, and Hartmann E (2012). Under Skinner's Skin: Gauging a Behaviorist From His Rorschach Protocol. Journal of personality assessment PMID: 22731841... Read more »
Grønnerød C, Overskeid G, & Hartmann E. (2012) Under Skinner's Skin: Gauging a Behaviorist From His Rorschach Protocol. Journal of personality assessment. PMID: 22731841
Good news for aspiring jelly-bean jar estimators who are under 30! Your intuitive grasp of numbers may not have peaked yet. Unlike other cognitive skills, the ability to approximate keeps improving well into adulthood. Since the skill is tied to mathematical smarts, this news might bring hope to struggling students.
Scientists call our intuitive understanding of numbers the approximate number system, or ANS. It lets us compare amounts or guess at the size of a solution without putting our thinking into words. An approximate number system has been observed in adults, kids, infants, remote Amazonians who don't have number words, chimpanzees, and pigeons.
Just because you have an approximate number system, though, doesn't mean it measures up to everyone else's. For English-speaking humans with internet access, an easy way to test your ANS is with a simple computer test. Available at panamath.org, the test flashes sets of dots and asks whether you see more yellow ones or more blue. Afterward, if you dare, you can find out how your skill compares to that of other people who have taken the test (though not pigeons, sadly).
A whole lot of people, in fact, have taken this test. When researchers led by Justin Halberda at Johns Hopkins University posted a version at www.testmybrain.org, a site where you can participate in ongoing psychology experiments, they got over 10,000 responses in just 3 months. This giant dataset became a new paper in Proceedings of the National Academy of Sciences.
Before taking the test, participants had filled out a questionnaire that included items such as their age (subjects ranged from 11 to 85) and how they felt they did in various school subjects compared to their peers. From this heap of information, two patterns emerged.
The first was that subjects' approximation skill was tied to their self-reported math ability. People who answered the dot questions faster and more accurately said that they were (or had been) good at math, compared to their classmates. This held true across all ages, from kids currently in school to retirees who hadn't seen a math class in 60 years.
Of course, people can misremember how well they did in school. But when the researchers asked a smaller group of subjects about their SATs, the math scores corresponded to self-reported math ability. And while the math SAT score also correlated to performance on the number sense test, verbal SAT scores didn't. This suggests the better ANS scores are truly related to math ability, not to overall intelligence or a tendency to inflate one's resumé.
The second finding was that number sense changes over a person's lifetime—and it peaks late. The accuracy of people's answers on the test steadily improved up until age 30 or so, before beginning a long decline. (As for speed, teenagers answered the fastest, even though they were less accurate than adults.)
Although the trends were clear across the 10,000 subjects, people within in each age group varied widely in their number sense scores. For example, the authors write, one out of eight adults in their study had a less precise number sense than the average 11-year-old. Since these scores seem to be linked to math performance in school, this variation might help explain why certain students sail through class while others struggle. But Justin Halberda says the results are a cause for optimism.
"That the gut number sense continues to improve up into our thirties means that it is malleable, and that we may be able to help those struggling with the number sense," Halberda says. Since the number sense is flexible throughout our lifespans, there may be ways to enhance it—and that might make people better at math in general.
Halberda adds, "I remain hopeful that we will be able to improve people's abilities even later in life." In other words, you might never be too old to return to your second-grade classroom and dominate a round of Guess How Many Pennies.
Halberda J, Ly R, Wilmer JB, Naiman DQ, & Germine L (2012). Number sense across the lifespan as revealed by a massive Internet-based sample. Proceedings of the National Academy of Sciences of the United States of America PMID: 22733748
Images: Philip Chapman-Bell/Flickr; Jay Rishel/Flickr... Read more »
Halberda J, Ly R, Wilmer JB, Naiman DQ, & Germine L. (2012) Number sense across the lifespan as revealed by a massive Internet-based sample. Proceedings of the National Academy of Sciences of the United States of America. PMID: 22733748
Students of human evolution tend to care a great deal about the diets of our ancestors and close kin. The …Continue reading »... Read more »
Amanda G. Henry, Peter S. Ungar, Benjamin H. Passey, Matt Sponheimer, Lloyd Rossouw, Marion Bamford, Paul Sandberg, Darryl J. de Ruiter, & Lee Berger. (2012) The diet of Australopithecus sediba. Nature. info:/10.1038/nature11185
Today is Wetherill Day, the anniversary of Richard Wetherill’s death in 1910, and as such I would like to continue my tradition of marking the occasion by discussing the complicated and often misunderstood legacy of Wetherill, the pioneering amateur archaeologist who excavated many sites in the Southwest, including most famously Pueblo Bonito at Chaco Canyon. [...]... Read more »
Browman, David L., & Givens, Douglas R. (1996) Stratigraphic Excavation: The First "New Archaeology". American Anthropologist, 98(1), 80-95. DOI: 10.1525/aa.1996.98.1.02a00080
Reed, Erik K. (1963) The Beginnings of Physical Anthropology in the Southwest. Journal of the Arizona Academy of Science, 2(3), 130-132. DOI: 10.2307/27641802
Snead, James E. (1999) Science, Commerce, and Control: Patronage and the Development of Anthropological Archaeology in the Americas. American Anthropologist, 101(2), 256-271. DOI: 10.1525/aa.19126.96.36.1996
This Wednesday question (or “wondering Wednesdays,” or something else witty and alliterative. Suggestions please) comes from Colin who asks Just wondering if there is evoanth suggesting hominids are monogamous creatures or monogomy just lies on the spectrum of dispositions? In case you don’t feel like reading through the second EvoAnth (Colin, you’re meant to capitalise … Continue reading »... Read more »
A. de Boer, E.M. van Buel, G.J. Ter Horst. (2012) Love is more than just a kiss: a neurobiological perspective on love and affection. Neuroscience, 114-124. DOI: 10.1016/j.neuroscience.2011.11.017
Henrich J, Boyd R, & Richerson PJ. (2012) The puzzle of monogamous marriage. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 367(1589), 657-69. PMID: 22271782
THOMAS R. INSEL, LAWRENCE E. SHAPIRO. (1992) Oxytocin receptor distribution reflects social organization in monogamous and polygamous voles. Proceedings of the National Academy of Sciences, 5981-5984. DOI: 10.1073/pnas.89.13.5981
Ophir AG, Gessel A, Zheng DJ, & Phelps SM. (2012) Oxytocin receptor density is associated with male mating tactics and social monogamy. Hormones and behavior, 61(3), 445-53. PMID: 22285648
What was the extent of human occupation and environmental impact in the pre-Columbian Amazonia?This question has been at the center of much of the research on pre-Columbian Amazonia since Betty Meggers published her paper ‘Environmental Limitation on the Development of Culture’ (1). The reconstruction of the Amazon’s past is based on evidence obtained from the study of the present landscape, sediments and archaeological remains. These ‘evidences’ are called proxies. Pollen is a proxy for past vegetation, tree rings are proxies for past climate variability, CO2 stored in the ice cores is a proxy for past levels of atmospheric CO2 and so on.Paleo-ecologists, geographers, archaeologists etc. trying to understand the region’s past have first to look for proxies (this means going to the field and taking samples of lacustrine sediments and/or soils, or going into the mountains after morains and other glacial deposits); then they have to interpret the data gathered and assess their significance (to what extent does this data represent a local or regional event?): we can say that past values of CO2 inferred from ice cores are proxies for past global concentrations of CO2 because the atmosphere is well mixed, but we cannot say that the extent of a moraine in a particular valley indicates past global temperature or precipitations, because local conditions in that valley could have been (and very likely were) different from the conditions of a similar valley in the other hemisphere. As the process involves different stages, datasets and interpretations, it is not uncommon for researchers to disagree on the conclusions. This has often been the case with regards to Amazonia.In this post, I will try to provide a brief overview of the proxies (and their interpretations and significance) that have been used to infer the extent of the impact pre-Columbian populations had on Amazonia and the contribution of a recent paper published in Science (2) to our understanding of the region’s past.The first proxiesWhen Betty Meggers wrote ‘Environmental Limitation on the Development of Culture’ in the fifties (1), there was not much data on Amazonia. At that time scientists relied considerably on anthropological studies of modern indigenous communities and on written documentation left by the first explorers. The fact that the ‘modern’ indigenous population in Amazonia was limited to small nomadic and semi-nomadic groups was attributed to environmental constraints: unfertile soils and frequent floods. As Amazonian soils cannot support large and stable populations in modern times, it was thought that, also in the past, Amazonia was inhabited by small groups of hunters and gatherers. In contrast, written reports from the first explorers described large and rich societies with plenty of food and gold. Myths such as El Dorado arose on the basis of these reports. However, as the written reports contained some statements that were clearly false, such as the existence of blond women warriors with only one breast (the “Amazonas” from whom the river and the region took their names), these historical documents were often disregarded and the consensus within the scientific community was that Amazonia in the past only hosted small nomadic groups that did not have a significant impact on the environment. The discovery of the “lost cities”In the last 30 years, when more funding, interest and technology became available to spur archaeological research, scholars started to find new evidence of pre-Columbian complex societies in those very places where Megger’s model of environmental determinism predicted that they shouldn’t be. The discovery of raised fields and monumental mounds in the Bolivian Amazon (3,4), the geometric ditches in the Acre (5), the terra preta sites, the earthworks in the upper Xingù (6), the mounds in the Marajo islands, were far more reliable proxies than ‘modern indigenous communities’ and ‘old written reports’. More importantly, these discoveries suggested that Betty Meggers’ model was wrong. Archaeologists (actually, in most cases, North American Anthropologists) started speculating about the significance of these discoveries and how they challenged the theory of environmental determinism. Archaeological evidence showed that environmental constrains did not limited cultural evolution in Amazonia because human intelligence overcame them. People built highly productive raised fields that were able to produce tons of Maize per hectare on a continuous basis (without fallow periods); people transformed infertile oxisols in extremely rich terra preta allowing the production of food surpluses that permitted the rise of large and complex societies all over Amazonia. Pre-Columbian Amazonia was now seen by many as a “cultural parkland” (6) and an “anthropogenic cornucopia” (7). Pre-Columbians practiced agroforestry to such an extent that they contributed to the modern patterns of Amazonian biodiversity. Some geographers, paleoecologists and climatologists speculated about the large impact that pre-Columbians had on world climate: As Amazonia was densely populated, then it was also extensively de-forested. Following the discovery of the Americas in 1492, 95% of the original population died because of the spread of the diseases brought by the Europeans. The sharp decrease in population meant the abandonment of the agricultural fields and the re-growth of the rainforest. The forest absorbed huge amounts of CO2 from the atmosphere and, because of this, contributed to trigger the Little Ice Age…The latest paradigm shiftThe above reconstructions, although exciting, have been considered too extreme by some scholars, including myself (4,8); because there is insufficient paleoecological data or archaeological evidence to support them. The main problems with the reconstructions of pre-Columbian Amazonia as an “anthropogenic cornucopia” are related to the interpretation and significance of the proxies taken into account. Although it is a fact that there are thousand of hectares of raised fields in the Bolivian Amazon (the proxy) it is not clear how they were used and how productive they were (the interpretation). Moreover, there is no basis for assuming that similar levels of landscape modification took place elsewhere in Amazonia (the significance or scope). The same is true for other proxies. For instance, terra preta. On what basis do we interpret terra preta as an improved agricultural soil? We all agree that within the Amazon basin there is evidence of past complex society, but can we extrapolate from a few sites to the whole of Amazonia? Till now, the most important argument against the “anthropogenic cornucopia” theory has been the lack of data supporting it. As Betty Meggers said, it is all about wishful thinking. But, a few days ago, a new paper by McMichael et al. (2) added two new proxies to the debate: charcoal and phytoliths. They are actually not new at all, but, for the first time, extensive parts of the Amazonian rain forest have been sampled for the presence of these two proxies. Charcoal is a proxy for fire and phytolithsare a proxy similar to pollen, phytoliths tell us which kinds of plants were cultivated (if any). Both of them have local significance because you can find them only in the very place were the fire or the plants were. But, as McMichael et al. sampled many spots in the Amazon rain forest (247 soil cores collected from 55 locations) , their results are now of regional significance. This is the first time that we have a dataset obtained from the random sampling of an extensive part of Amazonia, rather than mere generalizations of data obtained from small and selected archaeological sites. Based on the analysis of charcoal and phytoliths, McMichael et al. concluded that most of Amazonia was “predominantly occupied by relatively small and shifting human populations during the pre-Columbian era”. This opens up a great and fascinating perspective for future studies. If, as Meggers said more than half a century ago, environment matters: what are the environmental opportunities that allowed the rise of complex societies in some sites such as the Llanos de Moxos in the Bolivian Amazon? ... Read more »
B. J. Meggers. (1954) Environmental Limitation on the Development of Culture. American Anthropologist. info:/
McMichael CH, Piperno DR, Bush MB, Silman MR, Zimmerman AR, Raczka MF, & Lobato LC. (2012) Sparse pre-Columbian human habitation in western Amazonia. Science (New York, N.Y.), 336(6087), 1429-31. PMID: 22700926
Heckenberger MJ, Kuikuro A, Kuikuro UT, Russell JC, Schmidt M, Fausto C, & Franchetto B. (2003) Amazonia 1492: pristine forest or cultural parkland?. Science (New York, N.Y.), 301(5640), 1710-4. PMID: 14500979
Homo sapiens arose in Africa 195,000 – 160,000 years ago, emerging from our archaic predecessors. Nowadays we’re an international species, with an outpost on every continent (and even one in space). How we changed from one state of affairs to the other is the subject of great debate, with many competing hypotheses attempting to explain … Continue reading »... Read more »
Robin Dennella, Michael D. Petragliab. (2012) The dispersal of Homo sapiens across southern Asia: how early, how often, how complex?. Quaternary Science Reviews, 15-22. DOI: 10.1016/j.quascirev.2012.05.002
In the year after Hurricane Katrina made a toilet bowl out of New Orleans, baby names starting with "K" went up by nine percent. Why would new parents want to commemorate the costliest natural disaster in American history? It wasn't their fault, researchers say: The sounds we hear most often stick with us, and we end up bestowing them on our children.
Jonah Berger, a professor of marketing at the University of Pennsylvania's Wharton School, led a study of baby name popularity that will be published in the journal Psychological Science. The researchers looked at the frequency of all first names between 1882 and 2006, a dataset that included more than seven thousand names and 280 million babies.
Each of those seven thousand names was broken into sound chunks called phonemes. For example, "Karen" became five phonemes: K, eh, r, ah, and n. The researchers then asked whether a name's popularity in any given year could be predicted by the popularity of its component phonemes in the previous year. In a year with a glut of Karens, were there extra K's, eh's, r's, and so on popping up in non-Karen names the year before?
Berger and his team found that names were more popular when the phonemes inside them had been more popular the year before. (They didn't count the name itself; Karens from 1999, for example, were removed from the analysis of Karens in 2000.) And the first phoneme—the sound that starts each name—had the most powerful effect. When considered individually, phonemes from the middle or end of a name weren't nearly as influential.
The sounds of the names people hear often, then, seem to sway them when naming their own children. But there are giant tangles of cultural factors determining what names and sounds people have recently heard. To look for a cleaner example of the phoneme effect, the researchers turned to hurricane names.
Hurricanes are named using a rotating alphabetical list that was created in the 1950s. (The list runs A through W, excluding Q and U, which is why you'll sadly never see a Hurricane Xerxes or Quentin. Names that land on especially destructive hurricanes are retired from the list afterward, like MVP jersey numbers.)
The researchers guessed that after a very bad hurricane, when people were inundated with news reports mentioning Andrew or Bob or Irene, there would be an increase in babies with similar names. And since hurricane names are predetermined, the effect would be separate from any already-existing cultural influences (princesses, actors, tennis players).
After collecting data on every hurricane between 1950 and 2009, Berger and his colleagues looked at how baby names that shared phonemes with a hurricane changed in the following year. They found that damaging hurricanes were followed by a clear uptick in similar names.
Names are more likely to be trendy, Berger writes, when names with similar sounds have recently been popular. The effect might not be limited to names; other research has hinted that we favorite-playing humans prefer towns and occupations that share our initials. It seems we just can't help growing fond of familiar sounds.
If you want to see how popular your own name has been over the decades, what this year's top ten boy and girl names are, or how name popularity varies by state, you can do so at the Social Security Administration's baby names site. You'll also find all of Irene and Andrew's relatives at the Weather Underground hurricane archive. You may discover that your parents were just following the trends—or the tropical storms.
Jonah Berger, Eric Bradlow, Alex Braunstein, & Yao Zhang (2012). From Karen to Katie: Using Baby Names to Understand Cultural Evolution Psychological Science
Image: Tommy Lew/Flickr
... Read more »
Jonah Berger, Eric Bradlow, Alex Braunstein, & Yao Zhang. (2012) From Karen to Katie: Using Baby Names to Understand Cultural Evolution. Psychological Science. info:/
Bonobos (Pan paniscus) are a species of chimp, closely related to their more common cousins, the “chimps” (Pan troglodytes*). The latter are the only species to be referred to as chimpanzees by the general public, despite the fact the term technically applies to the genus Pan and thus both “chimps” and bonobos. However, this taxonomical … Continue reading »... Read more »
Prüfer, K., Munch, K., Hellmann, I., Akagi, K., Miller, J., Walenz, B., Koren, S., Sutton, G., Kodira, C., Winer, R.... (2012) The bonobo genome compared with the chimpanzee and human genomes. Nature. DOI: 10.1038/nature11128
Currently I am in Rome doing an archaeological investigation of cremation remains. At this stage however, it means doing the internal excavation of cinerary urns. While I can’t discuss my own work too much at this stage (I’m doing pre-dissertation research and its all quite hush hush), I can discuss some of the issues and … Continue reading »... Read more »
McKinley, J. (1993) Bone fragment size and weights of bone from modern British cremations and the implications for the interpretation of archaeological cremations. International Journal of Osteoarchaeology, 3(4), 283-287. DOI: 10.1002/oa.1390030406
Jim Thomeson – who gets a brofist for being one of the most frequent commenter here – asks I wonder about handedness. i am right handed, and my right hand can do things for which my left hand has no clue. On the other hand, both hands attended typing class at the same time, and … Continue reading »... Read more »
Cashmore L, Uomini N, & Chapelain A. (2008) The evolution of handedness in humans and great apes: a review and current issues. Journal of anthropological sciences , 7-35. PMID: 19934467
Francks C, Maegawa S, Laurén J, Abrahams BS, Velayos-Baeza A, Medland SE, Colella S, Groszer M, McAuley EZ, Caffrey TM.... (2007) LRRTM1 on chromosome 2p12 is a maternally suppressed gene that is associated paternally with handedness and schizophrenia. Molecular psychiatry, 12(12), 1129. PMID: 17667961
Halpern DF, Haviland MG, & Killian CD. (1998) Handedness and sex differences in intelligence: evidence from the medical college admission test. Brain and cognition, 38(1), 87-101. PMID: 9735180
Hopkins, W. (1996) Chimpanzee handedness revisited: 55 years since Finch (1941). Psychonomic Bulletin , 3(4), 449-457. DOI: 10.3758/BF03214548
Keller JF, Croake JW, & Riesenman C. (1973) Relationships among handedness, intelligence, sex, and reading achievement of school age children. Perceptual and motor skills, 37(1), 159-62. PMID: 4727991
Perelle, I., & Ehrman, L. (1994) An international study of human handedness: The data. Behavior Genetics, 24(3), 217-227. DOI: 10.1007/BF01067189
Toth, N. (1985) Archaeological evidence for preferential right-handedness in the lower and middle pleistocene, and its possible implications. Journal of Human Evolution, 14(6), 607-614. DOI: 10.1016/S0047-2484(85)80087-7
The classic “ascent of man” image has our lineage progressing upwards. First we were knuckle-walkers, like modern chimps, but then switched to bipedalism. Over time we gradually became more and upright, straightening our backs and striding forwards as modern man. It’s a noble image of our origins and almost ubiquitous with the field of human … Continue reading »... Read more »
Lovejoy CO, & McCollum MA. (2010) Spinopelvic pathways to bipedality: why no hominids ever relied on a bent-hip-bent-knee gait. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 365(1556), 3289-99. PMID: 20855303
Lately, I’ve got colors on the brain. In part I of this post I talked about the common roads that different cultures travel down as they name the colors in their world. And I came across the idea that color names are, … Continue reading →... Read more »
Regier, T., & Kay, P. (2009) Language, thought, and color: Whorf was half right. Trends in Cognitive Sciences, 13(10), 439-446. DOI: 10.1016/j.tics.2009.07.001
Gilbert AL, Regier T, Kay P, & Ivry RB. (2006) Whorf hypothesis is supported in the right visual field but not the left. Proceedings of the National Academy of Sciences of the United States of America, 103(2), 489-94. PMID: 16387848
Franklin A, Drivonikou GV, Clifford A, Kay P, Regier T, & Davies IR. (2008) Lateralization of categorical perception of color changes with color term acquisition. Proceedings of the National Academy of Sciences of the United States of America, 105(47), 18221-5. PMID: 19015521
Mark Achtman who led the international team that assembled the phylogenetic tree for Yersinia pestis participated in a Royal Society meeting on ‘Immunity, infection, migration and human evolution’ in June 2011. Achtman’s contribution placed plague evolution within the context of other ‘monomorphic’ pathogens. Here are some of my notes from his published contribution: Monomorphic pathogens [...]... Read more »
Achtman, M. (2012) Insights from genomic comparisons of genetically monomorphic bacterial pathogens. Philosophical Transactions of the Royal Society B: Biological Sciences, 367(1590), 860-867. DOI: 10.1098/rstb.2011.0303
Morelli G, Song Y, Mazzoni CJ, Eppinger M, Roumagnac P, Wagner DM, Feldkamp M, Kusecek B, Vogler AJ, Li Y.... (2010) Yersinia pestis genome sequencing identifies patterns of global phylogenetic diversity. Nature genetics, 42(12), 1140-3. PMID: 21037571
Haensch S, Bianucci R, Signoli M, Rajerison M, Schultz M, Kacki S, Vermunt M, Weston DA, Hurst D, Achtman M.... (2010) Distinct clones of Yersinia pestis caused the black death. PLoS pathogens, 6(10). PMID: 20949072
Researchers have found sexual selection important in the evolutionary history of humans, and a lot of researchers are focusing on the roles of mate choice and life history in major transitions in human evolution. I find the transition from hunter-gatherer to agricultural civilization the most interesting. This week I’ve read three interesting papers on three interesting facets of human sexual selection. These studies also did things in three different ways: there is a study of psychological study of modern (i.e. living) human mating preferences, a study of pre-industrial humans using historical data and a theoretical study using mathematical and computer models.... Read more »
Zietsch BP, Verweij KJ, & Burri AV. (2012) Heritability of preferences for multiple cues of mate quality in humans. Evolution; international journal of organic evolution, 66(6), 1762-72. PMID: 22671545
Alexandre Courtiol,, Jenni E. Pettayd,, Markus Jokelae,, Anna Rotkirchf, and, & Virpi Lummaaa,b. (2012) Natural and sexual selection in a monogamous historical human population. PNAS. DOI: 10.1073/pnas.1118174109
Sergey Gavrilets. (2012) Human origins and the transition from promiscuity to pair-bonding. PNAS. DOI: 10.1073/pnas.1200717109
One hundred years ago today, one of the biggest volcanic eruptions in recorded history took place in southwestern Alaska. The volcano, known as Novarupta, is located in what is now Katmai National Park, which was established in 1918 as a direct result of the eruption and its effects on the landscape. As a result, this [...]... Read more »
I just returned from Holland, where I spent a lovely few days talking to all manner of experts on ancient Rome during the Moving Romans conference and thanatouring Leiden's excellent Museum Boerhaave and the Rijksmuseum van Oudheden.
My own contribution to the conference was called "Etched in Bone," and I both summarized some of my recent research on identifying immigrants to Rome (which I've previously blogged about here, here, here, and here - whew!) and expanded on that work by including some new data that, while not statistically significant, offer a look at variation within the immigrant population and let me generate new hypotheses about the lives of immigrants to Rome (hypotheses that, of course, need to be tested with more data!).
Surely the immigrant experience was not the same for everyone - after all, some immigrants were free, some were rural slaves, and some were domestic slaves. What do these preliminary data suggest?
The immigrant sample I'm working with has just 19 individuals. I'm the first to admit that that's a pretty small number and certainly can't be extrapolated to the whole of Rome or the whole of the Empire. But it would do a disservice to the study of immigrants not to explore trends and patterns, even in this small data set.
Out of the immigrants, there were 7 adult males, 3 adult females, and 9 subadults of indeterminate sex (that is, under about 16 years of age). First, this tells us that all sorts of people were immigrating to Rome, not just young men. This is the basic demographic chart, which interestingly enough shows a spike in the 11-15-year-old age range:
Demographics of Immigrants to Imperial Rome
Based on what we know about general subadult mortality in the Empire, kids in the age range of 0-5 have the highest likelihood of dying. So what's going on here? Well, what intrigues me is that I tested six individuals in the 11-15-year-old age range -- and all of them came back as non-local or immigrants. My working hypothesis is that the large spike indicates that the 11-15-year-old age range is the time that many immigrants were coming to Rome. We might expect a high mortality of new immigrants, those people who just completed a physically exhausting journey and have arrived at a city with a different disease ecology than their homeland. Additional data are needed, of course, to see if the pattern holds, but we could also test third molars, which form between the ages of 12-16, to better pinpoint the age at arrival of immigrants.
Lead Poisoning and Immigrants
Another way of looking at the variation within immigrants is through lead concentrations (data from Montgomery et al. 2010). Now, we didn't test everyone, so both the locals and the immigrants are seen in the chart below, with larger circles representing higher concentrations of lead in the first molar:
Lead Concentration in Locals and Immigrants to Imperial Rome
For reference, a lead concentration of 1 mg/kg is the current upper limit, per the World Health Organization and the Centers for Disease Control and Prevention, for kids (but there's talk of lowering the limit to 0.6 mg/kg), and a lead concentration of 10 mg/kg is the current level for "very severe lead poisoning." It's evident from the chart that only two people had lead concentrations lower than the modern recommendation.
We know, of course, about the increase in anthropogenic lead in the Empire. But what I'm seeing here is that locals (that is, people from Rome) were incorporating a relatively small but consistent level of lead in their bodies - a level higher than modern recommendations but much lower than severe lead poisoning. Two of the immigrants, though, have levels over this severe lead poisoning level - it's likely they were mentally handicapped or suffered from physical or behavioral challenges because of the high lead exposure they suffered as kids.
So my current, again preliminary, interpretation of these data is that since lead use was rampant in Rome, people living there were all likely to get at least a little lead exposure in their childhoods. But in other parts of the Empire, where the immigrants hailed from, there may have been pockets of industrial production such that some people got intense exposure to lead but others didn't. If it becomes possible to isolate the homelands of these immigrants, it may be possible to line up archaeological evidence of the lead industry with lead concentration in the skeletons.
Porotic Hyperostosis: Diet, Malaria, or Lead Poisoning?
I've blogged before about the relationship among carbon isotopes, oxygen isotopes, and porotic hyperostosis after hearing a talk about it by Bethany Turner (whose article just came out in AJPA early view). In short, Turner found in Peru that porotic hyperostosis - which is an indication of the non-specific condition anemia - was much more likely to be related to environment (i.e., a parasitic condition creating anemia) than to diet (i.e., iron-deficiency anemia from eating too much maize) by demonstrating that people with porotic hyperostosis had higher O values but similar C values than people without it.
What I found in the immigrant population from Imperial Rome is that all the immigrants with porotic hyperostosis were from areas with higher O values than Rome - that is, they were coming from warmer, drier climates, possibly from south of Rome in the peninsula of Italy or possibly even from northern Africa. Yet almost all of them have similar carbon values, suggesting they were eating largely the same diet as the people from Rome:
Immigrants to Rome compared via C and O isotopes and porotic hyperostosis
(NB: triangles indicate higher Pb concentration than modern recommendations;
star indicates higher Pb concentration than severe lead poisoning)
This suggests, then, that environment rather than diet may be the proximate cause of anemia in this immigrant sample. It makes some sense, since people coming from warmer, drier areas may have been more exposed to malaria or another parasitic condition than people living in or near Rome, which did have malaria but also had a very good, reliable aqueduct system.
Still, this is Rome we're talking about, so no explanation can be that simple. Another factor in porotic hyperostosis is lead poisoning, which can cause severe anemia. Again, not all of these people were tested for lead, but 4 of the 5 people with porotic hyperostosis also had lead levels over the modern recommendation. So, there's a strong correlation among high O values, high Pb values, and porotic hyperostosis in immigrants to Rome.
It's possible that both malaria and industrial pollution affected these immigrants' health, resulting in systemic anemia that showed up in their bones. But it definitely appears at the moment like environment was a much bigger factor in anemia among immigrants living in Rome than was their diet.
Future Prospects on Moving Romans
Lots more work needs to be done on skeletons from Rome. There are some intrepid bioarchaeologists out there starting to w... Read more »
Montgomery, J., Evans, J.A., Chenery, S.R., Pashley, V., & Killgrove, K. (2010) 'Gleaming, white and deadly' : using lead to track human exposure and geographic origins in the Roman period in Britain. Journal of Roman Archaeology, 199-226. info:/
Turner BL, & Armelagos GJ. (2012) Diet, residential origin, and pathology at Machu Picchu, Peru. American journal of physical anthropology. PMID: 22639369
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