Two articles published last month in the American Journal of Physical Anthropology are starting to greatly complicate bioarchaeologists' use and interpretation of stable oxygen isotope ratios in an attempt to understand migration and mobility in the past. Science is constantly progressing, and it can be challenging to keep up with the latest research. The real challenge for me, though, is in interpreting the isotope analyses I have done on populations from Imperial Rome - first because only one other oxygen isotope study has been done in the entire Italian peninsula, and second because the ancient Romans were quite unlike other archaeological populations in their mobility and importation of food and water. This post, then, works through some of the ideas I laid out in my dissertation and adds to them in light of recent articles on oxygen isotope analysis.
Oxygen Isotope Redux
Studying the relative amounts of stable oxygen isotopes in organic material seems to have begun with palaeoclimate studies, as oxygen isotopes are related to various climatological factors that affect the elemental composition of water. The relative amounts of oxygen isotopes of both meteoric (rain, snow) and environmental water (rivers, springs, lakes) vary by region in relation to factors such as temperature, humidity, distance from the coast, latitude, rainfall, and elevation. This means that different water sources in different areas have different ratios of stable oxygen isotopes.
Graph showing variations in oxygen and hydrogen isotopes
(credit: fig. 6 from the SAHRA website)
The mammalian body needs oxygen to survive - not just in the form of air (inspired oxygen) but also in the form of water and food. Researchers became interested in looking at the amount of oxygen trapped in mammalian tissue decades ago and began measuring the abundance of two different isotopes of oxygen: 18O and 16O. The ratio between these two measurements - written as δ18O ‰ (per mil) - results from fractionation of the two isotopes, which is caused by different metabolic processes.
Starting in the 1990s, though, bioarchaeologists began studying stable oxygen isotopes in order to investigate ancient migration. If the majority of the oxygen that a person ingested or inspired while his teeth were forming came from local water sources, the measured δ18O value from his hard tissue would be characteristic of the geographical peculiarities of that water, taking into account metabolic fractionation processes. It should be possible, then, to use δ18O numbers to identify individuals who accessed either local or nonlocal water sources and, by inference, locals and immigrants. In the early 2000s, oxygen isotope analysis became widely used in answering questions about past human mobility, including identifying immigrants and pinpointing their geographical homelands.
Problems with Finding Immigrants' Homelands
Within the past decade, though, researchers have learned much more about oxygen isotope ratios, including the metabolic processes that affect fractionation. In fact, two articles published online on May 3 by the American Journal of Physical Anthropology demonstrate just how complicated it can be to interpret oxygen isotope ratios from past human populations - a topic that I've been thinking about a lot lately as I try to publish my own oxygen data from Imperial Rome.
δ18Ow contour lines in Italy
(credit: Longinelli & Selmo 2003)
Pollard, Pellegrini, and Lee-Thorpe (in press) are the first to put into print the issues with assigning a geographical homeland to immigrants identified through oxygen isotope analysis in their paper, "Some observations on the conversion of dental enamel δ18Op values to δ18Ow to determine human mobility." In essence, those of us working with oxygen isotopes have been attempting to relate our human dental enamel oxygen measurements to measurements of oxygen from groundwater, using one or more linear regression equations. These equations helpfully give us numbers that seem to put our interpretations of homeland on solid footing. Pollard and colleagues, however, do the math and show that the magnitude of the error introduced with the regression equation(s) means our approximations of immigrants' homelands based on the oxygen isotope ratio of local groundwater are really quite poor. They suggest instead that oxygen ratios derived from human enamel be compared directly to other human enamel samples.
Sickle Cell Disease Affects Oxygen Isotopes
Reitsema and Crews (2011) throw another wrench into oxygen isotope analysis with their paper, "Oxygen isotopes as a biomarker for sickle-cell disease?" Oxygen isotope fractionation results from various metabolic processes, as I mentioned above. In humans, differing oxygen isotope ratios can result from smoking, exercise, and disease. For example, there is increased fractionation in smokers, due to the compromised ability to diffuse oxygen through the pulmonary membranes. Conversely, people who engage in routine exercise appear to have a decrease in fractionation because of the increased rate of respiration. It has also been established that oxygen isotope fractionation is lower in people suffering from anemia, as the binding of oxygen to hemoglobin is a fractioning process.
Because of these known fractionation effects, Reitsema and Crews hypothesized that the bone tissue of an organism with sickle-cell disease would have a different oxygen isotope ratio than a healthy organism. They studied bone apatite from 24 mice - 8 control and 16 transgenic mice with human ... Read more »
Bianucci, R., Mattutino, G., Lallo, R., Charlier, P., Jouin-Spriet, H., Peluso, A., Higham, T., Torre, C., & Rabino Massa, E. (2008) Immunological evidence of Plasmodium falciparum infection in an Egyptian child mummy from the Early Dynastic Period. Journal of Archaeological Science, 35(7), 1880-1885. DOI: 10.1016/j.jas.2007.11.019
Pollard AM, Pellegrini M, & Lee-Thorp JA. (2011) Technical note: Some observations on the conversion of dental enamel δ(18) o(p) values to δ(18) o(w) to determine human mobility. American journal of physical anthropology. PMID: 21541927
Prowse TL, Schwarcz HP, Garnsey P, Knyf M, Macchiarelli R, & Bondioli L. (2007) Isotopic evidence for age-related immigration to imperial Rome. American Journal of Physical Anthropology, 132(4), 510-9. PMID: 17205550
Reitsema LJ, & Crews DE. (2011) Brief communication: Oxygen isotopes as a biomarker for sickle-cell disease? Results from transgenic mice expressing human hemoglobin S genes. American journal of physical anthropology. PMID: 21541922
Recent excavations in a sewer at Herculaneum uncovered a massive deposit of, well, poop. What can feces tell us about the ancient Romans' diet, diseases, and medicine?... Read more »
S.C. Bisel. (1988) Nutrition in first-century Herculaneum. Anthropologie, 26(1), 61-66. info:/
Capasso L. (2002) Bacteria in two-millennia-old cheese, and related epizoonoses in Roman populations. The Journal of infection, 45(2), 122-7. PMID: 12217720
Capasso, L. (2007) Infectious diseases and eating habits at Herculaneum (1st century AD, southern Italy). International Journal of Osteoarchaeology, 17(4), 350-357. DOI: 10.1002/oa.906
By Greg Downey
As any fan of the adventures of Daredevil, being blind in comic books can give you superpowers. Matt Murdoch was blinded by a radioactive accident that he befell because he tried to save a blind pedestrian from the truck carrying the waste (ah, the irony…). Murdoch developed a kind of ‘radar’ sense that allowed him to prowl Hell’s Kitchen, rooting out the miscreants and lowlifes who, like the blind Man Without Fear, preferred to lurk in the dark.
Although his personal life proved that nice guys often finish, if not last, certainly with a heavy burden of angst and personal tragedy, Daredevil built upon the observation that deprivation of one sense can lead to heightened ability in others.
Although the Man without Fear may seem implausible, in fact, researchers have examined a number of deaf individuals who seem to develop extraordinarily acute echolocation, a kind of active sonar that they use by clicking to produce echoes from their surroundings. In a recent edition of PLoS ONE, Lore Thaler from the University of Western Ontario, with Stephen Arnott and Melvyn Goodale, report on brain imaging research that tries to sort out how individuals who can echolocate – who have what one blind activist calls ‘flash sonar’ – accomplish this perception neurologically. Do they use an especially acute sense of hearing, or do they develop another kind of sense, able to transform echoes into spatial perception?
What the researchers found, in short, is that blind individuals who could echolocate did not really have better ‘hearing’; on normal tests of hearing acuity, they scored the same as two sighted subjects who could not echolocate. However, when a recording had echoes, parts of the brain associated with visual perception in sighted individuals became extremely active, as the echolocators were able to extract information from the echoes that was seemingly not accessible to the control subjects who were sighted.
Although I want to review the results from the recent article, I’m actually interested more generally in several things I think we can learn from human echolocation:
Sensing is broader than perception; that is, our nervous system may react to many things that we are not consciously aware it is noting in any meaningful way. Sensation is ‘bigger than’ consciousness (and I realize I’m using those terms loosely.).
Human echolocation highlights, again, that the anthropology of the senses needs to realize that the theory of ‘five senses,’ an idea that we really get from Aristotle it seems to me (although I have no interest in digging any deeper into the intellectual history of the concept), is a bit of cultural common sense and not at all a scientific approach or reflection of verifiable psychological or phenomenological reality.
Human echolocation is a capacity of any human being, but the extraordinary skill shown by exemplary practitioners like Daniel Kish and Ben Underwood requires much more than just a human nervous system and the right training: the skill requires a community that ‘gets it’ and supports the capacity.
For me, echolocation is not simply an oddity or a quirky case for the vast human carnival. Rather, human echolocators tell us something fundamental about the brain’s extraordinary flexibility and power to squeeze perception out of a range of information streams, some of which are normally non-conscious to us. But plasticity follows very specific patterns which helps to explain why the Canadian researchers report in PLoS ONE that they found activity in certain parts of the visual cortex.
If you’re not already fascinated by echolocation, the following clips, I hope, will ignite some spark of ‘gee whiz-ism’ in even the most blasé reader.
In this first video clip, CBS covers the story of Ben Underwood, a young man who could do remarkable things with echolocation. Ben passed away in 2009 at the age of 16, when the cancer that had led to his blindness returned. I remember the first time I saw this video clip and, even though I was already aware of human echolocation, some of what this young man could accomplish simply blew me away. It’s one thing to hear about subjects’ accuracy locating a 25 cm target at 4 meters distance, another to watch a young man bean a reporter with a throw pillow across a living room. At some points, it’s simply hard to believe how acute Ben’s echolocation was, easy to wonder if the video is some kind of hoax.
The second clip is of researcher, activist, and echolocation teacher, Daniel Kish, who, in addition to having an extraordinary capacity to maneuver by echolocation, is also one of the subjects studied in the research reported in PLoS ONE. Kish was partially blind at birth, fully blind after 13 months-of-age when his eyes were removed due to retinoblastoma in both.
Because Kish is so remarkable and such an interesting advocate for encouraging the blind to live as independently as possible that I’ve included a number of links to his websites and stories about him at the end of this piece (such as a link to World Access for the Blind).
As the authors of the PLoS ONE article write, their blind subjects used echolocation constantly in daily life, to get around familiar places, to explore cities, hike outdoors, mountain bike, and even play basketball.
Senior author Mel Goodale, Canada Research Chair in Visual Neuroscience, and Director of the Centre for Brain and Mind, says, “It is clear echolocation enables blind people to do things otherwise thought to be impossible without vision and can provide blind and visually-impaired people with a high degree of independence.” (from Science Daily)
How do they do it?
One of the interesting wrinkles in the study of echolocation by the blind is that, until some path-breaking research in the 1940s, blind individuals and psychologists alike were not sure how the blind were able to get around as well as they did. Many blind people reported what psychologists came to call ‘facial vision,’ a sensation supposedly of pressure on the face that let them know that they were approaching an obstacle when waking.
Karl M. Dallenbach
Early experiments led by Karl Dallenbach (Cotzin and Dallenbach 1950; Supa et al. 1944; Worchel and Dallenbach 1947; click here for a black and white, silent video of their experiments) on ‘facial vision’ found that blind individuals could detect a board placed in their paths as they walked toward it, but that blindfolded individuals with normal sight quickly also started to detect the obstacle on repeated trials. By thirty trials, the blindfolded subjects were as accurate as the blind in walking up to an obstacle without touching it.
But the researchers also found that the channel for perception was not touch or a mysterious kind of facial ‘sight,’ but instead linked to the sound emanating from the subjects and reflecting off the target obstacles. When Dallenbach, Supa and colleagues put their subjects in socks on carpeted floors, or interfered with their hearing, ‘facial vision’ dropped off. The sound of hard-soled shoes on the floor was likely the source of their perception (see Stoffregen and Pittenger 1995 for an excellent review of early research on echolocation).
Stoffregen and Pittenger (1995: 209) point out that echolocation is a distinctive form of perception because the sense is a ‘closed-loop system,’ that is, ‘stimulus energy that is generated by the animal propagates into the environment, is structured by the environment, and returns to receptors.’ In other words, to echolocate people and other animals must produce as well as perceive sound. They are using active rather than passive sonar. By comparing the outgoing energy with the incoming reflection echolocators can perceive their environment (although there some echolocators evidently can also pull information from passively perceived echoes, that is, of sounds that they themselves do not create).
The active nature of this sense means that the perceiver can query the environment, as we see in the video clips, pushing out more sonic energy, clicking more frequently or l... Read more »
COTZIN M, & DALLENBACH KM. (1950) "Facial vision:" the role of pitch and loudness in the perception of obstacles by the blind. The American journal of psychology, 63(4), 485-515. PMID: 14790019
Kellogg, W. (1962) Sonar System of the Blind: New research measures their accuracy in detecting the texture, size, and distance of objects "by ear.". Science, 137(3528), 399-404. DOI: 10.1126/science.137.3528.399
Merabet, L., & Pascual-Leone, A. (2009) Neural reorganization following sensory loss: the opportunity of change. Nature Reviews Neuroscience, 11(1), 44-52. DOI: 10.1038/nrn2758
Rosenblum, L., Gordon, M., & Jarquin, L. (2000) Echolocating Distance by Moving and Stationary Listeners. Ecological Psychology, 12(3), 181-206. DOI: 10.1207/S15326969ECO1203_1
Schenkman, B., & Nilsson, M. (2010) Human echolocation: Blind and sighted persons’ ability to detect sounds recorded in the presence of a reflecting object. Perception, 39(4), 483-501. DOI: 10.1068/p6473
Stroffregen, T., & Pittenger, J. (1995) Human Echolocation as a Basic Form of Perception and Action. Ecological Psychology, 7(3), 181-216. DOI: 10.1207/s15326969eco0703_2
Thaler, L., Arnott, S., & Goodale, M. (2011) Neural Correlates of Natural Human Echolocation in Early and Late Blind Echolocation Experts. PLoS ONE, 6(5). DOI: 10.1371/journal.pone.0020162
WORCHEL P, & DALLENBACH KM. (1947) Facial vision; perception of obstacles by the deaf-blind. The American journal of psychology, 60(4), 502-53. PMID: 20273385
Many recent interpretations of Chaco Canyon see it as a site of pilgrimage, and this is often specifically seen as taking the form of regular region-wide ritual events involving communal feasting, construction work on the massive buildings in the canyon, trade involving various mundane and exotic items, and ritual breakage of pottery and deposition of [...]... Read more »
Wills, W. (2001) Ritual and Mound Formation during the Bonito Phase in Chaco Canyon. American Antiquity, 66(3), 433. DOI: 10.2307/2694243
Sci has to say she’d have LOVED to take the data for this study. Get to go to Spain, hang out, put some heart monitors on people and watch some fire walking…sounds like a good time. Much more glamorous than my own daily life in the lab. Can I get a little glamour around here? [...]... Read more »
Konvalinka, I., Xygalatas, D., Bulbulia, J., Schjodt, U., Jegindo, E., Wallot, S., Van Orden, G., & Roepstorff, A. (2011) Synchronized arousal between performers and related spectators in a fire-walking ritual. Proceedings of the National Academy of Sciences, 108(20), 8514-8519. DOI: 10.1073/pnas.1016955108
In July 1914 Earl Morris, the pioneering Southwestern archaeologist who would later become famous for his excavations at Aztec and other sites in the region, happened to visit one Eudoro Córdoba, who owned a farm on the Animas River a short distance upstream of the major ruins at Aztec. On his mantelpiece were various artifacts [...]... Read more »
Morris, E. (1915) The Excavation of a Ruin near Aztec, San Juan County, new Mexico. American Anthropologist, 17(4), 666-684. DOI: 10.1525/aa.1915.17.4.02a00040
The Journal of Archaeological Science has just published a new study on ADE. The study, of Birk et al. is entitled: “Faeces deposition on Amazonian Anthrosols as assessed from 5b-stanols”. I have just read it and this is my very first impression:The new data are extremely interesting. The authors look at the presence of coprostanol (a marker for faeces) in Amazonian Dark Earth (ADE). They have found a clear change in the index used to asses different sources of stanols, when comparing samples from the topmost 10 cm with samples coming from a depth of 30-40 cm. It seems that litter degradation is responsible for this change. Moreover, it also seems that the normal indexes used to assess the human origin of the stanols do not work very well in Amazonia. This paper is going to be a valuable reference to similar studies performed in Amazonia in the future. However, while Birk et al. correctly notice that one of the most debated topics about ADE is its origin, they do not do very much to assess why the faeces were there and what is their meaning from an archaeological point of view. ADE is found in two different forms, terra preta and terra mulata. Terra preta is darker, contains more organic matter, P and charcoal and also contains lots of fragments of ceramic. Terra mulata is like a light version of terra preta, it contains more nutrients and charcoal compared with “natural” soils from the surroundings, but less compared to terra preta. Moreover, in the terra mulata sites there is no pottery. Terra preta is found in small patches of about 1 hectare and terra mulata if found surrounding the terra preta sites. Terra mulata can cover as much as 200 hectares. An interpretation could be that terra preta resulted from settlements while terra mulata resulted from agriculture. If this thesis was correct, the high fertility of terra preta would be a side effect of human waste disposal and not the intentional result of land fertilization. In the case of terra mulata, if we assume it has been produced by agricultural use, fertilization must have been intentional. In this case, it would have been very important to see if there is any coprostanol in terra mulata! But the study did not look at terra mulata. Many scholars talk about ADE as synonymous of terra preta, without making a distinction with terra mulata, despite the fact that the differences between the two are key to understanding the past of Amazonia (estimating past population density, the region’s carrying capacity, the levels of social complexity achieved, pre-Columbian settlement patterns, the extent of the human impact on pre-Columbian forest etc.) Birk et al. only compared samples from 4 terra preta sites with samples from natural soils. I think they missed a great occasion. If they had also looked at 4 samples from terra mulata sites they might have been able to shed new light on the matter. Perhaps they did look at terra mulata and just decided to publish the results in a second paper…keeping us waiting GRRRR JJago Jonathan Birka, Wenceslau Geraldes Teixeirab, Eduardo Góes Neves, & Bruno Glaser (2011). Faeces deposition on Amazonian Anthrosols as assessed from 5β-stanols Journal of Archaeological Science, 38 (6), 1209-1220 : http://dx.doi.org/10.1016/j.jas.2010.12.015... Read more »
Jago Jonathan Birka, Wenceslau Geraldes Teixeirab, Eduardo Góes Nevesc, & Bruno Glaser. (2011) Faeces deposition on Amazonian Anthrosols as assessed from 5β-stanols. Journal of Archaeological Science, 38(6), 1209-1220. info:/doi.org/10.1016/j.jas.2010.12.015
On June 7th, 2011, one of the world's pioneering primatologists, Toshisada Nishida, passed away at age 70. A look back at his career and his accomplishments.... Read more »
NISHIDA, T. (1973) The ant-gathering behaviour by the use of tools among wild chimpanzees of the Mahali Mountains. Journal of Human Evolution, 2(5), 357-370. DOI: 10.1016/0047-2484(73)90016-X
Nishida, T. (1976) The Bark-Eating Habits in Primates, with Special Reference to Their Status in the Diet of Wild Chimpanzees. Folia Primatologica, 25(4), 277-287. DOI: 10.1159/000155720
Kristina Killgrove has an interesting post on the numerous broken Cycladic figurines on the Greek island of Keros that have been documented over the past few years by the prominent British archaeologist Colin Renfrew. Renfrew’s interpretation seems to be that these figurines were deliberately broken in various Cycladic communities, then deliberately brought to Keros to [...]... Read more »
Renfrew, C. (2001) Production and Consumption in a Sacred Economy: The Material Correlates of High Devotional Expression at Chaco Canyon. American Antiquity, 66(1), 14. DOI: 10.2307/2694314
On the six-square-mile island of Keros, a part of the Cycladic island chain of the Aegean Sea, thousands of broken sculptures and pottery dating to about 2,500 BC have been discovered since archaeologist Colin Renfrew started excavating there in the 1960s. The caches of broken figurines are especially interesting, as archaeologists have been unable to find joins - pieces that fit together:
2500-year-old Broken Cycladic Figurines from Keros
(credit: Cambridge University via The Guardian)
The latest theory, outlined quite well by The Guardian today and further detailed in the Cambridge press release, is that, "the breaking of statues and other goods was a ritual and that Keros was chosen as a sanctuary to preserve the effects." Based on the discovery of a "guest house" made of imported marble, Renfrew thinks that people made specific pilgrimages to the otherwise uninhabited island of Keros to deposit or bury broken fragments of figurines and other goods. (Insert your own "Island of Misfit Toys" reference here.) This practice lasted for several centuries, until about 2000 BC.
I've always had a soft spot for Cycladic figurines - for their clean lines and serene, almost corpse-like poses. As an undergrad, I wrote a particularly terrible paper for my Prehistoric Art class comparing Cycladic figurines and the Venus of Willendorf, but that naive attempt to engage in cross-cultural comparison helped me realize I was meant to be an anthropologist rather than a classicist.
One of the few mementos I have of my summer excavating on Crete in 2003 is a Cycladic figurine magnet that lives on my fridge. Just this morning, before I saw the Renfrew story, my 2-year-old daughter took great interest in it, and we had the following conversation:
Chickpea: "What's that?"
Me: "That's a Cycladic figurine magnet. Can you say 'Cycladic figurine'?"
Chickpea: "'at's an old man."
Me: "So true."
We headed out on a shopping trip, and Chickpea insisted on taking her new friend the Cycladic figurine with her in the car. He made it to Target and the mall, but by the time we got home, he'd slipped between her carseat and the car door, and he met an unfortunate demise:
My poor fridge magnet
Looks like I may need to book a trip to Greece - and a lovely Aegean cruise - to bury him at Keros.
G. Papamichelakis, & C. Renfrew (2010). Hearsay about the "Keros Hoard" American Journal of Archaeology, 114 (1), 181-185 : http://www.atypon-link.com/AIA/doi/abs/10.3764/aja.114.1.181
A. Selkirk (2011). Keros: Sanctuary of the Cycladic Figurines Current World Archaeology, 26 : http://www.world-archaeology.com/features/keros-sanctuary-of-the-cycladic-figurines/... Read more »
G. Papamichelakis, & C. Renfrew. (2010) Hearsay about the "Keros Hoard". American Journal of Archaeology, 114(1), 181-185. info:/http://www.atypon-link.com/AIA/doi/abs/10.3764/aja.114.1.181
A. Selkirk. (2011) Keros: Sanctuary of the Cycladic Figurines. Current World Archaeology. info:/http://www.world-archaeology.com/features/keros-sanctuary-of-the-cycladic-figurines/
By most accounts, Anthony Weiner thinks highly of himself. Filled with bravado, Weiner considers himself to be a political warrior. Regaling one 17 year old girl with stories about congressional battles, he likened himself to Superman: “I came back strong. Large. In charge. Tights and cape shit.” Weiner even took cape-less photos of his pecs [...]... Read more »
Moore, J. (1990) The Reproductive Success of Cheyenne War Chiefs: A Contrary Case to Chagnon's Yanomamo. Current Anthropology, 31(3), 322. DOI: 10.1086/203846
There’s a persistent archaeological meme about there being a “lack of burials” at Chaco Canyon. The idea is that not nearly enough burials have been found there to account for the size and magnificence of the architecture, so something odd is going on. This has been interpreted in various ways and used as support for [...]... Read more »
Marden, K., & Ortner, D. (2011) A case of treponematosis from pre-Columbian Chaco Canyon, New Mexico. International Journal of Osteoarchaeology, 21(1), 19-31. DOI: 10.1002/oa.1103
A few months ago, the news media carried a story about "Bones of Leper Warrior found in Medieval Cemetery" in central Italy. The publication by Mauro Rubini and Paola Zaio was in early view at the time and was just published in the July issue of the Journal of Archaeological Science (see citation below). I noticed that Katy Meyers blogged about it today over at Bones Don't Lie, but I'm afraid I can't be as charitable as she is in pointing out the flaws.
8th c Avar Warrior
(credit: Wikimedia commons)
Rubini and Zaio studied skeletons from 234 graves in an early Medieval (6th-8th century) cemetery in Molise (south-central Italy). Based on grave goods, they suggest that the people buried in the cemetery were of different ethnic backgrounds - the Eurasian Avars, Lombards, and indigenous Italians - and were semi-nomadic. Three of the skeletons appear to have warfare-related wounds, and one of the three also suffered from leprosy in life. The authors therefore conclude that the three were "warriors from the East." The finding of a "leper warrior" is actually quite interesting, and I'll return to this at the end. But there is one very problematic feature of this article that quite frankly surprised me, considering the high profile of the journal and the research caliber of the first author.
The authors offer no evidence to back up their claim that the cemetery was the burial place of people of different geographical origins, aside from the off-hand statement that "the multicultural context of the necropolis is shown by the presence of Lombard, indigenous, and Asian grave goods" (p. 1552). Sure, different populations may have different artifacts, but the presence of, say, "typical Avar stirrups" does not prove an individual's ethnicity or background, nor does the similarity of the graves to "Pazyryk burials in the placement of the horse, body and grave goods" (ibid.). As every bioarchaeology student knows from reading The Archaeology of Death and Burial (Parker Pearson 1999), a grave and its associated goods is much more likely to represent the values and mores of the group burying a person than of the person himself. It's rather curious that Rubino and Zaio include a lengthy explanation of the fact that the Avars were not a distinct ethnic population but rather were "a heterogeneous, multi-ethnic population [... and] a union of multiple cultural patterns" (p. 1551) immediately before talking about the distinct "Asian" (whatever that means) presence in the Campochiaro cemetery.
Especially problematic is Rubini and Zaio's claim that the Lombard/Avar/indigenous classification is "supported also by the preliminary anthropological study of the skeletal sample" (p. 1552). The study is not specified here, but in the authors' later description of the three graves of interest, the questionable analysis becomes clear (pp. 1554-6):
Grave n. 20 (see Fig. 3) Individual of male sex, with age at death over 55 years. Height was estimated at about 161.5 cm. The skull shows, according to the suggestions of Corrain (2002), characteristics of Mongolic type: dolicomorphous with a superior profile of ovoid shape, flat face and large, low orbit. [...] Grave n. 102 (Fig. 5) Individual of male sex, with age at death 50-55 years. Height was estimated at about 169.7 cm. According to the suggestions of Corrain (2002), the skull shows characteristics of the Dinarico-Adriatic type: brachimorphous with superior profile of ovoid shape and narrow frontal.
[...] Grave n. 108 (Fig. 7) Individual of male sex, with age at death over 50 years. Height was estimated at about 161.1 cm. The skull shows a mesomorphous shape with a long and narrow face.Just as biological anthropology in the U.S. in the 19th century was influenced by Samuel Morton's racist ideology in the construction of biological "types" and "races" (q.v. yesterday's post), biological anthropology in 19th century Italy was influenced by Cesare Lombroso's theory of atavism and "born criminals." Morton interpreted his data on skull shape to fit his preconceived notions of race, and Lombroso did the same to fit ideas of "criminals," who all too often included the economically disadvantaged south Italians (Killgrove 2005).
Within biological anthropology in the U.S., we have worked hard to move on from Samuel Morton, Carleton Coon, and the use of the cephalic index in general. So it always disheartens me when clearly archaic terminology is used to discuss skeletons. Mongolic and Dinarico-Adriatic types? Dolico-, brachi- and mesomorphous? These terms have no place in today's biological anthropology, which is focused on understanding the diversity of the human population, both modern and ancient. Skulls are not pots - we can't create a typology of cranial features and expect to be able to pick someone's head out of a lineup. When we do this, we inevitably learn by using alternate methods that inter-population variation is low and gene flow was considerable (e.g., Killgrove 2009). Classifications such as Dinarico-Adriatic are based on Coon's The Races of Europe (1939), and we've pretty clearly posthumously castigated Coon for advancing segregation in the U.S. in spite of the lack of scientific data to support clear "racial" differences.
There's absolutely no evidence within the Rubini and Zaio article that the three individuals of interest were from another geographic area - skull morphology doesn't cut it, and "ethnic" artifacts in the grave don't convince me either. Were these "warriors from the East" as the article title implies? Maybe. But I'll need to see some aDNA or isotope data to consider the claim to be plausible.
Skull of the Leper Warrior
(credit: Rubini and Zaio, fig. 8a)
What is interesting about the article - and, I assume, the reason that JAS published it - is the authors' finding that a man over the age of 50 who was afflicted with leprosy likely engaged in warfare. It shouldn't be revelatory that lepers in the past went to war, just as it shouldn't be revelatory that women in the past were active agents in war. But considering the dearth of evidence we have for this kind of behavior in antiquity (and our own preconceived contemporary Western notions of alpha male warriors as different from frail, sickly lepers and powerless, weak women), the discovery of a warrior with leprosy is quite cool.
While I don't want to take away from Rubini and Zaio's fascinating discovery of the leper warrior, I do want to point out their employment of problematic and archaic terminology in discussing skeletal remains. It surprises me that in the 21st century, anthropologists are still using these racially-tinged terms, and it surprises me even more that reviewers for the top-tier journal JAS would let the authors claim they'd found "Eastern" people with no real evidence of it.
... Read more »
M. Rubini, & P. Zaio. (2011) Warriors from the East. Skeletal evidence of warfare from a Lombard-Avar cemetery in central Italy (Campochiaro, Molise, 6th-8th century AD). Journal of Archaeological Science, 38(7), 1551-1559. info:/http://dx.doi.org/10.1016/j.jas.2011.02.020
K. Killgrove. (2009) Rethinking taxonomies: skeletal variation on the North Carolina coastal plain. Southeastern Archaeology, 28(1), 87-100. info:other/
Stephen Jay Gould famously argued in his best-known work, The Mismeasure of Man, that Samuel Morton unconsciously manipulated his data on cranial capacity in different populations to fit his own preconceived, racist notions about human variation. Gould undertook a reanalysis of Morton's data and leveled a variety of accusations against Morton: he incorrectly measured skulls, made mathematical errors, picked and chose his sample populations, and didn't report all of the data he collected. I would be surprised if any biological anthropologist did not have to read The Mismeasure of Man in a college or graduate course somewhere along the line. I've even assigned chapters from it when teaching my own classes as well. The Gould vs. Morton case is often used to illustrate that scientists are humans and humans can be biased.
Yesterday, an article by Jason Lewis and colleagues came out in PLoS Biology contradicting Gould's conclusions about Morton: "The Mismeasure of Science: Stephen Jay Gould versus Samuel George Morton on Skulls and Bias". The authors remeasured Morton's skulls and reanalyzed both Morton's and Gould's data and have concluded that Gould's claims about Morton's bias are either poorly supported or falsified. It's a fascinating read, particularly the powerful last paragraphs:
[...] Our results falsify Gould's hypothesis that Morton manipulated his data to conform with his a priori views. The data on cranial capacity gathered by Morton are generally reliable, and he reported them fully. Overall, we find that Morton's initial reputation as the objectivist of his era was well-deserved. That Morton's data are reliable despite his clear bias weakens the argument of Gould and others that biased results are endemic in science. Gould was certainly correct to note that scientists are human beings and, as such, are inevitably biased, a point frequently made in “science studies.” But the power of the scientific approach is that a properly designed and executed methodology can largely shield the outcome from the influence of the investigator's bias. Science does not rely on investigators being unbiased “automatons.” Instead, it relies on methods that limit the ability of the investigator's admittedly inevitable biases to skew the results. Morton's methods were sound, and our analysis shows that they prevented Morton's biases from significantly impacting his results. The Morton case, rather than illustrating the ubiquity of bias, instead shows the ability of science to escape the bounds and blinders of cultural contexts.Morton's study of skulls published in Crania Americana seems to have been grounded in good science after all. His interpretation of the differences he saw, however, was not. We know now - thanks in large part to Franz Boas, the father of American anthropology - that environment most directly influences the size and shape of one's skull, not one's "race" or ethnic background. The study by Lewis and colleagues, though, shows that Gould's interpretations may have been as clouded as Morton's, and it seems that Gould may have set up a straw man in Morton, attacking his science rather than his interpretations.
Anyone out there who's read The Mismeasure of Man should read the eye-opening PLoS article. (And John Hawks' post on the topic here.) It might change the way you think about bias in scientific studies.
J.E. Lewis, D. DeGusta, M.R. Meyer, J.M. Monge, A.E. Mann, & R.L. Holloway (2011). The Mismeasure of Science: Stephen Jay Gould versus Samuel George Morton on Skulls and Bias PLoS Biology, 9 (6) : 10.1371/journal.pbio.1001071... Read more »
J.E. Lewis, D. DeGusta, M.R. Meyer, J.M. Monge, A.E. Mann, & R.L. Holloway. (2011) The Mismeasure of Science: Stephen Jay Gould versus Samuel George Morton on Skulls and Bias. PLoS Biology, 9(6). info:/10.1371/journal.pbio.1001071
In 1977, Stephen King published his short story “Children of the Corn” in Penthouse. Seven years later, movie audiences across the nation were horrified by the ritual doings of small town Nebraska kids who worshiped something malevolent in the corn.
It surely was no coincidence that later in the year, Nebraska experienced a sharp drop in [...]... Read more »
Atkinson, Quentin D., & Whitehouse, Harvey. (2011) The Cultural Morphospace of Ritual Form: Examining Modes of Religiosity Cross-Culturally. Evolution and Human Behavior, 32(1), 50-62. DOI: 10.1016/j.evolhumbehav.2010.09.002
One of my favorite paleoanthropological sites is Dmanisi, in the Republic of Georgia. It is the oldest securely dated hominid site outside Africa (just under 1.85 million years ago), and the hominids found there display a neat mix of primitive Homo habilis and derived H. erectus features. I consider myself lucky to have had the opportunity to excavate at Dmanisi last year, and to return to Georgia (lamazi Sakartvelo! [I hope I translated that correctly]) for more fieldwork next month.
Recently, Reid Ferring and others (2011) described the results of excavations of M5, a section of the site a bit aways from the area where the hominids were found. M5 is pretty cool because it presents a nice geological "layer cake," as Ferring described it to us: each of the strata (different layers of deposition) are nicely and evenly stacked on one another. Check out the labeled layers on the right of the figure, from Ferring et al. 2011:This is in stark contrast to the jumbled strata (like 'spaghetti') where the hominids were found. In geology and archaeology, there is a general "law of superposition," which states that the lowest layers in a sequence would have been deposited earlier than the layers above them. The A sediments at Dmanisi, as seen in the figure above, are thus older than the Bs. Hominids have only been found in the B sediments. But work at M5 has shown that stone tools are found in the older A sediments, meaning that hominids arrived at the site and used it continually, beginning just after 1.85 million years ago.
Tools from the site differ between the older A and slightly later (still older than 1.75 million years!) B sediments in both material and manufacture. As they say in the paper (p. 2/5), a major difference in tool manufacture between the strata A and B occupations could be that during the earlier A times, "either cores were more intensively reduced or selected flakes were made elsewhere and carried to the site." I'm not sure why this may be, but it is neat that within a fairly narrow time span, researchers can see habits change in our early ancestors.
The authors also note that the older tools from A sediments indicate "that Eurasia was probably occupied before Homo erectus appears in the East African fossil record" (from the paper's abstract). If only hominids also came out of the A sediments! The News is touting this as meaning H. erectus evolved in Eurasia and then some members of the 'new species' moved back into Africa, but I don't think this is necessarily the case. The Dmanisi hominids are described as H. erectus, but lack some key H. erectus apomorphies (most notably a large brain size) and really look pretty similar to contemporary hominids in Kenya (such as KNM-ER 3733) and Tanzania (such as OH 16). Plus, the E. African hominid fossil record around 1.9 million years ago leaves some tantalizing hints at hominids more erectus-like than habilis-like, such as the ER 2598 occipital fragment.
So while Dmanisi definitely demonstrates the presence of hominids outside Africa earlier than most well-accepted "Homo erectus" (or "ergaster") fossils in E. Africa, I don't think they necessarily indicate that the species arose in Eurasia. Rather, what the fossil record likely shows is the evolution of populations of early Homo, in Africa and Eurasia, toward the more 'advanced' H. erectus we know and love (due to gene flow w/in a widespread species, rather than parallel evolution of similar traits in different species).
ReferenceFerring R, Oms O, Agustí J, Berna F, Nioradze M, Shelia T, Tappen M, Vekua A, Zhvania D, & Lordkipanidze D (2011). Earliest human occupations at Dmanisi (Georgian Caucasus) dated to 1.85-1.78 Ma. Proceedings of the National Academy of Sciences of the United States of America PMID: 21646521... Read more »
Ferring R, Oms O, Agustí J, Berna F, Nioradze M, Shelia T, Tappen M, Vekua A, Zhvania D, & Lordkipanidze D. (2011) Earliest human occupations at Dmanisi (Georgian Caucasus) dated to 1.85-1.78 Ma. Proceedings of the National Academy of Sciences of the United States of America. PMID: 21646521
Does anthropological evidence support the idea of a universal moral grammar?... Read more »
Saba Mahmood. (2001) Feminist Theory, Embodiment, and the Docile Agent: Some Reflections on the Egyptian Islamic Revival. Cultural Anthropology, 16(2), 202-236. DOI: 10.1525/can.2001.16.2.202
We've all been there—the "Oh, [expletive]" moment. Perhaps the door just shut and your keys are still sitting on the counter. Or you get to the subway/bus stop just as your mass transit mode of choice is pulling away. Perhaps you've left your wallet at home, and there are blue lights flashing in your rear view mirror. Or maybe your expletive moment is a bit darker: a broken promise, a hurt friend, or a damaged relationship through some fault of your own. After all, regret is all about you and what you could have done differently. It can certainly vary in intensity, but we've all been there a time or two. Regret is a hard emotion to avoid. It is a curious emotion—a mixture of disappointment, shame, sadness, and self blame, and it can be both a hindrance and provide a much needed push in the face of opportunity. Does the experience of regret serve a purpose? Is it a necessary element of sociality?
One researcher suggests that there are two main forms of regret (1). The first is a "hot emotion" that carries a blow. For example, it's what you feel when you suffer a loss because you didn't follow instructions or seek guidance. It's the punch to the diaphragm as you think about the things you could have done differently, or that sinking feeling of despair as you're confronted with disappointment. The second is a form of wistful thinking. "If only" fills this category: If only I had taken the time to check where my keys were or if only I had walked away from that argument. Common to both forms is a sense that something could have been done differently. That is the nature of regret: the belief that a negative outcome is the result of one's own actions, and could have been avoided if one had taken an alternative path (2, 3).
The role of regret in decision-making is twofold. On one hand, it can be limiting. We tend to overgeneralize negative results, and so it may be that one poor choice can prevent you from taking any action that remotely resembles the regrettable course (4). For example, you may refrain from giving advice if your suggestion doesn't go as planned. Or you may stop purchasing a particular brand if you have problems with one of their products. Or you may avoid a particular topic if others seemed to have responded poorly to those ideas in the past. In this context, regret can easily become consuming. That is, the individual can be so focused on what he did wrong and what he would do differently, that it immobilizes him, rendering him incapable of accepting and resolving the situation. On the other hand, it can make us more attuned to missed opportunities. For example, if you paid more for something because the sale expired as you waited to see if the price would drop further, you may be less inclined to wait going forward. Or if you realize that you should have spoken up to prevent a friend from being hurt, you may decide to speak up sooner if it means saving a friendship.
Regret seems to operate as a social gauge. It may serve as a flag that a transgression has occurred that would not be acceptable on a continued basis. If this is indeed the case, then it may be possible to conceive of regret as a form of social apology, particularly if the regret is public—that is, if the regret is the result of an act that makes you look badly or lose status or standing, then regret may be a form of "remedial self-preservation" (5). In accepting blame for the event, the actor vilifies himself:Apologies split the self into two parts, a "bad" self that is vilified for the incident and a "good" self that proclaims a recognition of the misconduct and extends a promise (often implicit) of more acceptable behavior in the future (6).In this regard, regret is a personal assessment of perceived external judgment. It cannot be assigned, like blame. Regret is something we take upon ourselves. And the human tendency is to assume the worst: "People routinely overestimate the emotional impact of negative events ranging from professional failures and romantic breakups to electoral losses, sports defeats, and medical setbacks" (7). So we ultimately determine what to regret and what not to regret. If regret is consuming, is it because we allow it to be so?
Perhaps then regret stems from a conflict between this assessment and the true desires of the individual. It is possible to want something that society tells you is inappropriate—of course, we've moved beyond the regret of forgotten keys at this point, but regret truly does seem to exist on a sliding scale. More than just wistful thinking, which is a past-oriented perspective, regret may very much be rooted in the present in a sense of futility—firmly ensconced in the inability to pursue that which you desire most for whatever reason.
What are your thoughts on this emotion? Is it better to take a chance and pursue what you desire? Or should we wrestle with regret?
Cited:Gilbert DT, Morewedge CK, Risen JL, & Wilson TD (2004). Looking Forward to Looking Backward: The Misprediction of Regret. Psychological science, 15 (5), 346-50 PMID: 15102146
John Sabini and Maury Silver (2005). Why Emotion Names and Experiences Don't Neatly Pair Psychological Inquiry, 16 (1), 1-10
Schlenker, Barry, & Darby, Bruce (1981). The Use of Apologies in Social Predicaments. Social Psychology Quarterly, 44 (3), 271-278 DOI: 10.2307/3033840
Notes:1. Sabini and Silver (2005): 9. 2. Gilbert et. al. (2004): 346.3. Sabini: 7.4. Gilbert: 346. 5. Schlenker and Darby 1981: 271. 6. Schlenker and Darby: 272.7. Gilbert: 346.
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Gilbert DT, Morewedge CK, Risen JL, & Wilson TD. (2004) Looking Forward to Looking Backward: The Misprediction of Regret. Psychological science, 15(5), 346-50. PMID: 15102146
John Sabini and Maury Silver. (2005) Why Emotion Names and Experiences Don't Neatly Pair. Psychological Inquiry, 16(1), 1-10. info:/
There's a widespread belief that mental illness is getting more common, or that it has got more common in recent years.A new study in the British Journal of Psychiatry says: no, it's not. They looked at the UK APMS mental health surveys, which were done in 1993, 2000 and 2007. Long-time readers will remember these.The authors of the new paper analyzed the data by birth cohort, i.e. when you were born, and by age at the time of the survey. If mental illness were rising, you'd predict that people born more recently would have higher rates of mental illness at any given age.The headline finding: there was no cohort effect, implying that rates of mental illness aren't changing. There was a strong age effect: in men, rates peak at about age 50; in women the data is rather messy but in general the rate is flat up to age 50 and then it falls off, like in men. But there's no evidence that those born recently are at higher risk.The only exception was that men born after 1950 were at somewhat higher risk than those born earlier as shown by the "break" on the graph above. The effect for women was smaller. The most recent cohort, those born after 1985, were also above the curve but there was only one datapoint there, so it's hard to interpret.We also get a rather cute graph showing how life changes with age:As you get older, you get less irritable and, if you're a woman, you'll worry less. But sleep problems and, in men, fatigue, increase. Overall, 50 is the worst age in terms of total symptoms. After that, it gets better. Well, that's nice to know. Or not, depending on your age.Overall, the authors say:Our finding of subsequently stable rates contradicts popular media stories of a relentlessly rising tide of mental illness, at least for men. Stable prevalence in the male population, together with peaking of the prevalence of common mental disorder at about age 50 years, indicates that a large increase in projected rates of poor mental health is unlikely in the male population in the near future....Trends in women are less clearly identified, with considerable increases in the prevalence of sleep problems, but no clear increase or even some decrease in other measures. Further research is needed to relate these age and cohort differences to drivers of mental health such as employment status and family composition.Caution's warranted, though, because the APMS data were based on self-reported symptoms of mental illness assessed by lay interviewers. As I've argued before, self-report is problematic, but this is true of almost all of these kinds of studies.More unusual is that this study didn't attempt to assign formal diagnoses, it just looked at total symptoms on the CIS Scale; a total of 12 or more was considered to indicate "probable disorder".Purists would say that this is a weakness and that you ought to be making full DSM-IV diagnoses, but honestly, it's got its own problems, and I think this is no worse.Finally, this study only looked at "common mental disorders" i.e. depression and various kinds of anxiety symptoms. Things like schizophrenia and bipolar disorder weren't included, but from what I remember they're not rising either.Spiers N, Bebbington P, McManus S, Brugha TS, Jenkins R, & Meltzer H (2011). Age and birth cohort differences in the prevalence of common mental disorder in England: National Psychiatric Morbidity Surveys 1993-2007. The British journal of psychiatry : the journal of mental science, 198, 479-84 PMID: 21628710... Read more »
Spiers N, Bebbington P, McManus S, Brugha TS, Jenkins R, & Meltzer H. (2011) Age and birth cohort differences in the prevalence of common mental disorder in England: National Psychiatric Morbidity Surveys 1993-2007. The British journal of psychiatry : the journal of mental science, 479-84. PMID: 21628710
Actually, Papa Bear, humans are a bit similar to trees.... Read more »
E. Kerley. (1965) The microscopic determination of age in human bone. American Journal of Physical Anthropology, 23(2), 149-163. DOI: 10.1002/ajpa.1330230215
Kerley ER, & Ubelaker DH. (1978) Revisions in the microscopic method of estimating age at death in human cortical bone. American journal of physical anthropology, 49(4), 545-6. PMID: 216268
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