Williams, Richard Kay, Christopher Kirk and Callum Ross have published a new paper in the Journal of Human Evolution reassessing the phylogenetic placement of Darwinius masillae, the much-hyped Adapid fossil published last summer. Brian Switek at Laelaps and Eric Michael Johnson at The Primate Diaries have written some excellent posts summarizing the most recent [...]... Read more »
Williams, B., Kay, R., Christopher Kirk, E., & Ross, C. (2010) Darwinius masillae is a strepsirrhine—a reply to Franzen et al. (2009). Journal of Human Evolution. DOI: 10.1016/j.jhevol.2010.01.003
Franzen, J., Gingerich, P., Habersetzer, J., Hurum, J., von Koenigswald, W., & Smith, B. (2009) Complete Primate Skeleton from the Middle Eocene of Messel in Germany: Morphology and Paleobiology. PLoS ONE, 4(5). DOI: 10.1371/journal.pone.0005723
Artist rendering of Darwinius. Image: Julius T. CsotonyiLast year's publication of the fossil primate Darwinius masillae claimed it to be the oldest haplorhine primate ever discovered and a multimedia blitz campaign touted the find as the ultimate "missing link" (an erroneous term that should forthwith be forbidden to all science journalists). Brian Switek at Laelaps (who has an excellent review of this paper) made headlines for challenging the way that this fossil primate was rushed to market, and it seems that his concerns were more than justified.
According to Brian's Op-Ed in the Times of London:
Over the past two years they have worked with Atlantic Productions to launch a media blitz heralding Ida as one of our early relatives. With a scientific description in the journal PLoS One, a book, two documentaries, a website and even a Twitter feed prepared beforehand, Ida burst onto the scene as the "holy grail" of evolution, the "ancestor of us all".
Ida is undoubtedly a spectacular fossil. A nearly complete fossil primate, with a body outline and stomach contents, she is the sort of discovery palaeontologists dream about. It may come as a surprise, then, that Ida does not change everything we thought we knew about human evolution. Indeed, she may tell us more about the origins of lemurs than our own species.
Now, researchers at Duke University, University of Texas at Austin, and the University of Chicago have demonstrated that Ida is in fact more similar to other fossil strepsirrhines, the primate group that includes lemurs and lorises. Read the rest of this post... | Read the comments on this post...... Read more »
The exceptionally preserved skeleton of Darwinius, known popularly as "Ida." From PLoS One.
Almost ten months ago an international team of researchers introduced the world to an exquisitely-preserved primate from the 47 million year old oil shales of Messel, Germany. Dubbed Darwinius masillae, and nicknamed "Ida" and "The Link", the fossil was touted as one of our earliest primate ancestors in a massive media campaign worthy of a Hollywood blockbuster. Yet the trouble was that there was no solid evidence that Darwinius was one of our ancestors. Despite the marketing blitz promoting the fossil the team of scientists who described it did not provide sufficient evidence that the lemur-like primate was anywhere close to our ancestry, and it would take the description of a related fossil primate several months later to put "Ida" in her place. Darwinius was not one of our ancient progenitors, as had been proclaimed, but instead belonged to an extinct branch of early primates which were more closely related to living lemurs and lorises.
Now another team of early primate experts has published a new analysis of the famous fossil. Writing in the Journal of Human Evolution paleontologists Blythe Williams, Richard Kay, Christopher Kirk, and Callum Ross have independently confirmed that the original description of Darwinius which appeared in the journal PLoS One was deeply flawed. Understanding why, however, requires a bit of background. Read the rest of this post... | Read the comments on this post...... Read more »
Capitalists beware. No less a journal than Nature has just published a paper proving conclusively that the human brain is a Communist, and that it's plotting the overthrow of the bourgeois order and its replacement by the revolutionary Dictatorship of the Proletariat even as we speak.Kind of. The article, Neural evidence for inequality-averse social preferences, doesn't mention the C word, but it does claim to have found evidence that people's brains display more egalitarianism than people themselves admit to.Tricomi et al took 20 pairs of men. At the start of the study, both men got a $30 payment, but one member of each pair was then randomly chosen to get a $50 bonus. Thus, one guy was "rich", while the other was "poor". Both men then had fMRI scans, during which they were offered various sums of money and saw their partner being offered money too. They rated how "appealing" these money transfers were on a 10 point scale.What happened? Unsurprisingly both "rich" and "poor" said that they were pleased at the prospect of getting more cash for themselves, the poor somewhat more so, but people also had opinions about payments to the other guy:the low-pay group disliked falling farther behind the high-pay group (‘disadvantageous inequality aversion’), because they rated positive transfers to the high-pay participants negatively, even though these transfers had no effect on their own earnings. Conversely, the high-pay group seemed to value transfers [to the poor person] that closed the gap between their earnings and those of the low-pay group (‘advantageous inequality aversion’)What about the brain? When people received money for themselves, activity in the ventromedial prefrontal cortex (vmPFC) and the ventral striatum correlated with the size of their gain.However, when presented with a payment to the other person, these areas seemed to be rather egalitarian. Activity rose in rich people when their poor colleagues got money. In fact, it was greater in that case than when they got money themselves, which means the "rich" people's neural activity was more egalitarian than their subjective ratings were. Whereas in "poor" people, the vmPFC and the ventral striatum only responded to getting money, not to seeing the rich getting even richer.The authors conclude that thisindicates that basic reward structures in the brain may reflect even stronger equity considerations than is necessarily expressed or acted on at the behavioural level... Our results provide direct neurobiological evidence in support of the existence of inequality-averse social preferences in the human brain.Notice that this is essentially a claim about psychology, not neuroscience, even though the authors used neuroimaging in this study. They started out by assuming some neuroscience - in this case, that activity in the vmPFC and the ventral striatum indicates reward i.e. pleasure or liking - and then used this to investigate psychology, in this case, the idea that people value equality per se, as opposed to the alternative idea, that "dislike for unequal outcomes could also be explained by concerns for social image or reciprocity, which do not require a direct aversion towards inequality."This is known as reverse inference, i.e. inference from data about the brain to theories about the mind. It's very common in neuroimaging papers - we've all done it - but it is problematic. In this case, the problem is that the argument relies on the idea that activity in the vmPFC and ventral striatum is evidence for liking.But while there's certainly plenty of evidence that these areas are activated by reward, and the authors confirmed that activity here correlated with monetary gain, that doesn't mean that they only respond to reward. They could also respond to other things. For example, there's evidence that the vmPFC is also activated by looking at angry and sad faces.Or to put it another way: seeing someone you find attractive makes your pupils dilate. If you were to be confronted by a lion, your pupils would dilate. Fortunately, that doesn't mean you find lions attractive - because fear also causes pupil dilation.So while Tricomi et al argue that people, or brains, like equality, on the basis of these results, I remain to be fully convinced. As Russell Poldrack noted in 2006caution should be exercised in the use of reverse inference... In my opinion, reverse inference should be viewed as another tool (albeit an imperfect one) with which to advance our understanding of the mind and brain. In particular, reverse inferences can suggest novel hypotheses that can then be tested in subsequent experiments.Tricomi E, Rangel A, Camerer CF, & O'Doherty JP (2010). Neural evidence for inequality-averse social preferences. Nature, 463 (7284), 1089-91 PMID: 20182511... Read more »
Tricomi E, Rangel A, Camerer CF, & O'Doherty JP. (2010) Neural evidence for inequality-averse social preferences. Nature, 463(7284), 1089-91. PMID: 20182511
An adult chimpanzee in Bossou, Guinea uses hammer and anvil stones to crack nuts as younger individuals look on. From Haslam et al., 2009.
Before 1859 the idea that humans lived alongside the mammoths, ground sloths, and saber-toothed cats of the not-too-distant past was almost heretical. Not only was there no irrefutable evidence that our species stretched so far back in time, but the very notion that we could have survived alongside such imposing Pleistocene mammals strained credulity. Contrary to what might be immediately expected, however, it was not Darwin's famous abstract On the Origin of Species that changed appraisals of human prehistory. Instead it was a collection of stone tools found mingled among the bones of extinct mammals found in deposits on either side of the English Channel.
The discovery of stone tools from places like Brixham Cave in England and France's Somme Valley confirmed that industry was a very old human enterprise, and so some scholars naturally felt quite comfortable in giving out species the honorary title of "Man the Toolmaker." The ability of our species to make and use tools clearly separated us from all other organisms, at least until it was discovered that chimpanzees, too, made and used tools. More than that, studies since the 1960's have confirmed that different populations of chimpanzees have distinctive tool cultures affected by the contingencies of their surroundings, and a recent study published two years ago in PNAS illustrates that these cultures of tool use among non-human primates stretch back at least 4,300 years. Read the rest of this post... | Read the comments on this post...... Read more »
Mercader, J., Barton, H., Gillespie, J., Harris, J., Kuhn, S., Tyler, R., & Boesch, C. (2007) 4,300-Year-old chimpanzee sites and the origins of percussive stone technology. Proceedings of the National Academy of Sciences, 104(9), 3043-3048. DOI: 10.1073/pnas.0607909104
I’ve recently been looking a bit into the important issue of the migration of Athapaskan-speaking groups ancestral to the Navajos and Apaches into the Southwest. Although this is one of the most obvious examples of long-distance migration in prehistoric North America, surprisingly little is known about it. There’s basically no archaeological evidence establishing when it [...]... Read more »
PERRY, R. (1983) Proto-Athapaskan culture: the use of ethnographic reconstruction. American Ethnologist, 10(4), 715-733. DOI: 10.1525/ae.1983.10.4.02a00060
The current issue of PNAS carries an interesting paper on the evolution of human limb proportions. The authors, Young et al. (2010), propose that one key change in the evolution of humanlike limb adaptations is a reduction in the strength of the developmental links between fore- and hindlimbs, and moreover, that this change actually occurred in a non-hominin ancestor we shared with other great apes.The quadrupedal primates, like most vertebrates, have strong serial homologies between their limbs. Each limb is composed of three units, specifically the thigh/arm, the leg/forearm and the foot/hand, which are, in most species, tightly coupled such that changes in the relative proportions of the parts of the hindlimb will bring about corresponding changes in the forelimb and vice versa (Young et al. 2010). Humans, in contrast, have differently proprtioned fore- and hindlimbs, with the patterns linked to their different functions in fine manipulation and bipedal locomotion respectively. In addition, the fossil record of human evolution suggests that the changes from the ancestral pattern occurred in an evolutionary mosaic, with fore- and hindlimbs changing independently and at different times, in response to separate selective pressures (Young et al. 2010).For me, the most interesting part of this article is not the proposal that the move towards weaker coupling of fore- and hindlimbs was important to human evolution (as this seems fairly straightforward, although interesting), but Young et al.'s suggestion that the change actually happened in a human-ape common ancestor rather than within the hominin clade. Many great apes do have functionally differentiated and differently proportioned fore- and hindlimbs, likely as the result of a reduction in the number of pleiotropic genes. Pleiotropic genes are those which influence more than one anatomical structure. This, to me, suggests we are justified in spending more time developing our understanding of the locomotor anatomy of the great apes.ReferencesYOUNG, N., WAGNER, G., & HALLGRIMSSON, B. (2010). Development and the evolvability of human limbs Proceedings of the National Academy of Sciences, 107 (8), 3400-3405 DOI: 10.1073/pnas.0911856107... Read more »
Problems associated with low spatial and temporal resolution in datasets are a daily hazard of my particular field of research, palaeoanthropology. The fossil record, as everyone knows, is hugely incomplete and, in addition, biased. Those records we do have about the biogeography of extinct species, in particular, are usually patchy and likely to be biased in favour of those parts of the distribution where fossilisation was probable and disturbance since sufficient to uncover the remains but not so marked as to destroy them. It's a tall order - rather like Goldilock's requirements of porridge - and it's hardly surprising that only a small proportion of organisms become fossils that are found by researchers today.Those who work with the past, however, do tend to ignore the very similar problems facing biogeographers whose target organisms are still extant. This morning, though, I came across a paper reporting a piece of research into the use of museum collections to fill gaps in scientific knowledge of biogeography and hence to improve both conservation efforts and ecological understanding. The research, by Newbold (2010), focuses on one particular technique, called ecological niche modelling, which I have always assumed would be particularly useful to palaeontologists. Essentially, ecological niche modelling was developed to "fill the gaps" in our knowledge of a species' distribution. If we plot every known occurrence of a particular species, for example, the resulting distribution will be incomplete, because we are unlikely to have sampled every possible site where that species might occur. Some of the apparently empty sites on our distribution map, then, will actually represent sites that are not sampled. There are a number of ways we can deal with this. Most simply, we can ignore unsampled sites by assuming they are empty, although this is unreliable (Newbold 2010). Instead, then, models can be developed to assign each unsampled site a value (presence/absence or occupied/empty). This assignment can be random, or it can employ an ecological niche model, which analyses the distribution of known presences in light of their environmental conditions to identify a set of rules that describe an organisms' distribution in terms of its context. So, for example, an ecological niche model might determine that all occurences of species X are in woodland and within 20km of a water body, and then can use these rules to decide which unsampled cells are likely to be occupied.So far, so good. For palaeontologists, this technique holds potential - it would allow us to patch some of the gaps in species' distributions that are the inevitable result of using fossil data. However, Newbold then goes on to discuss the limitations of museum data in ecological niche modelling, which I had not yet thought much about. Museum collections are exactly what palaeoanthropologists would be working with: our fossils are kept in collections, with location data and environmental reconstructions published in the associated literature. However, as Newbold quite rightly notes, the records kept by curators and museums, particularly where the fossils were discovered a long time ago, may be both biased and even incorrect. For example, those fossils which were found are those which eroded from rock faces, but only where there were people to find them. Certain areas of Africa, for example, are likely to be poorly sampled by palaeoanthropologists because they are politically unsettled or hostile to Western nations, so any fossils that have emerged are unlikely to have been recognised. This is only a problem where the bias favours certain palaeoenvironments and hence affects the rules produced by the model(Newbold 2010), but, as of yet, we cannot know whether this is the case in palaeoanthropology. In addition, small errors in the location records of fossil finds may also affect our models (Newbold 2010). The Taung child, the famous first fossil of Australopithecus africanus, for example, was famously found in a limestone quarry in South Africa by workers - it's exact location was never noted. In addtion, prior to the use of GPS, many fossil findspots were difficult to locate with the accuracy possible using modern technology. This georeferencing problem is particularly common (Newbold 2010).Now, I would argue that these problems in their own right do not invalidate ecological niche models, particularly where - as in palaeoanthropology - there are limited opportunities for obtaining better sampling of distributions. But just after finishing this paper, I encountered a second, this time in the Journal of Biogeography, which highlights the dangers of niche modelling in a very different way. The authors, Lozier et al. (2009) have constructed an ecological niche model based on sightings of the sasquatch - bigfoot - to explore whether reasonable distribution models can be constructed from questionable observational data. The distribution their model produced, in fact, was very successful in tests (proving to be capable of producing a set of ecological rules which matched the conditons of all but one of over 500 sightings), and was very similar to that of black bear, despite being based only on uncertain sightings of a creature that has never been proven to exist. The paper, overall, not only gives grounds for serious thought about the use of uncertain data in ecological niche modelling, but also enables its authors to propose that bigfoot may, in fact, be a misidentified black bear....Clearly, it is very important to critically assess the nature and quality of data used in ecological niche modelling if the technique is to be useful and produce reliable results. This may particularly be the case in palaeoanthropology, where taphonomic processes (which are inherently biased towards certain palaeoenvironments) have been involved, even where we can be pretty sure that the subjects of the model actually existed!ReferenceNEWBOLD, T. (2010). Applications and limitations of museum data for conservation and ecology, with particular attention to species distribution models Progress in Physical Geography, 34 (1), 3-22 DOI: 10.1177/0309133309355630LOZIER, J., ANIELLO, P., & HICKERSON, M. (2009). Predicting the distribution of Sasquatch in western North America: anything goes with ecological niche modelling Journal of Biogeography, 36 (9), 1623-1627 DOI: 10.1111/j.1365-2699.2009.02152.x... Read more »
NEWBOLD, T. (2010) Applications and limitations of museum data for conservation and ecology, with particular attention to species distribution models. Progress in Physical Geography, 34(1), 3-22. DOI: 10.1177/0309133309355630
LOZIER, J., ANIELLO, P., & HICKERSON, M. (2009) Predicting the distribution of Sasquatch in western North America: anything goes with ecological niche modelling. Journal of Biogeography, 36(9), 1623-1627. DOI: 10.1111/j.1365-2699.2009.02152.x
The blogosphere is all a-twitter with talk of the recent commentary in Science that dolphins should be considered people. Well, sort of people. Non-human people.
On the heels of the incident at SeaWorld in Florida in which a trainer was killed by one of the killer whales, this is especially an important issue to consider.
Frequent commenter [...]... Read more »
The most popular species concept in use today, the Biological Species Concept (BSC) defines a species through reference to the limits of reproductive compatibility: essentially, through the idea that any pair (male and female) within a single species will be capable of producing viable and fertile offspring, while a couple which belong to different species will not. The boundaries of successful reproduction, then, can be used to delineate species, at least in sexually reproducing animals.Of course, it's not actually that simple. Baboons, for example, of the genus Papio, have been the subject of extensive debate, with some authors recognising as many as five separate species on the basis of morphology while adherents of the BSC, while not denying that these putative species are constant and stable, note that hybridisation between the various populations Papio means that only on species can be present. So biologists who favour the BSC lump all members of the genus Papio into one species, despite their differences, while many other researchers do not (Jolly 2001).Interestingly, though, Papio beboons do not only hybridise with one another. Dunbar and Dunbar, for instance, noted as early as 1974 that apparently fertile and reproductively successful hybrids can be produced between at least one Papio species and the gelada baboon, in the genus Theropithecus. These two genera are closely related, to be sure, next to one another on most phylogenetic trees of the old world monkeys, but have been distinct lineages for several million years. In addition to Dunbar and Dunbar (1974)'s wild hybrids between the gelada and anubis baboons moreover, Jolly et al. (1997) report hybrids between hamadryas baboons and geladas in the wild, and Markarjan et al. (1974) between Papio baboons and both geladas and rhesus macaques, the baboons' even more distant relatives in the genus Macaca. These so-called "rheboons", however, may not be fertile or capable of attracting mates (Jolly 2001).In light of these papers, I have been reading about hybridisation in monkeys, and it seems to be a lot more prevalent than I previously realised (there are papers galore out there, but to go into detail on all of them would take far more space than I have here!) At the same time, though, I started thinking about this after reading Jolly's paper from 2001, as cited in the last post, which is about the use of papionin monkeys as analogues for our ancestors. One interesting suggestion of Jolly's is that if baboons and macaques, or baboons and geladas, can hybridise after several million years as distinct lineages, why do we believe that all the species of australopithecine-type hominins (genus Australopithecus and genus Paranthropus) necessarily behaved as biological species? Or, for that matter, why do we think that early species of our own genus, Homo, couldn't have hybridised with one another? To me, although there is no clear evidence for hybridisation in our own lineage, there is no reason to rule it out; the evidence simply isn't clear enough. However, it is difficult to envision what evidence we might find that would inform us about hybridisation in past hominins. I suppose the real question is whether the morphological differences between the hominin species we have already identified are real discontinuities or simply artifacts of the incomplete fossil record. Whether we can tell from the fossil record or not, this is interesting stuff, and has substantial implications for hominin taxonomy and our understanding of the evolutionary process.ReferencesDUNBAR, R., & DUNBAR, P. (1974). On hybridization between Theropithecus gelada and Papio anubis in the wild☆ Journal of Human Evolution, 3 (3), 187-192 DOI: 10.1016/0047-2484(74)90176-6JOLLY, C.J., WOOLLEY-BARKER, T., BEYENE, S., DISOTELL, T.R., & PHILLIPS-CONROY, J.E. (1997). Intergeneric hybrid baboons. International Journal of Primatology, 18 (4), 597-627JOLLY, C. (2001). A proper study for mankind: Analogies from the Papionin monkeys and their implications for human evolution American Journal of Physical Anthropology, 116 (S33), 177-204 DOI: 10.1002/ajpa.10021MARKARJAN, D., ISAKOV, E., & KONDAKOV, G. (1974). Intergeneric hybrids of the lower (42-chromosome) monkey species of the Sukhumi monkey colony Journal of Human Evolution, 3 (3), 247-255 DOI: 10.1016/0047-2484(74)90183-3... Read more »
DUNBAR, R., & DUNBAR, P. (1974) On hybridization between Theropithecus gelada and Papio anubis in the wild☆. Journal of Human Evolution, 3(3), 187-192. DOI: 10.1016/0047-2484(74)90176-6
JOLLY, C.J., WOOLLEY-BARKER, T., BEYENE, S., DISOTELL, T.R., & PHILLIPS-CONROY, J.E. (1997) Intergeneric hybrid baboons. International Journal of Primatology, 18(4), 597-627. info:/
JOLLY, C. (2001) A proper study for mankind: Analogies from the Papionin monkeys and their implications for human evolution. American Journal of Physical Anthropology, 116(S33), 177-204. DOI: 10.1002/ajpa.10021
MARKARJAN, D., ISAKOV, E., & KONDAKOV, G. (1974) Intergeneric hybrids of the lower (42-chromosome) monkey species of the Sukhumi monkey colony. Journal of Human Evolution, 3(3), 247-255. DOI: 10.1016/0047-2484(74)90183-3
Male (right) and female (left, with infant) friends in a population of Chacma baboons. (From Palombit, 2009).
Among other things, friends are people you count on to come to your aid when you need help. If you were at a bar and a stranger started acting aggressively towards you, for example, you would expect your friends to rush over to help you rather than just stand there, mojito in hand. Contrary to our feelings of human exceptionalism, however, ours is not the only species of primate to create and maintain friendships.
For years primatologists have been puzzling over "friendship" in baboons. Across baboon species lactating females keep up close social relationships with unrelated adult males. The females are not reproductively available, and by devoting much of their attention to these females the males significantly reduce their opportunities to mate with other females, so why are these males so concerned with mothers and infants? What is the function of this behavior?
Several hypotheses have been forwarded. Perhaps friendship is a defense against infanticide, a way to reduce harassment of mothers and their infants by other group members, or a way for mothers to get their infants to bond with particular males so that they will continue to reap social benefits (such as food sharing and support during fights) as they mature. Of these, however, friendship as an anti-infanticide mechanism appears to be best-supported, especially since infanticide is a major cause of mortality among infant Chacma baboons. Baboon social groups are centered around female families that stick together, but males often move from one group to another. As a result immigrant males occasionally supplant the group's dominant male, and when this happens among Chacma baboons the new alpha picks off the group's infants one-by-one (hence the group's females come back into estrus sooner). In such situations a friendship between a male and female baboon can make the difference between life and death for her offspring.
That male friends provide such protection was confirmed through playback experiments in the field. When the distress calls of female Chacma baboons with infants were played in the vicinity of their friends the males reacted strongly to the sound by trying to find where that female was and determine if she was in danger. The control subjects, males of similar social rank but were not friends, glanced up when the sound was played but quickly went back to whatever they were doing. These results reaffirmed that at least part of the role of male friendship was to offer protection to mothers with infants.
Yet the threat of infanticide varies among baboon species even as friendships remain a common phenomenon. In olive baboons, for example, infanticide by an immigrant male is a rare event rather than the norm, and primatologists A. Lemasson, Ryne Palombit, R. Jubin took this as an opportunity to see if friendships in this species involved protection from harassment or some other social benefit. If male friends provide protection for mothers and infants then they would react strongly to distress calls, just like the Chacma baboons, but if the function of friendship is to provide infants with social benefits later in life it would be predicted that males would not be as concerned upon hearing the female's screams. To test this idea the scientists arranged a second playback experiment published in Behavioral Ecology and Sociobiology. Read the rest of this post... | Read the comments on this post...... Read more »
Lemasson, A., Palombit, R., & Jubin, R. (2007) Friendships between males and lactating females in a free-ranging group of olive baboons (Papio hamadryas anubis): evidence from playback experiments. Behavioral Ecology and Sociobiology, 62(6), 1027-1035. DOI: 10.1007/s00265-007-0530-z
This post explains variation in behavior through the menstrual cycle, hormonal variation, and problematizes the assumption that progesterone withdrawal explains premenstrual syndrome.... Read more »
Beckley EH, & Finn DA. (2007) Inhibition of progesterone metabolism mimics the effect of progesterone withdrawal on forced swim test immobility. Pharmacology, biochemistry, and behavior, 87(4), 412-9. PMID: 17597197
Brinton RD, Thompson RF, Foy MR, Baudry M, Wang J, Finch CE, Morgan TE, Pike CJ, Mack WJ, Stanczyk FZ.... (2008) Progesterone receptors: form and function in brain. Frontiers in neuroendocrinology, 29(2), 313-39. PMID: 18374402
Gracia CR, Freeman EW, Sammel MD, Lin H, Sheng L, & Frye C. (2009) Allopregnanolone levels before and after selective serotonin reuptake inhibitor treatment of premenstrual symptoms. Journal of clinical psychopharmacology, 29(4), 403-5. PMID: 19593190
Maguire, J., & Mody, I. (2008) GABAAR Plasticity during Pregnancy: Relevance to Postpartum Depression. Neuron, 59(2), 207-213. DOI: 10.1016/j.neuron.2008.06.019
Monteleone, P. (2000) Allopregnanolone concentrations and premenstrual syndrome. European Journal of Endocrinology, 142(3), 269-273. DOI: 10.1530/eje.0.1420269
Nappi, R. (2001) Serum allopregnanolone in women with postpartum “blues”. Obstetrics , 97(1), 77-80. DOI: 10.1016/S0029-7844(00)01112-1
Chapman, J., McIntyre, M., Lipson, S., & Ellison, P. (2009) Weight change and ovarian steroid profiles in young women. Fertility and Sterility, 91(3), 858-861. DOI: 10.1016/j.fertnstert.2007.12.081
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Probably no single material is more closely associated with Chaco than turquoise. The vast amounts found in Room 33 at Pueblo Bonito alone suggest its importance, but it has been found in considerable quantities at many different sites, both small houses and great houses and both inside and outside of the canyon. There is considerable [...]... Read more »
HULL, S., FAYEK, M., MATHIEN, F., SHELLEY, P., & DURAND, K. (2007) A new approach to determining the geological provenance of turquoise artifacts using hydrogen and copper stable isotopes. Journal of Archaeological Science. DOI: 10.1016/j.jas.2007.10.001
There’s a spot near the west end of the Pueblo Bonito parking lot, close to the spot where guided tours begin, where you can yell something in the direction of the canyon wall and hear a very clear echo back. Some of the tour guides at Chaco regularly demonstrate this impressive effect when beginning their [...]... Read more »
Mills, B., & Ferguson, T. (2008) Animate Objects: Shell Trumpets and Ritual Networks in the Greater Southwest. Journal of Archaeological Method and Theory, 15(4), 338-361. DOI: 10.1007/s10816-008-9057-5
Figure 1: Dogs are pretty intelligent.
Domesticated dogs seem to have an uncanny ability to understand human communicative gestures. If you point to something the dog zeroes in on the object or location you’re pointing to (whether it’s a toy, or food, or to get his in-need-of-a-bath butt off your damn bed and back onto his [...]... Read more »
Hare, B., Plyusnina, I., Ignacio, N., Schepina, O., Stepika, A., Wrangham, R., & Trut, L. (2005) Social Cognitive Evolution in Captive Foxes Is a Correlated By-Product of Experimental Domestication. Current Biology, 15(3), 226-230. DOI: 10.1016/j.cub.2005.01.040
This exchange between William of Baskerville and Adso of Melk, in The Name of the Rose seems pretty timely... “Some time ago, in the Cathedral of Cologne, I saw the skull of John the Baptist at the age of twelve”“Really?” I exclaimed, amazed. Then, seized by doubt, I added, “But the Baptist was executed at a more advanced age!”“The other skull must be in another treasury,” William said, with a grave face.I say timely because last week, a study reporting the results of genetic and radiocarbon assays on the putative skulls of St. Bridget (of Sweden) and her daughter Catherine was published (Nilsson et al. 2010). And, lo and behold, it turns out that the skulls apparently belong to unrelated female individuals. And because the genetic tests indicated that the two skulls displayed different degrees of DNA degradation, which suggested that they might be of significantly, radiocarbon dates were also obtained for them: the skull thought to be the saintly relic yielded a calibrated age of 1215–1270 AD, while the one thought to be the saintly daughter rung in at 1470–1670 AD. Since St. Bridget lived from 1303-1373, these dates essentially confirm that the skulls held at Vadstena Abbey are not those of the saints. It's always better to have mutually reinforcing lines of evidence when trying to answer an archaeological question. This is an elegant demonstration of why. At first glance, it may appear that simply dating the skulls would have been sufficient to demonstrate that they did not belong to who they were claimed to belong to, but then again, issues of contamination could have been raised, so the results of both the genetic and the radiocarbon analyses complement one another nicely in this case. I've always wondered why relics exert such fascination on believers, especially when the vast majority of them is unlikely to be real, as succinctly encapsulated by another great quote about relics from The Name of the Rose:"... don't succumb too much to the spell of these cases. I have seen many other fragments of the cross, in other churches. If all were genuine, our Lord's torment could not have been on a couple of planks nailed together, but on an entire forest." As concerns specifically human remains used as relics, I've always wondered how some of the more observant faithful would feel about knowing that the similar practices of ritualized handling of bits of dead people have considerable antiquity stretching all the way back to the Pleistocene. As I summarized in a previous post, there's some suggestive evidence that at least as far back as the Middle Stone Age, in distinctly non-Christian contexts, people handled both human teeth and crania in a likely ritual manner.References Nilsson, M., Possnert, G., Edlund, H., Budowle, B., Kjellström, A., & Allen, M. (2010). Analysis of the Putative Remains of a European Patron Saint–St. Birgitta PLoS ONE, 5 (2) DOI: 10.1371/journal.pone.0008986... Read more »
Nilsson, M., Possnert, G., Edlund, H., Budowle, B., Kjellström, A., & Allen, M. (2010) Analysis of the Putative Remains of a European Patron Saint–St. Birgitta. PLoS ONE, 5(2). DOI: 10.1371/journal.pone.0008986
In the deliberations over humanity and its perceived uniqueness, a link is frequently made between our ability to support a rich, diverse culture and the origin of complex human behaviour. Yet what is often overlooked in our view of these two, clearly connected phenomena is the thread that weaves them together: the ability to coordinate [...]... Read more »
Chater, N. . (2009) Language Acquisition Meets Language Evolution. Cognitive Science. info:/10.1111/j.1551-6709.2009.01049.x
Laland KN, Odling-Smee J, & Myles S. (2010) How culture shaped the human genome: bringing genetics and the human sciences together. Nature reviews. Genetics, 11(2), 137-48. PMID: 20084086
Lycett, S., & Norton, C. (2010) A demographic model for Palaeolithic technological evolution: The case of East Asia and the Movius Line. Quaternary International, 211(1-2), 55-65. DOI: 10.1016/j.quaint.2008.12.001
A discussion of a medical analysis of several Egyptian mummies including 'King Tut'... Read more »
Hawass Z, Gad YZ, Ismail S, Khairat R, Fathalla D, Hasan N, Ahmed A, Elleithy H, Ball M, Gaballah F.... (2010) Ancestry and pathology in King Tutankhamun's family. JAMA : the journal of the American Medical Association, 303(7), 638-47. PMID: 20159872
It is still unusual when the Catholic church allows a scientific study of one of their relics. So I was surprised to find the manuscript describing the study of the DNA of the remains of one of Europe's patron saints, St. Birgitta (Bridget of Sweden) in my PLoS One inbox one fine day in May, 2008. I'm a neurogeneticist by training, so I felt competent to take this manuscript on as academic editor. The manuscript stated that they had found through both DNA analysis and carbon dating that not only were the remains of St. Birgitta most likely not from the relevant time period, but that the remains stored with her, once thought to be her daughter, could not possibly have been from any of her relatives, let alone her daughter.Such claims, sure to stir some public attention, needed a thorough peer-review process. I selected a team of four high-caliber international experts in both the field of ancient DNA analysis and radiometric dating. I also used a scheduled visit to Uppsala, where the work had been done, to meet the last and corresponding author of the manuscript, Marie Allen, and have a good look at the laboratories where the experiments had been made. Marie was the most gracious host and took a lot of time out of her busy schedule to show me around her lab and explain how professionally she had handled the relics according to the latest techniques.The review-process was a lot more bumpy and time-consuming. The reviewers all liked the way she had handled and analyzed the DNA and only had minor suggestions for improvement in this respect. The radiocarbon dating itself was also ok, but two of the reviewers brought up the "reservoir effect". This could lead to a deviation in radiocarbon dating from the correct age if the two people had been on a high-seafood diet. To measure this reservoir effect, additional Nitrogen-dating techniques had to be applied. These proved difficult and time consuming, but after more than one year, the results were finally coming in. Indeed, there had been a measurable reservoir effect for both tested skulls, albeit not to a degree that would change the main conclusions of the study. Yesterday, almost 2 years after the initial manuscript had been submitted, the paper was finally published and I think both DNA and dating measurements are as accurate as they can possibly be, given today's technology. These measurements show that it is highly unlikely that the two skulls kept as relics by the Catholic church are the ones from St. Birgitta and her daughter. Most likely, not even one of the skulls comes from the person claimed by the church.Nilsson, M., Possnert, G., Edlund, H., Budowle, B., Kjellström, A., & Allen, M. (2010). Analysis of the Putative Remains of a European Patron Saint–St. Birgitta PLoS ONE, 5 (2) DOI: 10.1371/journal.pone.0008986... Read more »
Nilsson, M., Possnert, G., Edlund, H., Budowle, B., Kjellström, A., & Allen, M. (2010) Analysis of the Putative Remains of a European Patron Saint–St. Birgitta. PLoS ONE, 5(2). DOI: 10.1371/journal.pone.0008986
Bonobos retain juvenile traits related to tolerance and cooperation. Image: Vanessa WoodsHow many times as a kid would your parents tell you to grow up and act your age? It turns out that not acting our age may be the very reason why we're so successful as a species.
Brian Hare and colleagues have just released a video (see below) showing a bonobo juvenile voluntarily helping another individual out of their cage to share a few delicious treats. In their study, to be released March 8 in Current Biology, the Duke researchers wanted to see if bonobos would choose to share with an unrelated individual even if they didn't have to.
Bonobos have long intrigued researchers for their unusual (except for us) propensity to cooperate and share with others, a trait not found to the same degree in our common ancestor the chimpanzee. Read the rest of this post... | Read the comments on this post...... Read more »
Wobber, V., Wrangham, R., & Hare, B. (2010) Bonobos Exhibit Delayed Development of Social Behavior and Cognition Relative to Chimpanzees. Current Biology, 20(3), 226-230. DOI: 10.1016/j.cub.2009.11.070
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