john hawks weblog

Transport distance in MSA Botswana

Two years ago, I wrote about the archaeological assemblages and evidence of symbolic behavior at Rhino Cave, Botswana ("Views from Rhino Cave, Tsodilo Hills, Botswana". Another site in the same region is White Paintings Shelter, with MSA assemblages dating from 50,000 back to more than 90,000 years ago. A new paper by David Nash and colleagues has sourced the raw materials used in stone manufacture across this time range at the site [1] They show that long-distance transport of silcrete stone was a major component of the material record at the site. From the paper:

The people who used WPS were clearly aware of the available resources at Tsodilo Hills, anticipated a need, and procured silcrete from at least 220 km away for tool manufacture. The transport of raw materials from such distant sites represents a repeated procurement strategy for resource acquisition and suggests that these people made two conscious decisions. First, despite having ready access to local quartz and quartzite at Tsodilo Hills they chose to acquire silcrete. Second, they opted to use silcrete from south of the Okavango Delta (or possibly further afield during wetter periods) rather than from sources much closer to WPS. This is even though the hand specimen characteristics of silcrete samples from the Boteti River, Lake Ngami, Okavango River and Xaudum indicate that materials from these localities are equally fine-grained and well-cemented, and therefore likely to be of equivalent quality for tool manufacturing purposes.

The authors include a mini-review of other MSA sites with evidence of long-distance transport.

This is not the first study from the African MSA to identify the long-distance transport of stone raw materials by tool-manufacturing populations. In East Africa, for example, small numbers of obsidian artifacts from the Songhor and Muguruk MSA sites in western Kenya have been provenanced to volcanic flows up to 190 km distant (McBrearty, 1981, 1988). Obsidian artifacts from the Nasera Rock Shelter in northern Tanzania were procured from some of the same central Kenyan Rift sources, involving transport of up to 320 km (Merrick and Brown, 1984; Mehlman, 1989). The movement of raw materials over such distances has been interpreted to represent deliberate stone-collecting forays (see Merrick et al., 1994). What is, however, significant about our results is that, unlike the majority of sites where obsidian provenancing studies have been undertaken, silcretes are a major component of the MSA record at WPS. Indeed, obsidian artifacts make up typically only 1–5% of East African MSA assemblages (see McBrearty and Brooks, 2000; Ambrose, 2012; for reviews). The repeated long-distance transport of silcrete to WPS must therefore have represented a habitual resource procurement strategy for the MSA peoples who occupied the shelter.

Rare or occasional transport are not logistically difficult to explain. Neandertals transported raw materials in small quantities across more than 150 km. But this case is interesting because of the intensity of transport evidenced at White Paintings Shelter, in addition to the thousands of years across which the transport strategy was repeated.

References

Nash DJ, Coulson S, Staurset S, Ullyott SJ, Babutsi M, Hopkinson L, Smith MP. Provenancing of silcrete raw materials indicates long-distance transport to Tsodilo Hills, Botswana, during the Middle Stone Age. Journal of Human Evolution. 2013.

Tags:

MSA

technology

transport

Bead styles in MSA

Michael Balter covers a new paper on MSA shell beads by Marian Vanhaeren and colleagues: "Human ancestors were fashion-conscious". The study involves beads from Still Bay levels at Blombos Cave, South Africa.

To get an idea of how the shell beads were worn, Vanhaeren and her colleagues examined the wear (smoothing) around the perforations and on other parts of the shells. They then carried out additional experiments in which N. kraussianus shells were shaken together for many hours at a time and exposed to a diluted vinegar solution meant to mimic human sweat, among other tests, while strung together in various ways.

By stringing the shells themselves in various configurations, the team identified six possible ways that the beads could have been worn, including tying a knot around each shell, stringing them in a continuous row, braiding them with two strings at a time, and reversing the orientations of the shells to each other. Then, by analyzing the wear on the shells caused by these arrangements, Vanhaeren and colleagues determined just how the beads were strung. "In the lower [older] layers, the shells hang free on a string with their flat, shiny [sides] against each other," Vanhaeren says. But like all fashions, that one didn't last long: In the two upper, younger layers, "the shells are knotted together two by two, with their shiny side up" (see photos).

That's a pretty clever approach. With these beads it is not possible to trace stylistic aspects of form directly; they are just not subject to enough human alteration. But the traces of wear allow an indirect assessment of stylistic variation, in the way that they were strung. It makes for one of the earliest examples of studying stylistic variation over a time range in an archaeological context.

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MSA

art

style

"Average is over"

Today's Thomas Friedman column notes the growing craze at major universities for massively open online courses, or MOOCs: "The Professors’ Big Stage".

Clayton Christensen, the Harvard Business School professor and expert on disruptive innovation, gave a compelling talk about how much today’s traditional university has in common with General Motors of the 1960s, just before Toyota used a technology breakthrough to come from nowhere and topple G.M. Christensen noted that Harvard Business School doesn’t teach entry-level accounting anymore, because there is a professor out at Brigham Young University whose online accounting course “is just so good” that Harvard students use that instead. When outstanding becomes so easily available, average is over.

The theme of the column is that education must change, because:

We demand that plumbers and kindergarten teachers be certified to do what they do, but there is no requirement that college professors know how to teach. No more. The world of MOOCs is creating a competition that will force every professor to improve his or her pedagogy or face an online competitor.

Most great teachers are not at Harvard. It does seem possible that a ratchet effect will kick in, making free online courses better and better, until bad college professors must change their game. There is a visible lack of institutional quality assurance on most college courses.

On the other hand, there already is a strong competition among college professors in textbook authoring. We haven't seen a ratcheting effect, with better and better textbooks. Instead, we've seen textbooks metastasize with unneeded features, supplements, and cumbersome licenses. MOOCs are free, for now, so maybe they'll avoid the pressures that affect the textbook market.

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IRB review

Zachary Schrag points to a report by the American Association of University Professors , and gives a quoted excerpt that deserves to be forwarded on: "AAUP Publishes Final Report, Regulation of Research on Human Subjects: Academic Freedom and the Institutional Review Board".

As things now stand, the IRB system assembles local committees whose members have no special competence in assessing research projects in the wide range of disciplines they are called on to assess, whose approval is required for an only minimally restricted range of research projects and who are invited to bring to bear in assessing them an only minimally restricted body of what they take to be information, who are only minimally restricted in the demands they may make on the researchers, and whose judgments about whether to permit the research to be carried out at all are, in most institutions, final. When one steps back from it, one can find oneself amazed that such an institution has developed on university campuses across the country.

Different kinds of human research raise different kinds of ethical concerns. A good aspect of the IRB process is that the board members themselves often learn a lot about the ethical issues in other fields. But the composition of particular boards can make the process of review troublingly arbitrary.

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ethics

metascience

Thinking simply

Vaughan Bell has a nice piece in the Guardian on folk psychology -- how ordinary people tend to think about their own thinking: "Our brains, and how they're not as simple as we think". This is a very important concept in the study of the evolution of human cognition, because how we think about our brains today may have little to do with the reasons why they changed over time.

For example, a great deal of psychology research has shown that we tend not to have a good insight into why we make certain choices. In one of the many studies in the area, Lars Hall and colleagues gave people a survey about their moral beliefs but used sleight of hand to change the choices they had originally made. When asked to justify the beliefs they hadn't endorsed, more than two-thirds of people didn't notice the switch and happily gave reasons for why they supported the opposite of their original position. Folk psychology tells us that we can accurately explain our actions and, consequently, many people think that these well-validated psychological effects never apply to them or simply don't exist. Suggesting that someone may not fully know their own actions and that their post-event justifications might be improvised simply won't wash in everyday conversation.

This is a phenomenon where psychology affects how we do scientific reasoning. I was doing this with my graduate students this morning -- taking the opposite pattern of data and explaining it as a function of the same evolutionary hypothesis. It's all too easy to justify post hoc a pattern by explaining it in terms of well-understood assumptions.

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brain function

psychology

brain evolution

"Where did it go wrong for Wallace's reputation?"

The BBC has an article by Kevin Leonard, pondering "Why does Charles Darwin eclipse Alfred Russel Wallace?" They both thought of the idea of natural selection, and by Wallace's death he was recognized as one of the most famous scientists in the world. So how to explain this?

But while today Darwin is a household name synonymous with the theory, Wallace struggles to gain anywhere near the recognition of his friend.

This is illustrated by an appeal this year to raise funds for a life-sized bronze statue to honour Wallace - it only reached half of its £50,000 target.

Wallace expert Dr George Beccaloni, who is a curator at the Natural History Museum where the statue would stand, said: "We have enough money to pay for a torso and arms at the moment.

How sad! Of course, one might say the torso and arms of such a giant would be quite enough. And there were the seances...

There's something sociologically very interesting about this. I wonder if it's a misperception, though. I mean, how many really famous scientists -- of the kind that get memorial statues a hundred years after their deaths -- are there in each field of science?

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Alfred Russel Wallace

history of biology

Fieldwork survey for current and former student anthropologists

Kate Clancy directs readers' attention to a new research project examining the conditions under which students have field experiences in biological anthropology: "The Biological Anthropology Field Experiences Web Survey: Now Live".

We (Kate Clancy, Katie Hinde, Robin Nelson and Julienne Rutherford) invite you to participate in our Biological Anthropology Field Experiences Web Survey. The Biological Anthropology Field Experiences Web Survey is designed to solicit input on the ways in which fieldwork does or does not provide a safe scholarly and research environment for all. Rather than determining the total number of instances, or percentage risk of a negative experience, our interest is in gathering stories to inform Field Directors, faculty mentors, and other researchers and students on the scope of the problem, and identify some of the main contributory factors to a negative environment, both to encourage improvement and to identify future areas for research.

If you’re over 18 and have ever done research or been a student at a bio anthro field site, please take 20 minutes to fill out our survey.You can indicate interest at the end in participating in a follow-up phone interview. You can also enter the lottery at the end for a 1 in 10 chance of winning a $25 Amazon gift card.

It's an important project that is attempting to extend an understanding of field mentoring experiences beyond anecdotes. We all know of really good and really bad field experiences of our colleagues (or ourselves). If you have fieldwork experience as a student -- whether or not you continued on toward more anthropology training -- I encourage you to fill out the survey. Obviously, more people who have stuck around for training in anthropology are likely to hear about this survey, so please try to spread the word as much as possible to those who may have gone on to different careers.

Tags:

teaching

metascience

careers

Coprolite microbial ecology

The advent of metagenomic analysis of microbial communities has led to some unexpected insights about human biology. These techniques have quietly been leading to new discoveries from old archaeological contexts. One example is Alan Cooper's work demonstrating long-term changes in oral microbiota from ancient dental calculus ("Tracing teeth troubles with fossil bacteria").

Another is a recent paper from Cecil Lewis' lab, "Insights from characterizing extinct human gut microbiomes." [1]. The paper is open access in PLoS ONE. In it, Raul Tito and colleagues recover DNA data from ancient coprolites, from three archaeological sites in the Americas. As discussed in the paper, they obtain good data from a 1400-year-old site in Mexico. Those people, who lived near present-day Durango, were contemporaries of the classic Maya and Teotihuacanos. As such, their gut microbiomes may provide a really interesting picture of health and diet from a key period in the prehistory of the Americas.

Coprolites may seem simple, but each represents a unique history of deposition and subsequent preservation. The microbial community may shift during the early stages of this history, and subsequent DNA damage may shift estimates of microbial abundances away from their true values. They found one of their sites appeared to preserve a good signal, while the others were degraded:

Most striking, both Rio Zape coprolites exhibited a gut microbiome signature with similarities to the children from a rural African village with the exclusion of a sample of U.S. modern adult gut microbiomes (see Figure S4 for a heat map of these data and Figure S5 for the variability in the source proportion estimates). ZA04 also harbored similarities to non-human primate gut. The coprolites from Caserones and Hinds Cave showed little similarity to a gut microbiome environment. A portion of Caserones coprolite microbial community was similar to compost, which may be explained by the post-mortem gut serving as an organic bioreactor filled with carbon and nitrogen from decaying food detritus. The microbial community assignment for Hinds Cave failed to assign well to any source environment.

From this, we can see that any interpretation of data from a sample of ancient coprolites must be cautious. We're generally interested in how microbial communities may have changed in ancient populations, particularly in response to other factors such as shifts in diet. But as yet it's not very clear what kinds of changes we should predict in association with diet or other changes. That makes it hard to develop a convincing test of a hypothesis.

This paper is more of a proof of principle. And in its discussion, Tito and colleagues present different ways to explain the kinds of differences that they found in the ancient coprolite microbiota. To me, the most provocative hypothesis is that changes may have more to do with parasite load than diet:

Information from Rio Zape also supports a current hypothesis about the composition of human microbiomes in traditional communities, potentially revealing an important aspect of the ancestral human microbiome. Spirochaetes are atypical of gut microbiomes in cosmopolitan communities. However, Treponema was reported by Filippo et al. [21] in their comparative study of modern microbiota in children from Europe and rural Africa. In their study, Treponema was observed in the rural African children but was absent in the European children. They hypothesized that the Treponema may enhance the hosts ability to extract nutrients from fibrous foods and may provide anti-inflammatory capability. They raise the hypothesis that microbiota coevolved with ancient diets and that changes in food production greatly impacted the intestinal microbiota. Treponema was also observed in the published rural data for Malawi and Venezuela [22]. The results from Rio Zape provide further support for Treponema as part of the rural human microbiome. Specifically, Treponema now is observed in four rural communities from different continents, three extant communities and one community that has been extinct for over a thousand years.

As we uncover more comparative data from living people, we will begin to have a better picture of the covariates of microbial community structure. Today's oral bacterial populations in "cosmopolitan" post-industrial peoples are uncharacteristic of past variation. The gut microbiota of cosmopolitan peoples may be just as uncharacteristic. The diversity may have had great importance to ancient health, especially at key times when pathogens were spreading through post-agricultural populations.

References

Tito RY, Knights D, Metcalf J, Obregon-Tito AJ, Cleeland L, Najar F, Roe B, Reinhard K, Sobolik K, Belknap S, et al. Insights from characterizing extinct human gut microbiomes. PLoS One. 2012;7(12):e51146.

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Historical notes on yeti-hunting

From Slate, a memo outlining "The American Government's Advice for Yeti Hunters, 1959".

The memo came at the end of a decade of strenuous Yeti-hunting. This Outside Magazine timeline of Yeti hunts tells the story in compact form. In 1953, Sir Edmund Hillary and Tenzing Norgay climbed Everest, and reported seeing large tracks. In 1954, the Daily Mail (UK) funded a sixteen-week “Snowman Expedition” to Everest to look for clues. (The newspaper is still on the case today.) And in the late 1950s, American oil millionaire and cryptozoology enthusiast Tom Slick—whose colorful life, as Badass Digest points out, should definitely be made into a movie—bankrolled a number of Himalayan expeditions in search of the creature.

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cryptozoology

Anthropology's Spinal Tap problem

The Thesis Whisperer brings up the topic of prolonged rudeness in academic culture: "Academic assholes and the circle of niceness". When I write that it's time to "reclaim the name 'anthropology' from this earlier generation", I mean that the elite discourse within the field has become toxic. Rude behavior often yields short-term gains, but has obvious long-term costs for the discipline as a whole:

How does it happen? The budding asshole has learned, perhaps subconsciously, that other people interrupt them less if they use stronger language. They get attention: more air time in panel discussions and at conferences. Other budding assholes will watch strong language being used and then imitate the behaviour. No one publicly objects to the language being used, even if the student is clearly upset, and nasty behaviour gets reinforced. As time goes on the culture progressively becomes more poisonous and gets transmitted to the students. Students who are upset by the behaviour of academic assholes are often counselled, often by their peers, that “this is how things are done around here” . Those who refuse to accept the culture are made to feel abnormal because, in a literal sense, they are – if being normal is to be an asshole.

Not all academic cultures are badly afflicted by assholery, but many are. I don’t know about you, but seen this way, some of the sicker academic cultures suddenly make much more sense.

Yes, anthropology has been affected. Picking academic vendettas used to be a great way to get famous. The students -- at least the normal students -- suffered. The field has selected for bad behavior.

Many elite anthropologists still consider the New York Times to be an arbiter of quality work. That is, if you are featured in the Times, you are visible to the elite. Yet the Times itself has become actively hostile to cultural anthropology as a field, selecting the worst instances of bad behavior for promotion and coverage. Some of my friends have been agitated for the last week waiting breathlessly for the Times to publish letters decrying the recent coverage.

Seriously.

You know that scene in This Is Spinal Tap?

David St. Hubbins: I do not, for one, think that the problem was that the band was down. I think that the problem *may* have been, that there was a Stonehenge monument on the stage that was in danger of being *crushed* by a *dwarf*. Alright? That tended to understate the hugeness of the object.

Ian Faith: I really think you're just making much too big a thing out of it.

Derek Smalls: Making a big thing out of it would have been a good idea.

Yeah. That one. The curtain has risen on the old band, and they're playing behind a Stonehenge monument that can be crushed by a dwarf. Please, somebody, lower the curtain.

Tags:

history of anthropology

metascience

journalism

More on the reclamation proclamation

Michael E. Smith comments on the Chagnon/Sahlins flap from the perspective of archaeology: "Chagnon, Sahlins, and science":

What about archaeology? Are we exempt from this kind of serious but silly debate? We certainly have our sociobiologists and our cultural explanations partisans. Mostly they talk past one another, and if they do happen to engage, discourse takes the form of "Is so!" "Is not!" "Is too!" I've commented on a parallel manifestation of the serious but silly debates about the role of drought in the Maya collapse, and archaeological opinions on Jared Diamond's collapse book.

When we allow personal ideological bias rule to our scholarly work, we limit the value of our research to answer real questions and to contribute to broader social and scientific debates. If you have an ideological axe to grind, either leave scholarship and go into politics, or else find ways to achieve a level of scholarly objectivity in your research and writing.

Oh, how I wish I didn't have a grant proposal to finish tonight. More when I have a chance...

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history of archaeology

history of anthropology

politics

ethics

"Ancestry is complicated and very messy"

Mark Thomas has a Guardian piece reacting to some recent genetics promotion in the UK: "To claim someone has 'Viking ancestors' is no better than astrology". It is a good article to share with students because it clarifies some of the possibilities of genetic genealogy from the hype.

My colleague Prof David Balding and I wrote to the BBC and to the two main scientists at BritainsDNA – both of whom we knew – expressing our concerns about the claims being made. Our expressions of concern over accuracy were met with threats of legal action for defamation by Mr Moffat's solicitors.

Perhaps it is harmless fun to speculate beyond the facts, armed with exciting new DNA technologies? Not really. It costs unwitting customers of the genetic ancestry industry a substantial amount of hard-earned cash, and it disillusions them about science and scientists when they learn the truth, which is almost always disappointing relative to the story they were told.

My advice is consistently: Don't spend money you need for something else, and don't assume that the "interpretation" of your genetics will last more than two months.

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genetic ancestry

testing

genealogy

Sahlins and Chagnon

Essential reading today for anthropologists: Serena Golden's account of how Marshall Sahlins resigned from the National Academy of Sciences: "A Protest Resignation".

Sahlins' resignation highlights two serious and ongoing debates within anthropology: one, the appropriate relationship -- if any -- between anthropologists and the military (Sahlins has previously expressed his opposition to any such involvement); two, the role of hard science within the discipline.

...

Asked to offer his opinion on Sahlins' move, [Napoleon] Chagnon wrote in an e-mail, "I am surprised that Sahlins resigned from the NAS to protest my election last year to the NAS. One possible interpretation is that he is displeased with the gradual swing back to to the academic principle that scientists should tell the truth in their publications...."

I think it's time to reclaim the name "anthropology" from this earlier generation.

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history of anthropology

metascience

White House policy on data access

The White House this week announced a new policy on public access to results from federally funded research. The announcement has gotten

Michael Eisen comments: "No celebrations here: why the White House public access policy sucks".

The administration fell hook line and sinker for the ridiculous argument put forth by publishers that the only way for researchers and the public to get the servies they provide is to give them monopoly control over the articles for a year – the year when they are of greatest potential use.

Think about how absurd this is. Publishers, whose role should be to disseminate information as widely as possible, are now the only reason why the public will continue to not have access to research results their tax dollars paid for.

Why is Eisen so exercised? Here's an excerpt from the White House policy memo describing the policy on publication access:

In developing their public access plans, agencies shall seek to put in place policies that enhance innovation and competitiveness by maximizing the potential to create new business opportunities and are otherwise consistent with the principles articulated in section 1.

Agency plans must also describe, to the extent feasible, procedures the agency will take to help prevent the unauthorized mass redistribution of scholarly publications.

In other words, it's no longer just a matter of copyright agreements with publishers; now the federal agencies themselves must help police PDF sharing among researchers. I wonder where "mass redistribution" will kick in.

Further, the memo does not set a 12-month access embargo as a maximum, it directs agencies to adopt the 12-month embargo as a guideline. There is a lot not to like in the memo.

Most of the public attention to the decision has been directed at the effects on scientific publications. I have long been interested in a second area: the public access to data generated by federally funded research.

The White House Office of Science and Technology Policy last year requested public comment on two questions: open dissemination of federally-funded research and open access to data resulting from federally-funded research. I commented last year in response to the OSTP request ("Public interests in data from federally funded research") about the value of data to scientists and others who are not members of federally funded labs. The present announcement from the White House did not indicate how these comments from last year may have contributed to the decision, but it includes general recommendations on both publication and data access.

As it stands, the text of the memo essentially keeps in place the data access requirements established under the Bush administration. That is not a bad thing, and indeed the recommendations listed in the memo seem very reasonable. I quote them here at length:

Each agency’s public access plan shall:

a) Maximize access, by the general public and without charge, to digitally formatted scientific data created with Federal funds, while:

i) protecting confidentiality and personal privacy,

ii) recognizing proprietary interests, business confidential information,and intellectual property rights and avoiding significant negative impact on intellectual property rights, innovation, and U.S. competitiveness, and

iii) preserving the balance between the relative value of long-term preservation and access and the associated cost and administrative burden;

b) Ensure that all extramural researchers receiving Federal grants and contracts for scientific research and intramural researchers develop data management plans, as appropriate, describing how they will provide for long-term preservation of, and access to, scientific data in digital formats resulting from federally funded research, or explaining why long-term preservation and access cannot be justified;

c) Allow the inclusion of appropriate costs for data management and access in proposals for Federal funding for scientific research;

d) Ensure appropriate evaluation of the merits of submitted data management plans;

e) Include mechanisms to ensure that intramural and extramural researchers comply with data management plans and policies;

f) Promote the deposit of data in publicly accessible databases, where appropriate and available;

g) Encourage cooperation with the private sector to improve data access and compatibility, including through the formation of public-private partnerships with foundations and other research funding organizations;

h) Develop approaches for identifying and providing appropriate attribution to scientific data sets that are made available under the plan;

i) In coordination with other agencies and the private sector, support training, education, and workforce development related to scientific data management, analysis, storage, preservation, and stewardship; and

j) Provide for the assessment of long-term needs for the preservation of scientific data in fields that the agency supports and outline options for developing and sustaining repositories for scientific data in digital formats, taking into account the efforts of public and private sector entities.

These recommendations are all basically already in the NSF data access policies, meaning that the new White House memo will maintain the status quo at that level.

The problem is that the current policy is toothless. Continued data access is a very serious problem threatening the integrity of science. Self-archiving and institutional archiving have been sufficient to pass data management portions of grant applications, but have proven to be woefully insufficient to enable access to data. Meanwhile, some fields have intensive data collection but very little or no data entering the public domain as part of digital repositories. The recommendations listed above do nothing to change the current situation.

Nevertheless there is some room within the recommendations for agency directors to take bolder action on data access. Section (j) perhaps provides the best hope. If federal funding agencies actually assess the long-term needs of each field supported by funding, many (including anthropology) will clearly benefit from the establishment of standard digital repositories.

I hope that NSF will not sit on its current policy but will instead work to extend access more broadly. At the same time, I wish the White House had given clearer guidance to enable the creation of digital repositories and to require their standard use as a condition of continued funding of research projects.

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data access

open access

metascience

Dino size estimation

I know I'm linking a four-year-old post about dinosaurs, but I got this SV-POW post on my feed this morning and it is very relevant to those of us who think about variation among fossil hominins: "Brachiosaurus: both bigger and smaller than you think". Let's call it upcycling.

Maybe the most interesting thing about this is that, so far as we can tell, XV2 was almost exactly the same size as the holotype individual of Sauroposeidon. So anything I or anyone else has written about Sauroposeidon being bigger, absolutely, than Brachiosaurus, is bobbins. Sauroposeidon still had a considerably longer neck, 11.5 meters to XV2′s 9.5, but the cervical skeleton weighed about the same thanks to the higher air space proportion in Sauroposeidon. In fact, if the higher ASP of Sauroposeidon applied to the rest of the vertebral column, then the holotype individual of Sauroposeidon might have weighed less than XV2!

Much was published about the body size of australopithecines before a good male skeleton was found. Attempts to estimate body mass from single skeletal elements in hominins have a large associated estimation error. Human body size estimation by regression is very different from that within other ape species, because our different locomotor patterns load the hindliimb differently.

In this light, it is always frustrating to see very many conclusions based upon the body size estimate of any single skeleton. This is an argument made most effectively by Richard Smith, who wrote a classic review paper on the errors of interpretation that can spring from neglecting the error associated with body size estimation [1]. Individuals do not evolve. They are imperfect representations of variable populations.

References

Smith RJ. Biology and body size in human evolution. Current Anthropology. 1996;37:451–481.

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body mass

non-primate

statistics

Wisdom of Mann

Steve Mirsky caught up with Alan Mann for a recent Scientific American 60-second podcast: "Third Molars Illustrate Differential Reproduction". The result is a classic.

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Alan Mann

teeth

selection

Lucy returns to public display in California

The Orange County Register covers the final exhibition of the famous "Lucy" skeleton in the United States, at the Bowers Museum in Santa Ana, California: "Famous fossil Lucy makes a final stop at Bowers".

Lucy returned to the Houston Museum of Natural Science, where her remains were kept in storage for about four years. Thus, the Bowers waited for about five years to present this show.

"I think the Ethiopians thought it was time to let it rest," Keller said. "Frankly, the rumor was that the Americans stole Lucy and she's never coming back. And, of course, anyone in government there knew that that was not the case."

Recently, Ethiopia expressed a desire to bring Lucy back, particularly so an exhibit at the National Museum of Ethiopia in Addis Ababa could coincide with the African Union's next meeting in May.

Four years is 10 percent of the time Lucy has been out of the ground.

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museums

Lucy

A. afarensis

Tracing teeth troubles with fossil bacteria

Ed Yong has a great account today of some research from Alan Cooper's lab on the oral microbiome in pre-agricultural and post-agricultural Europeans: "Prehistoric Plaque and the Gentrification of Europe’s Mouth".

The hunter-gatherers had a diverse array of bacteria including several groups that are associated with good health. That fits with the relative absence of tooth decay or gum disease among modern or prehistoric hunter-gatherers. “They were at the end of a long period of happy co-evolution between us and oral bacteria,” says Cooper.

The advent of farming disrupted that tango. After the Agricultural Revolution, as humans began to chow down upon barley, wheat and other domesticated crops, the diversity of the mouth microbes fell, and species associated with oral diseases became more common. “Eating all this soft squishy carbohydrate and leaving it lying around the base of your teeth is effectively inviting in a whole new range of bugs to take up permanent residence in your mouth,” says Cooper.

I'll have some more comments on this new research when I can sit down to write them up. I've been waiting for this to come out for quite a long time -- I first heard about the research almost three years ago. The potential to characterize oral ecology across time is immense, and we have some excellent data on dental pathologies across the entire timespan. Caries and other dental pathologies are very new in human populations, and although starchy diets have been blamed, very little has been known about how oral bacteria themselves may have become more pathogenic over time. This study is really great because it opens a new door to looking at this evolution across time. We will need to compare this record with the evidence for morphological change in teeth across the same time span. Smaller teeth may have been a consequence of selection associated with dental pathology in agricultural peoples.

Next we will need to compare across space -- including greater sampling of oral microbiome variation among living humans. This is another new area in which we know more about prehistoric people than we do about living human variation!

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Education, not television, for science participation

Alice Bell comments on the non-interactivity of the most common means of science popularization: "Science on TV: it's not dumb, but it could be smarter".

I especially worry that science is often rendered as something to be simply consumed by the public. If we're using the metaphor of scientific "literacy", it's "read-only" research. Retelling science for explanatory or entertainment purposes might give us a great picture of what the scientific idea looks like but often removes a lot about how the scientists got to these conclusions. It doesn't show the workings of science or share the more slippery science-in-the-making, meaning it's harder to critique or get involved with (or simply enjoy these processes as entertaining and educational in themselves). I'd like to see an attempt to share the means of production of science, not just sell its products.

I note that actually participating in science is what we do in education. Transforming a television program from a passive experience to an active one would help transform its nature from informative to educational.

We can equally come at this from the other side. Why not take education and make broader use of storytelling, filming, and multimedia resources? Frozen Planet and other BBC productions have done much to show how technological progress in filming and broadcasting have enabled cinema-like qualities in long-form TV documentaries. These technologies are also transforming the classroom. We won't have cinema-quality, highly-edited classroom productions, not without a radical reallocation of effort and resources on the part of faculty. But we can produce material that would have been broadcast quality several years ago, and we can make it available anywhere the internet goes.

The trick is maintaining, or even increasing, the level of interactivity as we engage larger numbers of students online, potentially across multiple institutions and the public. I have some ideas for that, some of which will be rolling out over the next few months.

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