Tag Archives: archaeology

Racial migrations and human genetics: The “game changer” in the South Pacific that wasn’t – part 3

John Edward Terrell and Kevin M. Kelly


This is part 3 of a 3 part commentary


How many immigrants does it take to make a migration?

When presented with a sample comprising only 3+1 skulls, both scientific caution and parsimony suggest you should assume that colonists coming ashore back at the beginning of human history in Vanuatu and Tonga were probably more diverse, biologically speaking, than is witnessed by these four—at least until there is further evidence showing they did indeed come not just from a genetically homogeneous place of origin, but also a place where the inhabitants were as sui generis as they appear to be vis-à-vis others on earth (Skoglund et al. 2016: fig. 1b).

Logic such as this is well worth attending to. But in this instance, there is an equally logical way to get around the usual working assumption that people are likely to be more diverse than first appearances may suggest. Given how poorly specified are the two hypotheses under scrutiny here, it is anyone’s guess how big  we are supposed to think the boats must have been that brought early colonists to Vanuatu and Tonga around three thousand years ago. Even granting they may have arrived in more than one canoe, it would be reasonable to assume those arriving were fairly few in numbers. If so, then there is no need to assume blindly that those who came ashore in Vanuatu or Tonga constituted a representative (random) sample of the real human genetic diversity among those back home in the places where they came from, wherever on earth that was (Terrell 1986).

Furthermore, this is not all that might be reasonably assumed when trying to pin down the who, what, where, why, and when behind these four skulls. The number of pioneering colonists arriving  in canoes from elsewhere with them or before them may not only have been relatively few. They may also have been kin, i.e., biologically related to one another. If so, then possibly what makes these crania look sui generis in comparison with other people on earth, living and dead, may just be that we are seeing a “family resemblance” in these human remains (Terrell 1986; Walker and Hill 2014).

“Figure 1 New Guinea’s place in the southwestern Pacific (bathymetry downloaded from http://ingrid.ldeo.columbia.edu/SOURCES/ .WORLDBATH/.bath/based on the ETOPO5 5 · 5 min Navy data base).” Source: Terrell 2006: fig. 1
Homeward bound

For journalists and others, the real mystery of these remains, of course, is where these pioneers or their immediate forebears sailed from when they launched their boats to start a new life elsewhere. What is now known or can be reasonably assumed, therefore, about places to the west where they may have sailed from?

Until the Holocene stabilization of sea levels in the southwestern Pacific around 8,000–6,000 years ago, it is likely that much of the northern coastline of New Guinea was steep and uninviting of human settlement (as much of it still is today) except perhaps where favorable local circumstances may have at least temporarily trapped sediment in sandbars, coastal lagoons, and small river deltas. Little is currently known archaeologically about this coastline, which runs east-west for roughly 1,500 miles (2,400 km), and which would logically have been the most likely route between Asia and the farther reaches of the Pacific (Golitko et al. 2016). The best guess at the moment is that few people lived along this coast for the first 35,000–45,000 years of human history in the Pacific (Terrell 2006). In effect, earth and sea conspired to isolate New Guinea, like a sleeping giant, from frequent contact with islanders elsewhere both to the east in what is now popularly called Melanesia, and to the west in Island Southeast Asia (for biological support for this inference, see: Matisoo-Smith 2016: 391).

Following the Holocene stabilization of sea levels, however, coastal areas in Southeast Asia and the Pacific began to develop into rich floodplains, river deltas, and lagoons. By the mid Holocene, it is probable that people in the island realms to the east and west of New Guinea began to deal with one another back-and-forth more often as coastal people began to travel with greater reach along this immense island’s lengthy northern coastline (Torrence and Swadling 2008).

West meets East

Contrary to the notion that there are only two hypotheses about the prehistoric human settlement of the more remote islands in the Pacific east of New Guinea, there are numerous variants not only of those two old ideas but of others, too (for a recent review, see: Matisoo‐Smith 2016). Here we will introduce only one plausible reconstruction (Terrell, in press).

Initial baseline assumptions
  • Archaeologists now think people have been living in Southeast Asia for 50,000 years or so, and perhaps for not quite so long in the islands just east of New Guinea as far as Bougainville in the Northern Solomons.
  • The gradual flooding of the Sunda paleocontinent in what is now Southeast Asia since the Last Glacial Maximum ~21,000 years ago created extensive coastal environments that were ecologically rich and productive (Sathiamurthy and Voris 2006; Hanebuth et al. 2011: fig. 2). Similar extensive flooding did not occur in the area east of New Guinea labeled as Parkinson’s Islands (after the early ethnologist Richard Parkinson) on the map above (Lavery et al. 2016).
  • Due to this environmental advantage, it is probable that there were far more people living in Southeast Asia 6,000 years ago than there were in Parkinson’s Islands.
  • By the mid Holocene—contrary to the prevailing assumption in historical linguistics that doesn’t take this ecological advantage into consideration—it is probable that languages classifiable as Austronesian were widely spoken throughout Wallacea and elsewhere in Southeast Asia even as far north as Taiwan. But not yet in Parkinson’s Islands which had been isolated from Asia by the island of New Guinea.
  • Throughout the Late Pleistocene and early Holocene, Wallacea and Parkinson’s Islands were both areas of the Pacific where the advantages of travel by sea rather than by land nurtured the use of canoes and the development of local navigational methods and skills.
  • Canoes equipped with outriggers and sails were invented in Southeast Asia at some point in the Late Pleistocene or early Holocene. Simple dugout canoes remained the predominant boat type used for travel among coastal communities in Parkinson’s Islands.
Illustration taken from Labillardiere, (1800). Atlas pour servir a la relation du voyage de la recherche de la Perouse. Page Plate 43. Paris. Source: Labillardiere. (1800). Buka Island canoe (Solomon Islands) [digital image]. http://www.dspace.cam.ac.uk/handle/1810/239987 Modeling the relocation of immigrants from Wallacea
“The word proa comes from perahu, the word for “boat” in Malay.” Source: https://commons.wikimedia.org/wiki/File:Proa_(PSF).png
Modeling the relocation of immigrants from Wallacea
  1. A small Austronesian-speaking hamlet or village community left home for some particular local reason or reasons from somewhere in Wallacea—or possibly on the north coast of New Guinea—and made landfall in the Bismarck Archipelago.
  2. It is possible that wherever it was they came ashore, they arrived not as strangers but rather as old friends of some of the local people there in the Bismarcks (Terrell 2015).
  3. Among these immigrants were individuals skilled at pottery-making, and also skilled in the arts and rituals of building and sailing outrigger canoes with sails. Both of these technologies were new to the Bismarcks region. Moreover, such skills may not have arrived at the same time if travel back-and-forth between communities in Wallacea, northern New Guinea, and the Bismarcks became routine at least for awhile.
  4. The local people not only welcomed them, but often also acquired new ways of doing things—such as the art of pottery-making—from their immigrant neighbors, in some instances even their foreign language skills. The reverse may have also been true.
  5. Time passed, generations came and went. For now unknown reasons, it eventually became fashionable, prestigious, or perhaps even necessary for some people in the Bismarcks to set sail for islands yet farther to the south and east in the Pacific, although how many people in how many communities were involved, how often they sailed away, and for how many years this voyaging away from home in the Bismarcks went on are now all unknown and perhaps unknowable. 
  6. Even so, considering the passage of the time between (a) the first arrival of immigrants from the west and (b) the departure of some people generations later to settle down in other (more remote) places to the southeast, there is no reason to insist that these two separate episodes of human resettlement were similarly inspired or motivated (Walker and Hill 2014).
  7. Furthermore, given that both the voyaging technology and navigational skills required to colonize the more remote islands of the Pacific may have been available then only in some communities in the Bismarcks, it is not surprising that early settlers in Vanuatu, Tonga, and elsewhere had similar material culture traits (i.e., the so-called “Lapita cultural complex”).
Conclusions

Because the first immigrants who reached Vanuatu and Tonga were entering a vast and uninhabited part of the Pacific, it is probably not surprising that many nowadays have been seduced by the modern global distribution of Austronesian languages—from Madagascar to Rapa Nui (Easter Island) and from New Zealand to Taiwan—into thinking that such a vast geographic compass could only be the historical product of some kind of massive human migration that was singularly intentional and singularly premeditated from the very moment the first Austronesian-speaking immigrant stepped into the first canoe to sail from somewhere in island Southeast Asia  or on the north coast of New Guinea to the Bismarcks 3,000 and more years ago. It is wise to remember, therefore, that appearances can be deceiving.

Furthermore, today we know nothing about marriage (or sexual) practices in the Pacific in the prehistoric past. Although it is stating the case too simply, we do know that the basic building block of human genetic relatedness is the gene. Anyone who knows about the birds and the bees knows that genes can travel far and wide through sexual intercourse even if the people carrying them may only get as far away from home during their time on earth as the next village or two down the road. Consequently, there is no a priori reason to assume that race = language = culture. Or that genes necessarily traveled the Pacific millennia ago as the exclusive and enduring “property” of a massive and self-contained ethnic or ethnolinguistic migration that was able to keep its collective act together over thousands of miles and for hundreds, even thousands, of years. As some anthropologists like to say it, we need models of Pacific prehistory to work with that are “on the ground,” not “pie in the sky.”

Although we have been talking here almost exclusively about the Pacific Islands, the issue at stake is a global one. It is not just worrisome to find that even scientists may sometimes be unaware of the intellectual racism hidden in the conviction that the story of our species is a tale about ancestry, ancient migrations, and admixture. Commonsense ideas like these can be more than misleading. They can lend credence to other notions and old prejudices that can be harmful and sometimes deadly.  

Acknowledgments

We thank Ethan Cochrane, Mark Golitko, Tyrone Lavery, Lisa Matisoo-Smith, and Robin Torrence for assistance in the preparation of this 3-part commentary.

References

Bellwood, Peter. 2011. Holocene population history in the Pacific region as a model for worldwide food producer dispersals. Current Anthropology 52: S363–S378.

Gibbons, Ann. 1994. Genes point to a new identity for Pacific pioneers. Science 263: 32–33, p. 32.

Gibbons, Ann. 2001. The peopling of the Pacific. Science 291: 1735–1737.

Golitko, Mark, Ethan E. Cochrane, Esther M. Schechter, and Jason Kariwiga. 2016. Archaeological and Palaeoenviromental Investigations Near Aitape, Northern Papua New Guinea, 2014. Journal of Pacific Archaeology 7: 139–150.

Green, Roger C. 2003. The Lapita horizon and traditions – signature for one set of oceanic migrations. In C. Sand (ed.), Pacific Archaeology: Assessments and Prospects. Le Cahiers de l’Archéologie en Nouvelle-Calédonie 15. Nouméa: Service de Musées et du Patrimoine de Nouvelle-Calédonie, pp. 95-120.

Hanebuth, Till JJ, Harold K. Voris, Yusuke Yokoyama, Yoshiki Saito, and Jun’ichi Okuno. 2011. Formation and fate of sedimentary depocentres on Southeast Asia’s Sunda Shelf over the past sea-level cycle and biogeographic implications. Earth-Science Reviews 104: 92-110.

Lavery, Tyrone H., Andrew D. Olds, Jennifer M. Seddon, and Luke K‐P. Leung. 2016. The mammals of northern Melanesia: speciation, ecology, and biogeography.” Mammal Review 46: 60–76.

Matisoo-Smith, Elizabeth A. 2016. Human biology and population histories in the Pacific–Is there such thing as a Lapita people?. In: The Routledge Handbook of Bioarchaeology in Southeast Asia and the Pacific Islands, edited by M. Oxenham and H. Buckley, pp. 389–408. Routledge, London.

Sathiamurthy, E. V. H. K., and Harold K. Voris. 2006. Maps of Holocene sea level transgression and submerged lakes on the Sunda Shelf. The Natural History Journal of Chulalongkorn University, Supplement 2: 1-43.

Skoglund, Pontus, Cosimo Posth, Kendra Sirak, Matthew Spriggs, Frederique Valentin, Stuart Bedford, Geoffrey R. Clark, et al. 2016. Genomic insights into the peopling of the Southwest Pacific. Nature 538: 510–513.

Specht, Jim, Tim Denham, James Goff, and John Edward Terrell. 2014. Deconstructing the Lapita cultural complex in the Bismarck Archipelago. Journal of Archaeological Research 22: 89-140.

Specht, Jim, Chris Gosden, Carol Lentfer, Geraldine Jacobsen, Peter J. Matthews, and Sue Lindsay. 2016. A pre-Lapita structure at Apalo, Arawe Islands, Papua New Guinea. The Journal of Island and Coastal Archaeology: 1-22.

Terrell, John. 1986. Causal pathways and causal processes: Studying the evolutionary prehistory of human diversity in language, customs, and biology. Journal of Anthropological Archaeology 5: 187-198.

Terrell, John Edward. 2006. Human biogeography: Evidence of our place in nature. Journal of Biogeography 33: 2088-2098.

Terrell, John Edward. 2015. A Talent for Friendship. Oxford University Press.

Terrell, John Edward. In press. Understanding Lapita as history. In Oxford Handbook of Prehistoric Oceania, edited by Ethan Cochrane and Terry Hunt. Oxford University Press.

Terrell, John Edward, John Edward, Terry L. Hunt, and Chris Gosden. 1997. The dimensions of social life in the Pacific: Human diversity and the myth of the primitive isolate. Current Anthropology 38: 155–195.

Terrell, John Edward, Kevin M. Kelly, and Paul Rainbird. 2001. Foregone conclusions: In search of “Austronesians” and “Papuans.” Current Anthropology 42: 97–124.

Torrence, Robin, and Pamela Swadling. 2008. Social networks and the spread of Lapita. Antiquity 82: 600–616.

Walker, Robert S., and Kim R. Hill. 2014. Causes, consequences, and kin bias of human group fissions. Human Nature 25: 465-475.

© 2017 John Edward Terrell and Kevin M. Kelly. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Racial migrations and human genetics: The “game changer” in the South Pacific that wasn’t – part 2

John Edward Terrell and Kevin M. Kelly


This is part 2 of a 3 part commentary


Necessary, plausible, and sufficient

Nobody, as far as we know, has come up with a universally accepted checklist of what makes a scientific hypothesis about anything something worth paying attention to. There are three criteria, however, that strike us as items that ought to be on such a checklist. Here is how we see these three applying to the conclusions now being made about the biological origins of the Polynesians.

Visualization by David Eccles of the two popularly assumed racial migrations from Asia out into the Pacific. Source: https://commons.wikimedia.org/wiki/File:Polynesian_Migration.svg
  1. Necessity: What needs to be explained? Both of the hypotheses weighed by the 31 contributors to the paper in Nature (Skoglund et al. 2016) under discussion here are alternative ways of trying to understand certain widely accepted observations about islanders in the Pacific: (a) people in Polynesia speak languages assigned by linguists to the Austronesian (Malayo-Polynesian) family, as do many people in Melanesia and Island Southeast Asia; (b) archaeologists now generally agree that what they have labeled the “Lapita cultural complex”* dating to ca 3300–2800 cal BP (Specht et al. 2016) exhibits a mix of cultural traits, some local to Melanesia and others apparently having roots to the west in Island Southeast Asia (Specht et al. 2014); and (c) the Lapita skulls found in Vanuatu and Tonga are morphologically and genetically sui generis (as the authors of this paper note, in some respects these four individuals are unique unto themselves).
  2. Plausibility: The two hypotheses considered by this consortium of scholars differ in their plausibility. (a) The idea that people traveled directly from Taiwan to Vanuatu and Tonga is basically impossible to assess given that nothing is said about how they might have done so—a striking omission considering the major dimensions of space and time involved. (b) The second hypothesis put on the table is similarly deficient, but it at least acknowledges that the set of material culture traits associated with the four Lapita skeletons in Vanuatu and Tonga wasn’t  imported in toto direct from Taiwan.
  3. Sufficiency: As Richard Levins observed years ago, truth is the intersection of independent lies. (a) Not only are the two hypotheses considered by this consortium of authors basically left unspecified, but (b) no reason is given for limiting the field of possible hypotheses solely to the two considered by these contributors.
The problem of equifinality

In light of #2 and #3 just noted, consider the old cliché “there is more than one way to skin a cat.” If you are a feline lover, there is even another way of saying more or less the same thing. As the biologist Ludwig von Bertalanffy made famous in the last century, you can call it equifinality. However phrased, it is wise to remember there is usually more than one way to get from A to Z, or even just A to B. The corollary relevant to the present discussion is that one cannot just assert that B came from A without offering a sufficient explanation for how that would have been possible. And more to the point, granting for the sake of discussion that B did somehow come from A, the scientific way of doing the job that needs to be done entails offering more than just 1–2 inadequately specified hypotheses.

The absence of evidence is not evidence of absence

According to these 31 authors: “our modelling indicates that Philippine populations (Kankanaey) are the closest outgroup to the First Remote Oceanians [i.e., these 4 skulls], indigenous Taiwanese (Atayal) second closest, and mainland southeast Asians such as the Dai most remote, consistent with models of population movement along a route from Taiwan to the Philippines to Near Oceania to Remote Oceania.” Maybe yes, maybe no.

Recall that only 14 of the 83 places in their modern comparative genetics sample are located in Island Southeast Asia, and none of the other 69 localities included in their analysis is in the region between the Philippines and northern New Guinea except for a single sample of 10 individuals from Sulawesi. Now look at a map of the region in question (see below).

“Figure 1 | Data from ancient and present-day populations. a, Locations of 778 present-day individuals genotyped on the Affymetrix Human Origins Array and 4 ancient individuals (red symbols).” Source: Skoglund et al. 2016: fig. 1a. Note: blue letters A and B added to the original.

Note two things, in particular. First, if it is true, as the song goes, that it’s a long, long way to Tipperary, then it is an even longer way from (A) Taiwan to (B) Tonga—more than 5,300 miles (8,500 km) in a straight line if a bee could fly that way that far. Second, notice the total lack of genetics samples from the big gap between the Philippines and the Bismarck Archipelago east of New Guinea (the few samples from New Guinea don’t count for reasons we will not go into here).

You don’t have to be a grumpy skeptic, therefore, to ask: if the four Lapita skulls from Vanuatu and Tonga look genetically most like people today in the Philippines, what about folks today, say, in the Moluccas and Halmahera off the Bird’s Head region of western New Guinea? And possibly also people living along  the north coast of New Guinea itself? Must we assume these four individuals from Vanuatu and Tonga somehow came all the way from Taiwan or the Philippines to come ashore there?[*]

Part 3: How many immigrants does it take to make a migration?


* The three skulls from Vanuatu were not found with the rest of their skeletons (Skoglund et al. 2016: supplementary notes). How they had been buried as well as their condition as skulls prior to burial suggest they had been cared for as portable heirlooms for an unknown period of time after death: “Ancient DNA was successfully obtained from three skulls from striking mortuary contexts: a jar burial containing a single skull (B17), an alignment of three skulls lying on the chest of a skeleton without a skull (B10B)”. There is a possibility that these individuals might have been long dead before their skulls arrived in Vanuatu. In contrast, with regard to the single individual from Tonga: “Ancient DNA was successfully obtained from the right petrous bone of burial SK10, a single primary interment of an adult female . . .”.


References

Bellwood, Peter. 2011. Holocene population history in the Pacific region as a model for worldwide food producer dispersals. Current Anthropology 52: S363–S378.

Gibbons, Ann. 1994. Genes point to a new identity for Pacific pioneers. Science 263: 32–33, p. 32.

Gibbons, Ann. 2001. The peopling of the Pacific. Science 291: 1735–1737.

Golitko, Mark, Ethan E. Cochrane, Esther M. Schechter, and Jason Kariwiga. 2016. Archaeological and Palaeoenviromental Investigations Near Aitape, Northern Papua New Guinea, 2014. Journal of Pacific Archaeology 7: 139–150.

Green, Roger C. 2003. The Lapita horizon and traditions – signature for one set of oceanic migrations. In C. Sand (ed.), Pacific Archaeology: Assessments and Prospects. Le Cahiers de l’Archéologie en Nouvelle-Calédonie 15. Nouméa: Service de Musées et du Patrimoine de Nouvelle-Calédonie, pp. 95-120.

Hanebuth, Till JJ, Harold K. Voris, Yusuke Yokoyama, Yoshiki Saito, and Jun’ichi Okuno. 2011. Formation and fate of sedimentary depocentres on Southeast Asia’s Sunda Shelf over the past sea-level cycle and biogeographic implications. Earth-Science Reviews 104: 92-110.

Lavery, Tyrone H., Andrew D. Olds, Jennifer M. Seddon, and Luke K‐P. Leung. 2016. The mammals of northern Melanesia: speciation, ecology, and biogeography.” Mammal Review 46: 60–76.

Matisoo-Smith, Elizabeth A. 2016. Human biology and population histories in the Pacific–Is there such thing as a Lapita people?. In: The Routledge Handbook of Bioarchaeology in Southeast Asia and the Pacific Islands, edited by M. Oxenham and H. Buckley, pp. 389–408. Routledge, London.

Sathiamurthy, E. V. H. K., and Harold K. Voris. 2006. Maps of Holocene sea level transgression and submerged lakes on the Sunda Shelf. The Natural History Journal of Chulalongkorn University, Supplement 2: 1-43.

Skoglund, Pontus, Cosimo Posth, Kendra Sirak, Matthew Spriggs, Frederique Valentin, Stuart Bedford, Geoffrey R. Clark, et al. 2016. Genomic insights into the peopling of the Southwest Pacific. Nature 538: 510–513.

Specht, Jim, Tim Denham, James Goff, and John Edward Terrell. 2014. Deconstructing the Lapita cultural complex in the Bismarck Archipelago. Journal of Archaeological Research 22: 89-140.

Specht, Jim, Chris Gosden, Carol Lentfer, Geraldine Jacobsen, Peter J. Matthews, and Sue Lindsay. 2016. A pre-Lapita structure at Apalo, Arawe Islands, Papua New Guinea. The Journal of Island and Coastal Archaeology: 1-22.

Terrell, John. 1986. Causal pathways and causal processes: Studying the evolutionary prehistory of human diversity in language, customs, and biology. Journal of Anthropological Archaeology 5: 187-198.

Terrell, John Edward. 2006. Human biogeography: Evidence of our place in nature. Journal of Biogeography 33: 2088-2098.

Terrell, John Edward. 2015. A Talent for Friendship. Oxford University Press.

Terrell, John Edward. In press. Understanding Lapita as history. In Oxford Handbook of Prehistoric Oceania, edited by Ethan Cochrane and Terry Hunt. Oxford University Press.

Terrell, John Edward, John Edward, Terry L. Hunt, and Chris Gosden. 1997. The dimensions of social life in the Pacific: Human diversity and the myth of the primitive isolate. Current Anthropology 38: 155–195.

Terrell, John Edward, Kevin M. Kelly, and Paul Rainbird. 2001. Foregone conclusions: In search of “Austronesians” and “Papuans.” Current Anthropology 42: 97–124.

Torrence, Robin, and Pamela Swadling. 2008. Social networks and the spread of Lapita. Antiquity 82: 600–616.

Walker, Robert S., and Kim R. Hill. 2014. Causes, consequences, and kin bias of human group fissions. Human Nature 25: 465-475.

© 2017 John Edward Terrell and Kevin M. Kelly. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Racial migrations and human genetics: The “game changer” in the South Pacific that wasn’t – part 1

John Edward Terrell and Kevin M. Kelly


Here’s a hint about why scholars can be so captivated by what is basically an old-fashioned racial migration argument. They are apparently forgetting what they have been taught about the difference between a rhetorical argument and a scientific one.

The is part 1 of a 3 part commentary


THE IDEA THAT ONCE UPON A TIME the many islands of the South Pacific were colonized by different racial migrations out of Asia or the Americas (the latter a minority view) is as old as the hills. Or at any rate, at least as old as the earliest known encounters after 1492 between Europeans and the people living there.

1852 Bocage Map of Australia and Polynesia. The colored boundary lines show how this part of the world has long been subdivided into four cartographic regions labeled here as Malaisie (Malaysia), Micronesie (Micronesia), Polynesie (Polynesia), and Melanesie (Melanesia). Source: https://upload.wikimedia.org/wikipedia/commons/a/a2/1852_Bocage_Map_of_Australia_and_Polynesia_-_Geographicus_-_Oceanie-bocage-1852.jpg

The apparent remoteness and isolation of these islands and their inhabitants have long fueled the notion that here, if not necessarily elsewhere on earth, “race, language, and culture” all formerly tracked one another so closely that today, for instance, language differences can still be used successfully—and scientifically—not only to circumscribe and label separate “populations” in the Pacific (e.g., as different “ethnolinguistic groups,” ‘races,” and the like), but can also tell us how to reconstruct the prehistory and ancient migrations of separate and distinct “peoples” out into Oceania (Terrell et al. 1997).

It is generally considered impolite to say so, but the conventional word for this type of thinking is the word racism.

What seems astonishing is that racial thinking like this still frames how archaeologists, linguists, historians, social anthropologists, and human geneticists think about Pacific Islanders and write about their past. The most recent instance of this almost universal practice is possibly also the most revealing example of why otherwise informed scholars find themselves still under the spell of such an antiquated and unscientific idea.

Melanesians and Polynesians

As early as 1813 James Cowles Prichard was formally proposing—as others had earlier done more anecdotally—that the inhabitants of the Pacific Islands starting with New Guinea and neighboring places and moving on out eastward could be divided into “two principal classes.” In his own words (quoted in: Terrell et al. 2001):

The tribes which belong to the first of these are, strictly speaking, savages. They are universally in that rude unimproved state, which precedes all division of professions and employments. Consequently their political condition is that of perfect equality without any difference of ranks. Their physical character is of the rudest kind. Their form and complexion
approximate to those of the Negro.

Pritchard called these rude savages “the race of the Papuas.” Others would come to favor instead the term “Melanesians” (i.e., “black islanders”). He did not offer a name to use for the other—and supposedly superior—class of people except to say that such tribes were to be found in “the more distant regions of the Pacific Ocean.”

By 1843, his uncertainty about how to label the latter class of tribes had been resolved in favor of calling them “Malayo-Polynesians” since by then “a real kindred, or community of origin” had been established “by affinity of language” between islanders in Southeast Asia (i.e., “Malays”) and those in the more remote parts of Oceania, who were by then often labeled as Polynesians (i.e., “people of the many islands”).

Today the favorite label for the “affinity of language” noted by Pritchard and others in the 19th century between people in Polynesia and some of the inhabitants of Island Southeast Asia is the linguist’s label Austronesian.  Nowadays, too, those said to be in Pritchard’s so-called class of savages are generally called “Papuans,” although the label “Melanesians” is also still used by some.

Racial redux

Under the headline “‘Game-changing’ study suggests first Polynesians voyaged all the way from East Asia,” Ann Gibbons, a writer at Science magazine who had written previously about the origins of the Polynesians (Gibbons 1994, 2001), announced in surprisingly unqualified terms on 3 October 2016 that the identity of the first settlers of Polynesia was at last known, thanks to a paper then just published in Nature reporting on the first genome‑wide study of ancient DNA from  prehistoric Polynesians (Skoglund et al. 2016). Lo and behold, their ancestors were ancient East Asian mariners “who swept out into the Pacific. It wasn’t until much later that Melanesians, probably men, ventured out into Oceania and mixed with the Polynesians.”

To clinch the story, she then quotes experts who apparently ought to know what they are talking about.

“The paper is a game‑changer,” says Cristian Capelli, a population geneticist at the University of Oxford in the United Kingdom, noting that that it settles a decades‑long dispute. By showing that the East Asians hopscotched past islands already populated by Melanesians without picking up their genes, it is also a case study in how culture can initially bar mixing between groups. “Farmers move in and don’t mix much with the hunter‑ gatherers,” says evolutionary geneticist Mark Thomas of University College London. “We see this again and again and again” elsewhere in the world.

Not so fast

The late population geneticist and mathematical ecologist Richard Levins is famous in scientific circles for once having declared in no uncertain terms that “truth is the intersection of independent lies.’’  Given that what Gibbons, Capelli, and Thomas are saying is intellectually—if not necessarily politically—racist, why are they so confident? Particularly since the claim being endorsed is based on DNA extracted from only four skulls dating to around 3,000 or so years ago (three from Vanuatu, and one from the Tongan Islands) compared with the DNA of less than 800 present-day individuals from 83 places in Asia and Oceania.

To a cautious statistical mind, such figures ought to raise the worry that not enough is known about human genetic variation in this part of the world to warrant going far out on a limb by declaring resolutely that science has now told us not only where the ancestors of the Polynesians came from, but also how.

Add to this concern the additional information that all four of the women in the archaeological sample from the Pacific display their strongest apparent genetic ties with Taiwan—currently the most popular place to start the purported ancient migration to Polynesia—and with the Philippines.* Does a modern comparative DNA sampling of 778 individuals from 83 places in Asia and Oceania tell us enough about genetic similarities and differences throughout this immense region to overrule the reasonable doubt that linking the four prehistoric women with present-day people in Taiwan and the Philippines wasn’t exactly an unpredictable finding? Isn’t it reasonable to suspect this study might be biased, i.e., is an example of looking specifically for something—a genetic connection with Taiwan, in particular—where you most hope to find it?

Two alternative stories

The research report in Nature that Ann Gibbons wrote about in Science last October has 31 credited authors, a global mix of geneticists and archaeologists. Their report starts off with the assertion: “Pacific islanders today derive from a mixture of two highly divergent ancestral populations.” These authors then go on to tell us that there are two alternative stories—they call them hypotheses—about these two primal races (a word they do not use), and they say they now know which of the two to believe.

Both stories accept as true the unstated premise that biology, language, and culture co-vary closely with one another. The first story is an old tale still favored by some archaeologists (Bellwood 2011). If (a) race, language, and culture co-vary, and (b) Polynesians today speak languages of Southeast Asian origin (i.e., Austronesian, formerly called “Malayo-Polynesian”), then (c) it follows that the ancestors of the Polynesians came from Southeast Asia.  The second story is a more recent alternative reconstruction of Polynesian origins (Green 2003). If (a) race, language, and culture co-vary, and (b) the so-called “Lapita cultural complex” archaeologically associated with the first settlers of Polynesia is a cultural mix of Southeast Asian and Melanesian traits, then (c) the Polynesians racially must also be of similarly mixed biological origin.

Needless to say, these collaborators would not have written their report if they had found they couldn’t adjudicate the right choice between these two alternative stories. And they do not disappoint us: “Our study has shown that many of the first humans in Remote Oceania had little, if any, Papuan ancestry, in stark contrast [an odd choice of words?] to the situation today.” And if so, the second story evidently can’t be correct, right?

But this is not all they have to conclude. In their estimation: “Systematic study of ancient DNA from throughout Remote Oceania should make it possible to provide a detailed chronicle of the population movements and sex-biased population mixtures that shaped the ancestry of present-day Oceanians.”

Should we accept as true what they tell us? Is there a better way to think about what they report? In other words, what’s the chance they have been barking up the wrong stories altogether?

Part 2: Necessary, plausible, and sufficient


*  Only 14 of the 83 places in their comparative sample are located in Island Southeast Asia; 2 of these are on Taiwan and 6 in the Philippines. None of the other 69 localities is in the region between the Philippines and northern New Guinea except for a single sample of 10 individuals from Sulawesi. We return to these figures in Part 2 of this commentary.


References

Bellwood, Peter. 2011. Holocene population history in the Pacific region as a model for worldwide food producer dispersals. Current Anthropology 52: S363–S378.

Gibbons, Ann. 1994. Genes point to a new identity for Pacific pioneers. Science 263: 32–33, p. 32.

Gibbons, Ann. 2001. The peopling of the Pacific. Science 291: 1735–1737.

Golitko, Mark, Ethan E. Cochrane, Esther M. Schechter, and Jason Kariwiga. 2016. Archaeological and Palaeoenviromental Investigations Near Aitape, Northern Papua New Guinea, 2014. Journal of Pacific Archaeology 7: 139–150.

Green, Roger C. 2003. The Lapita horizon and traditions – signature for one set of oceanic migrations. In C. Sand (ed.), Pacific Archaeology: Assessments and Prospects. Le Cahiers de l’Archéologie en Nouvelle-Calédonie 15. Nouméa: Service de Musées et du Patrimoine de Nouvelle-Calédonie, pp. 95-120.

Hanebuth, Till JJ, Harold K. Voris, Yusuke Yokoyama, Yoshiki Saito, and Jun’ichi Okuno. 2011. Formation and fate of sedimentary depocentres on Southeast Asia’s Sunda Shelf over the past sea-level cycle and biogeographic implications. Earth-Science Reviews 104: 92-110.

Lavery, Tyrone H., Andrew D. Olds, Jennifer M. Seddon, and Luke K‐P. Leung. 2016. The mammals of northern Melanesia: speciation, ecology, and biogeography.” Mammal Review 46: 60–76.

Matisoo-Smith, Elizabeth A. 2016. Human biology and population histories in the Pacific–Is there such thing as a Lapita people?. In: The Routledge Handbook of Bioarchaeology in Southeast Asia and the Pacific Islands, edited by M. Oxenham and H. Buckley, pp. 389–408. Routledge, London.

Sathiamurthy, E. V. H. K., and Harold K. Voris. 2006. Maps of Holocene sea level transgression and submerged lakes on the Sunda Shelf. The Natural History Journal of Chulalongkorn University, Supplement 2: 1-43.

Skoglund, Pontus, Cosimo Posth, Kendra Sirak, Matthew Spriggs, Frederique Valentin, Stuart Bedford, Geoffrey R. Clark, et al. 2016. Genomic insights into the peopling of the Southwest Pacific. Nature 538: 510–513.

Specht, Jim, Tim Denham, James Goff, and John Edward Terrell. 2014. Deconstructing the Lapita cultural complex in the Bismarck Archipelago. Journal of Archaeological Research 22: 89-140.

Specht, Jim, Chris Gosden, Carol Lentfer, Geraldine Jacobsen, Peter J. Matthews, and Sue Lindsay. 2016. A pre-Lapita structure at Apalo, Arawe Islands, Papua New Guinea. The Journal of Island and Coastal Archaeology: 1-22.

Terrell, John. 1986. Causal pathways and causal processes: Studying the evolutionary prehistory of human diversity in language, customs, and biology. Journal of Anthropological Archaeology 5: 187-198.

Terrell, John Edward. 2006. Human biogeography: Evidence of our place in nature. Journal of Biogeography 33: 2088-2098.

Terrell, John Edward. 2015. A Talent for Friendship. Oxford University Press.

Terrell, John Edward. In press. Understanding Lapita as history. In

Oxford Handbook of Prehistoric Oceania, edited by Ethan Cochrane and Terry Hunt. Oxford University Press.

Terrell, John Edward, John Edward, Terry L. Hunt, and Chris Gosden. 1997. The dimensions of social life in the Pacific: Human diversity and the myth of the primitive isolate. Current Anthropology 38: 155–195.

Terrell, John Edward, Kevin M. Kelly, and Paul Rainbird. 2001. Foregone conclusions: In search of “Austronesians” and “Papuans.” Current Anthropology 42: 97–124.

Torrence, Robin, and Pamela Swadling. 2008. Social networks and the spread of Lapita. Antiquity 82: 600–616.

Walker, Robert S., and Kim R. Hill. 2014. Causes, consequences, and kin bias of human group fissions. Human Nature 25: 465-475.

© 2017 John Edward Terrell and Kevin M. Kelly. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Challenging our assumptions about the antiquity of trade and social networks in Middle Stone Age Africa

Nature human behavior has just published a research highlight written John Carson about work at the Sibilo School Road Site in Kenya done by Nick Blegen, Harvard University, that has recovered large quantities of obsidian along with Middle Stone Age (MSA) tools . The finds are thought to date back at least 200 kyr.

As Carson summarizes: “Geochemical analyses demonstrated that the majority of obsidian pieces had their provenance at a source site >160 km away, indicating long-distance transport of raw materials during the MSA.” Previously, East African sites evidencing long-distance resource transport have all be less than <50 kyr old.

Evidently known MSA sites of this age are rare in East Africa. If more sites can be found and excavated, the “big story” usually told about the evolution of human social behavior may need updating: far-reaching resource networks and/or intergroup trade in raw materials could have developed earlier than generally believed in the history of our species. If so, then in Carson’s words: “we may gain greater insight into the timeline of social evolution that eventually led to our modern group behaviours.”

Blegen’s report was just published (unfortunately behind a paywall) in the Journal of Human Evolution. Here is the abstract you will find available there for free:

Abstract

This study presents the earliest evidence of long-distance obsidian transport at the ∼200 ka Sibilo School Road Site (SSRS), an early Middle Stone Age site in the Kapthurin Formation, Kenya. The later Middle Pleistocene of East Africa (130–400 ka) spans significant and interrelated behavioral and biological changes in human evolution including the first appearance of Homo sapiens. Despite the importance of the later Middle Pleistocene, there are relatively few archaeological sites in well-dated contexts (n < 10) that document hominin behavior from this time period. In particular, geochemically informed evidence of long-distance obsidian transport, important for investigating expansion of intergroup interactions in hominin evolution, is rare from the Middle Pleistocene record of Africa. The SSRS offers a unique contribution to this small but growing dataset. Tephrostratigraphic analysis of tuffs encasing the SSRS provides a minimum age of ∼200 ka for the site. Levallois points and methods of core preparation demonstrate characteristic Middle Stone Age lithic technologies present at the SSRS. A significant portion (43%) of the lithic assemblage is obsidian. The SSRS obsidian comes from three different sources located at distances of 25 km, 140 km and 166 km from the site. The majority of obsidian derives from the farthest source, 166 km to the south of the site. The SSRS thus provides important new evidence that long-distance raw material transport, and the expansion of hominin intergroup interactions that this entails, was a significant feature of hominin behavior ∼200 ka, the time of the first appearance of H. sapiens, and ∼150,000 years before similar behaviors were previously documented in the region.

© 2016 Elsevier Ltd. All rights reserved

Is archaeology a science? 3. Problem solving

John Edward Terrell


This is part 3 of a 3 part commentary


Storytelling

There is nothing inherently bad or wrong about telling stories. In truth, our brains are always telling ourselves stories about all sorts of things. For example, figuring out what you need to buy at the supermarket. Or when it would be OK to cross the street. Or why your boss should give you a promotion at work. In short, stories are not always fictional accounts. They can also be factual.

While the thought may sound strange at first, even scientists tell stories to themselves and others (Terrell 1990). In truth, storytelling can be a creative way for them to develop new ideas and plausible explanations, say, about  badly broken bones dug up at an archaeological site in Kenya—although instead of calling them stories, scientists would probably label them as hypotheses (see: fig. 2).

Figure 2. Science differs from other kinds of storytelling is a critical way. Changing (a) the evidence available, (b) the assumptions made about the world and how things work when interpreting that evidence, or (c) the interpretations made (i.e., the working hypotheses) can also change the other two dimensions of the scientific endeavor.
Darwin’s famous letter

In a famous letter to a colleague in 1861, Charles Darwin reflects on what it means to do science:

About 30 years ago there was much talk that Geologists ought only to observe & not theorise; & I well remember some one saying, that at this rate a man might as well go into a gravel-pit & count the pebbles & describe their colours. How odd it is that every one should not see that all observation must be for or against some view, if it is to be of any service.

People writing about how science is done love to quote these words because, as Michael Shermer, a columnist at Scientific American, remarked a number of years ago: “If scientific observations are to be of any use, they must be tested against a theory, hypothesis or model. The facts never just speak for themselves. They must be interpreted through the colored lenses of ideas: percepts need concepts.”

Boiled down to a few words, therefore, what both scientists and lawyers call evidence isn’t evidence until it can be pinned to convincing stories about it. Hence, viewed from Darwin’s perspective, Lahr and her colleagues had been tasked with a research assignment that was a lot like counting pebbles and describing their colors. This kind of Plug & Play task has long been commonplace in archaeology because accidental discoveries and nowadays cultural resource salvage work are routine in this scholarly arena. Being routine, however, does not make a research assignment science. As Darwin said, all observation must be for or against some view if it is to be of any service.

The major reason Plug & Play archaeology isn’t science is that stories (hypotheses) about things (evidence) must be for or against stories that are bigger—scientists call them concepts, theories, models, and the like— than the kinds of particular stories that get called hypotheses.[*] Or if you are a trial lawyer, criminal indictments.

Stories, big and small

If hypotheses are stories about particular situations and things, then what makes concepts, models, theories, and so forth bigger stories? Philosophers love to argue about the answer, but I am not a philosopher. I will give you the answer that makes sense to me. Instead of calling them concepts, theories, models, and so forth, just call them assumptions.

The 25 grand challenges to archaeology  noted earlier are grounded on so many assumptions about how the world works and what needs to be better known to do archaeology right in the future that one is left almost speechless. In a more constrained fashion, the stories Lahr and her colleagues tell us about bones from Kenya similarly make allusions to grand assumptions about what life was like during the early Holocene, about the inherent violence or pacifism of human nature, and so forth. In both cases, it seems clear that the persuasive goal in part is to justify doing archaeology by relating particular issues to broad, general assumptions (sometimes called themes) that are compelling and sometimes seemingly quite magnificent in their scope and assumed relevance to the human condition.

“What’s the problem?”

Evidence, hypotheses, assumptions . . .  how do these components of the scientific endeavor fit together (Fig. 2)? Again, philosophers of science love to debate such a question, but here is a hands-on way to resolve it. Ask the “So what?” question that kicked off this commentary in a different way, one that is not just being more polite. It is also a more meaningful way to get to the heart of the issue. Ask instead “What’s the problem here?”

Critics of archaeology, anthropology, and the social sciences generally are likely to fault these fields of scholarly expertise in one or both of two ways. One is methodological, and might be expressed using the old cliché “you can’t get there from here.” In a word, there is doubt about whether the social sciences are rigorous enough in their objectivity, verifiability, and generality to merit being called real science. The other is more elusive and judgmental. Is the problem being tackled by the research work in question really worth doing?

One way of trying to avoid being on the receiving end of this second kind of criticism is to make the purpose of what you are doing elusive. A common way of trying to accomplish this dubious end is to make grand allusions in the opening paragraphs of a research report to work previously published on the same or a comparable theme (concept, hypothesis, model, theory, etc.) and then move swiftly on to discuss methods & materials, analysis, and the like.

This popular avoidance tactic is unlikely to work, however, when the critic is someone like Lamar Smith.

The intersection of independent lies

In 1966 the late biologist Richard Levins published a short paper on the role of model building in population biology that is now a classic in the philosophy and practice of science. One of his observations back then has become famous: “truth is the intersection of independent lies.’’ As he explains, the human mind can only cope with a few variables at one time, and almost any plausible proposed relation among aspects of nature is likely to be true in the sense that it occurs (although rarely and slightly). “Yet all models leave out a lot and are in that sense false, incomplete, inadequate. The validation of a model is not that it is ‘true’ but that it generates good testable hypotheses relevant to important problems” (Levins 1966).

Forty years after this article was published, Levins felt called upon to explain himself anew. Here, in part, is what he wrote:

In the dispute about climate change, a rising temperature in several cities is suggestive. Adding more cities to the list gives a diminishing return. But independent lines of evidence—ocean temperatures, cores from glaciers, decline of coral reefs, spread of species into places that had been too cold for them, accumulation of greenhouse gasses—each may have some separate idiosyncratic explanation or source of error but jointly converge on an unavoidable conclusion. We have to seek lines of evidence as independent as we can in order to support a large scale conclusion. (Levins 2006)

In other words, to do great science, you have to do different things based on different ways of looking at the problem being studied.

As I have said before, there is no disputing taste, and what one person judges to be a problem in need of solving may be seen as less worthy, even trivial, by someone else. The least I can do is offer two examples with the understanding you may not see them as grand, and therefore, may not be impressed that archaeologists are attempting to tackle the problem being addressed.

Two archaeological challenges to conventional wisdom

While perhaps not a universal truth, many people will tell you in one way or another that human beings come in different and enduring kinds that can be labeled variously as communities, races, ethnic groups, populations, societies, or cultures (Terrell 2012). As I have noted elsewhere at SCIENCE DIALOGUES,  such thinking is the bedrock of racism and social conflicts around the world.

My archaeological colleague John P. Hart at the New York State Museum and I have separately looked at this undeniable problem using different archaeological and ethnographic material culture datasets from entirely different regions of the globe—in Hart’s studies, northeastern North America (e.g., Hart et al. 2016), and in my work, the Sepik coast of Papua New Guinea (e.g., Terrell 2010). Our goals, however, have been similar. We want to see if material culture studies support the notion—the popular conviction—that people come in discrete social and biological “kinds,” and if they do, how long-lived such fundamental building blocks of humanity may be.

As Hart and his colleagues recently reported, archaeological sequences based on pottery designs have often been used by scholars to identify ethnic ties among prehistoric settlements in eastern North America, and to hypothesize population movements over the landscape through time. Recent work by his research team using ceramic motifs and social network analysis challenges these conventional interpretations of the archaeological record and the principles underlying them. Network analysis of local and regional pottery design sequences, for example, suggests that rather than being ethnic markers, ceramic designs were used to signal inclusion in social and political networks crosscutting supposed ethnic and political boundaries in this part of North America. Moreover:

With a very robust archaeological record that has produced evidence for major shifts in settlement patterns, regional coalescences of village populations, changes in regional strife, and ultimately the development of confederacies, southern Ontario is an excellent area to investigate how signaling networks adapt as a result of socio-political and settlement system changes.

Similarly, work by myself and others on New Guinea’s northern Sepik coast since 1990 suggests that isolation by distance had led to some geographic patterning in cultural variation among communities on this coast prior to World War I. However, the patterning of similarities and differences in their material culture inventories offers little empirical support for the conventional assumption accepted by anthropologists, government officials, missionaries, and others that there is “a strong relation between language and material culture”  (Moore and Romney 1994) among villages communities in this part of the world. When seen in the broader perspectives of geography, human ecology, and time, as the old saying goes, appearances can be deceiving.

Conclusions

Science can be viewed as a continuous conversation among  evidence, hypotheses, and assumptions.  Some scientific conversations however ponderously expressed are trivial, merely chit-chat, so to speak. Other conversations are far more meaningful. If archaeologists want to be seen as substantial scholars and productive scientists, they have the same obligations all other scientists have. They must be clear and forthright about the problems they are addressing, and why those problems deserve the respect—and yes, the financial support—of others.

Grand challenges are inspirational, but they must be brought down to earth if what archaeologists dig up or study in museums is to add up to something worthwhile.


* As Richard Levins (2009: 744) has written, something is basically nonsense if it does not help us answer any questions other than about itself.


This is part 3 of a 3 part commentary

Acknowledgments

I thank John Hart for his help with this commentary.

References

Binford, Lewis R. 1962. Archaeology as anthropology. American Antiquity 28: 217-225.

Hart, John P., Termeh Shafie, Jennifer Birch, Susan Dermarkar, and Ronald F. Williamson. 2016. Nation building and social signaling in southern Ontario: AD 1350–1650. PloS One 11, no. 5: e0156178.

Jones, Sharyn. 2016. Anthropological archaeology in 2015: Entanglements, reflection, reevaluation, and archaeology beyond disciplinary boundaries. American Anthropologist 118: 301-316.

Kintigh, Keith W., Jeffrey H. Altschul, Mary C. Beaudry, Robert D. Drennan, Ann P. Kinzig, Timothy A. Kohler, W. Fredrick Limp et al. 2014a. Grand challenges for archaeology. Proceedings of the National Academy of Sciences 111: 879-880.

Kintigh, Keith W., Jeffrey H. Altschul, Mary C. Beaudry, Robert D. Drennan, Ann P. Kinzig, Timothy A. Kohler, W. Fredrick Limp, Herbert D. G. Maschner, William K. Michener, Timothy R. Pauketat, Peter Peregrine, Jeremy A. Sabloff, Tony J. Wilkinson, Henry T. Wright, and Melinda A. Zeder. 2014b. Grand challenges for archaeology. American Antiquity 79: 5-24.

Lahr, M. Mirazón, F. Rivera, R. K. Power, A. Mounier, B. Copsey, F. Crivellaro, J. E. Edung et al. 2016. Inter-group violence among early Holocene hunter-gatherers of West Turkana, Kenya. Nature 529: 394-398.

Levins, Richard. 1966. The strategy of model building in population biology. American Scientist 54:421–431.

Levins, Richard. 1993. A response to Orzack and Sober: formal analysis and the fluidity of science. Quarterly Review of Biology 68:547–555.

Mizoguchi, Koji. 2015. A future of archaeology. Antiquity 89: 12-22.

Moore, Carmella C., and A. Kimball Romney. 1994. Material culture, geographic propinquity, and linguistic affiliation on the North coast of New Guinea: A reanalysis of Welsch, Terrell, and Nadolski (1992). American Anthropologist 96: 370-396.

Terrell, John. 1990. Storytelling and prehistory. Archaeological Method and Theory 2: 1-29.

Terrell, John Edward. 2010. Language and material culture on the Sepik coast of Papua New Guinea: Using social network analysis to simulate, graph, identify, and analyze social and cultural boundaries between communities. Journal of Island & Coastal Archaeology 5: 3-32.

Terrell, John Edward. 2012. Polynesians and the seductive power of common sense. Cultural Geographies 20: 135–152.

Terrell, John, Hunt, Terry L., and Gosden, Chris. 1997. The dimensions of social life in the Pacific: Human diversity and the myth of the primitive isolate. Current Anthropology 37: 155-195.

Yu, Pei-Lin, Matthew Schmader, and James G. Enloe. 2015. “I’m the oldest new archaeologist in town”: The intellectual evolution of Lewis R. Binford. Journal of Anthropological Archaeology 38: 2-7.

© 2017 John Edward Terrell. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Is archaeology a science? 2. “Plug & Play” archaeology

John Edward Terrell


This is part 2 of a 3 part commentary


New and improved archaeology?

In 1962 the archaeologist Lewis R. Binford had an article published in the journal American Antiquity titled “Archaeology as anthropology”  that electrified the field of academic research into things ancient and not so ancient (Binford 1962). Many saw this paper as a call to turn away from just counting potsherds and pretending to write history toward doing real science in the realm of historical studies (Yu et al. 2015).

Nancy Stone and Lew Binford on an Acheulean site at Yediyapur in the Hunsgi Valley, South India, June 1986. Source: http://antiquity.ac.uk/tributes/binford.html

Since those halcyon days of the 1960s and what came to be called “processual archaeology,” professionals and amateurs alike have voiced strong doubts about whether archaeology is a science. Some have more or less utterly rejected Binford’s claim that archaeologists could be or should be scientists—an unwillingness to play along with Binford and those who would follow in his footsteps that, needless to say, plays right into the hands of someone like Congressman Lamar Smith (Jones 2016; Mizoguchi 2015).

Lewis Binford died in 2011. Despite his many naysayers, the archaeologist Mark Leone observed in a memorial appreciation of the man and his work published in the British journal Antiquity that Binford had unquestionably shown the rest of us “his astonishing capacity to connect archaeological things to the questions that mattered.”

Which raises an obvious concern. What kinds of questions might these be?

Ask no small questions

In 2012, a number of archaeologists, mostly Americans, decided they needed to come up with a list of questions for archaeologists to tackle in the years ahead. The resulting compendium, billed as “Grand challenges for archaeology,” was published in 2014 in the Proceedings of the National Academy of Sciences (PNAS) (Kintigh et al. 2014a).

“The challenges had to be, in principle,” they agreed, “susceptible to a solution supported by data.” In all they came up with 25 worthy concerns. Reading through the listing makes it clear they concluded no challenge too big was beyond the scope of archaeology. Borrowing words from their published report:

These challenges focus on understanding the dynamics of cultural processes and the operation of coupled human and natural systems, recognizing that humans—mediated by culture—both affect and are affected by their natural environments. The challenges addressed questions of emergence, complexity, demography, mobility, identity, resilience, and human–environment interactions. There is a notable lack of concern with the earliest, the largest, and the otherwise unique.

What sorts of challenges are among the 25 listed? They are grouped into five separate categories labeled A–D. Here is a selection of five, one drawn from each category. Keep in mind as you read through them that these five are alike said to be within the reasonable pursue of archaeologists working as archaeologists.

A.7:  What is the role of conflict—both internal factional violence and external warfare—in the evolution of complex cultural formations?

B. 4:  How does ideology structure economic, political, and ritual systems?

C.1:  What processes led to, and resulted from, the global dispersal of modern humans?

D.2:  How do people form identities, and what are the aggregate long-term and large-scale effects of these processes?

E.7:  How do humans perceive and react to changes in climate and the natural environment over short- and long-terms?

What seems most astonishing about these five and the remaining 20 others is that none of these identified challenges said to be of global significance is accompanied by clear statements—specific research hypotheses—that might be taken to be unambiguously testable using archaeologically recovered empirical data. Not one. Yet the claim is made, nonetheless, that

the facts of the past provide the evidence that is essential to confront all of these questions. We harbor no illusions about the difficulties of addressing these classes of problems. Rather, we share a conviction that these are the domains in which the most important problems reside.

These scholars note at the end of their PNAS commentary that they have made a longer version of their collective statement available in American Antiquity (Kintigh et al. 2014b). However, whether what they outline there in more detail would satisfy Congressman Smith is questionable. With regard to challenge A.7, for example, they say:

Exploring the dialectical relationship between conflict and complex cultural formations will undoubtedly foster new approaches to the archaeological record. Conflict is notoriously difficult to identify and quantify through archaeological remains. Though some methods have been developed, more systematic and large-scale analyses are certainly necessary before this question can be thoroughly explored. These methods will involve innovations in osteology and molecular anthropology, as well as advances in comparative studies of material culture and technology.

Plug & Play archaeology

You don’t need to be as skeptical nor as dismissive as Lamar Smith to wonder what these experts have in mind to do in the years ahead to give substance to their 25 grand challenges. Being neither clairvoyant nor a mind-reader, the best anyone else can do is suggest what might or might not fit the bill—if not for Lamar Smith, at least for others.

First, therefore, what wouldn’t meet these challenges? There are many possible ways to answer such a provocative  question. Here is one. Archaeologists should avoid doing Plug & Play archaeology (fig. 1). What does my pairing of these two words refer to? Here is an example.

Figure 1. Source: the author

In January 2016 Marta Lahr at Cambridge University and her colleagues made the cover of the prestigious science journal Nature with a detailed report on human remains dating back about 10,000 years to the early Holocene that had been excavated at Nataruk in northern Kenya (Lahr et al. 2016). Some of the skeletons recovered have traumatic lesions suggesting the probable cause of death (see: fig. 1, left). Not surprisingly perhaps, given this seemingly gruesome physical testimony, Lahr and her co-authors inferred that they had in hand evidence of inter-group violence against people who, given the antiquity of the remains, were probably wandering hunter-gatherers rather than settled agriculturalists.

Now if you were Lamar Smith you might be asking yourself right now “So what?” At the close of their Nature report, Lahr and her colleagues acknowledge directly that the apparent violence attested at Nataruk might be an “ephemeral, but perhaps not unusual, event in the life of prehistoric foraging societies.” Before then in their report, however, and certainly in the press coverage around the world that this report quickly received, what is featured are possible stories about interpersonal violence that could be told given such ancient cold-case injuries.

Both in their report in Nature and in subsequent popular accounts, the central claim made is that these scholars have caught humanity red-handed doing something fundamental—and nasty—long ago strongly hinting that violence is, as many still popularly assume, one of the defining characteristics of our species.

Here is where plug & play come into operation. All that it takes to reach this kind of conclusion about ourselves as human beings is evidence such as these fossil bones (fig. 1, left), a few seemingly reasonable assumptions about human nature (fig. 1, center), and before you know it, you have a story to tell (fig. 1, right).

In fairness, it must be said that at the end their report, Lahr and her co-authors do comment that Nataruk may be showing us little more than “a standard antagonistic response to an encounter between two social groups.” But then why write about these bones, and why feature them on the cover of Nature?

There is no disputing taste, and these authors have clearly done a good job of coming up with what might be said about these prehistoric finds. But “plugging” them into an interpretation—into a story—however appealing is not what STEM education is all about, and surely not what someone like Lamar Smith would take to be real science. It may be true, as these authors conclude at the very end of their report in Nature, that “the deaths at Nataruk are testimony to the antiquity of inter-group violence and war.” So what?

But if not Plug & Play archaeology, then what?

Part 3: Problem solving 

References

Binford, Lewis R. 1962. Archaeology as anthropology. American Antiquity 28: 217-225.

Hart, John P., Termeh Shafie, Jennifer Birch, Susan Dermarkar, and Ronald F. Williamson. 2016. Nation building and social signaling in southern Ontario: AD 1350–1650. PloS One 11, no. 5: e0156178.

Jones, Sharyn. 2016. Anthropological archaeology in 2015: Entanglements, reflection, reevaluation, and archaeology beyond disciplinary boundaries. American Anthropologist 118: 301-316.

Kintigh, Keith W., Jeffrey H. Altschul, Mary C. Beaudry, Robert D. Drennan, Ann P. Kinzig, Timothy A. Kohler, W. Fredrick Limp et al. 2014a. Grand challenges for archaeology. Proceedings of the National Academy of Sciences 111: 879-880.

Kintigh, Keith W., Jeffrey H. Altschul, Mary C. Beaudry, Robert D. Drennan, Ann P. Kinzig, Timothy A. Kohler, W. Fredrick Limp, Herbert D. G. Maschner, William K. Michener, Timothy R. Pauketat, Peter Peregrine, Jeremy A. Sabloff, Tony J. Wilkinson, Henry T. Wright, and Melinda A. Zeder. 2014b. Grand challenges for archaeology. American Antiquity 79: 5-24.

Lahr, M. Mirazón, F. Rivera, R. K. Power, A. Mounier, B. Copsey, F. Crivellaro, J. E. Edung et al. 2016. Inter-group violence among early Holocene hunter-gatherers of West Turkana, Kenya. Nature 529: 394-398.

Levins, Richard. 1966. The strategy of model building in population biology. American Scientist 54:421–431.

Levins, Richard. 1993. A response to Orzack and Sober: formal analysis and the fluidity of science. Quarterly Review of Biology 68:547–555.

Mizoguchi, Koji. 2015. A future of archaeology. Antiquity 89: 12-22.

Moore, Carmella C., and A. Kimball Romney. 1994. Material culture, geographic propinquity, and linguistic affiliation on the North coast of New Guinea: A reanalysis of Welsch, Terrell, and Nadolski (1992). American Anthropologist 96: 370-396.

Terrell, John. 1990. Storytelling and prehistory. Archaeological Method and Theory 2: 1-29.

Terrell, John Edward. 2010. Language and material culture on the Sepik coast of Papua New Guinea: Using social network analysis to simulate, graph, identify, and analyze social and cultural boundaries between communities. Journal of Island & Coastal Archaeology 5: 3-32.

Terrell, John Edward. 2012. Polynesians and the seductive
power of common sense. Cultural Geographies 20: 135–152.

Terrell, John, Hunt, Terry L., and Gosden, Chris. 1997. The dimensions of social life in the Pacific: Human diversity and the myth of the primitive isolate. Current Anthropology 37: 155-195.

Yu, Pei-Lin, Matthew Schmader, and James G. Enloe. 2015. “I’m the oldest new archaeologist in town”: The intellectual evolution of Lewis R. Binford. Journal of Anthropological Archaeology 38: 2-7.

© 2017 John Edward Terrell. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Is archaeology a science? 1: The “So what?” question

John Edward Terrell


           Is archaeology more than storytelling with the help of            visual aids and esoteric props?

This is part 1 of a 3 part commentary


The brahmin sport?

Back in the early 1960s when I was an undergraduate, I was asked by a graduate student in my department what I wanted to be when I grew up. That may not have been the phrasing of the question, but that was the spirit of his inquiry. This individual was the self-identified son of an academically famous father. When I told him I wanted to be an archaeologist, his response didn’t surprise me, although I will leave it to you to decide why I wasn’t taken aback by his retort. With an air of seeming good humor, he quipped: “Ah, the brahmin sport.”

I have no idea who were the particular brahmins he had in mind. Perhaps he was thinking of Agatha Christie and Max Mallowan, or maybe Lord Carnarvon of King Tutankhamun fame. In any case, by the 1960s such a quip was off target.

Agatha Christie (2nd from the left), Max Mallowan (center, with cigarette), and others at the ancient Sumerian city of Nippur in southern Iraq. Source: https://www.penn.museum/blog/collection/archival-practice/mystery-in-the-stacks-a-discovery-is-made-in-the-museum-archives/.
A waste of the taxpayer’s money?

The National Science Foundation was established by an Act of Congress in 1950 to “promote the progress of science; to advance the national health, prosperity, and welfare; and to secure the national defense.” All well and good perhaps, but whether social sciences such as anthropology and archaeology should be viewed as rigorous enough in their objectivity, verifiability, and generality to be included under the umbrella of the NSF was a matter of great and continuing contention even before the establishment of this government agency. Nevertheless, by 1958 an office for the social sciences had been established at the NSF despite the fact, as one board member commented in 1958, “we have to face up to the fact that the social sciences—except for a few extremely limited areas—are a source of trouble beyond anything released by Pandora.”

Given the availability of federal funding for research in the social sciences, anthropology and archaeology by the 1960s were no longer beholden to the whims or the fanatical ideas of the rich and socially privileged. Provided, of course, the research proposals getting funded could convince not only peer reviewers in these disciplines, but Congress, too, that the work lucky enough to be funded was worthy of being labeled as “scientific” not just in name but also in deed.

As the saying goes, that was then, this is now. Over the course of the last half century or so has archaeology lived up to the prospect that it is a science? Or have archaeologists been pulling the wool over the eyes of congressmen and everyday civilians alike as often as some critics of archaeology—and anthropology—then and now contend?

Science—The Endless Frontier

Here’s a bit more history to ponder. World War II had brought the federal government into the arena of basic science research as never before in the history of the United States. Interest in Washington in supporting whatever could be done to win the war was clear and pressing.  Ignorance about what the world was like beyond our borders was no longer excusable and could be deadly. Even anthropologists and other scholars of the esoteric who had lived and worked in the Near East, Asia, and the Pacific found themselves being sought out for their advice and guidance in advancing the war effort (Terrell et al. 1997).

In 1945 Vannevar Bush, the engineer who had led the government’s wartime Office of Scientific Research and Development, wrote a report for President Roosevelt outlining the future for science in the nation cleverly titled Science—The Endless Frontier. He argued persuasively that government support for scientific research and education would prove beneficial to both the peacetime economy and national security. Arguing in graphic terms that scientific progress is essential, his report makes the stakes involved as down to earth as anyone can get: “Science, by itself, provides no panacea for individual, social, and economic ills. It can be effective in the national welfare only as a member of a team, whether the conditions be peace or war. But without scientific progress no amount of achievement in other directions can insure our health, prosperity, and security as a nation in the modern world.”

The newly found sense of relevance to solving the world’s problems carried over after the war in many of the academic disciplines that had hitherto defined themselves as being more about history and diversity than about pattern and process.  Notably geography, ecology, and natural history all experienced what soon came to be called the “quantitative revolution” marked by deliberate and carefully mastered efforts to make such previously descriptive studies more mathematical, more generalizing, and hence more “scientific.” And as I have already noted, eventually even the social sciences were able to convince federal decision makers that these so-called soft sciences were worthy of financial support.

But to repeat: that was then, this is now. And despite claims to the contrary, history can repeat itself.

The “So what?” question and STEM education

Lamar Smith, a Republican, has represented the 21st congressional district in Texas since 1987. He currently serves as the Chair of the House Committee on Science, Space, and Technology which has jurisdiction over programs at NASA, the Department of Energy, the Environmental Protection Agency, the National Science Foundation, the Federal Aviation Administration, and the National Institute of Standards and Technology. He supports Donald Drumpf on border security, not using federal tax dollars to fund abortions under the Patient Protection and Affordable Care Act (also known as Obamacare), and reigning in the “costly, overly burdensome regulations” of the Environmental Protection Agency. He is also strongly opposed to wasting taxpayer’s dollars funding frivolous or low-priority projects, particularly in the social sciences. In 2016, for example, Democrats in Congress viewed his actions as Committee Chair as “a political litmus test that would allow Smith and other Republicans to trim research by social scientists and those studying climate change.”

Lamar Smith evidently likes to take the social sciences head on. Currently, however, there are also less direct ways of challenging whether they are wasteful and frivolous. Take STEM, the acronym that stands for Science, Technology, Engineering, and Mathematics educational programs and curricula. In the words of one prominent advocacy group:

The STEM Education Coalition works aggressively to raise awareness in Congress, the Administration, and other organizations about the critical role that STEM education plays in enabling the U.S. to remain the economic and technological leader of the global marketplace of the 21st century. Members of the STEM Coalition believe that our nation must improve the way our students learn science, mathematics, technology and engineering and that the business, education, and STEM communities must work together to achieve this goal.

In November 2016 the Coalition sent a memorandum to President-elect Donald Trump titled “STEM Education, Good Jobs and American Prosperity.” Nowhere in this statement do the words “social science” or “humanities” occur. Furthermore, the memorandum notes, for instance, that the “top 10 bachelor-degree majors with the highest median earnings are all in STEM fields.”

Is archaeology science?
Koster Site, Kampsville, Illinois in the 1970s. Source: http://users.stlcc.edu/mfuller/koster.html

Few would question that archaeology can be fun, fascinating, entertaining, and an entirely worthwhile summer camping experience. How would cable channels such as Discovery and National Geographic keep the viewing audiences they have without the mysteries and thrilling excitement of archaeological discoveries in places near and far?

Source: https://commons.wikimedia.org/wiki/File:Stonehenge_(sun).jpg

Granting archaeology’s genuine entertainment value and emotional appeal may not, however, be good enough to position such work as worthwhile enough to merit taxpayer’s dollars. At least not in the eyes of someone like Lamar Smith.

Therefore, the question cannot be artfully avoided. Is archaeology more than storytelling? Is it also a science? An honest answer would have to be maybe yes, maybe sometimes.


Part 2: Plug & Play archaeology


References

Binford, Lewis R. 1962. Archaeology as anthropology. American  Antiquity 28: 217-225.

Hart, John P., Termeh Shafie, Jennifer Birch, Susan Dermarkar, and Ronald F. Williamson. 2016. Nation building and social signaling in southern Ontario: AD 1350–1650. PloS One 11, no. 5: e0156178.

Jones, Sharyn. 2016. Anthropological archaeology in 2015: Entanglements, reflection, reevaluation, and archaeology beyond disciplinary boundaries. American Anthropologist 118: 301-316.

Kintigh, Keith W., Jeffrey H. Altschul, Mary C. Beaudry, Robert D. Drennan, Ann P. Kinzig, Timothy A. Kohler, W. Fredrick Limp et al. 2014a. Grand challenges for archaeology. Proceedings of the National Academy of Sciences 111: 879-880.

Kintigh, Keith W., Jeffrey H. Altschul, Mary C. Beaudry, Robert D. Drennan, Ann P. Kinzig, Timothy A. Kohler, W. Fredrick Limp, Herbert D. G. Maschner, William K. Michener, Timothy R. Pauketat, Peter Peregrine, Jeremy A. Sabloff, Tony J. Wilkinson, Henry T. Wright, and Melinda A. Zeder. 2014b. Grand challenges for archaeology. American Antiquity 79: 5-24.

Lahr, M. Mirazón, F. Rivera, R. K. Power, A. Mounier, B. Copsey, F. Crivellaro, J. E. Edung et al. 2016. Inter-group violence among early Holocene hunter-gatherers of West Turkana, Kenya. Nature 529: 394-398.

Levins, Richard. 1966. The strategy of model building in population biology. American Scientist 54:421–431.

Levins, Richard. 1993. A response to Orzack and Sober: formal analysis and the fluidity of science. Quarterly Review of Biology 68:547–555.

Mizoguchi, Koji. 2015. A future of archaeology. Antiquity 89: 12-22.

Moore, Carmella C., and A. Kimball Romney. 1994. Material culture, geographic propinquity, and linguistic affiliation on the North coast of New Guinea: A reanalysis of Welsch, Terrell, and Nadolski (1992). American Anthropologist 96: 370-396.

Terrell, John. 1990. Storytelling and prehistory. Archaeological Method and Theory 2: 1-29.

Terrell, John Edward. 2010. Language and material culture on the Sepik coast of Papua New Guinea: Using social network analysis to simulate, graph, identify, and analyze social and cultural boundaries between communities. Journal of Island & Coastal Archaeology 5: 3-32.

Terrell, John Edward. 2012. Polynesians and the seductive
power of common sense. Cultural Geographies 20: 135–152.

Terrell, John, Hunt, Terry L., and Gosden, Chris. 1997. The dimensions of social life in the Pacific: Human diversity and the myth of the primitive isolate. Current Anthropology 37: 155-195.

Yu, Pei-Lin, Matthew Schmader, and James G. Enloe. 2015. “I’m the oldest new archaeologist in town”: The intellectual evolution of Lewis R. Binford. Journal of Anthropological Archaeology 38: 2-7.

© 2017 John Edward Terrell. This is an open-accessarticle distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Social network analysis: Hypothesis testing and what-if projections

John Edward Terrell


Please note: this commentary, recovered on 28-Jan-2017, was originally published in Science Dialogues on 13-June-2014.


GIVEN A RELIABLE DATABASE of information and a good computer program (such as Microsoft Excel), it is possible today to simulate a broad range of hypothetical real-world situations under differing possible opening and subsequent conditions (Embrechts and Hofet 2014). Said differently, by changing the parameters and values of a spreadsheet in meaningful ways it is possible to do informative what-if analyses of many kinds of situations—thereby gaining better understanding not only of possible but also plausible outcomes.

Similarly, it is possible to use a good network analysis program (such as UCINET; Borgatti et al. 2013) to simulate differing social situations and their plausible impacts. Here briefly described is one example based on research currently being done to explore the history of social networks along the north coast of Papua New Guinea.

Research question

During the last glacial maximum (~21,000 BP), sea-levels were ~125 m (410 ft) lower than they are today. It is likely that New Guinea’s northern coast was mostly a steep rocky shoreline offering few resources supporting human settlements (Chappell 1982).  As one consequence, New Guinea during the last Ice Age served more as a vicariant barrier than a land bridge between Asia and island Oceania (Terrell 2004).

Figure 1. New Guinea is the second largest island in the world. The northern coastline is over 1,600 miles (2,600 km) long. Shown here in comparison with the 48 mainland states in the U.S.A.

Both historical and archaeological evidence (Welsch and Terrell 1998; Terrell and Schechter 2011) suggests that villages on the northern coastline of New Guinea and the nearby offshore islands have been linked with one another by far-reaching social and economic networks for the past 2,000 years. An obvious and historically important question, therefore, is whether people and places there in the more distant past were similarly integrated in comparable widely-distributed communities of practice (Terrell n.d.).After the last Ice Age, however, sea levels rose steadily and then began to stabilize around their modern levels ~6,000–7,000 years ago. The resulting formation of coastal plains and environmentally productive lagoons and estuaries led to peak biodiversity (Hope and Haberle 2005) and probably also peak human population densities along this coastline between ~4000–2000 BP.

Materials and methods

Figure 2 shows two mini-max networks (Cochrane and Lipo 2010) drawn using UCINET 6 (version 6.289) and NetDraw (version 2.109) with the edges weighted at two different thresholds. The upper network shows the connectivity of places in this region given a maximal customary voyaging distance of 220 km or less—the greatest distance known to have been locally traversed during the Pleistocene and the mid-Holocene prior to ~3300 BP (Golitko and Terrell n.d.). The lower network has a threshold of 360 km—the greatest voyaging distance (from Makira-Ulawa in the Solomon Islands to Temotu in the Reefs/Santa Cruz group) documented as having been crossed during the first settlement of Remote Oceania ~3300–3100 BP (Irwin 1992).

Also shown in this figure are (a) the network positions (blue) of this region’s major sources of obsidian, a volcanic glass widely transported both historically and prehistorically in this region of the world; and (b) the location of our study area (red) on this coast in the Aitape district (Terrell and Schechter 2011).

Figure 2. Connectivity of obsidian sources (blue nodes) and Aitape (red node) on the Sepik coast of Papua New Guinea. Top: when the edge distance is 220 km or less; bottom: when it is 360 km or less (baseline image source: Mark L. Golitko). Likely cut lines in these networks projected using the Girvan-Newman algorithm (Girvan and Newman 2002) are shown here as heavy black lines. The same four groupings in the upper mapping occur at any assumed what-if linkage distance between 186 and 270 km.
Network analysis

Given these analyses, it is readily apparent that the what-if connectivity of these mappings differs markedly. Under the upper scenario, it can be hypothesized that obsidian from sources southeast of Aitape (they are on New Britain Island) has probably been transported from place to place at least as far west as Aitape, but it is less likely that obsidian from the other sources—located in the Admiralty Islands—has also arrived there despite the fact that these sources are geographically closer to our study area. The situation is different in the lower mapping. Instead of four probable groupings within the network shown, there are only two, and given this scenario, when obsidian has reached Aitape, it is more likely to have been mined at the nearer Admiralty sources.

Hypothesis testing

The presence of Admiralty Islands obsidian at prehistoric sites has not been securely documented archaeologically outside the Admiralty Group earlier than the mid 2nd millennium B.C. Its widespread popularity at Aitape and elsewhere in this part of the world thereafter is generally associated with suspected improvements in canoe-making design and technology thought to have been introduced from Island Southeast Asia around this same time (Specht et al. 2014; Terrell n.d.). However, it is also generally accepted that the movement of animals, obsidian, and people between islands and coastal villages was characteristic of life in this part of the world for many millennia before then—in other words, the suspected improvements in watercraft design and voyaging prowess did not initiate coastal and inter-island mobility in this region but instead made longer-distance travel more feasible and routine (Specht et al. 2014).

Figure 3. The actual geographic locations of the obsidian sources (blue dots) and the study area (red dot) at Aitape on the Sepik coast of Papua New Guinea.

While obsidian from Admiralty sources has been found at archaeological sites on the north coast of New Guinea that are younger than ~2000 BP, almost all of the obsidian that has been recovered archaeologically on mainland New Guinea older than ~3,500 BP has been sourced to the the Kutau/Bao locality on the Willaumez Peninsula of western New Britain (Summerhayes 2009).

Our fieldwork at Aitape in 1993/1994 and 1996 supported by the National Science Foundation ((BNS-8819618 and DBS-9120301)  discovered large quantities of obsidian and chert at localities along the former mid-Holocene shoreline (which at Aitape is now located several kilometers inland) including assemblages with notably high frequencies of  obsidian from New Britain marked by large average flake sizes (Golitko 2011)—an archaeological signature consistent with pre-2000 BP obsidian assemblages found elsewhere in northern Melanesia (Summerhayes 2009).

Therefore, given our two what-if network analyses and this archaeological evidence it may be hypothesized that obsidian has probably been indirectly available to people living in what is now the Aitape district ever since the stabilization of world sea levels around 6,000–7,000 years ago, but it is likely that the major sources of this natural glass prior to ~3,500 BP were those located on New Britain.

With funding from the National Science Foundation my colleague Dr. Mark Golitko is currently (June–July 2014) leading a research team at Aitape that is surveying archaeological sites there on the mid-Holocene (~5000 BP) shoreline (as reconstructed from estimated local uplift rates and sea-level records) to document how far-reaching or alternatively how restricted were cultural and material exchanges on this coast at that time. Discovering how isolated or widely linked communities at Aitape were during the mid-Holocene is  critical to understanding the patterning of modern human diversity in northern New Guinea and elsewhere in the Pacific (Terrell 2010a, 2010b).

Conclusions

Obsidian has long been a popular although largely nonessential raw material in the Pacific (as elsewhere on earth) despite the fact that alternative and equally useful cutting materials (such as bamboo) are readily available. Hence the ancient transport of obsidian through inter-community networks is commonly interpreted by archaeologists as more a social phenomenon than a practical (“economic”) necessity (Torrence 2011). As suggested by the what-if analyses discussed here, we anticipate  that Golitko and his team will discover this summer that obsidian was reaching communities on the Sepik coast well before ~3,500 BP.

Funding for this research was provided by National Science Foundation Grant No. BCS-1155338–”Archaeological and Environmental Investigations along the mid-Holocene shoreline near Aitape, Northern Papua New Guinea,” Mark L. Golitko and John E. Terrell.
References:

Borgatti, S. P., M. G. Everett, and J. C. Johnson. 2013. Analyzing social networks. Los Angeles: Sage.

Chappell, J. 1982. Sea levels and sediments: some features of the context of coastal archaeological sites in the Tropics. Archaeology in Oceania 17:69–78.

Cochrane, E. E. and C. P. Lipo. 2010. Phylogenetic analyses of Lapita decoration do not support branching evolution or regional population structure during colonization of Remote Oceania. Philosophical Transactions of the Royal Society B 365:3889–3902.

Embrechts, P. and M. Hofet. 2014. Statistics and quantitative risk management for banking and insurance.  Annual Review of Statistics and It Application 1: 493–514.

Girvan, M. and M. E. J. Newman. 2002. Community structure in social and biological networks. Proceedings of the National Academy of Sciences of the United States of America 99:7821–7826.

Golitko, M. 2011. Provenience Investigations of Ceramic and Obsidian Samples Using Laser Ablation Inductively Coupled Plasma Mass Spectrometry and Portable X-Ray Fluorescence. In Exploring prehistory on the Sepik coast of Papua New Guinea, J. E. Terrell and E. M. Schechter, eds., pages 251–287. Fieldiana Anthropology New Series No. 42. Chicago: Field Museum of Natural History.

Golitko, M. and J. E. Terrell. n.d. Modeling cultural patterning and prehistoric interaction along the “inland” Bismarck Sea using network analysis. Unpublished manuscript, 2012 NEOMAP Project “Inland Seas in a Global Perspective,” Leiden, Netherlands.

Hope, G. S. and S. G. Haberle. 2005. The history of the human landscapes of New Guinea. In Papuan Pasts: cultural, linguistic, and biological histories of Papuan-speaking peoples, A. Pawley, R. Attenborough, J. Golson, and R. Hide, eds., pages 541–554. Canberra: Pacific Linguistics.

Irwin, G. J. 1992. The prehistoric exploration and colonisation of the Pacific. Cambridge: Cambridge University Press.

Specht, J., T. Denham, J. Goff, and J. E. Terrell. 2014. Deconstructing the Lapita cultural complex in the Bismarck Archipelago. Journal of Archaeological Research 22:89–140.

Summerhayes, G. R. 2009. Obsidian network patterns in Melanesia—sources, characterisation and distribution. IPPA Bulletin 29:109–124.

Terrell, J. E. 2004. The “sleeping giant” hypothesis and New Guinea’s place in the prehistory of Greater Near Oceania. World Archaeology 36:601–609.

Terrell, J. E. 2010a. Language and material culture on the Sepik coast of Papua New Guinea: using social network analysis to simulate, graph, identify, and analyze social and cultural boundaries between communities. The Journal of Island and Coastal Archaeology 5:3-32.

Terrell, J. E. 2010b. Social network analysis of the genetic structure of Pacific Islanders. Annals of Human Genetics 74:211–232.

Terrell, John Edward. n.d. Understanding Lapita as history. In The Oxford handbook of prehistoric Oceania, Ethan Cochrane and Terry Hunt, eds. Oxford: Oxford University Press.

Terrell. J. E. and E. M. Schechter. 2011.Archaeological investigations on the Sepik coast of Papua New GuineaFieldiana: Anthropology42:1–303.

Torrence, R. 2011. Finding the right question: learning from stone tools on the Willaumez Peninsula, Papua New Guinea. Archaeology in Oceania 46: 29-41.

Welsch, R. and J. E. Terrell. 1998. Material culture, social fields, and social boundaries on the Sepik coast of New Guinea. In The archaeology of social boundaries, Miriam Stark, ed., pages 50–77. Washington: Smithsonian Institution Press.

© 2014 John Edward Terrell. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Network science: The language of integrative research


Please note: this commentary, recovered on 9-Jan-2017, was originally published in Science Dialogues on 16-May-2015.


Mathematics, they say, is the language of science. When it comes to what is happening—or has happened—down here on earth, it is beginning to look like the right dialect of mathematics to learn is what is now being called (somewhat confusingly) network science.

When the goal is integrating research discoveries across disciplines as diverse as archaeology, primatology, neurobiology, and geochemistry, the mathematics of networks is the Esperanto of choice.

Field Museum in Chicago is one of the world’s largest natural history and anthropology museums. Scientists working there study the world and its human inhabitants from scores of different research directions, both pure and applied. Integrating these often seemingly disparate specialities so that the results of so much scholarship can be communicated to the public through exhibits and publications has always been a problem.

Under the leadership of Thorsten Lumbsch, Ph.D., the Director of Integrative Research at the Museum, “The Field” as it is affectionately known in Chicago is pushing back against research specialization using network science. Here is one example.

A social network is a set of actors defined by their ties, links, or relationships with one another (e.g., friendship networks, ecological networks, global trade networks, and protein interaction networks) rather than by their individual characteristics (attributes) as actors. Since the research focus is on relationships rather than on characteristics, statistical methods  in network science are being developed that do not need to assume—unlike in traditional statistical analyses—that the observations being studied are independent of one another.

Dr. Termeh Shafie, who is currently a Visiting Bass Scholar at the Field,  arrived in mid April from the Algorithimics Department at the University of Konstanz in Germany to help the Field’s scientists apply the statistical methods and models of network science to their research datasets which are as seemingly dissimilar as gorilla social interactions, sharks swimming in the ocean, the genetics of lichens, and the decorations on prehistoric American potshards.

When asked about her work at the Field Museum in Chicago, Termeh Shafie explains:

"The first step will be to learn more about the empirical data at hand, the hypotheses about these data being considered, and how to embed a network approach to them. The second step will be to develop network models based on these hypotheses. This requires the mathematical formulation of models, programming these models using statistical software, and then running simulations. Goodness-of-fit tests can be used to test the fit of the models to the data. Once suitable models are identified, statistics can be used to measure different properties of the networks under study and unlock information in them using the models as predictive tools. Within a level of certainty, we can then predict trends and behavior patterns even for parts of the networks we don’t yet have data for."

On Wednesday, May 13th, Dr. John P. Hart (Director, Research & Collections Division, New York State Museum), Dr. Mark Golitko (Regenstein Research Scientist), and James Zimmer-Dauphinee (2015 Regenstein Intern) participated with Shafie in a small-group Network Science Workshop at the Museum exploring ways to apply network analysis to a large database of information about pottery designs on ancient vessels from 102 archaeological sites to help unravel how communities across southern Ontario coalesced between ca. A.D. 1350 and 1650 into the larger regional populations that ultimately became the historically documented Huron confederacy.

Left to right: John Hart, Termeh Shafie, James Zimmer-Dauphine, Mark Golitko

Left to right: John Hart, Termeh Shafie, James Zimmer-Dauphinee, Mark Golitko

Shafie will be at the Field until August 15th, but even after she returns to Germany, she will continue to be the “networks link” between scientists at the Museum and the Algorithmics Unit under the direction of Professor Ulrik Brandes in the Department of Computer & Information Science at the University of Konstanz.

 

Migration, admixture, and human populations

Mark L. Golitko


Please note: this commentary, recovered on 8-Jan-2017, was originally published by Mark L. Golitko on Science Dialogues on 30-Jun-2015.


Cellarius_ptolemaic_system

The Ptolemaic universe as depicted by Johannes van Loon, ca. 1611–1686.

TWO NEW STUDIES IN EUROPEAN PREHISTORY have recently made headlines. The first (Haak et al. 2015) purports to show, using genetic data from ancient skeletons, that massive migration from the Central Asian Steppes into Europe during the Bronze Age likely introduced Indo-European languages, thus supporting the venerable “Kurgan” hypothesis championed by Marija Gimbutas decades ago. The second study (Smith et al. 2015) identified DNA from domesticated wheat (triticum) in submarine peat deposits off the southern coast of England dating to 8000 years ago, two millennia before such plants formed an identifiable component of crop assemblages in known terrestrial sites in England, and thus well ahead of the Neolithic agricultural “front.”

The validity of the later results remains to be seen—the DNA in question was cored out of the ocean bottom, and while the published results appear robust, it is unlikely that these data will single-handedly overturn the long-standing archaeological narrative of the Neolithic. That study does however provide a convenient point of digression for reexamining the first study and other similar studies of ancient genetics. Archaeologists have typically used two kinds of models to explain the past—diffusionist models in which ideas, things, and practices move, and migrationist models in which ideas, things, and practices move because people move. The movement of domesticated plants and animals of Near Eastern origins into Europe—the so-called “Neolithic Revolution”—has been the bell-weather case for testing these two types of explanations in archaeology. In the last three decades or so, human genetics has entered the picture as a way of testing competing hypotheses, first using modern DNA samples from living people in Europe and the Near East, and increasingly in the last decade, using ancient DNA (aDNA) extracted from archaeological burials (Pinhasi et al. 2012).

European population genetics, modern and ancient

Early studies of modern biological patterning (initially using blood types and other proteins) suggested a broad SE-NW trend in frequencies (Ammermann and Cavalli-Sforza 1984), one that was later confirmed when DNA sequencing became possible. This pattern was immediately interpreted as the outcome of a Neolithic period migration out of the Near East into Europe beginning after 8000 BC, swamping out “indigenous” European peoples (and their genes) that had been in place since at least the end of the last ice age (c. 12,000 years ago or longer). Vigorous debate ensued as some researchers argued that this trend could have resulted from a much earlier peopling of Europe by modern humans c. 45,000 years ago, or possibly during the reoccupation of Europe after the last glacial maximum (c. 22,000 years ago) by people who had occupied glacial refugia further south in Europe (see Pinhasi et al. 2012 and Deguilloux et al. 2012 for reviews of this work).

In 2005, the first study of DNA from actual early Neolithic skeletons was published (Haak et al. 2005), and the results were quite different from what most researchers had expected. As it turns out, early Neolithic skeletons, at least in central Europe (associated with an archaeological culture called the Linienbandkeramik or LBK) contain gene frequencies that are quite unlike those found in modern European populations. Specifically, mitochondrial DNA (mtDNA) haplogroups (sets of genomes related by shared mutations at particular locations on the genome suggesting common origins) thought to be clear markers of Neolithic population growth and movement were only present at relatively low frequencies, while one particular haplogroup—N1a—present at extremely low frequencies anywhere in modern day Eurasia and Africa, was quite common in the early Neolithic genepool. In the ensuing ten years, there has been a rapidly growing set of aDNA analyses performed in Europe, both on mtDNA (tracing descent through females) and Y-chromosome aDNA (tracing descent through males). As with modern DNA, measuring descent through males and females provides somewhat different answers, and suggests that on a whole, women have been more mobile than men in Europe (likely indicating a very old predominant pattern of patrilocality, e.g., Seielstad et al. 1998). In some places (parts of Northern Spain, for instance—see Sampietro et al. 2007), early Neolithic gene frequencies are not that different from earlier ones or modern ones, while in central Europe at least, the early Neolithic did witness a massive reshaping of the genetic landscape from a relatively genetically homogenous late-Paleolithic and Mesolithic background to a much more diverse Neolithic one, and little similarity is evident between the Neolithic and the present day (see Pinhasi et al. 2012 and Deguilloux et al. 2012 for reviews of this work).

The Haak et al. study (published earlier this month) identifies gene flow between central Asia and Europe in the Bronze Age, and a series of other recent studies also clearly demonstrate that the Neolithic is not the end of the story either. The researchers postulate a massive migration of Steppe populations into Europe associated with the Yamnaya archaeological culture, one that has been previously hypothesized to have spread Indo-European languages both eastwards and westwards out of Central Asia. aDNA research is for the most part slowly hammering the nail in the coffin of diffusionist models for the spread of agriculture, and for many, is now offering strong support for the spread of languages through massive migratory events (including Renfrew’s [1988] hypothesized spread of Indo-European during the early Neolithic).

Human “populations”

Care needs to be taken in interpreting these results, however. Population geneticists model the human past as a series of admixture events between discrete populations (see Hellenthal et al. 2014 for a recent attempt to define how many such populations there are). These populations may be defined in a number of ways—by geography (typically by continent), by language, by self-defined or externally perceived ethnicity, and in the case of palaeogenetics, by archaeological culture. There is thus an “LBK” or a “PPNB” set of gene frequencies which can admix or not (see for instance Fernández et al. 2015). This is a convenient shorthand, because it allows a small number of analyses (aDNA studies have sampled at most a few hundred individuals to date, while even modern studies are based on only thousands of individuals) to be taken as representative of some larger analytically meaningful population.

By Mike88n (Mike88n) [GPL (http://www.gnu.org/licenses/gpl.html)], via Wikimedia Commons (originally from Novembre et al. 2008).

Modern genetic map of Europe. (By Mike88n (Mike88n) [GPL (http://www.gnu.org/licenses/gpl.html)], via Wikimedia Commons (originally from Novembre et al. 2008)).

But what is a human population? That we have many ways of categorizing each other is unquestioned—we divide people up by race, income, clothing style, dialect, neighborhood, country, and a thousand other ways. It is also not implausible to imagine that real geographical boundaries such as major mountain chains, oceans, deserts, and so forth, may produce long-term vicariant barriers inhibiting interaction (i.e., people having sex with one another). That this is so is clearly demonstrated by the fact that modern gene frequencies are strongly patterned by geography in Europe, so much so that a multi-dimensional scaling plot (a way of representing many axes of variability on a single two-dimensional plot) of gene frequencies virtually recreates the geographic shape of Europe (Novembre et al. 2008). It is also everyone’s experience that humans live in social groups that can feel very real and rigid, and thus it might seem clear that human populations can be defined. However, the issue in palaeogenetics is different, namely, whether people live in sexual groups impermeable and long-lasting enough to explain the long-term configuration and development of gene frequencies, as well as serving as the basic scaffolding for other forms of human identity including the transmission of learning through time (i.e., culture and languages, including Indo-European ones).

Analytical simplification and historical reality

If the goal is simply to abstractly model how genes may have moved across the landscape historically, then perhaps an analytical fiction of discrete human “populations” is adequate for the job, similar to the use of the “gene” as analytical shorthand for modeling the complex network of DNA-RNA-protein interactions that drive biological function (e.g., Dawkins 2009). In econometrics, Friedman (1970) argued that it didn’t matter whether models were based on plausible assumptions, as long as those theories generated testable predictions that matched observations and resulted in predictive power. However, while predictive power may result even from a model with unrealistic starting assumptions, if social scientists want to explain what actually happened, our starting assumptions do matter. Their plausibility must be evaluated by examining how consistent they are with our knowledge of the world, updated in light of new information—if those assumptions are subsequently found wanting, we must reject the basic plausibility of our models, even if they produce outcomes consistent with empirical data (Nooteboom 1986). This is simply another way of stating that the same outcome can often be generated by several different models, and we need to turn to other lines of information to choose between them. In a recent paper, Pickrell and Reich (2014) use simulation to demonstrate that a number of opposing population genetic models used to explain human genetic patterning can produce the exact same results when operating over long periods of time.

As more aDNA analyses are published, the number of population migrations required to explain observed palaeo- and modern-gene frequencies in Europe (and by implication elsewhere) appears to be steadily increasing, in some cases seemingly at a rate of one per study (e.g., Hervella et al. 2015). This situation reminds me somewhat of the addition of spheres to the Ptolemaic system of planetary motions. Eventually, the Ptolemaic system grew so ponderous that some doubted it merely on the principal of parsimony. It took a radical rethinking of planetary positioning to generate a far simpler explanation of planetary motion. In the case of palaeogenetics (and other explanations of the past), perhaps a similar shift in thinking is required, one that moves away from the monolithic “billiard-ball” model of cultures and populations to something more plausible.

The human network

What should be the unit of analysis in historical genetics (and historical explanation more generally), and how do we create models that are consistent with other observations about human social structure and sexual behavior? In other words, how do we distinguish between competing historical genetic models by evaluating the basic plausibility of those models? One promising avenue comes from the recent explosion of interest in network analysis, which provides a robust method and body of knowledge for describing human social structure and comparing it to genetic patterning (e.g., Terrell 2010), and which does not necessarily require that one define broader units of analysis in advance, such as archaeological cultures. The challenge is to combine our knowledge of network structure in the human population (small-worlds and the like) with our understanding of genetics to create more plausible models of the human past. How this is to be accomplished in a formal mathematical sense remains to be seen.

This is more than just an academic concern—the popular media picks up on these studies and reinforces the viewpoint that humans do in fact come in particular “types” that can be identified through the new science of genetics—for instance, a recent distillation of one such aDNA study in a major media outlet described the results as indicating that modern Europeans derive from “three tribes” of ancient people, one of whom may be previously “unknown” to science (Rincon 2014). Do we really need “pulse-stasis” models for human population structure in the past? How do we adequately account for the fact that archaeological evidence suggests expansive social networks wherever and whenever we look, and that modern political/continental boundaries and perceived historical and cultural areas are not adequate units of analysis for splitting populations then or now? What happens if we resample our data and begin arbitrarily drawing lines that don’t correspond to these perceived political, geographical, linguistic, or archaeological categories? Does the story stay the same? A social networks perspective on the past is one way to transcend these problematic but common-sense ideas of human population(s) structure. If wheat can move beyond “Neolithic” communities thousands of years earlier than previously supposed, what else was moving?

References

Dawkins, R. (2009) The Selfish Gene. Oxford, Oxford University Press.

Deguilloux, M.-F., R. Leahy, M.-H. Pemonge, and S. Rottier (2012) European Neolithization and Ancient DNA: An Assessment. Evolutionary Anthropology 21: 24-37.

Fernández, E., A. Pérez-Pérez, C. Gamba, E. Prats, P. Cuesta, J. Anfruns, M. Molist, E. Arroyo-Pardo, and D. Turbón (2014). Ancient DNA Analysis of 8000 B.C. Near Eastern Farmers Supports an Early Neolithic Pioneer Maritime Colonization of Mainland Europe through Cyprus and the Aegean Islands. PLoS Genetics 10(6): e1004401. doi:10.1371/journal.pgen.104401.

Friedman, M (1970) “The Methodology of Positive Economics.” In Essays on Positive Economics. Chicago: The University of Chicago Press, pp 1-43.

Haak, W., P. Forster, B. Bramanti, S. Matsumura, G. Brandt, M. Tänzer, R. Villems, C. Renfrew, D. Gronnborn, K. Werner Alt, and W. Burger. 2005. Ancient DNA from the First European Farmers in 7500-Year-Old Neolithic Sites. Science 310: 1016-1018.

Haak, W., I. Lazaridis, N. Patterson, N. Rohland, S. Mallick, B. Llamas, G. Brandt, S. Nordenfelt, E. Harney, K. Stewardson, Q. Fu, A. Mittnik, E. Bánffy, C. Economou, M. Francken, S. Friederich, R. Garrido Pena, F. Hallgren, V. Khartanovich, A. Khokholov, M. Kunst, P. Kuznetsov, H. Meller, O. Mochalov, V. Moiseyev, N. Nicklisch, S.L. Pichler, R. Risch, M.A. Rojo Guerra, C. Roth, A. Szécsényi-Nagy, J. Wahl, M. Meyer, J. Krause, D. Brown, D. Anthony, A. Cooper, K. Werner Alt, and D. Reich (2015) Massive migration from the steppe is a source for Indo-European languages in Europe. Nature522: 207-211.

Hellenthal, G., G.B.J. Busb, G. Band, J.F. Wilson, C. Capelli, D. Falush, and S. Myers (2014). A Genetic Atlas of Human Admixture History. Science 343: 747-751.

Hervella, M., M. Rotea, N. Izagirre, M. Constantinescu, S. Alonso, M. Ioana, C. Lazăr, F. Ridiche, A.D. Soficaru, M.G. Netea, and C. de-la-Rua (2015). Ancient DNA from South-East Europe Reveals Different Events during Early and Middle Neolithic Influencing the European Genetic Heritage. PLoS ONE 10(6):e0128810. Doi:10.1371/journal.pone.0128810.

Nooteboom, B (1986) Plausibility in Economics. Economics and Philosophy 2: 197-224.

Novembre, J., T. Johnson, K. Bryc, Z. Kutalik, A.R. Boyko, A. Auton, A. Indap, K.S. King, S. Bergmann, M.R. Nelson, M. Stephans, and C.D. Bustamante (2008) Genes mirror geography within Europe. Nature 456: 98-103.

Pinhasi, R., M.G. Thomas, M. Hofreiter, M. Currat, and J. Burger (2012) The genetic history of Europeans. Trends in Genetics 28(10): 496-505.

Renfrew, C. (1988) Archaeology & Language: the Puzzle of Indo-European Origins. Cambridge, Cambridge University Press.

Rincon, P. (2014) Europeans drawn from three ancient ‘tribes’ BBC News Science and Environment, 9/17/2014.

Sampietro, M.L., O. Lao, D. Caramelli, M. Lari, R. Pou, M. Martí, J. Bertranpetit, and C. Lalueza-Fox (2007) Palaeogenetic evidence supports a dual model of Neolithic spreading into Europe. Proceedings of the Royal Society B 274: 2161-2167.

Seielstad, M.T., E. Minch, and L.L. Cavalli-Sforza (1998) Genetic evidence for a higher female migration rate in humans. Nature Genetics 20: 278-280.

Smith, O., G. Momber, R. Bates, P. Garwood, S. Fitch, M. Pallen, V. Gaffney, and F.G. Allaby (2015) Sedimentary DNA from a submerged site reveals wheat in the British Isles 8000 years ago. Science 347: 998-1001.

Terrell, J.E. (2010) Social Network Analysis of the Genetic Structure of Pacific Islanders. Annals of Human Genetics 74: 211-232.

© Mark L. Golitko. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.