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.

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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.

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

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© 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?

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© 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.