Comment on "A parsimonious neutral model suggests Neanderthal replacement was determined by migration and random species drift"

Note: This comment was originally posted on the article's Nature Communications site on Nov. 10, 2017.  

As strong supporters of open, reproducible science, we are happy to see that Kolodny and Feldman replicated our research, published six years ago, and obtained results very similar to ours—results that they, like us, referred to as a “neutral model” for apparent Neanderthal extinction.

To obtain their results, Kolodny and Feldman use a protocol that parallels our 2011 paper, using both an analytical panmixia model and a spatially explicit model as we did. However, our modeling experiments also showed that given demographic imbalances between semi-isolated Neanderthal populations and more widespread 'modern' human populations, migration (very difficult to demonstrate empirically in the paleoanthropological record) is not necessary to eliminate Neanderthals as a morphologically recognizable group. It can be accomplished by gene flow and demic expansion alone, probably triggered by ecological responses to the onset of glacial conditions that can be identified empirically.

A subsequent paper in 2012 further explored the impact of fitness differences and also demonstrated that culturally mediated mating taboos have minimal to no biocultural impacts on these processes in the long-term. Both our papers predicted low-level introgression of Neanderthal genes into the modern human genome on the basis of the modeling work.

Although our 2011 paper was published in the well-known journal Human Ecology, Kolodny and Feldman seem to have missed it, so we provide the citation here.

Barton, C. M., Riel-Salvatore, J., Anderies, J. M. & Popescu, G. Modeling human ecodynamics and biocultural interactions in the Late Pleistocene of western Eurasia. Human Ecology 39, 705–725 (2011).

The authors did cite our 2012 paper but not in reference to our methods, results, or conclusions. We provide the citation here for those who are interested in this work.

Barton, C. M. & Riel-Salvatore, J. Agents of change: modeling biocultural evolution in Upper Pleistocene western Eurasia. Advances in Complex Systems 15, 1150003-1-1150003–24 (2012).

A subsequent paper, also in Human Ecology, discusses additional dimensions of the modeling environment.

Barton, C. M. & Riel-Salvatore, J. Perception, Interaction, and Extinction: a Reply to Premo. Human Ecology 40, 797–801 (2012).

We have published the code of the models used in all three papers in the NSF supported Model Library of the Network for Computational Modeling in Social and Ecological Sciences (CoMSES Net). This code is freely accessible for downloading and use.

Barton, C Michael (2011). Hominin Ecodynamics v.1. CoMSES Computational Model Library.

Barton, C Michael (2012). Hominin Ecodynamics v.2. CoMSES Computational Model Library.

Barton, C. Michael (2012). Hominin Ecodynamics v.1.1 (update for perception and interaction). CoMSES Computational Model Library.

C. Michael Barton, Arizona State University
Julien Riel-Salvatore, Université de Montréal
J Marty Anderies, Arizona State University
Gabriel M Popescu, University of Bucharest

Trigger on teaching archaeology in Canada

This quote stood out, as part of the thinking and reading I've been doing since my last post on Canadian trends in the hiring of PhD to staff archaeology faculty positions:

"By December, however, I had accepted an appointment at McGill for the following academic year. [Raoul] Naroll urged me not to accept this appointment, arguing that in Canada I would find myself in an academic backwater from which all the best students would gravitate to the United States to do graduate work. I thought to myself that if Canadian academics did not return home, such a brain drain would certainly continue. If I and others did return home, the situation might change. My mind was made up." B. Trigger (2006: 241)

Reference:

Trigger, B.G. 2006. Retrospection. In The Archaeology of Bruce Trigger: Theoretical Empiricism (R.F. Williamson & M.S. Bisson, eds.), pp. 225-258. McGill-Queen's University Press, Montréal.

A 'Canadian connection' in North American faculty jobs in Archaeology?

In a paper in press in American Antiquity, Speakman and colleagues (2017) present some data about which archaeology programs in the US and Canada have been most successful at placing their graduates over the past 40 years or so. They conclude that “success in obtaining a faculty position upon graduation is predicated in large part on where one attends graduate school” and that “success in landing a faculty position begins the moment one applies for graduate school” because “being accepted into a top program, as well as the reputation of scholars in that program… really does make a difference.” To me (and for them), these overall conclusions are unsurprising, though it is nice to see impressions and rules of thumb being backed up with some hard numbers. In a nutshell, if you’re interested in being an archaeology prof in North America, you better graduate from Michigan, Arizona, Berkeley, UPenn, ASU, Harvard, TAMU, UCSB, Chicago or UNM, in that order, since these are the ten North American programs in their “tier I”. The second tier also does pretty well in placing grads, and it comprises UCLA, Florida, Pitt, UT Austin, Wisconsin, Tennessee, OSU, UNC Chapel Hill and Virginia.

The authors indicate some readers might be uncomfortable with their approach which divided the 110 North American universities in their sample into six tiers (I, II, III, IV, V, and 0), based on the number of their grads who have secured a faculty position. I’m personally not too bothered by it, as I think this is a rather apt reading of the data they present, rather than a direct judgement of the quality of the faculty in these different programs.

What did strike me, from my position as an archaeology professor at a Canadian university, is how these trends don’t quite seem to jive with the reality of the Canadian market. Based on the data presented, Canadian program are not particuarly great at placing their graduates into faculty positions. The Canadian institutions they list are, in decreasing order of success, McMaster (Tier III – 8 grads placed in 20 years), Calgary (Tier III – 6 grads), followed by Alberta, McGill and Toronto (all three in Tier IV, tied with four grads each), Simon Fraser University (Tier V, 2 grads), and finally UBC, Manitoba and Montréal in Tier 0, meaning programs that haven’t placed a single grad between 1994 and 2014.

Looking at this from a Canadian perspective, I was struck that this list excluded two Canadian universities with dedicated Archaeology programs leading to the PhD, namely Memorial University and Université Laval, though this is likely a result of the bias the authors themselves bring up about the completeness of the AAA AnthroGuide from which they gathered most of their data. Also excluded is the new PhD program at the University of Victoria, which didn’t exist for the period the authors consider.

Additionally, my admittedly subjective impression is that there are a proportionally a lot more archaeology faculty trained at Canadian institutions hired into Canadian program. In the database provided as part of the article’s supplementary material, only 59 of the 1084 (or 5.4%) archaeology faculty listed obtained their PhDs from Canadian programs; this drops to 4.6% (or 28/608) if you consider only those PhDs awarded between 1994 and 2014. This is much lower than my gut feeling of the proportion of Canadian-trained archaeologists is in actuality in most Canadian programs. For instance, at UdeM, out of our seven archaeology and bioarchaeology faculty, two (so 28.4%) received their PhD from Canadian institutions (actually, Québec, in this case); these figures will have to be adjusted next year, following the hire of a public archaeologist we're currently advertising for. Looking more broadly, at SFU, out of 16 tenured/tenure-track faculty listed on their website, fully 8 (50%) come from Canadian institutions, while neighboring UBC has 2/6 (33%) graduates from Canadian programs. At the other end of the country, at MUN’s archaeology department 7/11 (63.6%) tenured/tenure-track faculty listed received their doctorate from a Canadian program. The disparity between these numbers and the overall representation of Canadian PhDs in archaeology programs in North America as a whole is pretty staggering.

There are a couple of ways to think about this trend. On the one hand, it is probably not terribly surprising, considering that, by law, priority is given to Canadian citizens for positions in Canada; insofar as having a Canadian PhD is loosely correlated with being a Canadian citizen, this probably reflects that fact up to a degree. Likewise, scholars working on topics in Canadian archaeology are more likely to be trained in Canada and, in turn, to be appealing to Canadian programs wanting specialists in these issues. The flipside of both these considerations, of course, is that correspondingly fewer Canadian-trained archaeologists must serve as faculty in US archaeology programs, which would have the effect of depressing the already low representation of Canadian programs south of the border. Whether it also has the effect of creating a distinctive Canadian archaeological tradition is an open question; I would surmise that it doesn’t, considering the level of methodological and theoretical integration that currently characterizes the field, but this is just an impression. That said, these (admittedly partial) data suggest one thing rather clearly: if you want to teach archaeology in Canada, receiving a PhD in archaeology from a Canadian program would appear to give your chances a serious boost.

References: 

Speakman, R.J., C.S. Hadden, M.H. Colvin, J. Cramb, K.C. Jones, T.W. Jones, C.L. Kling, I. Lulewicz, K.G. Napora, K.L. Reinberger, B.T. Ritchison, M.J. Rivera-Araya, A.K. Smith and V.D. Thompson. 2017. Choosing a path to the ancient world in a modern market: The reality of faculty jobs in archaeology. American Antiquity: https://doi.org/10.1017/aaq.2017.36.