Tag Archives: EKAS

Archaeological futures III

[This post is a continuation of two other blog posts: part one and part two.]

I think that a basic structure of the talk I’m giving at Smith College is coming into shape. I’ll start with a brief description of the accelerating sophistication of archaeological methods since I began as a student in the mid-1990s, focusing first on the proliferation of archaeological sciences and their integration into Mediterranean archaeology and the proliferation of data produced by archaeological projects. (I’ll hopefully use data from Corinth Excavations to get a quantitative sense of the increase in data produced).

This leads to the issue of data and digitization. One of my big take-aways from the Mobilizing the Past for a Digital Future book was a more clear sense of how this proliferation of data has encouraged archaeologists to go digital, for a couple of different reasons, two of which I’ll highlight here: (1) The quantities of data are so immense that digitizing them (or better, creating them digitally to begin with) is an elegant solution to basic storage and dissemination needs, and (2) the types of data are so divergent, largely because of the increase in specialist and scientific studies in archaeological projects, that integrating these data are a significant hurdle, and digital integration is again a good solution.

A couple of personal anecdotes come to mind here. The archaeological survey that I was trained on, EKAS, started fieldwork with a “fully functional GIS” – that was exciting in 1999. When I was planning a survey in 2011 (WARP), one of the first things that I did was to think about the GIS and how we could integrate all of our data within it. Although I haven’t exactly been successful at pulling in non-archaeological data to the GIS framework, it still remains the basis for much of our analysis. When I write papers about WARP – as I was this week for a paper I’m giving tonight – I usually write on my desktop and keep my laptop reserved for ArcGIS (I run GIS on my laptop because it’s that indispensable to me). When I started excavating at Corinth in 2004, on the other hand, Corinth Excavations still used hard-bound notebooks, although they had become increasingly form-driven (we used a stamp). To figure out what had been excavated in my area prior to 2004, I had to flip through two or three different hard-bound notebooks. They proved to be not very well-written or illustrated, and I found myself increasingly frustrated by the fact that I was “digging blind.” (Actually that is why I was put there, to figure out what was going on and to “clean up” the interpretive knots created by past supervisors who hadn’t done such a good job).

One of the best arguments for digitization and born-digital data is (in my opinion) to give supervisors more interpretive tools in the field, by allowing them to call up previous years’ work easily on their computers or tablets in the field (additionally reference works and scholarly literature in the field can be extremely useful). This is a way to bring everything that we can to bear on solving interpretive problems in the field. I stress this point because if archaeology is anything, it is that: thinking through problems in the field, at the trowel’s edge (to use the excavation metaphor). Excavators are not just collecting data – they are interpreting as they go, and their interpretations shape their data. To do better archaeology, we need better interpretations more than anything else, and digital tools have allowed us to stretch our capabilities to pull up information of various kinds, especially outside of the library.

In that respect, digital technologies have the ability to help us bridge the field/library divide that is such an important structuring device of archaeological discourse, so much so that it even made it into an Indiana Jones movie (note: Vere Gordon Childe didn’t spend most of his time in the field). On the other hand, there can be a tendency, at least in some writing on “digital archaeology,” to emphasize the importance of data collection in a way that seems to separate it from interpretation. The word “data” appears 1619 times in the Mobilizing the Past book, “interpret*” only 164 times, and the general tone of much of the discussion focuses on interpreting data that have already been collected, thus reifying the field/library divide as it is being transformed into a field/computer lab divide. The section entitled “Interpretation” in the introduction to the Mobilizing the Past book is less than two pages long and focuses on a discussion of Bill Caraher’s “slow archaeology” work – in the same chapter, we get more words devoted to Apple’s famous “1984” commercial. Likewise Roosevelt and his colleagues briefly discuss the importance of interpretation trench-side in their introduction, but at no point is their born-digital system described as improving interpretation, nor do they talk about interpretation very much at all. In fact, I only see one contribution to interpretation in the entire article: an assertion that technologies that model space in three dimensions would aid in interpretation. This is how they describe their system (emphasis mine):

Conceived and designed before excavation commenced, the system was ‘‘born digital’’ (Austin 2014: 14), operating with integrated databases and aiming for the production of high-quality data with manifold improvements in accuracy and efficiency.

I don’t want to linger too long here, since I’ve already made my feelings clear. This is not a criticism of the tools or practices of digital archaeology, but rather of its discourses. But discourses are important: they reveal what we value and what we don’t.

What I want to say, then, is that we’re barely realizing the potential of our new digital tools, but that to make them work for us, we need to avoid this obsession with high-quality data, efficiency and accuracy. All those things are wonderful, but they are all a means to an end: productive interpretations and analyses of research questions. It’s true that high-quality data aren’t just produced for us but for future generations of archaeologists, but I think it’s a mistake to think that if we just produce the highest-quality data then one day someone might make interpretive hay of them. Our primary goal has to be productive interpretations in the here and now.

“Digital archaeology,” if that is even a thing, then, is at once an opportunity and a challenge. The opportunities are obvious, and they’ve encouraged even the most skeptical of us to become digital archaeologists in a very meaningful way. The opportunities are made very clear in the Mobilizing the Past book and in the article of Roosevelt et alii. The challenge is to unthink data and methodological sophistication as ends in themselves.

Let me end with another personal anecdote, which reveals that I am as guilty of this as anyone. When I started working on EKAS, I was extremely suspicious of defining “sites” in the field. I still am. What I wanted to do was to plug all of the artifactual evidence into the GIS and produce maps that would help us to understand artifactual distributions better and to define “sites” (if that’s we wanted to do) in the computer lab. I still think that’s a better way of doing things than declaring “ooh, there’s lots of stuff here” and defining a site on the fly. The on-the-fly way of doing things is data-poor and isn’t meant to require a lot of thought. You might feel rushed to make a decision as you pace back and forth trying to decide if it’s “really” a site while your undergraduate field walkers look at you impatiently, waiting to get on with it. The GIS-y way of doing it is data-rich and involves more thinking. In fact, that’s the value of the digital way of doing it: you can display and comprehend more evidence than is easily comprehensible when you’re in the field. So on the one hand, there is a separation made between fieldwork and analysis, which is something I’ve argued against. On the other, that separation gives you more information and more time to contemplate your decision-making. It gives you a little more information, and a bit of space to think.

Sampling and collection strategies in Mediterranean survey

I’ve just finished reading Andy Bevan’s and James Conolly’s book on their archaeological survey of Antikythera, Mediterranean Islands, Fragile Communities and Persistent Landscapes: Antikythera in Long-Term Perspective (Cambridge University Press 2013). It is a very impressive book about a very impressive archaeological project. In two seasons, they surveyed virtually the entire island (18.58 sq km, 90% of the island’s total area) with walkers spaced fairly tightly (15 m). They collected their tract data every 10 m, so every sherd collected in fieldwalking can be located within a 20 sq m strip. There is some error involved in this, but nevertheless this is, as far as I know, the best spatial control that has been achieved by any field survey in the Mediterranean.

I’m going to skip discussion of the analyses (which equally impress) because I was particularly interested in their collection strategies (for regular tractwalking, as opposed to more intensive “site” collection strategies).  Fieldwalkers counted all artifacts they saw in a corridor extending 1-2 meters on either side of their line and collected feature sherds: i.e., “rims, bases and handles, decorated body sherds” (14). Now obviously such a strategy is a compromise, as all collection strategies are. Bevan and Conolly write that “we see the collection of feature sherds as a reasonably sensible fieldwork compromise” (53) and I don’t disagree. Where I do disagree is when they go on to say (in the next sentence, same page) that

Many of the proposed alternatives, such as only collecting a ‘representative’ example of each type of sherd found in the current survey unit (Moore 2008), are substantially less effective because they tend to force very high-level interpretative decisions (e.g., about what exact kinds of pottery styles and fabrics are present) to be made very early on in the field, prior to artefact cleaning and without much overview of the entire assemblage (which also leads to significant practical delays if only one or two specialists are asked to make this decision or much greater bias if a wider group of semi-trained surveyors are asked to do so).

Moore 2008 is an article by Scott Moore, a ceramicist with whom I’ve worked in Cyprus (PKAP); the article describes the Chronotype system developed by Timothy Gregory, with whom I’ve worked in the eastern Corinthia (EKAS), so I’m pretty familiar with the system. I’ve worked with it for six or seven field seasons at those projects. And I don’t think that the critique of it by Bevan and Conolly is fair.

The criticism, to recap, is that this system (and others like it) require high-level interpretive decisions in the field, prior to cleaning and without much overview of the entire assemblage. What is this high-level interpretive decision? Field walkers are instructed to pick up the first artifact they see and every other artifact that is different (with respect to fabric, surface treatment, body part, and thickness), and that if they are uncertain whether an artifact is different, to collect it.

Now this doesn’t seem to me to require much high-level interpretation. My experience is that it’s pretty straightforward. The walkers don’t need to know “what exact kinds of pottery styles and fabrics are present” nor do they need to have an “overview of the entire assemblage” (Bevan and Conolly 2013, 53). They just pick up what they see, and if it might be different, they collect it. The experience of everyone who has used the Chronotype system (and this is also based on experimental data) is that field walkers overcollect, i.e., collect redundant data, so that if the field walkers make any mistakes, it is in the direction of total collection. (This is a summary of Gregory 2004: 28-29, published here and cited elsewhere by Bevan and Conolly).

The other issue is that the identification of what is and what is not a feature sherd is a kind of decision (high-level or otherwise), so that the “feature sherd” collection strategy is open to the same criticism: i.e., that it forces field walkers to make a decision before the artifact has been cleaned. I suppose that a critic would point out that it’s easy to identify handles and rims and bases, and I suppose that it is. But it’s not clear to me — maybe it’s clear to everyone else — that it’s so much easier than what Chronotype asks you to do. The other issue is what happens when a fieldwalker is uncertain? In the Chronotype system, the impulse drilled into fieldwalkers is “when in doubt, collect.” What if, using the “feature sherd” strategy, a sherd looks like a plain body sherd, but in actuality preserves a tiny portion of the rim that goes unnoticed? Perhaps the fieldwalker would collect it anyway. But I would guess that in most cases, s/he would not.

In any case, this brings us to the weakness of “feature sherd” collection strategies: they do not collect sherds that are potentially diagnostic. As Bevan and Conolly repeatedly point out, fabrics are important indicators of chronology, function, and even origin, and they are becoming more and more important over time, not less. I point this out because as Bevan and Conolly (52) correctly observe, the

significant discrepancy between what we now know and what we might know in <the> future, is one of the reasons we feel strongly that surface survey, like other kinds of archaeological fieldwork, should make systematic, permanent artefact collections …*

All this is not to say that the Chronotype system is perfect: it is certainly not. In fact, if I were doing survey in Antikythera, I would not use it. So I am certainly not questioning their decision to collect feature sherds. After all, the proof of the pudding is in the eating, and there is no doubt that Bevan and Conolly have provided us with rich and nourishing results (to extend the metaphor rather awkwardly). But neither do I think that the critique of Bevan and Conolly is fair, nor do I think that we can solve all of our problems by collecting feature sherds only.

The problem here is rather more complex, I think, and it has to do with research design, a theme that featured prominently in an article that I co-authored with Bill Caraher and David Pettegrew in 2006. Selective collection (i.e., collecting feature sherds, and especially the Chronotype collection method) is a way to reduce the collection of redundant data. On the Eastern Korinthia Archaeological Survey (EKAS), for instance, the project counted 146,599 artifacts in only 3.85 sq km. The Antikythera survey, in contrast, counted 66,000 artifacts in 18.58 sq km. That is a huge difference! It is somewhat larger than it seems, of course, because EKAS used a tighter 10 m walker spacing as opposed to Antikythera’s 15 m, but if we correct for that, we will see that EKAS counted over 7 times as much pottery as Antikythera did. What about collection? EKAS collected 38,337 artifacts (26%), Antikythera collected 25,675 (39%) by my count of their open data, which I downloaded here.

It’s probably impossible to find a place to do survey in Greece that is more different than the Corinthia than Antikythera (or the other way around, depending on your perspective!), and so the differences in the collection strategies aren’t that surprising. The Corinthia is a high-density artifactual landscape, even for Greece. Antikythera is very low-density, in part because (a) there are virtually no rooftiles (my dream!!!) and (b) for significant periods of its history, the island was abandoned or had a very low population. So a survey in Corinthia needs to find ways to cope with the fact that a high-intensity collection strategy would have produced insane numbers of artifacts. This is simply not a concern of a survey in a place like Antikythera (or at least, it’s a pretty minor concern). All of us, I think, would agree that it makes no sense to sample a high-density artifactual landscape the same way you would sample a low-density artifactual landscape. The lower the density, the more sense it makes to move towards total collection and towards piece-plotting individual finds.

In sum, I’d argue that the Chronotype collection strategy, flawed as it may be, is one way to deal with a particular problem. I’d readily concede that it may not be the best. On the other hand, it does do a good job at (a) reducing the collection of redundant data, (b) collecting useful qualitative and (to a lesser extent) quantitative data about the surface assemblage, and (c) avoiding the potential biasing effect of ignoring non-decorated body sherds that can, despite their humble appearances, be highly diagnostic (my ceramicist friends insist that they can do a lot with body sherds, and I believe them).

This is not to say that Bevan and Conolly did the wrong thing: I don’t think that at all. But I do think that we need to weigh the advantages and disadvantages of our methods with clarity. This is something that is a real strength of the Antikythera survey book, in fact. Their second chapter ends with a page of meditations on “methodological limitations.” So it is a minor criticism to pick them up on their brief discussion of collection strategies. My point is not to nitpick, but to extend the discussion about survey collection a bit further, beyond the text of their immensely rewarding book.

Notes
* In the … I have omitted reference to the same article by Timothy Gregory (2004), which advocates for processing artifacts in the field, although it should be pointed out, as Gregory indeed does (2004:30), that this procedure was instituted by necessity, due to restrictions placed on the survey in the archaeological permit.