Ethan Watrall and I have been playing around with data mining as a way of writing a historiography of digital & computational archaeology. We’d like to invite you to play along.
We’ll probably have something to say on this at the SAA in April. Anyway, we’ve just been chugging along slowly, sharing the odd email, google doc, and so on – and a monstrous huge topic model browser I set up. Yesterday, an exchange on twitter took place that prompted us to share those materials.
This prompted a lot of chatter, including:
So let’s get this party started, shall we?
While there’s a lot of movement towards sharing data, and open access publications, there’s also this other space of materials that we don’t talk about too much – the things we build from the data that we (sometimes) share that enable us to write those publications we (sometimes) make open access. This intermediate stage never gets shared. Probably with good reason, but I thought given the nature of digital work, perhaps there’s an opportunity here to open not just our research outputs & inputs, but also our process to wider participation.
Hence this post, and all that follows.
Here’s what I did. I scoured JSTOR’s DFR for anglophone journals, from 1935 onwards (full bibliography right here: http://graeworks.net/digitalarchae/20000/#/bib. Then I fitted various topic models to them, using Andrew Goldstone’s dfr-topics which is an R package using MALLET on the bag-of-words that DFR gives you, running the result through Andrew’s dfr-browser (tag line: “Take a MALLET to disciplinary history!”).
The results can be viewed here. Like I said, this is the middle part of an analysis that we’re sharing here. Want to do some historiography with a distant reading approach? We’d love to see what you spot/think/observe in these models (maybe your students would like a go?) In which case, here’s an open pad for folks to share & comment.
Why would you bother? Well, it occurred to me that I’ve never seen anyone try to crowdsource this step of the process. Maybe it’s a foolish idea. But if folks did, and there was merit to this process, maybe some kind of digital publication could result where all contributors would be authors? Maybe a series of essays, all growing from this same body of analysis? Lots of opportunities.
Stranger things have happened, right?
Just to get you going, here are some of the things I’ve noticed, and some of my still-churning thoughts on what all this might mean (I’ve pasted this from another document; remember, work in progress!):
remembering that in topic modeling, a word can be used in different senses in different topics/discourses (thus something of the semantic sense of a word is preserved)
-stanford tmt for detailed view on CAA (computer applications in archaeology)
-mimno’s browser based jslda for detailed view of correlations between topics (using CAA & IA) (internet archaeology, only the open access materials before it went fully OA in October 2014)
-Goldstone’s dftropics for R and dfrbrowser to visulaize 21 000 articles as entire topic model
-same again for individual journals: AJA, JFA, AmA, CA, JAMT, WA
stanford tmt of caa 1974 – 2011
-no stoplist used; discards most prominent and least likely words from the analysis
-its output is formatted in such a way that it becomes easy to visualize the patterns of discourse over time (MALLET, the other major tool for doing topic modeling, requires much more massaging to get the output in such a form. The right tool for the right job).
-30 topics gives good breakdown; topic 26 contains garbage (‘caa proceedings’ etc as topic words)
In 1974, the most prominent topics were:
topic 1 – computer, program, may, storage, then, excavation, recording, all, into, form, using, retrieval, any, user, output, records, package, entry, one, unit
topic 6: but, they, one, time, their, all, some, only, will, there, would, what, very, our, other, any, most, them, even
topic 20: some, will, many, there, field, problems, may, but, archaeologists, excavation, their, they, recording, however, record, new, systems, most, should, need
The beginnings of the CAA are marked by hesitation and prognostication: what *are* computers for, in archaeology? There is a sense that for archaeologists, computation is something that will be useful insofar as it can be helpful for recording information in the field. With time, topic 1 diminishes. By 2000 it is nearly non-existent. The hesitation expressed by topics 6 and 20 continues though. Archaeologists do not seem comfortable with the future.
Other early topics that thread their way throughout the entire period are topics 5, 2, 27 and 28:
Topic 5: matrix, units, stratigraphie, relationships, harris, unit, between, method, each, attributes, may two diagram, point, other, seriation, one, all, stratigraphy, sequence
Topic 2: area, survey, aerial, north, features, sites, region, located, excavation, river, areas, during, field, its, large, project, south, water, over, fig
Topic 27: sites, monuments, heritage, national, record, management, cultural, records, development, systems, england, database, english, its, survey, new, will, also, planning, protection.
Topic 28: museum, museums, collections, project, national, documentation, all, database, archives, about, archive, objects, sources, documents, university, text, our, also, collection, reports.
These topics suggest the ‘what’ of topic 1: how do we deal with contexts and units? Large surveys? Sites and monuments records and museum collections? Interestingly, topics 27 and 28 can be taken as representing something of the professional archaeological world (as opposed to ‘academic’ archaeology).
Mark Lake, in a recent review of simulation and modeling in archaeology (JAMT 2014) describes various trends in modeling [discuss]. Only topic 9 seems to capture this aspect of computational/digital archaeology:
model, models, social, modeling, simulation, human, their, between, network, approach, movement, networks, past, different, theory, how, one, population, approaches, through
Interestingly, for this topic, there is a thin thread from the earliest years of the CAA to the present (2011), with brief spurst in the late 70s, and late 80s, then a consistent presence throughout the 90s, with a larger burst from 2005-2008. Lake characterizes thus…. [lake]. Of course, Lake also cites various books and monographs which this analysis does not take into account.
If we regard ‘digital archaeology’ as something akin to ‘digital humanities’ (and so distinct from ‘archaeological computation’) how does it, or does it even, appear in this tangled skein? A rough distinction between the two perspectives can be framed using Trevor Owens meditation on what computation is for. Per Owens, we can think of a humanistic use of computing as one that helps us deform our materials, to give us a different perspective on it. Alternatively, one can think of computing as something that helps us justify a conclusion. That is, the results of the computation are used to argue that such-a-thing is most likely in the past, given this model/map/cluster/statistic. In which case, there are certain topics that seem to imply a deformation of perspective (and thus, a ‘digital archaeology’ rather than an archaeological computation):
topic 03: cultural, heritage, semantic, model, knowledge, systems, web, standards, ontology, work, domain, conceptual, different, crm, between, project, based, approach
topic 04: knowledge, expert, process, its, artefacts, set, problem, different, concepts, human, systems, but, they, what, our, scientific, about, how, all, will
topic 07: project, web, digital, university, internet, access, online, service, through, electronic, http, european, technologies, available, public, heritage, will, services, network, other
topic 14: virtual, reality, museum, public, visualization, models, reconstruction, interactive, museums, multimedia, heritage, envrionment, scientific, reconstructions, will, computer, technologies, environments, communication
topic 29: gis, spatial, time, within, space, temporal, landscape, study, into, social, approaches, geographic, applications, approach, features, environmental, based, between, their, past
Topic 3 begins to emerge in 1996 (although its general discourse is present as early as 1988). Topic 4 emerges with strength in the mid 1980s, though its general thrust (skepticism about how knowledge is created?) runs throughout the period. Topic 7 emerges in 1994 (naturally enough, when the internet/web first hit widespread public consciousness). Should topic 7 be included in this ‘digital archaeology’ group? Perhaps, inasmuch as it also seems to wrestle with public access to information, which would seem not to be about justifying some conclusion about the past but rather opening perspectives upon it. Topic 14 emerges in the early 1990s.
Topic 29, on first blush, would seem to be very quantitative. But the concern with time and temporality suggests that this is a topic that is trying to get to grips with the experience of space. Again, like the others, it emerges in the late 1980s and early 1990s. [perhaps some function of the personal computer revolution..? instead of being something rare and precious -thus rationed and only for ‘serious’ problems requiring distinct answers – computing power can now be played with and used to address less ‘obvious’ questions?]
What of justification? These are the topics that grapple with statistics and quantification:
Topic 10: age, sites, iron, settlement, early, bronze, area, burial, century, one, period, their, prehistoric, settlements, grave, within, first, neolithic, two, different
Topic 11: pottery, shape, fragments, classification, profile, ceramics, vessels, shapes, vessel, sherds, method, two, ceramic, object, work, finds, computer, fragment, matching, one
Topic 13: dating, radiocarbon, sampling, london, dates, some, but, betwen, than, e.g. , statistical, chronological, date, there, different, only, sample, results, one, errors
Topic 15: landscape, project, study, landscapes, studies, cultural, area, gis, human, through, their, its, rock, history, historical, prehistoric, environment, our, different, approach
Topic 17: sutdy, methods, quantitative, technqiues, approach, statistical, using, method, studies, number, artifacts, results, variables, two, most, bones, based, various, analyses, applied
Topic 19: statistical, methods, techniques, variables, tiie, statistics, density, using, cluster, technique, multivariate, method, two, nottingham, example, principal, some, university
Topic 21: model, predicitve, modelling, models, cost, elevation, viewshed, surface, sites, gis, visibility, van, location, landscape, areas, one, terrain, dem, digital
topic 23: image, digital, documentation, images, techniques, laser, scanning, models, using, objects, high, photogrammetry, methods, model, recording, object, surveying, drawings, accuracy, resolution
topic 24: surface, artefact, distribtuion, artefacts, palaeolithic, materials, sites, deposits, within, middle, area, activity, during, phase, soil, processes, lithic, survey, remains, france
This detail of the overall flow of topics in the CAA proceedings points to the period 1978 – 1983 as a punctuation point, an inflection point, of new topics within the computers-and-archaeology crowd. The period 1990-2011 contains minor inflections around 1997 and 2008.
In terms of broad trends, pivot points seem to be the late 70s, 1997, 2008. Given that our ‘digital archaeology’ themes emerge in the late 90s, let’s add Internet Archaeology to the mix [why this journal, why this time: because of the 90s inflection point? quicker publication schedule? ability to incorporate novel outputs that could never be replicated in print?]. This time, instead of searching for topics, let’s see what correlates with our digital archaeology topics. For this, David Mimno’s browser based LDA topic model is most useful. We run it for 1000 iterations, and find the following correlation matrix.
[insert discussion here]
-1000 iterations. Your 1000 iterations will be slightly different than mine, because this is a probablistic approach
- the browser produces csv files for download, as well as a csv formatted for visualizing patterns of correlation as a network in Gephi or other network visualization software.
-stop list is en, fr, de from MALLET + archaeology, sites, data, research
-running this in a browser is not the most efficient way of doing this kind of analysis, but the advantage is that it allows the reader to explore how topics sort themselves out, and its visualization of correlated topics is very effective and useful.
-note word usage. Mimno’s browser calculates the ‘specificity’ of a word to a topic. The closer to 1.0, the closer the word is distributed only within a single topic. Thus, we can take such words as being true ‘keywords’ for particular kinds of discourses. [which will be useful in exploring the 20000 model]. “Computer” has a specificity of 0.61, while “virtual” has a specificity of 0.87, meaning that ‘computer’ is used in a number of topics, while ‘virtual’ is almost exclusively used in a single discourse. Predicitve has a specificty of 1, and statistical of 0.9.
In the jsLDA model, there are three topics that deal with GIS.
topic 19, gis landscape spatial social approach space study human studies approaches
topic 18, database management systems databases gis web software user model tool
topic 16, sites gis landscape model predictive area settlement modelling region land
The first, topic 19, seems to correspond well with our earlier topic that we argued was about using GIS to offer a new perspective on human use/conception of space (ie, a ‘digital’ approach, in our formulation). Topics 18 and 16 are clearly about GIS as a computational tool. In the correlation matrix below, blue equals topics that occur together greater than expected, while red equals less than expected; the size of the dot gives an indication of how much. Thus, if we look for the topics that go hand in hand with topic 19, the strongest are topic 16 (the predictive power of GIS), and topic 10 (social, spain, simulation, networks, models).
The ‘statistical, methods, techniques, artefact, quantitative, statistics, artefacts’ topic is positively correlated with ‘human, material, palaeolithic’, ‘time, matrix, relationship’, and ‘methods, points, point’ topics. This constellation of topics is clearly a use of computation to answer or address very specific questions.
-in jslda there’s a topic ‘database project digital databases web management systems access model semantic’ – positively correlated with ‘publication project electoric’, ‘text database maps map section user images museum’, ‘excavation recording’, ‘vr model’, ‘cultural heritage museum’, ‘italy gis’, ‘sites monuments record’ [see keys.csv for exact label]. These seem to be topics that deal with deforming our perspectives while at the same time intersecting with extremely quantitative goals.
So far, we have been reading distantly some 40 years of archaeological work that is explicitly concerned with the kind of archaeology that uses computational and digital approaches. There are punctuation points, ‘virages’, and complicated patterns – there is no easy-to-see disjuncture between what the digital humanists imagine is the object of using computers, and their critics who see computation as positivism by the back door. It does show that archaeology should be regarded as an early mover in what has come to be known as ‘the digital humanities’, with quite early sophisticated and nuanced uses of computing. But how early? And how much has archaeological computing/digital archaeology permeated the discipline? To answer these questions, we turn to a much larger topic model
Zoom Out Some More
Let’s put this into a broader context. 24 journals from JSTOR were selected for both general coverage of archaeology and for regional/topical specialities. The resulting dataset contains 21000 [get exact number] articles, mostly from the past 75 years (a target start date of 1940 was selected for journals whose print run predates the creation of the electronic computer, thus computer = machine and not = woman who computes). 100 topics seemed to capture the range of thematic discourses well. We looked first for topics that seem analogous to the CAA & IA topics (CAA and IA were not included in this analysis because they are not within the JSTOR DFR database; Goldstone’s DFR Browser was used for the visualization of the topics). [better explanation, rationale, to be written, along with implications]. We also observe ‘punctuation points’ in this broader global (anglosphere) representation of archaeology that correspond with the inflection points in the small model, many trends that fit but also other trends that do not fit with standard historigoraphy of archaeology. We then dive into certain journals (AJA, JFA, AmA, JAMT) to tease these trends apart. Just what has been the impact of computational and digital archaeology in the broader field?
The sillouhette in the second column gives a glimpse into the topic’s prevalence over the ca 75 years of the corpus. The largest topic, topic 10, with its focus on ‘time, made, work, years, great, place, make’ suggests a kind of special pleading, that in the rhetoric of archaeological argument, one always has to explain just why this particular site/problem/context is important. A similar topic was observed in the model fitted to the CAA & IAA [-in 20000 model, there’s the ‘time’ topic time made work years great place make long case fact point important good people times; it’s the largest topic, and accounts for 5.5%. here, there is one called ‘paper time work archaeologists introduction present important problems field approach’. it’s slightly correlated with every other topic. Seems very similar. ]
More interesting are the topics a bit further down the list. Topic 45 (data, analysis, number, table, size, sample) is clearly quantitative in nature, and its sillhouette matches our existing stories about the rise of the New Archaeology in the late 60s and early 70s. Topics 38 and 1 seem to be topics related to describing finds – ‘found, site, stone, small, area’; ‘found, century, area, early, excavations’. Topic 84 suggests the emergence of social theories and power – perhaps an indication of the rise of Marxist archaeologies? Further down the list we see ‘professional’ archaeology and cutlrual resource management, with peaks in the 1960s and early 1980s.
Topic 27 might indicate perspectives connected with gender archaeology – “social, women, material, gender, men, objects, female, meaning, press, symbolic” – and it accounts for 0.8% of the corpus: about 160 articles. ‘Female’ appears in four topics, topic 27, topic 65 (‘head, figure, left, figures, back, side, hand, part’ – art history? 1.4% of the corpus) topic 58 (“skeletal, human, remains, age, bone”- osteoarchaeology, 1.1% of the corpus), and topic 82 (“age, population, human, children, fertility” – demographics? 0.8% of the corpus).
[other words that would perhaps key into major trends in archaeological thought? looking at these topics, things seem pretty conservative, whatever the theorists may think, which is surely important to draw out and discuss]
Concerned as we are to unpick the role of computers in archaeology more generally, if we look at the word ‘data’ in the coprus, we find it contributes to 9 different topics (http://graeworks.net/digitalarchae/20000/#/word/data ). It is the most important word in topic 45 (data, analysis, number, table, size, sample, study) and in topic 55 (data, systems, types, information, type, method, units, technique, design). The word ‘computer’ is also part of topic 55. Topic 45 looks like a topic connected with statistical analysis (indeed, ‘statistical’ is a minor word in that topic), while topic 55 seems to be more ‘digital’ in the sense we’ve been discussing here. Topic 45 is present in 3.2% of the corpus, growing in prominence from the early 1950s, falling in the 60s, and resurging in the 70s, and then decreasing to a more or less steady state in the 00s.
Topic 55 holds some surprises:
The papers in 1938 come from American Antiquity volume 4 and show an early awareness of not just quantitative methods, but also the reflective way those methods affect what we see [need to read all these to be certain of this]
- punctuation points – see http://graeworks.net/digitalarchae/20000/#/model/yearly
major – 1940 (but perhaps an artefact of the boundaries of the study)
minor- early 1950s
minor- mid 1960s
major- 1976 (american antiquity does something odd in this year)