Digital Ghosts

Here’s a preview of my upcoming talk at the Turing Festival in Edinburgh.

Credit: Motion in Place Platform Project

3D imaging is prevalent in archaeology and cultural heritage. From the Roman forum to Cape Town harbour, from the crypts of Black Sea churches to the castles of Aberdeenshire, 3D computer graphic models of ancient buildings and ancient spaces can be explored, manipulated and flown-through from our desktops. At the same time however, it is a basic fact of archaeological practice that understanding human movement constitutes a fundamental part of the interpretive process, and of any interpretation of a site’s use in the past. Yet most of these digital reconstructions, and the ones we see in archaeological TV programmes, in museums, in cultural heritage sites and even in Hollywood movies, tend to focus on the architecture, the features, and the physical surroundings. It is almost paradoxical that the major thing missing from many of our attempts to reconstruct the human past digitally are humans. This can be traced to obvious factors of preservation and interpretation: buildings survive, people don’t. However, this has not stopped advances in 3D modelling, computer graphics and web services to support 3D images from drawing archaeologists and custodians of cultural heritage further and further into the 3D world, and reconstructing ancient 3D environments in greater and greater detail. But the people are still left behind. This talk will reflect on the Motion in Place Platform (MiPP) project, which seeks to use motion capture hardware and data to test human responses and actions within VR environments, and their real-world equivalents. Using as a case study domestic spaces – roundhouses of the Southern British Iron Age – it used motion capture to compare human reaction and perception in buildings reconstructed at 1:1 scale, with ‘virtual’ buildings projected on to screens. This talk will outline the experiment, what might be learned from it, and how populating our 3D views of the past with ‘digital ghosts’ can also inform them, and make them more useful for drawing inferences about the past.

End of project MiPP workshop

At the closing MiPP project in Sussex last week. Due to a concatenation of various cirumstances, I had to take a large broomstick, which will be used in next week’s motion capture exercises at Butser Farm and in Sussex, on a set of trains from Reading, via the EVA London 2011 conference in Central London, to the workshop in Falmer, Sussex. Given this thing is six feet tall and required its own train seat (see picture), I got a variety of looks from my fellow passengers, especially on the Underground, ranging from suspicion to pity to humour. Imagined how one might have handled a conversation: ‘There’s a logical explanation. Yes, it’s going to be used as a prop in an experiment to test the environment of Iron Age round houses in cyberspace versus the real thing in the present day.’ ‘Oh yes? And that’s your idea of a logical explanation is it?’

Of course I could have really freaked people out be getting off the train at Gatwick Airport and wandering around the terminal, asking for directions to the runway.

As with the entire MiPP project, the workshop was highly interdisciplinary. A varied set of presentations included ones from Bernard Frisher of the University of Virginia, on digital representation of sculpture, and from colleagues at Southampton on the fantastic PATINA project. All of which coalesced  around questions of process, and how we represent it. Tom Frankland’s presentation on studying archaeological processes, including such offsite considerations as the difference between note taking in the lab and in the field, filled in numerous gaps of documentation that our work at Silchester last summer left.

When I got to my feet on day to two present, I veered slightly off my promised topic (as with most presentations I have ever given) and elected instead to reflect on the nature remediated archaeological objects. I would suggest that there is a three-way continuum on which any digital object representing an archaeological artefact or process may be plotted: the empirical, the interpretive and the conjectural. An empirical statement, such as Dr. Peter Reynolds, the founder of Butser Farm would have approved, might state that ‘the inner ring of this round house comprised of twelve upright posts, because we can discern twelve post holes in ring formation’.  An interpretative conclusion might be built on top of this stating that, because ceramic sherds were found in the post hole, cooking and/or eating took place near to this inner ring. This could in turn lead to a conjecture that a particular kind of meat was cooked in a particular way at this location, based not on interpretation or empirical evidence immediately to hand, but on the general context of the environment, and on what is known more broadly about Iron Age domestic practice.

More on all this next week, after capture sessions at Butser.

MiPP: Forming questions

The question about our MiPP project which I’m most often asked is ‘why?’ In fact that this is the whole project’s fundamental research question. As motion capture technologies become cheaper, more widely available, less dependent on equipment in fixed locations such as studios, and less dependent on highly specialist technical expertise to set them up and use them, what benefits can these technologies bring outside their traditional application areas such as performance and medical practice? What new research can they support? In such a fundamentally interdisciplinary project, there are inevitably several ‘whys’, but as someone who is, or at least once was, an archaeologist, archaeology is the ‘why’ that I keep coming back to. Matters became a lot clearer, I think, in a meeting we had yesterday with some of the Silchester archaeological team.

As I noted in my TAG presentation before Christmas, archaeology is really all about the material record: tracing what has survived in the soil, and building theories top of that. Many of these theories concern what people did, and where and how they moved while they were doing them. During a capture session in Bedford last week (which alas I couldn’t attend), the team tried out various scenarios in the Animazoo mocap suits, using the 3D Silchester Round House created by Leon, Martin and others as a backdrop. They reconstructed in a practical way how certain every day tasks might have been accomplished by the Iron Age inhabitants. As Mike Fulford pointed out yesterday, such reconstructions – which are not reconstructions in the normally accepted sense in archaeology, where the focus is usually on the visual, architectural and formal remediation of buildings (as excellently done already by the Silchester project) – themselves can be powerful stimuli for archaeological research questions. He cited a scene in Kevin Macdonald’s The Eagle, where soldiers are preparing for battle. This scene prompted the reflection that a Roman soldier would have found putting on his battle dress a time consuming and laborious process, a fact which could in turn be pivotal to the interpretation of events surrounding various aspects of Roman battles.

One aim of MiPP is to conceptualize theoretical scenarios such as this as visual data comprising digital motion traces. The e-research interest in this is that those traces cannot really be called ‘data’, and cannot be useful in the particular application area of reconstructive archaeology, if their provenance is not described, or if they are not tagged systematically and stored as retrievable information objects. What we are talking about, in other words, is the mark-up of motion traces in a way that makes them reusable. Our colleagues in the digital humanities have been marking up texts for decades. The TEI has spawned several subsets for specific areas, such as EpiDoc for marking up epigraphic data, and mark-up languages for 3D modelling (e.g. VRML) are well developed. Why then should there not be a similar schema for motion traces? Especially against the background of a field such as archaeology, where there are already highly developed information recording and presentation conventions, marking up quantitative representations of immaterial events should be easy. One example might be to assign levels of certainty to various activities, in much the same way that textual mark-up allows editors to grade the scribal or editorial certainty of sections of text. We could then say, for example, that ‘we have 100% certainty that there were activities to do with fire in this room because there is a hearth and charring, but only 50% certainty that the fire was used for ritual activity’. We could also develop a system for citing archaeological contexts in support of particular types of activity; in much the same way that the LEAP project cited Silchester’s data in support of a scholarly publication. It boils down to the fundamental principle of information science, that an information object can only be useful when its provenance is known and documented. How this can be approached for motion traces of what might have happened at Silchester in the first century AD promises to be a fascinating case study.