Yes, there are similarities between my work and things that people actually want to spend time listening to. But you really have to look hard for them. I’ve given a lot of presentations over the last few years and noticed that one of the best ways of getting a difficult idea across is to use a movie analogy. I also learned I was very bad at preparing my presentation in time to think up movie analogies. So here’s a blog post to make up for it, inspired by a new paper I wrote that just came out in Journal of Archaeological Method and Theory. My work is a bit like Lord of the Rings and Mulan.
But not in the way you hope it is. There is nothing near as exciting in my research as the cavalry charges in both those movies, and I definitely never experienced a ‘montage’ moment that provided me in a ridiculously short timespan with the crazy skills needed to destroy the baddie.
What my work has in common with both Mulan and Lord of the Rings are fire signals. This video shows the memorable scene from Return of the King when the fire beacons in Gondor are lit, triggering the lighting of a chain of other beacons. The message is clear and reaches its target quickly: Gondor looks to Rohan for help.
The opening scene of Disney’s Mulan is similar: when the bad guys attack, beacons are lit all along the great wall of China to warn the Chinese people of the coming threat.
These scenes are not completely unthinkable fantasy scenarios, but are inspired by early communication systems that actually existed in the past. In times before telephones and telegraphs, signalling systems using fire, smoke, sound or light could have been used to spread messages over very long distances.
Archaeologists studying the Iron Age of Spain believe such a communication system might have existed in some regions. And it is easy to understand why. The settlement pattern in much of Spain during the Iron Age was dominated by large fortified urban settlements on hills, hence they are sometimes referred to as hillforts. These large urban settlements were surrounded by smaller rural settlements. The surrounding landscape could be visually controlled from many of these hillforts, and the hillforts were visually prominent features that could be seen from far away.
Now what scene of Lord of the Rings does this remind me of? That’s right: the Eye of Sauron perched on top of the massive tower of Barad Dur, scanning the surrounding landscape for his enemies, and to his followers acting as a visible reminder of who’s boss.
Many archaeologists believe these large urban settlements were located on hills on purpose, and not just because a hill was easier to defend but because of the views it offered: visually controlling the landscape, being visually prominent from its surroundings and acting as a good link in a fire signalling network.
And this is where networks come in! If archaeologists argue that settlements might have been located with visibility in mind for the three reasons mentioned here, then we should approach these statements as hypotheses that need testing. And we can do that in three ways using network science:
1) visualise the network of inter-visible settlements using our knowledge of the settlement pattern;
2) explore its structure to see whether it would function well as a communication network, or whether some settlements are more visually prominent;
3) simulate a process where places are settled so that a well-functioning communication network and/or a few more visually prominent settlements is established, and compare this simulated settlement pattern with the observed one.
This is what I do. The first approach uses network data representation and network layout algorithms to show a network of inter-visible settlements, and explore this pattern in a new way by extracting it from its geographical context and focusing just on its structure for a change. The second approach then uses exploratory network analysis techniques that tell us something more about individual nodes in the network and about the network as a whole (e.g. identify most visually prominent settlements, identify chains of inter-visible settlements). The third approach is in my eyes the most interesting one because it is totally new: using simulation models we generate millions of networks according to the process we hypothese might have taken place and we compare the simulated networks with the oberved ones using the same exploratory network analysis techniques as in the second approach.
This new approach to simulating our hypotheses about visibility networks is called exponential random graph modelling for visibility networks. A pair of papers just came out in which we introduce this method and apply it to Iron Age and Roman Southern Spain. The results are really interesting: there is no evidence for a well-functioning communication network, but there is definitely reason to believe that the pattern of visually prominent settlements that visually control surrounding rural settlements was purposefully established in the Iron Age. The importance of visibility as a factor determining settlement location then gradually decreases throughout Roman times.
Our recently published paper in Journal of Archaeological Method and Theory tells you the full story. The method is explained in detail in our paper in Journal of Archaeological Science. Both are available through my Academia.edu page or my bibliography on this blog. Enjoy!