The Passage of Time in Neolithic Orkney

Excavations taking place at Ness of Brodgar. Can we really compare the development of this site with that of other Neolithic archaeology around Orkney?

Many years ago (more than I care to remember) I used to meet with a group of archaeological colleagues for a relaxing drink on a Friday night in Edinburgh. Most of us were involved, at one time or another, in working on the Neolithic archaeology of Orkney. Even then Orkney was regarded as something special. Being archaeologists we rarely left our work totally behind but rather used the time to discuss some of the most pressing dilemmas in our archaeological interpretations. I remember animated debates as to the meaning of the two very different pottery styles to be found in Neolithic Orkney. Did they, as some people thought, overlap, or had one supplanted the other. Radiocarbon dating had not long been employed and it was still something of a blunt tool – in many ways it did not lend much to our discussion. Another favourite topic was the meaning of the different styles of tombs and houses to be found in Orkney. It all seemed very bipartite. Were we simply observing the transformations in society that lead to changes in material culture? But was it a simple linear, evolutionary change? Or were there more nefarious elements at play. In short, did the advent of new styles of tomb and house (and other material culture) mean the advent of new people with new ways, did it signal some sort of social unrest or change, or was it just a matter of time?

You will notice that the uncertainties of dating at the time were such that we were able to assume that everything had changed at much the same time.

Now, I read with interest a new paper, by Alex Bayliss and colleagues, recently published in Antiquity. Alex is one of the wizards of radiocarbon dating. Using a statistical technique, known as Bayesian analysis, she is able to produce much tighter estimates of age from calibrated radiocarbon dates in conjunction with existing understanding of the archaeological record. Together with her colleagues they have been looking at the dates available for the sites of Neolithic Orkney, and taking many new dates as well, in order to provide a detailed chronology for Neolithic Orkney and consider what it may mean.

It is an interesting, thought provoking paper that pulls together a huge amount of information. It has received much attention since it was published. There is a lot of useful information relating to issues like the length of use of specific sites, and the ways in which they may relate to one another. But I am left questioning some of their conclusions, and somehow I ended up feeling a little disappointed. One of the problems with publishing in Antiquity is that you have to keep your papers short, and, in this case, it meant that the evidence needed to back up their statements was often lacking.

There is useful information relating to the antiquity of timber houses in Orkney together with the stone buildings that became more common. There is information relating to the dating of different types of tomb, and to the pottery types. The general conclusion seems to be that some social differentiation and the concurrence of new ideas took place fairly early on in Neolithic Orkney (the overlapping of the different styles in tombs and pottery for example), but that around 2800 BC something happened that led to a geographical shift in settlements and the development of larger houses and more elaborate pottery. The authors note that events in the Neolithic heartland of Stenness-Brodgar were, however, very different.

One of my problems relates to this comparison of the sites in the Stenness-Brodgar area with those elsewhere in Orkney. Stenness-Brodgar is a very different place with a very different type of site. Ness of Brodgar is discussed as a ‘place of human dwelling’. Now there is not much yet published about Ness, but all the material that one can find leads one to believe that it is not a common or garden settlement. Surely, it is not, therefore, surprising to find that events there were different to those elsewhere. The authors are not, as I understand it, comparing like with like.

There is also a general assumption that the archaeology of Orkney is such that the known sites provide a representative sample of what went on in the past. I find this very doubtful. Not only does general research suggest that this is not so, the known sites represent only the places where we have looked for (or found), sites. But also, the very existence of sites like Ness of Brodgar, totally unknown until some ten years ago, tells us that we don’t know everything about Neolithic Orkney.

The authors conclude by suggesting that the variety of style and material culture in the earlier centuries of Neolithic Orkney may represent a competitive society in which communities sought to outdo each other in the monuments and houses that they built and the goods that they used. In this, the advent of elaborate flat-bottomed Grooved Ware pottery and different types of tomb might be seen as a way for one community to differentiate itself from others. Continual elaboration of house form and material culture is used to back this up and the paper talks of political tension and social concerns. Finally, the arrival of the Orkney vole is brought into play as a proxy for the introduction of new ideas and possibly even people directly from Europe in the later fourth millennium cal BC.

As I say it is an interesting paper. But I am left wondering whether, in nearly 40 years, we have really advanced at all in our archaeological deliberations. The arguments of the paper sound so much like those I used to hear in the pub. The dates are more tightly constrained, we have more sites, more variation in our sites, and, perhaps, more sophistication in our ideas. But I don’t really feel that I have learnt anything new. The dates presented confirm the old conundrums, they don’t explain them. For that we are left with unsupported speculation, just as we always have been. As you know, I don’t believe in an ‘archaeological truth’, and I guess we all love speculation, but we need to be careful not to suggest that it is founded in scientific fact.

Type Fossils, Seriation and Dating

A modern take on becoming the animal, from Lunar Festival 2015
Sometimes it is difficult to fit everything in to one chronological or cultural envelope

I’m still on my high horse about type fossils, seriation and dating.

Unlike our predecessors in the early days of archaeology, we have the luxury of several different techniques by which we can provide dates for our sites that approximate, within envelopes of accuracy, calendar years. The most commonly used is radiocarbon dating, but various technicalities about the way in which radiocarbon isotopes accumulate and decay mean that the dates have to be carefully calibrated.

Recently, the accuracy and usefulness of radiocarbon dates have been refined by the introduction of a technique known as Bayesian Dating. It is a complex statistical process by which known information about the sample to be dated can be added into the process to increase the resolution of a date. Thus, for example, if we are dating a carbonized hazelnut shell we might also consider the types of tool with which it is found, the stratigraphy of the sample in comparison to other samples, and our interpretation of the site in comparison to similar sites.

Bayesian dating reduces the size of the envelope of accuracy meaning that we get determinations that approximate more closely to human events. It has been used very successfully to help interpret sites in a way which is more meaningful. Instead of saying that a site might generally have been in use between say 3500 – 2900 BC, we can now incorporate a close analysis of the stratigraphy of different structures on that site, and the finds within the site in order to tease out more precise dates and a sequence for individual structures to suggest that while some of the earlier structures may have been built between 3100 – 3050 BC, the last building activity on site occurred between 3000 – 2950 BC. It is a revolution in the way in which we can think about the use of the sites that we study.

But, I’m concerned that some of the analyses that I see appear to go to considerable lengths in order to reconcile the type fossils and the dates. If we only use type fossils in combination with Bayesian dating in order to confirm our preconceptions, then we will never be able to expand our understanding of the peoples of the past.

For example, a recent study looked at assemblages from 61 sites in order to produce a chronology of the sites in relation to one another. The hypothesis was that these sites fell into a sequence of five different cultural types. The type fossils from each site were identified and used to refine the dating. But there were problems. Several of the sites had combinations of type fossils that apparently fell into more than one of the periods. Others had type fossils that did not appear to be in the right chronological group. So, the study had to start by excluding sites where the type fossils did not easily conform to the hypothesised chronology. Thirty-one sites (half of the original number) were excluded. In this way, it was possible to confirm a tight and interesting chronological sequence for the sites and the type of material they held. But, some of the phases in that sequence comprise very few sites indeed.

I’m just wondering whether a phase that apparently holds good across the UK but only comprises two or three sites, is really valid as a phase? Could it possibly be a regional development? And what about all the sites that were excluded because their type fossils did not conform to the pre-existing pattern? Could they possibly identify new patterns – either a local pattern or a chronological one (or both)? Reading the paper, I came away with the impression that the authors were struggling hard to make the data produce the results they wanted.

It is difficult because we tend to publish only positive results, but I would like to have seen some analysis and discussion that tried to make sense of all the material. Even if it did not seem to confirm accepted wisdom. Bayesian dating is a wonderful new tool but we should be using it to push the boundaries of our interpretation forward, not to confirm our existing thoughts.

The real import behind all this is that we can’t just undertake quick projects to double check our old ideas. In a project like this, we need to go right back to basics and look at the stratigraphy and content of all the sites that relate to our study, whether or not they conform to our pre-existing ideas. And perhaps look for some new ideas? Even when the uncertainties are acknowledged, it often does not stop people from publishing reports wherein they point out how the results from one site can skew the results.

It is also clear that we need to stop looking for patterns that appear to work across the whole of the UK. Of course, the political boundaries that we use today are meaningless in terms of prehistory, but that is not to say that people lived in some bland uniformity across the British Isles. Research suggests that life has got more uniform, not less, with the passage of time.