 Well, it's just me, Kathleen, stayed home, but he's obviously an important part of this work. So let's really move into economy now, and more specifically, proto-currency. The origins of money and formulation of coherent weight and measurement systems are amongst the most significant prehistoric developments of the human intellect, of human cognition. Yet, it's interesting to see that there's actually a lack of methods that help us identify commodities serving a monetary purpose. There you have candle, towel, you have some statistical approaches, but these sort of very typical statistical approaches, they're often inadequate for dealing with the approximation that characterizes prehistoric weight. Prehistoric weight was not precise, of course. So today I would like to present an innovative statistical method that calculates similarity indexes based on psychophysics, which is a subfield of psychology. And we've tested this methodology on a database of rings, ribs, and axis. So to very quickly situate ourselves, looking at late neolithic early Bronze Age, central Europe, and mainly sort of three areas. This was, at least three areas were defined by Halle van Kielde, who looked at Euse-Ringen. The rings and ribs are mostly in the south. And then we have the Unitisch area where you have the really big X-horts and the Nordic realm. We'll mainly be discussing these, where the southern one and the Nitisch. Now, perhaps one of the best known examples of what we think is a protocurrency from the European Bronze Age are these so-called Euse-Ringen and Spangenbier, which I will refer to as simply rings and ribs. And this idea has a very long history with archeologists. So, for instance, Brun, already in the 1940s, suggested that the interpretation that these might be a kind of money, a kind of currency, and many after. But it was only in 1995 that it was properly tested, an article that I'm sure most of you are aware of, Mario Lenox de Wilder, who actually looked at the data, looked at the weights of all these rings and ribs. She later substantiated this with additional papers in 2002 and 2011. Now, so far, she's the only one who has tested this idea on the basis of an empirical analysis, collecting the weights of over 3,000 rings and ribs. And given that it's over 20 years that this article has come out, I think it's a good time to reflect on it and also to retest it with new data and with a new method. And surprisingly, this was not done before. So everybody simply accepted the conclusions while Lenox de Wilder. That's also partly because that data was not available. But let's first have a look at some of the findings of Lenox de Wilder. She used sort of a rather banal method, simple, just histograms. And the histograms do clearly show that something is going on. And that there seems to be a kind of standardization when you're looking at these rings, around 200 grams, or basically sort of within 170, 220 grams. That's where most of these rings fall. Well, we can ask several questions here. First, if they were aiming for a particular weight, as it seems here, then where did this weight standard, this idea, where did it come from? Because I doubt whether someone in the old Bronze Age someday said like, okay, look, we're going to do 200 grams, that's it. So this assumes a weight unit to be present, of which the material is a representation. But some of you may know this work. So lately, looking into material engagement theory, where there are actually archaeologists who think that it's the other way around. You first actually have the experience of differences in weight. So you first have the material, and from there on, you develop the concept. So that turns it around. Now that's a theoretical critique of this work that we will come back to. More importantly, is a more practical issue. And that's the question of how were they weighing? So if you look at these categories, these histograms, we should ask, do they make sense? And I mean that quite literally. And I can say they do not, because if you look at the difference between 190 and 200 grams, so these are two separate categories in this histogram, suggesting that these are these weighing differently. It literally doesn't make sense because people are not able to distinguish between 190 and 200 grams if you weigh them by hand. Now, where does that come from? Am I just making it up? No, I'm not. We know this thanks to psychophysics. So first, because we know they were not using balances, at least we don't have evidence for balances in yearly bronzings. So they must have been weighing in a different way, their body, meaning yeah, basically by hand. And I wanted to know how precise people are when they are doing that, when they are weighing by hand. How are we in distinguishing weights? So I just argued we can't see the difference between 190 and 200 grams. They are perceptibly similar. And this comes from the field of psychophysics. So psychophysics is an experimental psychology. It's actually quite old data because it's not being done that much anymore. This is from the 1930s, I believe, this article. But they've been testing how well people do when they compare different stimuli. It's not only with weights, it's been tested on sound, on light intensity, so different kind of things. And it's been tested how acute our senses are. There's obviously a lot to comment on here. I mean, the numbers that come from this field, you can critique them because there's a lot of, there are a lot of assumptions being made. It really matters, for instance, whether you can weigh passively, which means I put a weight here, and don't do anything, and just see whether they're different, or I weigh actively, so I move my body, and then you get different results. But, as a general rule, it's accepted that the vapor fraction, and the vapor fraction is the measure used to express people's sensory and acuity. This field puts that number at 0.1, which is in a way very simple. That means 10%. You need to have 10% difference between two weights for most of us to recognize that. So if I have 200 grams here and 225 grams here, I will likely be able to notice it, that they are different. If it's 190 and 200, most of us will not notice it. You can go home, test it yourself. That's also, that's simply how this field did it. But this is, of course, interesting, because it gives us a number through which we can test these errors in the anger. It's in a way, it's sort of a phenomenological approach, but a quantitative one. So, to go back to rings and ribs. Most authors emphasize that exchange of commodity money is based on perceived alikeness, which means commodity money displays rough similarities in terms of shape and weight. Because of standardization, without necessarily following a very strict meteorological system, counting was probably the preferred method of quantification, but the constant objects had to be perceptibly similar, and therefore weight mattered. So, as I argue, lacking balance is the only way to observe a reasonable degree of uniformity is through sensory perception, so weighing by hand. And with the numbers from psychophysics, we can now quantify whether they, whether a bunch of these ribs were perceptibly equal. And this is where my colleague comes in, as writing an algorithm like this is really not my aim. Okay, five minutes, I need to hurry up, then. Basically, we wrote it into an algorithm and then went to the data. And the data consists of the original data by Lena Siter-Weldisch, she was kind enough to share it with us, so that's all her, basically two big folders full of numbers that we digitalized, we went with literature, collected more weights if they were available. Interestingly, weights are rarely available, I don't know why, but we do isotopes, we do compositional analysis, but we don't write down the weights. And simply going to museums and adding more. That led to a huge database of over 6,000 objects, over 5,000 used in the analysis, you can see it's rings, ribs, and axes. And what this algorithm did is basically it takes every single object from that database, looks at the weight and compares all the other objects and whether they will be perceived as similar. So it calculates for each object, it calculates the similarity index. And this is what you get, these are some of the results. Isn't that right? I don't have that much time, let's focus on this one. These are just the rings, the earth and things like that. And what the graph showed shows is the similarity between them. So the top one here, the dot is an actual ring and that ring weighs 195 and a half grams, gram. And this algorithm shows that 70% of all other rings that we have would have been perceived as equal. You know, if we take them in our hands and we just compare them, we would think that 70% of all the other rings weigh the same. We can't notice the difference. We did the same for the ribs. The ribs are slightly later. That's at least what we think. And there is a group that has a heavier one and a lighter one. And when we use cluster analysis to sort of to separate them, then the heavy ribs are also really, really convincing. They have a similarity index of 71%. So there's really unprecedented sameness between these objects. We did the same for axers. This was actually, I think, the most interesting one because we hypothesized that the axes of the unit-teacher culture, these really big hordes, bannanese, and these cowl, and damsdorf, these really big axe hordes, that these axes were, in fact, also a kind of protocrine scene. Sort of a local version of rings in the south. Now I must say they are less convincing. The, for instance, for early Bronze Age I, they're also very difficult to date and we have less objects. The similarity index is 44%. It's still higher than randomly produced data, but they're clearly not as convincing as the rings and ribs. We also tested them together. So we took a random amount of rings and ribs and the same amount of axes and we checked whether the statistical method would actually be able to distinguish them. And it couldn't. So if you put them together, the rings, ribs, and axes, you get this graph, and a ring. I think it's a ring that is at 198 grams and you would have 61% of all the other objects would be perceived as similar. Now, conclusions. I think it's an innovative method for detecting commodity money in balanced ways and it would be interesting to see whether we can also use it on other examples. I think one of the, some of the really clear conclusions is the very high similarity between the rings, but it must be noted that this, that I'm not arguing that this is an exact way that they were aiming for. It's the result of a rule of thumb. Similarly for the ribs, very high similarity. And especially actually for this one it's interesting because they come from 112 different hordes. So it's really remarkable that they're so alike. The X-blades, it's, you know, they really get a good amount of the amount perceived as similar to the rings and the ribs. And we call this a perceptive category. And within this perceptive category sort of that they form the opposite ends. So you have the ring in the middle and basically the ribs and the X-blades seem to be the opposite ends of that perceptive category. Now this is really conclusions from the numbers themselves. And to push this a little bit further to sort of try and interpret this and see what's going on, we'd like to suggest the following. What we can see is that the rings of ribs are actually mostly the nudian area. You have some mixed hordes. So you have hordes where the rings are together with axes, also suggesting a functional overlap. But we can see actually that the X-hordes are mostly around the area where the rings and ribs circulate. So our suggestion is that it's a local economic articulation of commodification and perhaps it's a way of vaulting the gap between commodity and prestige economies. This is what's suggested by Halifam Kildes. She said she sees three areas in which these rings circulate and she said, well, okay. The nudian area, commodity economy, unitity area, prestige economy, and the north is a gift exchange. So perhaps it's the axes helped to vault this gap. And then the last, the most tentative point that I would like to make is that we think this is an emerging system in which we see the development of a weight unit from experience. So this comes back to the theory that I mentioned in the beginning. Basically argues from experience, people came to expect that rings weigh about the same. So around 195 grams, resulting in a cognitive stereotype of these rings and their weight. And a cognitive stereotype is part of our cognitive toolbox. And from this weight, from this sort of the notion of weight could be divorced from the actual physical ring and thought of separately. So it's in a way, it's thanks to the particular affordances of bronze that equality in weight became a matter of concern and a cognitive tool to think with, resulting in an abstract notion of weight. And because bronze afforded an unprecedented savings between objects, so moles, or probably they were cast in sand, but you can still see them as moles. They're the very first blueprints through which copies could easily produce. From which I would like to suggest perhaps material is the mother of innovation. That's it, thank you.