Video: Exploring Humanity’s Technological Origins

Human evolutionary scholars have long assumed that the earliest stone tools were made by members of the genus Homo, 2.4–2.3 million years ago, and that this technological development was directly linked to climate change and the spread of savannah grasslands. In the last decade, fieldwork in West Turkana, Kenya, has revealed evidence of much earlier technological behavior. Sonia Harmand discusses the discovery of stone tools in a 3.3-million-year-old archaeological site in Kenya known as Lomekwi 3. She shows how this discovery is reshaping our understanding of the emergence of human-like manipulative capabilities, as well as the development of cognition in early hominins—the group consisting of modern humans and all our immediate ancestors.

Speaker: Sonia F. Harmand, Associate Professor, Department of Anthropology, Turkana Basin Institute, Stony Brook University; Director, Mission Préhistorique au Kenya/West Turkana Archaeological Project

Hallam L. Movius, Jr. Series Lecture recorded April 6, 2022

Transcript

Exploring Humanity’s Technological Origins

[00:00:08.75] Good evening, everyone. My name is Jane Pickering. And I'm the William and Muriel Seabury Howells director of Harvard's Peabody Museum of Archeology and Ethnology located on the traditional territory of the Massachusetts People. I'm delighted this evening to welcome you to the annual Hallam L. Movius Jr. lecture.

[00:00:32.54] Our next speaker will introduce you to Dr. Movius' distinguished career. He was a Paleolithic archeologist at Harvard, a member of the Department of Anthropology, and a long-time curator in the museum. I would like to personally thank the Movius family for their generous support of this annual lecture. And I know several are in attendance out there in Zoom land. So thank you.

[00:00:56.81] We're delighted to have Dr. Sonia Harmand with us tonight, who will discuss her research on humanity's technological origins. Please use the Q&A button at the bottom of your screen to submit questions or comments at any time during the program. Our speaker will address as many questions as time allows at the end of her presentation.

[00:01:21.04] It is now my pleasure to introduce Daniel Lieberman, Edwin M. Lerner the Second professor of Biological Sciences and Professor of Human Evolutionary Biology at Harvard, who will introduce our speaker. Dan.

[00:01:37.38] Thank you, Jane. So welcome, everybody. I'm Dan. As Jane says, I'm Dan Lieberman, a professor in the Department of Human Evolutionary Biology. And it's a real pleasure and honor today to introduce Sonia Harmand to deliver this year's Hallam Movius lecture.

[00:01:50.95] So for those of you who don't know about Hallam Movius, he was a giant in the field of Paleolithic Archeology. He is most known for his excavations at the site of Abri Pataud in the town of Les Eyzies in the Dordogne. But Movius also studied the entire depth and breadth of the Paleolithic in every corner of the planet, including, famously, the differences between the Lower Paleolithic in East Asia versus the rest of the old world.

[00:02:14.04] And I'm sure he would have been super excited to attend this talk by Sonia Harmand. So to introduce Sonia, Sonia is a professor of anthropology and a researcher at the Turkana Basin Institute at Stony Brook University. She also has a longstanding affiliation with the Laboratoire de Préhistoire de Technologie of the CNRS in France.

[00:02:33.66] And if that were not enough hats, since 2012, she's been the director of the incredibly important West Turkana Archeology Project. And we invited Sonia for this year's-- excuse me-- Movius lecture because, simply put, Sonia is a superstar in the field, whose exciting research and discoveries have transformed our understanding of the origins of toolmaking. Sonia will be forever famous for her discovery of stone tools at the West Turkana site of Lomekwi dated to 3.3 million years ago.

[00:03:02.44] And apart from pushing back the date of the first stone tools by a good 700,000 years, these amazing artifacts are sufficiently different from the Oldowan industry to merit being classified as a different industry, the Lomekwian. Sonia has also done extremely important work on how these tools were fabricated and used, integrating biomechanical studies with elegant technological analysis of the processes by which early hominins acquired, made, and used, and then discarded these artifacts.

[00:03:29.29] She's also published key studies in the origins of the Acheulian. And she's been deeply involved in outreach activities in Kenya. In fact, I was just in Kenya a few weeks ago and was blown away by the gorgeous, fantastic exhibit she helped create in the National Museums of Kenya in Nairobi that beautifully makes available to the Kenyan public the exciting work that she and her colleagues are doing in West Turkana.

[00:03:50.56] Sonia has to leave at 7 o'clock on the dot. So to make sure we have enough time for questions, I'll shut up now and pass the baton to Sonia. Sonia, thank you so much for giving this year's Hallam Movius lecture.

[00:04:00.85] OK. Thank you, Professor Lieberman. I think you can see now my screen and you can hear me. So thank you very much for your kind introduction, Professor Lieberman. I'm glad I can be with us tonight. And I would like to thank you-- to thank-- sorry-- the Peabody Museum and the Departments of Anthropology and Human Evolutionary Biology for the invitation to share my work with you all tonight.

[00:04:29.60] I am a French Paleolithic archeologist. And I worked a lot in Dordogne during my undergrad studies. But I never had the chance to meet Hallam Movius. I heard that he retired from teaching the year I was born. So I feel particularly lucky tonight and honored to still be part of an event sponsored by family and to contribute to honor Movius' legacy as a Paleolithic archeologist myself. So thank you very much again for the invitation.

[00:05:04.30] But let's leave France and Upper Paleolithic of Dordogne. I am going to take you much further back in time and to another continent. The talk I am going to present today is about a major discovery we made a few years ago with my team in northern Kenya. And I am, of course, going to talk tonight on behalf of the many people forming my team of scientists and excavators from the West Turkana archeological project.

[00:05:38.42] So I would like to start by, of course, stating that technological innovation are the hallmark of our species. Technology is everywhere. Technology has changed all aspects of our lives. We have now the technologies to decode the human genomic puzzle. Scientists announced in Science last week that they managed to map a full human genome for the first time, including previously hard to read DNA.

[00:06:09.58] And this, thanks to new computing power, gene-editing technology, and biotech startups. Innovations are reported every day. And the pace of innovation continues to increase exponentially. For example, I can talk to you today from my office at Stony Brook. And you can attend my talk from your computer, your tablet, your smartphone from anywhere you have internet.

[00:06:39.09] These accomplishments can be traced back in time through the major milestones of our evolution. They define the species we ultimately became. They separate us from other animals. And they define our identity as humans.

[00:07:00.76] But strangely, too often, when we think about human evolution, we think of biological evolution. But human evolution is not just about physical changes. It is also about behavioral changes. And it is about technological innovation.

[00:07:22.41] Yet, when exactly technology emerged in the fossil record and started to shape our evolution has appealed to researchers since the beginnings of paleoanthropology. Although our ancestors probably used a diversity of organic materials, stones are usually the only artifacts preserved in the archeological record and, on which, we can work. Stone tools are crucial to trace the dawn of technology in human evolution. And I'm going to talk about some very special stone tools tonight.

[00:08:02.21] So this is a quote from Louis Leakey that I always like to present because it says what has to be said about stone tools. They are fossilized human behavior. And it is exactly what we do as lithic experts. We read stone tools to reconstruct how they were made and qualify the knowledge associated with it.

[00:08:26.36] For the little story here on the picture, regrettably, the website from where I took this picture of Louis Leakey provides a picture of Louis Leakey measuring skulls rather than stone tools. So I decided to replace one of the skulls by one of my tools here on the picture. And I am sure Louis Leakey would have been very pleased about that.

[00:08:52.83] So for many decades, the early evidence available of toolmaking came from the Oldowan, a lithic industry that is well known and that is now dating to around 2.5, 2.6 million years. And I'm sure this name is familiar to you. The Oldowan is very important. It marked, at the time it was found, the crucial shift from using a natural stone toward producing stone flakes intentionally.

[00:09:25.73] The Oldowan was described first by Mary Leakey when she was working at the Olduvai Gorge site in Tanzania-- sorry-- in the 1960s. Although, if you search carefully, you can find the first use of the term Oldowan in a publication by Louis Leakey from 1934. In the 1970s, the Leakeys assigned the Oldowan one to the species Homo habilis because its remains were found in the same deposits dating from about 1.7 million years ago.

[00:10:04.27] Since the 1960s and since this work in Olduvai, we have made many discoveries, some of us, archeologists, working in East Africa. And many other sites have been found. And they have shown that this early record that was to start with quite concentrated, this early record became more widespread than what we thought. And there is a map here showing you some of the major Oldowan localities in Africa, including, of course, the one in East Africa, South Africa, and North Africa.

[00:10:49.51] But not only geographically we made progress with the older one, but the age of the older one has also been pushed back to 2.6 million years. This date of 2.6 million years marks the beginning of the earliest Oldowan, the evidence we have of the oldest Oldowan, especially with, recently, the discovery of a new site in Ethiopia.

[00:11:16.78] But the evidence for the Oldowan technology is still scarce and fragmented. We don't have a lot of sites. We only have several dozens of sites to work with. They are here on the map again.

[00:11:31.93] I just would like to signal here that some of the localities mentioned here include large number of sites. For example, Olduvai Gorge is not only one site but a series of sites. Koobi Fora, the same thing and also for West Turkana, where I work.

[00:11:51.03] So when we only consider what we call the earliest Oldowan, one so sites that are older than 2 million, the evidence is even more reduced. We've only roughly a dozen of sites. And when we consider the oldest evidence for the Oldowan, what we call the earliest Oldowan, we count only two sites, which for now mark the beginning of the Oldowan. And they are both located in Ethiopia.

[00:12:25.13] Many things have been studied on the earliest Oldowan and the Oldowan in general. And I would say that, starting 2.6 million years ago, what we do need to remember is that the Oldowan tools show that toolmakers already possessed abilities for planning for manual dexterity and raw material selection. And there are a lot of papers about describing this achievement that we see during the Oldowan.

[00:13:01.39] We have new discoveries for the Oldowan since Homo habilis. It seems that we can now attribute the Oldowan technology not only to our own genus but also potentially to members of the hominid genus Australopithecus. But I will come back to that a bit later.

[00:13:27.19] A new development came in 2011 when my research team discovered new stone tools at a new archeological site in Kenya on the western shore of Lake Turkana. We call this site Lomekwi Three, which is the local name for the area given by the local community, Turkana people. So this area, if I remember well, indicated is used-- Lomekwi is used to describe little bushes that are found in the area of the site.

[00:14:02.72] So you are going to hear me now using the name of the site Lomekwi Three. But I'm also going-- you're also going to hear me probably using Lom Three, which is a shorter way to refer to the site. So this site was dated by several geologists after we found it using a combination of several methods, which gave an age of 3.3 million years for the sediments enclosing the artifacts.

[00:14:36.74] This discovery was a revolution in our field. We presented the preliminary finds from 2011 in April 2015 at the Paleoanthropological Society meeting in San Francisco. And believe me, it was, for me, a turning point in my career. And we revealed the stone tools we had found at Lomekwi Three, stone tools that are pushing back the beginning of stone knapping of 700,000 years.

[00:15:11.57] So we proposed the name Lomekwian in our publication in Nature in 2015 for this new group of tools and for this technology or for what we also call this industry based not only on its antiquity compared to the earliest Oldowans but also based on the fact that the tools differ in very significant ways from the Oldowan. And I'm going, of course, to show you a little bit more what I mean by that.

[00:15:51.31] So this is the slide that I should have shown you when I was talking about the publication in Nature. We were very lucky to make the cover. Just not very often that we make Nature covers with stone tools. So we were very pleased about that. And the map here is showing you where the site Lomekwi Three was found west of Lake Turkana.

[00:16:21.98] So a little bit about the discovery itself. We found the site exactly-- I remember very well-- on the morning of July 9, 2011. And this is one of my favorite photos, maybe not the best photo we have of the site, but one of my favorite photos. Because this is basically one of the first pictures we took after we discovered the site.

[00:16:48.49] The little [INAUDIBLE] on top of my slide here is a picture of my dear colleague and friend Sammy Lucarotti, who is a local Turkana, who actually is the person who spotted the stone tools the first time. So we were surveying the area of Lomekwi-- and I'll come back to that a bit later-- when Sammy Lucarotti spotted some what he calls strange tools that should interest me that morning.

[00:17:24.49] And this is a picture showing you part of the team looking at what Sammy had found. And believe me, here, a couple of stone tools from Lomekwi Three from the site are already coming out from the surface. And of course, I'm going to go back to that and see-- show you a little bit more how we proceeded after we found the site in 2011.

[00:17:56.87] The area of Lomekwi might maybe sound familiar to some of you. It's an area that had been already surveyed quite a lot by paleoanthropologists and an area that was rendered famous by Meave Leakey and her team, as they have found Kenyanthropus platyops, so very, very famous hominin fossils that I will also come back to a bit later.

[00:18:30.47] So how did we find the site? That's a question I regularly have during conferences. Well, I always say that, of course, you have to be very well prepared. We are not a team of archeologists going into the field and just walking for hours trying to find something.

[00:18:49.19] Of course, we prepare a lot in advance our survey. And for that, we basically use geological maps. And we target deposits that are of age interest for us.

[00:19:06.17] So in 2011, we started this exact process. We started to look at geological maps, where we could find deposits that were older than 2.3 million years old here on the Western shore of Lake Turkana. And so why 2.3? Why we wanted to find deposits older-- sites older than 2.3?

[00:19:31.82] Well, just because the oldest Oldowan sites, the sites of Lokalalei in Kenya, so the oldest Oldowan in Kenya is dated to 2.3 million years old. So this is the boundary we had for the earliest technologies here in Kenya. And so we wanted, knowing that in Ethiopia site, we have found that 2.5, 2.6 million years, we wanted to try to find the equivalent here on the western shore of the lake.

[00:20:03.05] And if, in my previous slide, I mentioned that the area that we surveyed was already known for Kenyanthropus platyops, no archeologists had ever been-- had ever surveyed in this area. So that was, for us, a first and a must. So in 2011, we funds-- we started to do a systematic survey in the south of the Nachukui formation.

[00:20:36.28] And we started to survey targeted sediments that were older than 2.3 million years old, which are sediments that are related to the geological members of Lokalalei, Lomekwi, and Kataboi. I have to say that, at that time, we had no idea of what we were going to find. We were ready for everything. And we certainly had no idea that we were going to find something so old.

[00:21:07.99] So survey, again, you need to be quite organized. But it's also a little bit simplistic. So we had to use Google Earth and print a lot of maps of the area we wanted to survey. We, of course, were using GPS. And we decided to break down all our areas of survey during our work. Trying to move here my-- yeah. So we decided to cut our areas of survey in a grid of 200-- of square 200 meters by 400 meters. And we were doing that every day systematically crossing these areas.

[00:22:18.55] So looking for stone tools is exactly what you do when you're looking for hominin fossils. You walk a lot of kilometers. So you have to be fit.

[00:22:31.60] This is one picture of how the landscape looked like around Lomekwi, so very desertic. The great thing is that we don't have vegetation to hide anything from the ground. The problem is when you're looking at stone tools, you have also here thousands and millions of other rocks that I call pollution. And that could prevent you from looking or finding stone tools.

[00:23:02.67] But still, so we see here a couple of people from my team, Jason Lewis, who is the codirector of the project, Sammy Lucarotti in the middle that I talked to you about earlier. And you can see far. If you look far, there are other people surveying.

[00:23:20.31] So we all walk in line. And we have flags, again, like paleoanthropologists. And we flag everything that we see that could be of interest. Means stone tools maybe, bones, or anything that is worth coming back to later during the day.

[00:23:44.40] Toward the end of the day, usually, we come back to what we have flagged. And we start to unflag if what we found is not interesting enough. And of course, we start to record everything we have found. And this is exactly here what we are doing.

[00:24:08.12] So the way we found Lomekwi Three is basically the way we always identify new archeological sites in the region and I believe elsewhere. What you need to find stone tools and archeological sites are, first, artifacts on the surface. If they are not on the surface, of course, you can't see them. And you can't identify a site.

[00:24:38.45] So we were lucky enough here. And you see that on the picture on the left that we found a couple of stone tools eroding from the surface. And this is this little channel that you see here on the right that cut the hill where I'm sitting on and making, by erosion, these first artifacts coming on the surface.

[00:25:07.19] So we collected quite a lot of stone tools from the surface to start with. But the goal in 2011 was, of course, to find stone tools at an excavation, so still embedded in the sediment. And the reason is that it's very difficult to give an age to anything that comes from the surface.

[00:25:28.21] So your chance is to find something that is still going to be embedded in the sediment. Because this is the way we date our discoveries. Basically, it's in dating the sediment itself. But I'll come back to that later.

[00:25:45.70] So what you see here is the first pictures of the first core that we recovered from a very small excavation that I conducted in 2011, four square meters. This core is going to be the masterpiece for us. And the main reason is it's a very interesting cause that-- core-- sorry-- that I will describe a bit later.

[00:26:18.94] But it's also the core that is going to be refitted, a bit later. A few weeks after the field work when I came back to Nairobi to the National Museum of Kenya, I started to look a bit more carefully at what we had found in that year in 2011. And I had the surprise to be able to fit a flake on that core.

[00:26:50.08] And the flake is the one you see on top. That's a photo of the flake taken from the surface. And down below, you understand that this flake fits on the core. And I will also come back to that a bit later.

[00:27:10.22] Here, if you pay attention, you can see how evidence of the fractures on the core. You can see that the core has a lot of scars of previous removals. So these are representing basically the negative of all the flakes that have been removed from the core.

[00:27:34.44] I'm going to show you a couple of pictures of the progress of the excavation. We came back to the field in 2012. And you can see here the site in the landscape. It's a bit more green in 2012 compared to 2011, if you remember the previous photos. And you see what we are now starting to do in 2012. We are starting to go into this hill to follow what we call the archeological layer.

[00:28:08.92] So from the excavation, we always talk about the stone tools. But fossils are also present. They are not very abundant. This may be due to taphonomic bias against bone preservation. We don't really know.

[00:28:23.32] But I wanted to, of course, mention that we also find-- we had also found a couple of bones. Here, you have very well preserved bones of an alcelaphinae. And down there also a well preserved camel, which appears to be one of the oldest camel ever found.

[00:28:47.85] So that's the start of the excavation in 2014. We didn't do any excavation in 2013. 2014, we started a lot of work from above the site itself because we knew we had to go down to start excavating the archeological layer.

[00:29:10.53] And I'll take here the time to say that the Pliocene sediments that we are excavating is extremely hard. It's like cement. So if you use a hammer or a pickaxe, your pickaxe usually rebound onto the sediment. So it's just here to mention that we are progressing very slowly at the excavation. It takes a lot of time to uncover artifacts because we, of course, want to be very delicate when we extract them from the sediment but also because the sediment is extremely hard.

[00:29:51.23] That also is one of my favorite pictures of the excavation in 2015. This is a closeup of one of the core coming out from the Pliocene sediment. We are at least three people here working on it. It can take several hours to uncover this kind of artifact.

[00:30:14.51] You see, if you have expert eyes, you see already the fractures that are on the edge of this core. Again, they are the negative of previous removals. And you see also here a discoloration of the material due to chemical processes in the sediment.

[00:30:35.93] All the artifacts found at Lomekwi Three are from volcanic rocks. And they are normally very dark in color, grayish black. But again, with time, millions of years, the discoloration here is very characteristic of the preservation and the condition of preservation in Pliocene sediments.

[00:31:05.74] 2014, 2015, we found-- I think it's the year we found the most bones. Here, you have some ribs and some vertebra still in anatomic connection for the vertebra. So also, it tells you something about the good state of preservation of the site.

[00:31:27.43] We are now here in 2019, which was the last year we excavated the site. We didn't go after 2019 for obvious reasons, for COVID restriction. And you can see here that we are now really, really deep inside the sediment. We have now removed three meters of sediment, very hard sediment to be able to follow the archeological layer.

[00:32:03.62] So we did no work since 2019 due to COVID restrictions. But in 2018, we reached an excavation of 145 square meters, which is quite large for a site of that age. And we recovered around 200 artifacts. A paper is in preparation for an update on our work since we published our first result in 2015.

[00:32:34.07] And we're going to go back to the field. We are very happy about that. We're going to go back to the field and to the site this summer to excavate a bit more.

[00:32:47.37] So over the years, we uncovered many artifacts for a site of that age. It's not thousands. But it's dozens and now hundreds, which is fantastic for a site of that age. And what is striking is that we uncovered everything used to make the tools.

[00:33:09.51] So we uncovered cores and fragments. We uncovered flakes. And these are pictures of the flakes that we uncovered. Some of them also very well preserved, very sharp. You can probably see here, have a sense of how sharp they still are if you look at the edges.

[00:33:35.41] We also found anvils, which are this big block of raw materials. Anvils have been brought to the site by the toolmakers. There is no way the granulometry here of the sediment allowed this kind of natural transportation of anvils. So anvils, and we're going to see how anvils are important to describe the way the tools were made at Lomekwi Three.

[00:34:15.77] So the Lomekwi Three artifacts are spatial. I'm going to describe a little bit more in what sense we say they are spatial. But for sure, they are very different from the ones from the earlier Oldowan.

[00:34:31.94] Here, it's a sort of graph that I like to show showing you the size, the scale of one of the cores at Lomekwi Three compared to an artifact from the Oldowan and also a handaxe from the Acheulean. Of course, there is a variability in such sizes. But the Lomekwi artifacts, what is very striking with them are the sizes. They are absolutely enormous, gigantic.

[00:35:04.60] I hope I can make this work. So I wanted to show you a very quick 3D movie of one of the cores that we discovered at the site. There is no scale here, unfortunately. But we have something here that is around 15 centimeters in length and about the same in width.

[00:35:31.15] And it's a scan. So the resolution is not perfect. But you can see what one part of the core is-- sorry. One part of the core is completely natural. We see the cortex on it. And one part already here shows some negative flake removals.

[00:35:54.96] So the flakes at Lomekwi Three are much larger like the cores than those from the early Oldowan. The flakes from the early Oldowan usually goes between two to five centimeters long. And the size of our flakes at Lomekwi Three have been used basically and the size of the core to differentiate the Lomekwian from the Oldowan. But this is not the only feature that made us distinguish the Lomekwian from the Oldowan.

[00:36:34.89] What is particularly interesting, and this is something that I had been immediately interested in when I looked a bit more carefully at the artifacts, is that the Lomekwi Three toolmakers use techniques that we don't see so much during the Oldowan. So I don't say that they don't exist. But we don't see them so much during the Oldowan.

[00:37:00.63] Two simple techniques have been used to make the tools at Lomekwi Three. The first one is called the passive hammer technique, very rare, if not maybe absent, for the Oldowan. And in this technique, the core is held in both hands-- you see it on the right here on the slide-- and struck downwards onto an anvil with both arms performing the same motion.

[00:37:31.57] The other technique that we recognize at Lomekwi Three is something that we see during the Oldowan and even later in time. It's called the bipolar technique. This time, one hand stabilizes the core on an anvil. And the other strikes the hammer down vertically onto the core.

[00:37:52.78] So we've recognized these two techniques because they leave specific scars or features in the cores and the anvils. We have not recognized yet a technique that is going to be the technique most used after Lomekwian. So during the Oldowan and for the rest of the Stone Age is the freehand percussion technique. So we haven't recognized this technique at all.

[00:38:24.76] But we have a couple of cores that could fit into this category. But we need to conduct a little bit more analysis to be sure of that. But if the freehand percussion technique exists, for sure, it's not something that had been dominant at Lomekwi Three.

[00:38:43.99] Another very interesting characteristic that defined the Lomekwi Three, in my opinion, is that we observed a lot of percussive marks on many of the artifacts. And you see them here in red. These percussive marks are placed, usually, on the cortex of artifacts.

[00:39:11.32] They indicate that the tools-- and especially here, this core that I was showing you earlier, the first one that came out from the excavation indicates that these cores had been used for multiple purposes. And this is something we are going to see with many other artifacts. Here, you see that this artifact is a core.

[00:39:36.73] Again, you see, in blue, scars or flake removals. But you also see, of course, the percussion marks on the cortex. And sometimes so percussion marks, meaning that these cores have been used as for flaking-- sorry-- and also for pounding tasks.

[00:40:04.45] So now it is, for me, important to insist here that the Lomekwian is not exclusively a pounding or a bashing industry. And it's something I start to see in some publications. I think because we insisted in the simple techniques used at Lomekwi Three and we insisted in the cut marks-- sorry-- the percussion marks on the cores, I start to see interpretation of Lomekwi Three that are not what we see.

[00:40:41.37] The Lomekwian main technological goal was to produce flakes from cores. Most of the percussion marks that we see on cores have been, so far, linked also to flaking and to the use of some artifact as anvils or hammerstones. What is sure is we have a technology that is a multipurpose technology with a flexibility in the function of these tools. It's very clear that the knappers at Lomekwi Three were able to detach a series of adjacent or even superpose flakes from the cores and to continue knapping by rotating and reducing the cores.

[00:41:36.35] I've decided to show you this slide just to show you the complexity of already the rejection sequence at Lomekwi Three. I can't comment too much because this is a work in progress and publication soon from my colleague archeologist Nicholas Taylor. But just to give you an idea of the complexity of the rejection sequence with the use of different techniques, passive and bipolar, at the different stages of the direction of cause.

[00:42:25.52] So both the bipolar and passive technique we used at Lomekwi Three that we see-- sorry-- used at Lomekwi Three do not require-- sorry. I switched the slide. They don't require the human-like manipulative capabilities that are necessary when using the freehand technique that we're going to see during the Oldowan.

[00:42:54.90] So we were interested in trying to evaluate, of course, the level of skills required to make the Lomekwi tools. And we've conducted some replication work and also biomechanical analysis to try to evaluate this degree of dexterity and skills for the Lomekwian tool knappers.

[00:43:17.19] And we've shown that because of the use of these two simple techniques, bipolar and passive, we've shown that the technology here is compatible with what we know of the Pliocene hominin capabilities based, of course, on what we know from the morphology of the hand of Australopithecus afarensis.

[00:43:39.19] So I agree that we don't have a lot of evidence of how hands look like 3.3 million years ago. But from what we've seen with afarensis, we think that it was not very complicated to apply the techniques used at Lomekwi. So you needed, of course, to control the force you put in place to detach flakes repeatedly.

[00:44:10.51] You needed to have an understanding of fracture. You needed to know how to produce flakes in series via adjacent and superposed flakes. The cores have been rotated during the reduction process. So all that shows a significant hand motor control.

[00:44:28.14] But we showed that we could replicate this flaking with the two techniques we identified at Lomekwi Three without the need for forceful precision grips and without precision handling. If you are interested by this result, we published a paper that I can, of course, communicate earlier. It's a paper by my colleagues Domalain, Berlin, and Daver published in 2017.

[00:45:05.58] So for sure, the pounding techniques that we see at Lomekwi Three showed that pounding has been playing a central role at the dawn of technology. And we suggest in our paper in 2015 that the earliest stone knapping developed within hominins from pre-existing forms of pounding behavior, maybe to process plant food, for example, rather than independently to create flakes for cutting edges.

[00:45:47.04] So carbon isotope analysis at Lomekwi Three suggest that the knappers at Lomekwi Three may not have been living in an open savanna grassland environment but in a landscape that was probably a bit more woody. Again, if you want more information about that-- because I need to hurry up a little bit-- I can refer to you to my colleague and paper in 2021.

[00:46:14.73] I have to say that the precise function of the Lomekwi Three tools are not yet known. And we are still working on it. But as you can imagine, it's very difficult to understand the function of these tools or to go further than to say, OK, they were used. And the flakes were used to process animals.

[00:46:37.63] So who could have been the toolmakers at Lomekwi Three? Pending new discoveries, of course, we have only three hominin species that have been living in the region 3.3 million years ago, Australopithecus afarensis, Australopithecus deyiremeda, and Kenyanthropus platyops. Kenyanthropus platyops being the closest to our site.

[00:47:02.91] But unfortunately, as you know, fossils do not come with stone tools in their hands. So it is really difficult to say. Plus, when we find hominin remains, they often come to us with no hands at all, by the way. So it's really complicated nowadays to be sure and to attribute the Lomekwian industry with a specific hominins-- sorry-- or specific hominins.

[00:47:33.59] What we know for sure is that Lomekwi Three dates 500,000 years before the emergence of the genus Homo. And now we know that stone toolmaking can no longer be considered as a characteristic only of Homo but also of Australopithecus or Kenyanthropus.

[00:47:58.29] So to conclude, the Lomekwi tools have pushed the earliest known tools back in time but by 700,000 years with a surprising degree of complexity for the time period that shows that their makers had a good understanding of the stone fracture using a combination of techniques for both core reduction and pounding. We know now, but pending new discoveries, that toolmaking preceded homo. And that large brains and human-like hands are not indispensable requirements for stone knapping.

[00:48:36.69] Now we have a lot to do. As we say, knowledge brings more questions than answers. And for us paleoanthropologists, there is only one way to respond to the many new questions that our discoveries generate. And it's to make even more discoveries. Going back to the field is crucial for this time period, pushing the boundaries of time and space.

[00:49:02.49] So the WTAP future investigations, of course, are going to be centered into improving the Pliocene stone tool evidence. We have no archeological evidence so far between 3.3 and 2.6 million years. And the link, if any, between the Lomekwian technology and the Oldowan technology is currently unknown.

[00:49:27.93] And this is, in my opinion, only due to a lack of research. I think the sites are there waiting for us and waiting to be discovered. And so the other focus for the WTAP in the coming years is also to try to find new sites, new stone tools that are either contemporaneous to Lomekwi Three or even from before 3.3.

[00:50:02.22] For now, it's terra incognita. And I think it's important to mention that Lomekwi Three is one site only so far. And so we need to work on finding more sites of the same age, if ever they exist, or even older ones.

[00:50:22.10] So the absence of evidence is not evidence of absence. I would like to finish very soon with this quote. Further field investigations in this area by the WTAP will very surely lead to new, exciting discoveries on our technological origins.

[00:50:49.53] So thank you all very much. And I would like to also thank all who had been inspirational to this work and particularly Richard Leakey thank you very much again and I think now it's time for a couple of questions.

[00:51:12.42] Thank you so much, Sonia. That's a great talk and a fantastic introduction to these really exciting discoveries. There's a lot of questions. And I don't think we can get through them all in just a few minutes. So let me just ask a few here. And I apologize that I'm not going to be able to get to everyone.

[00:51:27.89] One very good question is from Levi. Have there been-- are you planning to conduct microwear analyses on the artifacts? If so, what has it shown? And also, do any of the ribs and bones found associated with Lomekwi Three show cut marks similar to those found at Dikika?

[00:51:44.84] Mm-hmm. Yep. Two very good questions. So yes, we have been conducting useware analysis. Not me, but my colleagues Nicholas Taylor and its area of expertise. It is his area of expertise. So we have been doing that.

[00:52:05.45] We also have tried-- we were very ambitious residue analysis. I have to say that the residue analysis didn't give anything. And I think it's understandable for a site of that age.

[00:52:20.28] In term of microwear, we haven't also been able to really identify anything that was very conclusive. This is also something we are going to publish in our update paper. So you will find a little bit of information about that. But for now, yeah, we didn't go too far with this.

[00:52:41.31] So the second question about cut marks at Lomekwi Three, this is something I cannot talk about, unfortunately, tonight. But yeah, stay tuned.

[00:52:54.99] Well, along those lines, the cut marks from Dikika, do you have a sense that the size of tools from Lomekwi could be responsible for the size of the cut marks that have been currently found?

[00:53:08.41] So the cut marks at Dikika are, yeah, definitely possibly been created with the kind of flakes we have at Lomekwi. I didn't mention that, at Lomekwi Three, we have a lot of large flakes. But we also have smaller size flakes. So definitely, we could imagine that the flakes are similar to what we have at Lomekwi Three could have created these cut marks at Dikika, which makes it super interesting, of course.

[00:53:49.37] I haven't mentioned Dikika here. I had no time. But of course, it will be wonderful if we could relate these two discoveries in the future.

[00:54:00.42] God, there are too many questions here. So another one from Richard. Were the Lomekwi hammer and anvil stones local? Or were they brought from a distance?

[00:54:08.84] So they were local. But they were also brought. So we have identified a conglomerate that is 100 meters away from the site. And that was there when the hominin started to knap at the site.

[00:54:28.10] So definitely, the hominins were taking some raw materials from this conglomerate. They were bringing them to the site. But it's not very far. We don't have a long distance transportation of raw materials.

[00:54:45.11] Also, when you look at the size of the raw materials, of course, it makes sense not to want to transport them too far. If anything, you transport the flakes. But you leave the anvils and the cores.

[00:54:57.71] Yeah. So another question is, how many stone tools have you found at Lomekwi?

[00:55:07.50] So I mentioned earlier that we are now around 200 artifacts. I don't have the exact breakdown. Because I still need to look at some of them and confirm their attribution. But yeah, it's a group. It's a good group of artifacts now. We're very happy about that. And we hope to find a bit more in the coming years.

[00:55:34.80] So I'd like to maybe end with a rhetorical question, which is, given that that chimpanzees make tools, right, should we be surprised that there's something older than the Oldowan? Is there something special about making tools out of stone as opposed to tools out of other? I mean, certainly, Australopiths were making digging sticks and things like that. Should we be surprised that there are tools older than the Oldowan? And also, is there something special about making tools out of stone as opposed to other materials?

[00:56:09.59] So I'm very open, of course, to have any other primates, the idea of any other primate making tools. But chimpanzees are not. Chimpanzees are not making tools and especially not when we talk about the nut-cracking activities that are involving stones manipulation. We've never seen a chimpanzee in the wild making a tool. So what they do is they create flakes from time to time from their nut-cracking activities using a hammer against an anvil.

[00:56:47.86] But these pieces, I don't even want to call them flakes. Because they are totally unintentional. They are never used. And so again, if I'm very open with the idea of extinct primates different from hominins creating artifacts, for now, we don't have any proof of that with chimpanzees.

[00:57:14.50] And with capuchin monkeys, if you remember, there was a publication a few years ago about capuchins creating flakes, which is, I admit, quite disturbing for an archeologist like me. Because we see conchoidal fractures with these assemblages. But fortunately, capuchins were never interested in using these flakes. And again, they are completely unintentional and accidental.

[00:57:44.67] Excellent. Well, it's now 7:00. And we know that you have to leave for another engagement. So I'm sorry we didn't get to all the questions.

[00:57:54.12] But let me just, once again, thank you for giving this year's Movius lecture. Your work is super exciting. And we can't wait to hear about the next set of discoveries. So thank you very much. Merci.

[00:58:07.17] Thank you then. Bon soir. Abierto.