 My main research interest is to understand what makes humans different from other creatures and especially other hominins that lived in the past. We have today only one species of human living on Earth. All these humans have a recent common origin, but this situation is completely new at the scale of geological times. In the past, almost always, we had several species groups of hominins living on the planet. And it happened two times in the past, once about 2 million years ago and again about 50,000 years ago, that one group out-competed all the others. And we are one of these groups, the modern humans, and these modern humans expanded all over the planet starting about 100,000 to 50,000 years ago and eventually colonized the whole planet. We want to understand what made them different from other hominins and what is the reason for their demographic success and the fact that they replaced all these other hominins. To investigate the reasons for this very successful expansion of modern humans, we tend to concentrate on a special case, which is western Eurasia, where Neanderthals lived before the arrival of modern humans. And why we focus on this area, because we have a lot of information, we have a lot of sites, we have quite a lot of fossils of Neanderthals and early modern humans. The question is that we don't know exactly why one group eventually replaced completely or almost completely the other. And there are many possibilities. People came with biological hypothesis. Some others have supported that it's mostly demography that plays a central role. Others that in terms of technology, behavior, social organization, modern humans were sort of superior. And this could explain their success somehow. There are also some others who think that environment and climate played a major role in this sort of dramatic transition in Europe. And so it's important to investigate all these aspects and to investigate the biology of the Neanderthals and early modern humans. We study the fossil remains of these groups in terms of anatomy, of course, and we are very interested also in the development when we can in demographic indicators. We also, of course, look on the behavioral side of the story. And this is mostly a matter of archaeology working on their dwellings, on their artifacts. And recently there is a new domain that developed a lot, which is using molecular techniques to investigate both biology and behavior. And so we're interested in all sorts of things, starting with DNA, going on with stabilized autos, and more recently with ancient proteins and things like that. And we try to understand what was the biology of these groups and also what was their behavior. What we have found is that it's very unlikely that Neanderthals got extinct because of some natural causes. So in other words, it's very difficult to match climatic changes or natural disasters to the extinction of Neanderthals. And it's clearly the arrival of modern humans in Western Eurasia that led the Neanderthals to extinction. So we are the cause of the extinction of the Neanderthals. I think this is quite clear today. This being said, this process of replacement was not a simple one. And what we have found, and this is a clear result, is that there was interactions between the two groups, maybe not always very friendly interactions. But we know that there is gene flow from one group to another. So there was some mating between Neanderthals and modern humans, at least sometimes. And we also know that the behavior of the last Neanderthals, after hundreds of thousand years of separate evolution, have been altered by the arrival of modern humans. And we have cases where we see the Neanderthals adopting technique behaviors that are brought into Eurasia by these African invaders. And this is something really fascinating. So probably one of the main results of the last few years is that even if modern humans were the cause of the extinction of the Neanderthals, there is a certain level of assimilation of these last Neanderthals by the invaders. And there's a complex and long story of several millennia in Europe where you have groups of Neanderthals, group of modern humans, maybe groups of hybrids of the two. And they have different type of cultures and behaviors. And we are just starting to understand who did what and why. All these findings about the late Neanderthals and the early modern humans makes our views on the Neanderthals changing a lot. In the past we had a sort of very simple perception of the situation. So Neanderthals were primitive, they had very simple technologies and they were outcompeted by modern humans coming into Europe and replacing them. The very fact that we have these two groups living in Europe, not together in the same region, but in different regions, for such a long time, several millennia suggest that the superiority of modern humans was not so abused somehow. And it took a long time and it's a long process with movement back and forth and replacement of one group by another, but also a mixture and diffusion of behaviors from one group to another that tell us that finally Neanderthals were more complex creatures that we had thought. They are very well adapted to their environment and to put it maybe in a way a little bit blunt, they resisted rather well and rather a rather long time to this development of our species in western Eurasia. And I think this is something that is somehow new because we tended not to envision the Neanderthals as complex as they were, in fact, in their capabilities, adaptability and the way they were able to cope with not just the environment of Pleistocene Europe, but also the presence of other hominins around. So we have opened some windows on this remote past and we have a couple of pictures and we try to make sense of all these pictures, but truly there is a lot of work to be done and we would like to know in each part of Europe along this period from 50 to 40,000 years ago what has been going on and to do that we still have to collect a lot of information. So there is, for example, a series of archaeological units, what we call techno complexes for which we don't know exactly if they were made by Neanderthals or modern humans and we want to know that because of course it will probably make a clearer picture of what's going on. So it's a bit frustrating to ask these kind of questions because we don't have a lot of fossils of human remains. So what people are doing now is trying to approach this problem a complete different way. So in the past we have been waiting for new discoveries of spectacular human fossils, for example. Now people are using other techniques, for example, to investigate all the small fragments of bones that are found by thousands in archaeological sites and from which we cannot really say much in terms of anatomy, but investigating these large assemblages by molecular techniques it's a way, A, to screen off human remains that has been so far invisible to our eyes, B, determining whether there are Neanderthals or modern humans and then extracting a wealth of information in terms of genetics, paleoproteomics, stable isotopes, all sorts of techniques will give us information on the biology, the demography and the behavior of these ancient hominins.