Dr. Reich is a Professor of Genetics at Harvard Medical School. His lab analyzes the DNA of ancient human remains to better understand major human migration patterns, adaptations, and population mixing throughout prehistoric and more recent eras. David’s book, Who We Are and How We Got Here, explores the deep history of humanity and how the discoveries of ancient DNA challenge the popular stories we tell about the past. David joins the podcast to explain why every human outside of Africa has some Neanderthal ancestry and how human migration patterns for tens of thousands of years have reshuffled populations and cultures over millennia.

Transcripts of our episodes are made available as soon as possible. They are not fully edited for grammar or spelling.

Tom: David, welcome to the show. I want to start by asking you a little bit about yourself. Can you tell me where you grew up and, what are the things that most captivated you when you were young?

David: I grew up in Washington, D. C., or just outside on the Maryland side, and I was interested very much in science and in history. When I was in high school, I read book after book about medieval Europe, mostly, and read a lot of American history, beyond the required coursework. And at the same time, I was doing science internships in the summer in different areas of science, trying to find some area that caught fire for me. So, when I was in college, I started as a major in social studies, and then I switched, and my final degree was in physics, but I think that was an unusual straddling of areas that were not so like each other, but I was taking courses in both areas throughout.

Tom: Yeah, straddling the sciences and humanities. The research that you do now, centers on people groups all over the world. Did you do any international travel or have experiences, in your formative years that catalyze your interests, in people groups far, far removed from you or is that kind of more flights of imagination?

David: We had maps all over our house. We had a map of the world at our kitchen table, and my room for many years had at least 20 maps on the wall. I would sort of pace them up in every possible corner. So, I was very interested in geography and maps. I, like ninth or tenth grade, I would create and work on different kinds of map projections and draw the world out on sort of pieces of paper and have little sliding slats to create mobile reprojections of, the world in different shapes.

I think I’m, I’m interested in how, a person like me or someone else connects to the worlds around them. And I think maps are one way of doing that, trying to connect your tiny body with the reality that you live into the universe around you.

Tom: You mentioned that when you’re in college, your academic interests really straddle the sciences and humanities; you wound up with an undergraduate degree in physics. Tell me a little bit about how your interest gravitated towards genetics and the kind of research that you wound up dedicating your career to.

David: And the end of college, I applied for second bachelor’s degree in biochemistry. I didn’t complete that second bachelor’s degree in biochemistry, but instead I replaced it with a master’s in research, and so I interviewed a lot of investigators, and I just stumbled into the group of, researchers.

American researcher, David Goldstein, who was just starting out, he didn’t yet have any graduate students. Still, he was working in this area I’m in now, which was very early on in the DNA revolution in terms of the studies of human history. I, started writing papers, doing useful research that pushed the boundary and so that caught fire.

Tom: Yeah, school was one of the kind of areas that you had considered pursuing, and you wind up on faculty. At Harvard Medical School. Is there some connection between your work and say clinical medicine and some of the other work that your colleagues do?

David: Definitely. So, I went to medical school and did most of the degree.

And there are many, many connections. So, the first work that I did when I was starting out faculty and at the end of my postdoctoral period was trying to use, the history of human populations as a way of trying to find risk factors for disease.

So, we’re looking at African Americans and Latino Americans who are affected largely mixtures of African, Native American, and European ancestry. And that’s recent mixture to the history of transatlantic movements in the last 500 years.

And we were trying to see whether a particular risk factors for disease that are more common in some groups than in others might be coming more from the Native American or European or African ancestry component. And so, I designed statistical methods. to do this and laboratory experiments and resources for carrying out these studies and spent a huge amount of time and energy implementing this and, finding risk factors, for example, for prostate cancer and multiple sclerosis and end stage kidney disease.

And, Later, one of the things that we’ve we did in our work in South Asia, where we’ve published many papers, is identified that there’s many, many subgroups in India that are each. quite different from each other.

And there’s thousands and thousands of subgroups in India that have traditions of endogamy and not mixing across communities. And many of these descend from founder events, relatively small numbers of individuals giving rise to hundreds of thousands or millions or even tens of millions of people today.

And because of that, rare, risk factors for disease that occurred in those founders have gotten amplified in frequency in the descendant groups and cause risk factors for disease today, so looking into that’s also been an important strand. Finally, something that I work on now is trying to use ancient genomes and People who lived in the last 10 or 15, 000 years to try to understand how genetic variants that are risk factors for disease and, other traits, how they’ve moved in frequency over time. And we’re able to do this now with really striking resolution and that’s an exciting development. And it’s interesting to think how that impacts medicine,

Tom: Yeah, I think most of us thinking about studying of DNA is something from taking blood samples of people who are alive and learning maybe something about our history, some of our health. but you study DNA from people who live thousands or sometimes tens of thousands of years ago. what can you learn about humans, by studying these ancient remains that you can’t learn by studying humans from blood samples taken, today?

David: One thing that you can learn is about histories of populations. So, people have moved over time. We know about the most recent layers of movement. So, for example, the movements of people across the Atlantic, in the last 500 years associated with the Atlantic slave trade and, movements of European colonists to the new world and so on and so forth, large movements of people.

Both willingly and unwillingly in this last 500 years. But what we don’t know as well is some of the movements of people in the past, and it turns out that when you actually get data from people who lived in the past, from known places in known and again you see evidence of dramatic movements and transformations of people, with one group coming in and mixing with or even often displacing the group.

People who were lived there before. And that’s not just a phenomenon of the last 500 years. It’s occurred again and again, deep, deep, deep into the past. And that’s been really the biggest first lesson of the ancient DNA revolution, which is that large scale migration, mobility, and population transformation is a feature of our past. We’re all mixed and nobody’s pure in any sense, going back deep, deep, deep, deep in time, probably forever. So that’s a very, very important lesson. powerful lesson.

Tom: Gotcha. So, come across some ancient, remains of humans. They’re thousands or ten thousand of years old. What conditions must be in place for you to be able to encounter and find DNA and process it?

David: Yeah. So, one of the things that’s been a miracle of, of ancient DNA is that bone, like the substance bone, which contains mineral content in it, is an amazing preservation context for DNA. So, DNA is a robust molecule. And when the cells explode after a person dies, But the DNA sticks to the

Hydroxyapatite mineral content in bone and seems to be preserved well enough over thousands or tens of thousands or even hundreds of thousands of years to be analyzed. And We see examples of this, for example, if you see natural mummified remains, where you see even in a dry, high-altitude cave or another context, you see even pieces of skin occasionally preserved.

The skin will almost never contain DNA, but the bones will. Bones are just an amazing, beautiful material. They are a context for preserving DNA. That’s one issue, but there are other issues that affect whether DNA is preserved. One is what part of the skeleton it is. So, the ear bone is an incredibly good place for preservation, as is the inner ear, the cochlea, 100 times better than any other skeletal element for some contexts.

There’s some context where only the ear bones produce good data, and they produce amazing data, and everything else fails. After that, the teeth are somewhat good preservation context, but not nearly as good in many cases. The other types of bones and ribs are particularly bad, and so on.

So, there’s this hierarchy of preservation within the skeleton. And there are also other factors that matter. So, if there’s not a lot of change over time in the type of conditions, so if you are in a desert where the conditions are very cold at night, very hot in the day,

That’s terrible for DNA. Or if you’re in a place that is in the Indus Valley floodplain, where the water rises and the waterfalls, change is, I think, difficult and bad for DNA. And then age, it gets worse with age, but quite slowly.

Okay. Yeah. To follow up on the questions about what, bones preserve DNA the best. what is it about the ear bones, that enables them to preserve DNA so well? Is it the position of where they are or, something special about the bone itself in the ear We don’t know. It’s also the little bones of the middle ear, the, the, the Hamel, the anvil and the stapes, are also well preserved. then, petrous bone, the cochlea, is essentially fully formed when a person is born. It’s like one of the only bones or in the body that’s like whole essentially fully formed and of the same size when a person’s born as when a person gets bigger. And it’s made from woven bone rather than, the other, types of bone. So, it’s, it’s a different type of bone tissue. It’s particularly rich in cells. These are all speculative ideas, and we don’t know the answer.

Tom: I imagine that, even with this weird quirk of nature that these ear bones seem to preserve well. It must be incredibly rare to find these remains. and thus, maybe each new discovery you make, could have wide implications because your data set is small. is that what you’re seeing that basically with each discovery, there’s not a lot of rewriting of history follows from that.

David: I think yes and no. So, um, every time we get a discovery from a place where we don’t have data before, that’s exactly what happens. We get data for the first time from an archaic human, and then we ask the question about how that archaic human is related to other people, other archaic humans or people living today. And almost always it’s a

surprise, because it shows us how little we knew about the past, that when we get this unique data from people who lived long ago, we can ask how they relate to people and almost always it’s different from the mainstream theory, so that’s very interesting.

On the other hand, when you’re getting DNA from contexts where we’ve already had DNA, sometimes the answer becomes quite boring and consistent. So, for example, if you’re looking at early European farmers who lived 7, 000 years ago in Germany, for example, or Hungary, again and again they look almost all the same as each other, and we’re not seeing new patterns in terms of history.

Tom: when you find these, big surprises, what’s often your first reaction? Is this elation of being surprised or sometimes this confusion and consternation of like, ah, I must rethink so many of my assumptions. what’s the first gut feeling you have when you hit these surprises?

David: skeptical. So, we think that we made a mistake. And so, we try to make the result go away. We immediately notice it because we’re looking for signals. So, we’re looking for surprising observations. and we see a surprising observation and then we try to torture the signal and make it go

Tom: Mm hmm.

David: And then at some point. Once we’ve tortured the signal enough and tried to make it go away enough and we can’t make it go away and then we look at it from several different angles, we say, well, this seems to be what the data are

Tom: Yeah. Yeah. So, it’s, it’s really a kind of a process of surprise rather than an immediate kind of lightning

bolt of everything is different.

David: mean, sometimes things are a lightning bolt of everything is different. So, for example, the discovery of the Denisovan sequence, that’s such an example. It’s just like, uh, uh, this is a fully formed, high quality sequence, and it’s from outer space. It’s completely different from anything we’ve ever seen before, but it looks like a valid mitochondrial sequence, a valid whole genome sequence.

It just is different from anything we’ve seen before, and in a radically different sort of relationship to the samples that we’ve analyzed before. Or for example, the ancient North Eurasian genome from 24, 000 years ago, it was like a missing puzzle piece. And once that was in place, everything clicked.

The nature of what we study is changing very dramatically. So, we just passed 12, 500 ancient, published genomes, in 2015, so nine years ago it was 350 or so, so it was a super dramatic rise and, in 2009 there was nothing. So, it makes it possible to ask and answer questions about the past that were simply not possible to, answer before.

Tom: In terms of the material that you work with, no matter how ancient they are, they’re still human remains. And I’m wondering how you handle some of the sensitivities maybe when you’re investigating a new geographic space or in an area that haven’t studied yet? Mm hmm.

David: That’s an incredibly important question and uh, it, the question must be dealt with in my view, and I think in the view of many other people in a case-by-case basis, depending on the type of place that one is in. So, if one is studying very, very old. samples, people who lived many tens of thousands or even thousands of years ago that have no discernible cultural or obvious connection to people living today, then community connection to these samples is, not clear at all.

And I think that there’s relatively little obligation to consult with or engage with local communities except to the extent that people who live in these regions should be part of the conversation about the remains that are studied, even if there’s not a direct connection.

There are also different parts of the world where there’s different cultural attitudes. So, in Europe, people have a relatively unsentimental relationship to the dead compared to other parts of the world. If I had time, I might become a historian or something for a few years and try to understand the attitudes to the dead in different parts of the world, but I think the Europeans are a real outlier.

I think that especially Christians, in many contexts really don’t, have a lot of worry about disruption of the dead and digging up of human remains and a lot of Christian cemeteries in Europe, people are okay with digging up remains and putting in new skeletons and having the remains from one.

be in the fill of another grave, and so this is very difficult in a Muslim context or a Jewish context or many traditional other contexts. where people are more worried about this type of disruption, and I’m sure there’s exceptions also to this in the Christian context.

And so, the, uh, but experience that European archaeologists have of not being concerned about this type of disruption it doesn’t directly apply in that, straightforward way.

I think that there’s also, issues about, for example, if we’re studying ancient Egyptian material, this is not directly connected culturally to people living today. But clearly these people had a lot of concern about, what would happen to their bodies in the past. after they died, they would, build protections against grave robbery.

They would, have a book of the dead, which describes what happens to the body. And if you take out a skeleton from the tombs, it’s clear from that religion that we have evidence of that this is not what these people would have liked, but they don’t have advocates today for their view of the world.

So how should we think about that? I think we should take it seriously because those are the remains that were disrupting.

In the end, if you’re studying people who lived relatively close in the past, then it becomes ever more requirement to engage with the communities who live in those places, whoever they are, but especially when it’s communities where these issues are more sensitive or more central. especially when they’re also disenfranchised communities.

Tom: I think I learned in school there’s a hypothesis that all humans, if you go far enough back, ultimately derive their origins from Africa. how did scientists come to this conclusion and, how has the study of ancient DNA informed this, view?

David: There was a discovery in the late 1980s, based on sequencing of mitochondrial sequences, which you get from your mother, and she gets from her mother and so on and so forth back in time. And if you look at the relationship of all mitochondrial sequences living in the world today, all non-Africans stem from a common ancestor who lived maybe 000 years ago, and that within Africa there’s many deeply splitting lineages, including some representatives of that same group, but also transcript ends with a subset of the variation in Africa.

Subsequent work looked at the Y chromosome, which men, get from their reproductive Fathers and they get them from their fathers. And it’s the same story. It’s all non-African variation as a subset of African, exactly what you’d expect if, there was a small subgroup of random Africans or semi-random Africans that spread out of Africa sometime.

And so that genetic observation coincided with increasing evidence of the spread of a transformative, later Stone Age slash Upper Paleolithic culture out of side of Africa in the Near East for the first time after about 50, 000 years ago.

So, there was a synthesis of the archeological evidence of this transformation, and then the physical anthropological evidence where you start seeing skeletons of African humans appearing out of Africa at this time.

And then the genetic evidence that non-African are descended, a subset of African variation. 1980s to demonstrate this.

I’ve read that, um, a human, someone in our lineage, Homo erectus, ventured out of Africa, like 1. 8 million years ago, but the humans that it seems globally we’re all related to ventured out of Africa, as you said, maybe 50, 000 years ago.

Tom: What was going on 50, 000 years ago that say wasn’t going on half a million or a million years ago. What is the magic there that made humans populating You know, every continent versus being in a smaller region. Hmm.

David: with a number of these spreads, including the one 1. 8 million years ago. I mean, that occurs shortly after the appearance of, for example, tool use for the first time, or, you know, possibly the use of fire, right? These are major plausibly associated with the spread of humans out of Africa.

into, you know, large parts of Eurasia. And there’s other massive technical innovations. For example, the creation of the hand axe, um, you know, on the order of 800, 000 years ago, or the creation of Levallois technology, Middle Stone Age technology, three or 400, 000 years ago, which is associated with taking, uh, cores like, uh, Rocks that you hit in a particular way to pop off the blades that you want.

So, there’s all sorts of profound and important technical and cultural innovations that occur, that appear to be potentially associated with dispersals of people in different directions. so, it’s not clear that the one 50,000 years ago was somehow the only such event, but it was. apparently, such an event.

So, what happens 100 to 50, 000 years ago is the appearance of, later Stone Age Upper Paleolithic technology. And that’s associated with a different type of core and, tool production technique and much greater use of symbolic behavior and creation of art, cave paintings and beginning around this time going back probably up to 100, 000 years or so in Africa.

These people were very successful. They spread into areas where these techniques were not used as much. So maybe what you’re seeing is the spread of a culture that did these things, or maybe some biological capacity to do these things, but in my view, most likely just a cultural set of innovations, but it could have been biological to some

to some Yeah. Yeah. So, with each kind of each major migration or movement in human history that you see, there’s some questions to be asked, some mysteries to be solved, I guess, with every success of change, you got to wonder what has prompted it.

Tom: Mm hmm. Yeah. Someone talked about Neanderthals, which it’s been fascinating humans for, quite a while. finding the remains, the physical remains of Neanderthals is, been around for a long time. It may be 19th century, but the fact that there’s DNA from Neanderthals in living humans today, I think it’s relatively new.

How on earth did that get in there into the humans that we know? and what kind of significance does that play for us? Wow.

David: non-African people today typically have about 2 percent of their DNA derived from archaic humans who lived in Europe and Western Asia, Neanderthals. And we didn’t think this before 2010, but in 2010, we got sequences from the Neanderthal genome, and we compared it to diverse modern human genomes, and there looked to be segments of DNA, that looked very close to Neanderthals.

In fact, soon after we could show they’re related within tens of thousands of years, or in some cases, a couple of hundred thousand years to the Neanderthals we sequenced. So multiple lines of evidence provide unambiguous evidence that there was gene flow, migration, interbreeding between Neanderthals and modern humans and non-Africans today descend from that.

And in fact, it’s not 2 percent of ancestors. It’s probably more like 30 percent of the ancestors of non-Africans. And there’s just been natural selection that’s removed these segments of DNA. from Neanderthals because they were not as biologically helpful to the people who received them. But in fact, if you count your genealogical ancestors 70, 000 years ago, and you’re, for example, an Indian person, like not 2%, 30 percent will be Neanderthals.

So, it’s like a profound contribution, ancestrally and genealogically. And these are spread across the genome, and they do stuff because the genome is full of function. And so, there’s variants that are risk factors. For example, the greatest risk factor for COVID 19 is a variant that is coming from Neanderthals and is highest frequency today in South Asians, for example.

The high-altitude adaptation variant in Tibet for, being able to survive at high altitude, it comes from another archaic group that we’ve discovered through DNA

Tom: Okay, we’ve, we’ve tackled some big questions out of Africa hypothesis Neanderthals. I want to talk about the Agricultural Revolution, which is a term that, looms large, in many books that have been written, let me give you a very basic formulation I’ve heard before.

So, for most of human history, Archaic humans, modern humans, have been some form of hunters, gatherers, foragers, Then, as the story goes, perhaps about 10, 000 years ago or so, humans started domesticating crops, domesticating animals, were able to develop some kind of farming, sedentary societies.

These societies were Where successful enough strong enough that they expanded and then either displaced or replaced most of the hunter gatherers Across the world a process that continues today Does the story that I just told in it.

in its basic form does that map on to? What you’re seeing and studying DNA analysis?

David: I think it does to some extent. So, the farming revolution in many places is demographically transformative. So, the people who develop farming spread from their place of origin and largely displace some of the people who were there before with some amount of mixture. So, you see this, for example, in Europe, where the first farmers of Western Eurasia, that appears in the Middle East 12, 000 to 11, 000 years ago.

And then those people explode into Europe after 8, 500 years ago, first into Greece and then spreading across Europe in a couple of thousand years. And what you see is that the first farmers in the Balkans, places like Greece and Bulgaria have almost no mixture with local European hunter gatherers, but as they get to Western Europe to places like Iberia or to Britain, they pick up Lots of hunter gatherer ancestry, 10, 20, 30 percent, even 40 percent in some cases.

And so, they’re mixing with the locals they encounter along the way as part of this expansion process. And

Tom: One of the things I learned from your book that utterly fascinated me is, in studying the long history of Europe, you’ve got hunter gatherers there, uh, long time ago, largely. either displaced or integrated with farmers, but when farmers were there, another people group just rolled on in and it seemed to completely change the population. Once again, it wasn’t just farmers always win against other gatherers, but in this case, farmers seem to be, if there’s a competition on the losing end can you tell me just very briefly for those who don’t know, what was that like the next wave in which farmers themselves got either displaced or replaced.

David: Yeah, so 5, 000 years ago, the people in Central and Western and parts of Eastern Europe had no ancestry from Eastern Europe. But today, half of the ancestry is from steppe in many parts of Europe. For example, Northern Europeans, half of their ancestry is from the steppe. This happens after 5, 000 years ago when, um, extreme mobile pastoralists, uh, who are the, some of the first users of the domesticated horse and wheeled vehicles, spread explosively, toward the west, toward Hungary, and to the east all the way to Mongolia.

And these people or their descendants and other cultural guises move into central and western Europe and could, largely displace many of the populations that were there before. In some cases, at least 75 percent as in Germany, in some cases, at least 90 percent as in Britain or 60 percent as in Iberia.

It’s a very dramatic population turnover associated with the spread of these people and why they were able to do this, given that they weren’t farmers at the beginning and displaced densely settled farming people is unclear. There’s an increasing amount of evidence that there were epidemics associated with these spreads.

So, for example, Yersinia pestis, which is the Agent of the Black Death, has been found in the teeth of, quite a number of these people beginning around this time, and one possibility is that there’s a pandemic that occurs or a sustained pandemic in European farmers that, steppe people are already somewhat immune to that, allows them to spread into this area.

Tom: Fascinating. The last big geographical topic I want to discuss is the origin of humans’ movement into the Americas. The basic story that I’ve learned is that during the last ice age, sea levels were low enough that people could move from Asia to the Americas by walking across what we now know as Siberia straight into what we know of as Alaska.

From the studies that you’ve done of ancient DNA, does that story still, ring true or, what are some ways in which I can get a more kind of robust understanding of the history of, humans in the Americas?

David: Yeah, I think ancient DNA is beginning to complicate that story. I think that the great majority of Native Americans, except for present day Inuit Eskimos or, Athabaskans who have their own special stories, descend from Native Americans. a single common ancestral population that comes to a common ancestor, maybe on the order of 15, 000 years ago.

So, about the time you’re talking about, if you look at early ancient DNA from South and North America, the earliest samples date to between 12 years ago, you can see the beginning of the diversification of the lineages that are all ancestral to the people living today. So, there are two main branches.

There’s the Northern North American branch, and there’s the Southern North American branch, and the Clovis expansion, which is the large-scale expansion of people making these beautiful arrow points that give them their name from Clovis, New Mexico. That began at the tail end of the last ice age; at the beginning, the beginning of this period, some people used to think that this was the first expansion of humans south of the ice sheets, maybe going through an ice-free corridor that opened just before then.

But it looks like there are different earlier lineages outside the variation of this Clovis group that we have data from. For example, some South American populations have more Clovis-related ancestry, and some have less. So, it seems there are more complicated and deeper splits.

So, I think what we’re seeing is evidence that genetically, there are spreads of people that are too early to be accommodated by the time the ice-free corridor would have opened. They are too early to be explained by Clovis expansion, but only by a couple of thousand years.

Tom: Yeah, multiple groups may have come across over thousands of years and somehow navigated ice in ways that perhaps defy imagination.

David: Maybe, maybe by using boats along the west coast of North America.

Tom: Okay. Seems to find some very clever ways to explore and expand. So, little time we have remaining, I want to ask you just a couple more kind of general questions. So, I’m wondering if your study of ancient history, vast stretches of time, does that influence, the way you look at the present and, and perhaps near future?

David: Anybody who’s looking seriously at the data we have learns from the data a few very strong lessons. One is that there’s no sense in which anybody is pure. And there’s no sense in which, a particular people have been separate from other people for very, very long periods of times. We’re all the results of mixtures again and again in the past. So, any, narratives that harken to an idea of purity, are flawed. Fundamentally, and I think that it also gives one a sense of the huge churn of people that’s constantly happening over different time periods, that the situation we’re in right now is not static, that it would have looked very different if we were able to be in the world, thousands of years ago, tens of thousands of years ago. So, I think that it gives us some humility about our position in

Tom: Yeah. Yeah. Does that study of, of the ancient past, does. that help you get any insights about where things might go in the future of humanity? Yes.

David: I mean, I think past is prologue. And I think that, we live at an extreme time right now. The human population size is, very extreme relative to what it’s been at many points in the past. So, it’s hard to imagine that it’s stable. so, I think that what this does tell us is that

the idea of stability of human populations is an illusion and radical population crashes and displacements are common in history. So, I think it’s important not to have a sense of complacency that we’ll be able to get Keep the situation we’re in for an indefinite amount of time.

The other thing is that biologically we can look at the genomes of people living in the last 10, 000 years and ask the question, is there change over time and what is the trajectory of changes? And we’ve begun to do this and what we can see is, the predicted values of all sorts of traits, like for example, risk for diabetes related traits, has decreased.

Genetically predicted to decrease over time. So, what does that mean? And that sort of predicts, a trajectory in, some of those traits relative to the past. Risk for what now manifests itself as schizophrenia or bipolar disease, that’s been predicted to decrease in the present compared to the past, there’s been natural selection against that combination of variants that must reflect exposure to variety of traits, but it also perhaps predicts how we might continue to change in the future as a species.

Tom: Yeah. I want to ask a personal question to wrap us up here today, what’s your motivation that, that gets you up each morning, to pour your heart into doing this kind of research?

David: Finding out how we’re all related to each other and to try to understand and help people understand the connection between the small moat that is yourself and the vast sea of people around you. You know, how can you build up that connection? And I think that this type of work helps one to do that.