#928 Charles Roseman: The Evolution of Complex Traits, Hereditarianism, and Understanding Sex

00:00 Ricardo Lopes: Hello everybody. Welcome to a new episode of the Decent. I'm your host, Ricardo Lob and the MG by Doctor Charles Roseman. He is an Associate Professor of Evolution, Ecology and Behavior at the University of Illinois at Urbana Champaign. He studies the evolution of complex traits. And today we're going to talk about complex traits, how they evolve in in evolution, particularly focusing on neanderthals and homo sapiens hereditary is differences between human populations and sex. So, Doctor Roseman, welcome to the show. It's a pleasure to everyone.

00:37 Charles Roseman: Thank you very much for the invitation.

00:40 Ricardo Lopes: So let's start then with complex traits. So, first of all, what is a complex trait from an evolutionary perspective? I mean, what it, it makes the difference between a complex trait and I guess we could say a simple rate.

00:59 Charles Roseman: So, uh the the funny thing is that the complex traits are often simpler than the, the the simple traits. Um AND that a complex traits are usually the ones where there are many, many different genetic and environmental influences that come together either in combination or in interaction to produce variation in a trait and the in humans, the canonical complex trait is height stature. So I'll tell you, I'll tell you are. And, um, this contrast from what we think of as simple Mendelian traits. So, uh, the, the various, uh, things that Mendel was looking at in his pea plants and that sort of thing, it turns out that there are not that many of those simple traits, those Mendelian traits, most of the traits that we deal with when we're dealing with organisms in just about any context are complex in that they have lots and lots and lots of different influences. Now, complex isn't necessarily a, a very good word. Uh Complexity is a bit of a trap because everybody thinks they know what it is and I haven't heard a satisfactory definition for it in general. Um So, uh one of the nice things about complex traits, like stature that is height and um any of the morphological characteristics that I tend to study is that they're amenable to uh kind of a uh a statistical summary approach. We don't need to know the identity of every single gene or environmental influence to make statements about how relatives are going to resemble one another and to predict how they're going to evolve.

02:54 Ricardo Lopes: But uh I mean, how do you approach the study of complex streets? Because I know that particularly for evolutionarily minded researchers many times the way they go about things is that they start from an adaptation is perspective. But uh of course, there are other mechanisms through which it rates evolve or come about. Like, for example, sometimes they are by products or uh how some people call them spend rolls other times they come about through genetic drift. So how do you approach their study? Exactly?

03:37 Charles Roseman: OK. So uh the you brought up the adaptation approach and um well, I think that natural selection is, is quite important and don't, don't get me wrong on that. Um I get a little worried about the adaptation approach. So, and the reason for that is that uh uh if you are looking at an organism and you see it doing something that strikes you as interesting and then you say, then it must have evolved to do that. Well, what are you doing? Well, um this is very similar to the natural theological argument that say William Paley came up with quite a long time ago. He was an influence on Darwin. And the idea is that in his thought experiment, Paley is walking through a heath and a meadow or, or something like that and finds a watch and the watch is complex and it seems to, to track time and all those sorts of things. And he said that, well, this is well designed and that means there must have been a designer. And if you take natural selection as the designer and put it into that argument, uh you have only solved a part of the problem, you've solved the, the deity problem, the designer problem, the conscious designer problem. But you haven't solved the evolutionary problem. And the evolutionary problem is the one where, yeah, we would like to know something about the uh what did the, what did the organism start as when we are interested in the evolution of AAA trait? So we want to know the ancestral state and then we want to know the processes, the dynamics that led up to the characteristic that we're looking at today or the difference between the organism we're looking at and the uh and the uh the rest of the living world. So uh that is um that's the evolution part. And as you said, that involves a number of things, recombination. It involves genetic drift. There might have been gene flow and hybridization. Uh MUTATION, of course, is very important for keeping variation around in the first place, all that type of thing. So, um if we want to do that, having a dynamical approach is what I would, what I would say, I'd say evolutionary approach. But uh you know, that seems to dismiss adaptation as not being evolutionary and that's not, not really my meaning. Um And the study of complex traits give that to you. It gives you a way to formalize the study of the evolution of complex traits so that you can build models and test hypotheses about how things changed uh when they did change.

06:40 Ricardo Lopes: But so just for the audience to get a better, a more clear picture picture of what we're talking about here. Let's say that you uh get across a complex trait in any kind of species out there. It might be a behavioral trait or psychological trait. Uh MORPHOLOGICAL trait. How do you first approach it study uh theoretically methodologically to really then understand and know whether it was the result of natural selection or sometimes specifically sexual selection uh or if it was the result of something like genetic drift, or if it's a by-product of certain specific adaptations.

07:32 Charles Roseman: Ok. Well, the first thing you need to do is have a good sense of the organism. You need to know what you're measuring and you need to have a sense of how the organism is put together, that includes how it develops so on and so forth. Let's leave that aside for the moment. Let's assume that we have that and just deal with the evolutionary issues. Well, one of the uh great tools of evolutionary biology is the neutral theory. And um so this is the idea that evolution might take place only uh by random genetic drift and uh random genetic drift. And um the neutral uh neutral theory of evolution supposes that uh the circumstance under which evolution is taking place only because of a random genetic drift and neutral mutations being put into the population. So these are mutations that don't affect the survivorship and reproduction of the organisms. So it's uh they're neutral with respect to fitness. So no natural selection arises as a result. So, uh what's nice about that is that it gives us some clear connections between what molecular variation ought to look like and what phenotypic variation ought to look like. So, rather than having a coming up with a infinitely large series of hypotheses and models and explanations that feature natural selection which can operate in all kinds of different ways. This allows us to write out some very simple expectations under some uh under uh that are restricted in number so that, you know, the possibility space is really small. And what this lets us know is that uh if we reject the neutral hypothesis or if another model fits better than the neutral model, then we have a warrant to go and look deeper, try to find out if natural selection might have been operating on something or if there's phenotypic plasticity that's involved in the variation in the characteristic.

09:50 Ricardo Lopes: But in your mind, because uh we've mentioned here, the uh the adaptation is approach, what would you say are perhaps some of the issues with approaching the study of uh traits, complex traits or even simple traits uh with an adaptation is uh approach in mind that is assuming uh that they must have been the result of natural selection, sexual selection, that is that they are adaptations starting with that assumption. What are, what do you think are the issues or might be the issues with that.

10:30 Charles Roseman: Well, um so one of the issues is that there are very, very many ways in which you can produce exactly the same thing using natural selection. Uh You can know a lot about the natural history. You can tell that if say you reject a neutral hypothesis uh of the evolution of a characteristic, uh you can still then have very, very many uh hypotheses about uh what um uh what natural selection might have done to adapt an organism. And this is one of the wonderful things about Darwin's insights and a few other people as well is that it, it can explain a lot, that's also its shortcoming. If natural selection explains everything, it doesn't really explain much of anything. It doesn't allow us to make the kinds of distinctions that allow us to uh you know, uh talk about the dynamics, what's or come up with plausible alternatives. It's also an empirical issue. Um uh YOU know, the, and this is where there's a difference between the study of humans, what makes humans unique, which is one instance and the study of say how body size and brain size evolve together, that involves a comparative study of lots and lots of organisms as opposed to just looking at one organism. And the, the general trends that you might see across, across vertebrates, across mammals, across whatever uh may give you a sense of what tends to drive the evolution of any one of these features. But the, it doesn't necessarily give you a indicator of what drove any one transition. So, you know, we could have a very, very clear picture from comparative studies about what's going on with the evolutions of, of brains or bodies or whatever and still not have much of an idea for what is going on with humans. And we have conspicuously large brains uh that evolved over, you know, let's say the last 2 million years or so, it's the important bit. And uh I don't think that there are very many satisfactory adaptations explanations, even though we're really pretty sure from another in a number of angles that uh that natural selection was probably involved. Um It's just that, you know, and everybody is coming up with these accounts that propose functions that might relate to fitness, but we don't really have a uh uh a good reason to believe many of the stories over a lot of the other stories. So the dynamical account is, is quite good in that you can understand the evolution of something without necessarily understanding the function. And that's important because there have been very, very few studies that actually relate what uh you know, what a morphological characteristic does uh in the functional biology of an organism to the fitness of the organism. And then put that in the context of genetic variation in all of those parts to describe how it might change. So, uh uh and that, that is a, um, I'm not saying it's a, we should expect that of every study. That's the ideal study that would be absolutely wonderful to have. But it's certainly beyond the reach. But it's worth knowing that, uh, that there are serious limitations that come from the, uh, perspective where you see something, it seems to do something really well and it must have evolved for that function that, that doesn't get you as close to a satisfactory answer as you might think.

14:34 Ricardo Lopes: Do you think that perhaps one of the specific risks here is that if people start from an adaptation perspective, that they are more prone to developing what some people call just so stories about the evolution and the origins and the development of any specific trait. Because I would imagine that trying to uh assume that because a particular trait is there, then it's because it might uh it probably increased uh fitness for the organism or the whatever kind of species we're talking about perhaps makes people more prone to trying to come up with stories for why that link is supposedly there or not?

15:27 Charles Roseman: Yeah. Um So the uh I, I think that is, that is true. If you don't take the uh dynamic of evolution, if you don't take the evolutionary history into account, uh then you are prone to just telling a just so story. I don't think that's nearly as common as a lot of people would have us believe certainly not in evolutionary biology, maybe in some other corners of the world. But um the, the dynamic approach, the sort of the evolutionary genetic approach, the the complex trait approach allows you to do a number of other things. So, one of the things that, uh you know, if, if we talk about brain size, um you know, it becomes cons conspicuously large in humans over the last 2 million years, it was proper natural selection, driving it along with a few other things. And um uh most of the models don't believe it was brain size itself. So, you know, it's the capacities for certain kinds of behavior, certain kinds of cognitive uh abilities and so on and so forth that are supposedly drove it. So what we're looking at is a correlated response or under this, under this model would be a correlated response to natural selection on something else. Now, that happens when you have a genetic correlation between characteristics, natural selection works on one, it changes the frequencies of the alleles that are involved in that one trait. But those, those uh loci where those uh genetic variants I should say are um uh those loci, those places in the genome also affect the other trait. And so the other trait gets dragged along with it. So you can have strong natural selection on something else and it can also cause a change in whatever you happen to be looking at. Now, um This this raises a problem because that there are many, many ways in which to measure an organism and the natural selection can behave in all kinds of very strange ways. So you very infrequently, you very, very infrequently think that, um, or are justified in thinking that you're actually measuring the thing that is important for driving the fitness differences that make natural selection. Ok. So that's one thing we could talk about correlated responses. There's always the problem. Um Not a problem. There are always the possibility that you're looking at phenotypic plasticity. So uh the same genotype, if you raise an organism with the same genotype under different circumstances, you may end up with a rather different phenotype depending on the environmental conditions. Uh THAT that happens quite a bit. Um And then there is also the feature of organisms. Uh Well, if you, if you look at complex multicellular organisms like us, and uh there's, you look at our genomes, eukaryotic genomes, they're very messy places. Uh The, the the genome is uniquely inappropriately named for eukaryotes because almost nothing in it is a is, is a gene. It's a very, very small percentage is actually a gene. And there are all these repeated elements and transpo elements and retroviral inserts and any number of other things that go on. And um so, uh and this is the grounds for a, a lot of natural selection at a different level that we don't necessarily appreciate when we're looking at or at, at full organisms. But also what's interesting about it is that uh you know, why is there all that slop in the genome? It takes forever for us to replicate cells? It's just incredibly energetically expensive bacteria are just the epitome of efficiency by comparison. So how does that work out? Shouldn't natural selection be getting rid of all of this uh the slop in the system, all this waste of energy. And um if you think about bacteria versus humans, uh one notable thing about bacteria is that there are a lot more bacteria than there are humans, a lot more bacteria than there are humans on you right now or on me right now. And uh what this means is that the effect of random genetic drift, just those random changes because of sampling in the in populations very, very practically negligible in bacteria, but profound in organisms like us or mice or, or mushrooms or whatever. And what this means is that natural selection is only so efficient, it's only so good up to a point and we have to leave room for that in the model. Uh Because uh the genetic drift is is ubiquitous and there are lots and lots of things out there that seem quite mysterious until you think uh natural selection just isn't that powerful.

20:47 Ricardo Lopes: So to try to illustrate all of this with an example, you've already mentioned a couple of times there, the evolution of the cranium in hominids, uh tell us a little bit more about that. And I know that you've done work, for example, on the evolutionary path to the genus Homo, that is the transition from Aus uh Australopithecus to Homo. Uh And you've done work specifically on the evolution of the cranium. So, could you tell us about that? What did you find then in terms of these different mechanisms uh that make for a trade to evolve or to develop? How do they apply here? I mean, the evolution of the Ukrainian, the uranium as far as we know, has been mostly the result of natural selection or any other mechanism that we talked about here? Yeah. So

21:46 Charles Roseman: um the early part of the human, of human evolution and the work that I did on that the Australopithecus leading up to Homo and then uh later on in the Pleistocene, uh most of that work was done by um Lauren Schroeder and, and Becky Ackerman. And I was, I was uh helping out with some of that. But um later on when we're talking about human variation today, that's where my uh expertise is. Yeah, and that's where I've been focused. Now, I, I talked about brain size getting bigger and I talked about how natural selection was probably involved. And I, I mean, probably in the scientific sense in which I'd be very, very, very surprised if it wasn't. Um Yeah, but uh the rest of it, the, the morphology of your face, uh the morphology of parts of your cranial base, the which uh the part of your skull, that breasts on top of your, of your spine. Um, A lot of that looks to be quite neutral. That is, it doesn't seem to affect fitness or hadn't affected fit fitness. And, uh, we know this for a couple of reasons I mentioned earlier that there is a nice relationship between genomic variation and phenotypic variation. If nothing interesting is happening. So if it's only random genetic drift, then uh we expect a certain kind of relationship between the phenotypic variation and the molecular variation genomic variation. And we see that in human populations today with some exceptions here and there, you know, there's natural selection is apparent in some places. What drove that natural selection is a total mystery. Now, what's interesting about this is that uh human cranial form, outside the outside brain side has evolved very, very quickly, very high evolutionary rates over longish uh spans of time. And this is in comparison to other mammals and the rates themselves look quite neutral. So, uh you know, uh this is awfully corny. But I'd like to say if, uh you know, if we're made in the image of God, then God played dice because most of our, our, our, our visages is uh sort of cobbled together randomly. And uh this is not to say that, you know, and um you know, when I was first proposing this, I, I was not the first to propose this, but I was one of the first to link it up with the genomic variation to bring it along. There was a lot of pushback because a lot of people had their adaptation of stories or their stories about plasticity that they quite liked. And um they didn't really care for the idea that uh it was just lots and lots of random changes. So, um that's, I guess an example, getting back to the hazards of adaptation is that if you have tons and tons and tons of anthropologists looking at very, very few fossils, everybody is going to want to find something. And it's sort of the, the worst degrees of freedom problem. You could possibly imagine um you know, more researchers than there are objects of study. And uh and that, that can be j strike in uh in fundamental ways. And I think that was an example of it.

25:18 Ricardo Lopes: So at least at this point according to the best evidence we have and the way you read it, you would say that uh most of the morphology of our uranium was the result of random processes and not something like adaptation or phenotypic plasticity is that it?

25:42 Charles Roseman: Yeah. Yeah. There, there, there are secondary effects of both adaptation and, and foy plasticity. Um I'd say that we can say the natural selection happened. I don't know how adaptive it was. That's a distinction that we have to bear in mind. Um So, uh, you know, uh David Cates and Noreen, Von Kramon Th Bell and a few other people have done these, uh quite uh interesting studies where they, um take a comparative approach and they're able to test hypotheses about what happens when you do say a transition from hunting and gathering to um to, to farming. What happens to the skeleton in that kind of a context and uh they're able to do it controlling for the evolutionary history behind it and you could discover it, they found the effects of plasticity kind of small in comparison to the old arguments, but they're, they're pretty robust findings because they're done in this process informed comparative framework.

26:46 Ricardo Lopes: And so could you tell us about the differences uh at the level of the cranium between neanderthals and homo sapiens? What are the main differences we find there? And, uh, I mean, what kinds of information can we get from that? Can we get, for example, any possible information about uh differences in terms of their brains, for example, or not really? Well. Um

27:17 Charles Roseman: I, I don't know a whole lot about how to uh recover information about brain structure from, uh the uh from fossils. And there are certainly people out there who do it and I, I can't really comment on it. Uh, um, uh AT a, at a professional level, what I can say is that the differences between humans today and neanderthals um are are largely neutral, uh quite strikingly. So, and the rate of evolution between uh neanderthals and humans uh today is the same or give or take a little tiny bit as the very quick evolution among different groups of humans today. So we're just looking at a extension of the same dynamic going back in time. And um you know, it uh it's, it, it seems to scale linearly with time. It's a or properly scaled, it scales linearly with time. It's a um uh it, it's, it's really quite fascinating and unusual. So there were lots and lots and lots of adaptive explanations for uh differences between neanderthals and humans that had to do with adaptation to one thing or another or plasticity because neanderthals uh a characteristic tooth wear that indicates that they chewed on things maybe s while they were processing them or something like that. And um yeah, and the, the, and that made their uh that made a plastic response to their uh to their behaviors. Uh I think that a lot of these stories are, um you know, it's not to say that they aren't true. Some of them might be, it's just the evidence for them is, is, is weakened by quite a bit. Um So a lot of it looks quite random and I should say that that is unusual for mammals. Uh Mammals typically don't have that very rapid evolutionary uh rates that look like random genetic drift. Over very long periods of time

29:29 Ricardo Lopes: and, and do we have any idea why that's the case? I mean, what would have been the forces or factors playing a role there? Do, do we know anything about it?

29:41 Charles Roseman: Yeah. Um, WELL, uh, that's a, it's a, it's a very, very difficult question and, uh, in 20 years of thinking about it, I don't think that I've come up with a satisfactory answer for it. Uh, Typically, if you, so if I were to reach back into the literature, it might be um that there's something about humans uh using technology, tradition, culture, whatever to uh to modify our environments, such that we don't end up with um uh with natural selection, affecting the bodily form nearly as much as you as you might expect in other organisms. But that's, I'd, I'd file that under speculation. Um It's a, it's a little difficult, you know, it's hard to tell what natural selection is doing when it's doing it. It's hard harder still to say why natural selection isn't doing something. Um So that's uh the, you know, occasionally we have to be content with ignorance and, and uh wait for more, more findings. And I'd, I'd say that's where this is. Mhm

30:53 Ricardo Lopes: And another thing we haven't talked about yet here has to do with gene ex change between species. Uh Yes, something like hybridization occurred a lot during human evolution. And if so, what do we know about it? And its potential effects. Yes. So this is,

31:15 Charles Roseman: uh, something that, uh, Becky Ackerman at the University of Cape Town has done quite a bit of work on and the extent to which I've done work on it has been connected with her work. And, uh, of course, this is something that is very popular among the paleo genomics people and they can address those topics much, much better than I can. The, um, it's clear that say uh different differentiated groups of humans have hybridized. Um It doesn't appear to be a gene flow that's sort of constantly going back and forth between regions uh at a very low level through time. It seems like there are episodic uh sort of events in which hybridization might take place. Now, that's interesting because many people living today carry with them, a Neanderthal component or a denisovan component uh of, of their, of their genomes. Uh THAT might uh in some cases have something to do with uh with how they've been able to adapt to certain environments, uh might have something to do with your immune function. That that is uh that sort of thing is very much in its infancy uh or figuring out exactly what that does. And one of the reasons why that's a difficult problem to deal with is that uh when you deal with organisms that have evolved separately for a while and then come back together, you end up with something called heterosis where the expectation for the hybrid offspring is not sort of an average of the parents or anything like that. It's, it's somewhere else. And um that is very, very difficult to get a handle on because it involves uh interactions involves uh dominant and recessive uh effects at, at various losi uh in the genome. And then what are called epis static effects the interactions among different parts of the genome. So if you shuffle up two genomes and throw them together, you can end up with uh things, changing their functions in really radical and unpredictable ways. Now, this is interesting because you, you, you display a whole new way of generating variation. And that might be interesting for our uh for uh telling us about how organisms are human organisms in the past, uh did respond to natural selection and how they might have adapted. But it's um um that, that's a very difficult problem.

33:56 Ricardo Lopes: So, changing topics. Now, I know that you're very interested and you've written a lot about this uh very interested in the debate between the so-called hereditary and the anti hereditary. So, uh I mean, just to first frame the debate, could you tell us what the debate is really about? And what are the main points of contention here when it comes to understanding uh differences between human populations or differences between people that have different ancestries.

34:33 Charles Roseman: So, uh starting with a hereditary position, um I'd say that the hereditary position is that uh there are uh biological races of humans. So, race as we might experience it today is not necessarily a uh a, a artifact of a social process. It's, it, it reflects evolutionary processes over deep time, evolutionary time. So that's the first thing. Um And you can organize people into these races based on their characteristics and ancestry and so on and so forth. That's the first claim. So the second claim is that um those groups differ um And uh those, uh and the third claim is that those groups uh differ in ways that are not just environmental, there is also a evolved genetic component. Two. And um so the uh uh the response to that is pretty highly varied across uh academia and that there are certainly social scientists who don't want anything to do with genetics. They immediately think it's eugenics and they uh leave the conversation right away. Um uh I don't uh they tend not to like me, not to like me as much as they uh you know, dislike the hereditary. So, you know, we're in the same boat together in that, in a lot of ways. Uh The, the main things boil down to uh are races, biological categories that is evolved categories that we can attribute to processes acting over deep time or are they uh social uh constructions in the product of the social dynamics? And what do differences mean? And what does it mean to be a genetic difference or an evolved difference between the two and so this uh uh now I, I study genetic differences between groups of humans. So, am I hereditary? No. Um The reasons I'm not a hereditary uh would be that I don't think that race is a deep evolved biological feature of humankind. Um And I also think that the hereditary perspective on genetics relies on a set of popular misconceptions about what genetics is. So, um and this, this relates to genetic determinism in one way or another, uh a very specific flavor of it where if you see a genetic difference in one context, that must necessarily mean that it, it, it, it will manifest itself in all other contexts. So what this means is that, um you know, I might say that, OK, well, there's a difference here. Um Let's say it's something we care about. Um Let's say that we change the circumstances. We might end up with a situation in which the differences are flip flop. We might end up in a situation where they are uh completely ameliorated, we don't know. Um WHEREAS a hereditary would say that these differences are driving the social outcome differences that we see in society today. And um you know, so uh I guess that when it comes to the question about biological race and uh and um whether race is a social destruction or not. Um uh Well, uh I think that, I think that you might have something to ask about that a little later. So it's uh you just go ahead from

38:30 Ricardo Lopes: there. Yeah, let me just clarify one point there when you mentioned genetic determinism. What that means exactly is that whenever people endorse a view that goes along, uh or that falls under the umbrella, let's say of genetic determinism, they are making a claim that uh a particular trait is the result of whatever set of genes and it is mostly or uh completely impermeable to environmental influences is that it,

39:07 Charles Roseman: yeah, in, in sensitivity to changes in environmental context. So and the uh and then as a set of it's, it's a very diffuse type of thing. Um uh AND uh it, the lack of clarity uh leaves a lot of room for mischief, but that's, that's the core of it.

39:30 Ricardo Lopes: So also perhaps to illustrate these, uh of course, there are many trades out there that people make claims about threats where uh I mean, some of them are clear differences that we find between people of different ancestries, others are disputed. And of course, one of the most disputed ones has to do with intelligence and IQ. So uh there are people, people that argue very strongly for IQ being mostly genetically determined and for uh clear differences in IQ between different races, for example, between whites and blacks in America, between Jews and Europeans, between Jews and East Asians, et cetera, et cetera. So, what do you make of that, I mean, because the, there are several different aspects to this argument that we can tackle it. But generally speaking, what do you make of, uh, the arguments put forth by people who argue that first of all IQ is mostly genetically based and second that differences in IQ between, uh, human groups or population are mostly explained by genetic differences.

41:01 Charles Roseman: Yeah. So, um, the first thing that I'd say is that they're, they're really not doing any research into that front that they come at you with tables of numbers and, you know, they're relying on, uh, a, uh, I shouldn't say they're relying on, uh, the, the arguments get shaped by people's impressions of what's being delivered to them. And, uh for instance, there's lots of arguments about her heritability, which is the proportion of uh variation in a population with respect to a trait that is attributable to genetic effects as opposed to environmental effects. And heritability just doesn't tell you anything in and of itself about how uh malleable or plastic a trait might be. Ok. So, it just did, you know, you, we could write the math out and there's just absolutely nothing there. The within group heritability doesn't tell you anything about the, between group heritability unless you add in some actual evolutionary theory that tells you how you got the differences between the groups in the first place. Now, hereditary ins don't do that. They, uh will, uh, they don't have the evolutionary component to that argument. So they can't tell me how, um how strong natural selection is, was when they can't tell me any of these types of things. We're not proposing any evolutionary argument. They're just saying these numbers are different now. Uh And that's true. The number 100 is different from the number 85 but that's not terribly interesting. So, towards the beginning of our discussion, I talked about how you really need to know the organism and um educational attainment and uh cognitive ability. IQ whatever you want to talk about it behaves very strangely as a complex trait. Now that we've had genome wide association studies coming in. Uh It's the, the uh the difference between the estimates of the effective genetics from the genome wide association studies where you just go through and count up everything that looks like it has an effect on the trait, compile them. And uh you come up with a summary statistic of how much variation you can account for. Um uh THAT tends to be very small, especially when you get rid statistically control for a lot of the tendency for uh different things to be inherited together in humans that aren't strictly speaking inheritable. So your economic situation, your uh uh what hap what area you happen to live in, uh what your family is like and so on and so forth. It's very, very attenuated. Um And it's rather different than looking at something like height or something like, uh, uh even body mass or something like that is something very different going on. And the hereditary seem to be wedded to their old twin estimates which, you know, uh people in evolutionary biology don't take very seriously and we, we tend not to use mostly because a lot of organisms don't display twins. But even in cattle where you do have regular twinning, people don't go out of their way to find the twins because they know that the estimates tend to be bad. That is the estimates of the effects of, of genes on variation that you get from comparing twins or, or just upwardly biased in a big way. Ok. So, um so what I say is that uh the hereditary ins claim that they're arguing for, they're making an evolutionary argument for differences among groups, but there's no evolution there, the genetics are pointed in the wrong direction. They're not looking at the right issuess. Uh It really is a just a collection of summary statistics of dubious quality that uh they get thrown out there. And um you know, the between group heritability versus within group heritability discussion is a prime example that um there, there's no relationship between those two quantities unless you add in some evolutionary theory, which the hereditary ins refuse to do. And hereditary ins like to use between group heritability and within group heritability to figure out how plausible a difference between groups might be if it were entirely environmental and there's a pretty basic algebra errors in it and it just keeps on going through the literature. So, um, the, you know, the main problem with hereditary is, is not that, uh, you know, the other problems with it, but when we speak about it scientifically, uh is that it's just not there, they're not making the relevant arguments. They're not producing science that we would, uh, that we would understand as being informed by modern evolutionary biology. Um Now, with their motivations are their own, I don't, I don't read minds. I, I don't pretend to uh be able to peer into the, their souls or that sort of thing. I can say that they're not doing the science that they claim to be doing.

46:51 Ricardo Lopes: And, and I, I mean, if you will allow me and uh uh please uh comment on what I'm about to say. I mean, even when it comes to just the science because of course, let's try to leave motivations and politics aside here just focusing on the science, even when it comes to uh trying to, I, I mean, extrapolate from within group heritability to between group heritability, even if someone takes uh very seriously, for example, the work done in behavioral genetics when it comes to studying twins, adopted kids, adopted people, et cetera. Uh I mean, even the behavioral geneticists themselves say, and I know this because I've talked with people like Robert plumbing for the show and others, they say that uh their methodologies, the work they do does not allow for someone to act to do that kind of extrapolation. I mean, they're studying within group heritability within group differences between people that are part of the group. They're studying in a particular environment. They uh they, for example, Robert Loman told me that, for example, it doesn't allow for us to really study very well, differences between men and women, between different groups of people, between different races if you want. And also when it comes to the databases, many times, hereditary point to when talking about or making claims about differences in IQ between uh people from Africa and people from Europe. Just to give an example, those databases are extremely poor and they are based on an extremely small sample. And I would add convenient sample, convenient for the narrative that they are putting forth uh particularly when it comes to the samples from Africa. I mean, they are extremely limited and extremely small number of people and we can't really tell anything from those data. Scientific. Right.

49:16 Charles Roseman: Yeah. And uh behavioral, the point about the behavioral genetics is is important in that um there's really nothing evolutionary about behavioral genetics as it's practiced. Uh This may sound a little strange but um you need the extra theoretical evolutionary component to relate within group heritability to between group heritability. And that's simply not appearing either in behavioral genetics because it's not really the point of the field, it's not appearing in the hereditary literature because they don't appear to be all that interested in, in evolution. So. Mhm.

49:57 Ricardo Lopes: And then another thing that I read about in your work and now focusing more on the anti reds, you say in one of your papers that uh they bring to the table arguments based on complexity and a demand for a mechanistic as opposed to variational explanations. Could, could you explain uh the argument you're making there and why that might be an issue that they're using those kinds of arguments?

50:30 Charles Roseman: Yes. So, um, anti hereditary are against hereditary is, um uh that's about all that unifies anti hereditary. Uh There were lots and lots and lots of different flavors. So, um there, uh and that I, I the paper is not about sort of groups of her. It's anti hereditary. It's more about the different flavors of argument that I find objectionable. Um And uh in terms of the wanting a causal mechanistic explanation of what's going on. They usually mean they want to know what genes are involved and they want to know what the protein products of those genes are doing and what the metabolism is, is doing and so on and so forth. And, um uh that's sort of, besides the point because we, um just as a matter of fact, we can do quite a bit of evolution without knowing the, uh or you can do a lot of evolutionary biology without knowing the uh uh the mechanistic basics, we can use quantitative genetics. We can use those elegant simplicities that come out of the bewildering complexity of the genotype phenotype map. It's, you know, and uh this is where a lot of statistics come from in the first place, you know, you have to do it very, very carefully. That's true. Uh Now, what's interesting about this is that, that demand for mechanism, that demand for uh this very highly reduced account of what is going on is kind of a uh expression of, of the bad habit that they attribute to hereditary. Its, they call them reductionist, they call them determinist. And what they're doing is they're saying, yes, we agree with you that genetics is deterministic and reductionistic. We agree with hereditary ins on that. Uh And we want more of it. We just don't have enough of it. And so, you know, the, the correct answer for, uh when somebody says some characteristic is uh exh heritable. And I'm going to talk about the social poli, political, social and political ramifications of that is to say, you know, you, you're dealing with the wrong statistic. That's not gonna tell you anything. It's not to say I want to see the genes because that goes that, that is a validation of the same kind of determinism and reductionism that anti hereditary ins complain about in hereditary complexity is another thing. Um I think I mentioned at the beginning of a discussion that uh complexity is a, is awfully convenient, uh, rhetorical trick to hide behind. And that you, you can say just about anything is, is bafflingly complex. And people seem to like to hear that that's, that plays well with a certain kind of audience. Um It really explains nothing and uh if you know, if it's, you know, if it's complex is the answer, you know, what's the question? And at a practical level, uh to tell that something is complex, takes quite a lot of data sometimes and those are data that we just don't have in a lot of con context. Um, YOU need to be able to find some signal in a system that looks very noisy. And this is one of the problems is that if you don't have that variational sense going in, you don't have that statistical sense, you can take any random set of data and concoct a very, very convincing story about it. And we, um, lots and lots of stories about how people, uh get, uh sucked into gambling addictions and so on and so forth because they're absolutely convinced that they have a system, they see through the complexity, they can apprehend it and they can manipulate it and they are absolutely wrong. So it's a kind of a dangerous rhetorical device because on one hand you, uh you, uh, it, it, you, you're saying somehow, uh, well, we can't really know what's going on. Uh, BUT I can see that something that somebody else can't, it's, it's a, it turns you into an oracle and people tend to tend to be attracted to that when they're charismatic enough and so on and so forth. But, um, it really doesn't explain a whole lot and it comes with the danger of telling stories about noise to that. Those would be the, my complaints and, you know, II I think that one of the problems with anti hereditary is, is both a tendency to say everything is complex to the point where uh you can't have a theory about anything. Theories involve simplifications, theories involve abstractions, they evolve, involve generalizations. Um And if everything is so complex that you can't have any of those, you have no theory, you don't have the possibility of science. And uh and it's, it just seems to be a uh uh it, it's a non answers to a non question. It's just a, it's just a statement for statements sake, a rhetorical trick.

56:26 Ricardo Lopes: Mhm So uh just to ask you about this point directly, how do you think we should think about the role of genes and their potential causal power when it comes to uh understanding differences between human population?

56:48 Charles Roseman: So uh in terms of their causal power? Well, so the first thing to remember is that genes are parts of organisms. And um we want to get to know the organism as, as biologists as anthropologists, as social scientists or humanists in general. And we need to have some sense about what the context in which those genes are operating is like. Um And what we can say is that care in carefully controlled settings uh where we have the, the right uh study design, they're, they're usually epidemiological rather than experimental. And if they're experimental in humans, you probably shouldn't be doing them. Um You have a uh you can come up to the conclusion that substituting this very variant of the gene for another in this context will cause this change. All right. So, and this goes back to R A Fisher's uh idea of causation. What happens if not, what happens under the counterfactual situation. Now, the problem is is that we don't know what the organism is like across all sorts of uh the uh uh all sorts of the of possible environments in which you could find yourself. And a really good example of this is uh the use of genomics for medical purposes. The whole point of that is to basically people look for drug targets. They're looking for things that they can add a chemical to you and they will, they will fix you and then probably make a whole bunch of side effects that they can make drugs to treat. It's a, it's a, it's a great business model. Um But the uh you know, the, the whole point behind uh genomics, pharmacogenomics medical genomics is to use properties of the organisms to find environments. That is a new chemical that you ingest to change a life outcome. So it's a search for environmental possibility. It's not a statement about genetic determination and the way that I take that is that if we're interested in other characteristics that uh you know, behavioral characteristics or morphological characteristics, um we really need to have a sense of what the organism might do in other circumstances. And humans have a bad track record of, of conforming to our expectations. So, um I would say that it's very, very difficult beyond certain well known systems to say what will happen. You know, if you completely lack a re uh the ability to digest something past a certain age, you know, the lactose and uh val absorption and into adulthood or the lactase persistence into adulthood. Um Then, you know, you have a pretty good idea of what environments in which you might face problems if you don't produce lactase as an adult, that is the enzyme that breaks down lactose. Um And you also know what to do about it with cultural innovations, like uh a um a pill with a, a bunch of enzymes in it. So, um the uh it's, it's very, very difficult to go from a uh very general property of an organism to a statement about what they're going to do in, in general. Now, this is not to say, you know, you that there are going to be very, very general things that you need to uh be, be aware of. We need water, we need proper shelter. Can't be too hot, can't be too cold, so on and so forth. Um But those are very generic properties of organisms that are tailored a little bit to humans but not so much. Um So it's extremely difficult to say that um there's a uh that there are genetic differences in the first place. Then it's very difficult to find the causal mechanisms. It's very difficult to predict what they're going to do across context. So at that point, um you know, you can have an evolved difference between two groups and you can change the environment and then that might completely reorder or entirely disappear. So that is something that you're uh that it's a, is a profound challenge for all of biology and anthropology and it's not something that you get at with heritage estimates or even GW, it's quite a bit more going on. Sorry for the vague answer. That was

1:01:59 Ricardo Lopes: uh no, no, no, no, no worries at all. I, I was just going to say, I, and I guess that probably this point would also apply to the medical field, isn't, isn't it also? I mean, a little bit limiting and perhaps in a sense worrying that many times we are making some influences when it comes to, for example, thinking about races just on the basis of uh skin color. I mean, because for example, in the medical field, I know that there are populations in Africa where people are more susceptible to developing fals form anemia. But, uh, ii, I mean, if you're assuming, for example, in the medical field that just because someone has a, a darker skin color that they have some African ancestry, that they would be more, potentially more susceptible to that kind of disease. I mean, you, you might miss, uh, a lot in terms of diagnosis because the skin color itself does just by itself doesn't tell you much about even the subpopulation in Africa where the ancestry of that person might have come from. Right. I, I mean, does this make sense or?

1:03:25 Charles Roseman: Yes. Yeah. So, um, this, uh, using race as a diagnostic category, ha in medicine as a, uh, uh, a long and not, not terribly useful history, uh, it's, uh, you know, oftentimes quite shocking what happens and, um, and the point there that you're making, uh, is that, uh, uh, the, the correlations between different characteristics at different levels may be different. So, at the worldwide level, it may be quite different than it is at the local level. You know, Simpsons paradox, that sort of thing. And, uh, they're very seldom good enough to have a very strong indicator of what based on one property of an individual, what else they might be, uh, might, might be likely to present as a symptom or as a as a susceptibility or, or something along those lines. So, yeah, um that is a um it's a persistent worry. Um And this is kind of where the difficulty with uh talking about uh either race as an evolved category or race as a social construct comes into things because um race is a social construction. Uh That's not a very informative thing. It's kind of like saying adaptation comes from natural selection. It's a such a broad explanatory uh uh tool that it, you know, you really need to refine it. So the question I like to approach is uh I, I like to say that, well, you know, uh race as, as we understand, it isn't a terribly uh it isn't a deep evolutionary phenomenon. We know that because race models don't predict human variation at all. Well, um so a lot of the principal components analysis plots that you see floating around on the internet where you've got brightly colored patches of, of peoples. Um uh The, the, you know, the problem with principal components analysis is that it's not an analysis, it's a depiction and people are just sort of painting race onto it as they see fit. Um And you'll see clustering algorithms going around. Well, it turns out that they miss so much of the variation even between groups that uh that you need much better uh models that don't include race that include much more complex structures. And I could say complex legitimately because we have the data and to test with the complexity and we, we can see that. Um SO racism doesn't explain the evolution of humans. We cannot say that uh humans come in these deep evolved races. Mhm Talk about today. Well, race is a very real part of our everyday experiences in United States. Um Certainly in, in Portugal and uh your experience in in Portugal and my experience in the United States are going to be rather different. They are going to be some commonalities that's for certain. But who gets counted as what and how the dynamic works out can be very different? Mhm Bye bye. Now, the question then becomes uh if races are social constructions and they're driven by uh these political processes, if racism is what's sort of shaping and, and reinforcing them, why do you see genetic differences between groups? So I, I'd like to ask it's very simple answer. Uh OR very, very simple question I should say. Um uh Where did, where did you get your jeans?

1:07:31 Ricardo Lopes: Where did I get my gym? I guess that from my parents,

1:07:37 Charles Roseman: right. Great. OK. Yeah, perfect. Where did you get your parents

1:07:42 Ricardo Lopes: from? My grandparents?

1:07:46 Charles Roseman: Well, not really. They, they kind of had to go through a social milieu to end up meeting and then producing

1:07:55 Ricardo Lopes: it. Uh Yeah. Yeah, that

1:07:58 Charles Roseman: and you know, uh there are lots of social factors that go into that. So, you know, uh and that is one of the things that uh one of the ways in which you do get obvious genetic differences between groups of humans that we call races that are social constructions. So the way I like to put it is that um you know, the genome, you know, a collection of genes that typifies any organism that's not a social construction, but my genome and your genome are quite literally social constructions because of the ways in which parents need to reproduce. So, um if uh the what this does is this way of thinking about things and this is not original to me, Ashley Montague, who's a anthropologist, talked about this a whole bunch of people a long time ago whose work has been forgotten about, talk about this. But the very act of reproduction in a society is heavily influenced by various social dynamics. Racism is one of them, class is a big deal in terms of who, who gets to marry one another. So, so the very act of reproduction in humans is socially mediated in important ways by race and racism by class and uh class snobbery and, and various things like that. So you end up with a situation where uh we have to think about the ways in which our histories as a uh as, as, as societies, not just our prehistory uh as, as human beings uh or as organisms um shape the variation that we see in societies. And that's a, that's a little bit unsettling for people in a lot of ways. But, um, and I don't think that we really know how to talk about that. Uh, VERY well. There are some social scientists who are starting to talk about it and, um, they'd be much better at it than I would, uh, my, my ability to deal with some of the subtleties and nuances, uh, limited and, um, I'm certainly not a historian. So, uh, but this is one of the problems with the humanity scientific divide so much pushback against anything that mentions genetics in the humanities. And people in the sciences tend to look down on the, on the uh humanities uh in ways that are, you know, uh sort of mean and, and not at all productive, but that we want to understand it. That's what we have to, that's what we have to understand.

1:10:53 Ricardo Lopes: So, uh uh I mean, just to close off the section on uh the topic of race. So would you say then that race, even though it is not a scientifically valued concept from the perspective of genetics, biology and anthropology, if we're talking about humans, of course, it is um something that we can talk about scientifically, I guess from uh from the perspective of sociology, cultural anthropology and other disciplines like that, because it's very much a social category that we use across the societies and that clearly has a real effect on people's uh sociality, how we relate to one another. There sometimes uh even effects on their, on how they reproduce with whom they reproduce and, and so on. Right. So it is a scientifically valid concept. But uh when approached this way,

1:12:01 Charles Roseman: yeah, I, I would say that we need a new way of doing science to approach it. The way science got set up means that this kind of fall the the issue falls into the cracks, the issue of human organisms as social beings uh is very, very difficult to get across. And you know, there are whole swans of the humanities who will talk about bodies, but they're not talking about actual bodies. It's a very abstract notion, the actual uh body that to, you know, manifest hunger and desire and, and pain and whatnot doesn't seem to enter into the discourse on bodies. And then you end up with uh the sciences who kind of ignore a lot of the messiness of, of, of society. So a new kind of science needs to be developed to deal with that. And it's the type of thing where uh disciplines as they evolved in in academia just aren't well suited to doing it.

1:13:10 Ricardo Lopes: Mhm So of course, when we earlier talked about the hereditary, we mentioned things like uh in intelligence like you and we were focusing mostly and that's also uh also the, the reason for that is the fact that many times they also tend to focus on more psychological behavioral traits than really uh more anatomical physical traits. But when it comes to body form, what do we know about the main factors that play a role in its variation among human populations?

1:13:49 Charles Roseman: Um Not nearly as much as we think we did. So, uh I, I think that if we're dealing with uh issues of um what I'll call the body form composition or body composition, um The things that go along with the rules that are supposed to uh match mammals to their environments based on how the prevailing temperature. So Bergman's law and Alan's Law having to do with how sort of big and round you are. Um YOU know, or how, how long your limbs are and things like that. Um Now, in humans, you do see a bit of that. Uh It's quite a bit of, it is not attributable to natural selection. Uh So it doesn't appear to be an adaptation. Uh There is a sort of incidental correlation that arises from the way that uh that uh human variation was set up in the last 50,000, 60,000, 100,000 years and, and latitude so that you end up with a correlation, a correlation is highly diminished when you control for the fact that human groups are related to one another. Now, there's also the, there are also some issues of um how differences in nutrition and differences in uh consumption of different foodstuffs or, or whether you tend to face uh uh food scarcity at different points in uh in time in different environments um that affects growth in, in a number of different ways that can affect body form. So you see interesting secular changes uh as societies uh end up with more secure food supplies and, and uh different kinds of food often types. So, uh stature is a wonderful example of that. Over the past 100 years, many, many different societies have grown uh many centimeters in height as uh as diets have changed as you end up with, uh you know, uh waterborne diseases are taken out of the equation by sewer systems, things like that.

1:16:06 Ricardo Lopes: And actually we saw the opposite when humans adopted agriculture, right? I mean, our uh the height diminished for po I mean, comparing to, for example, Foragers center gatherers, the people who lived in societies initially that were uh based on agriculture looking at their skeletons, they, their height was reduced.

1:16:34 Charles Roseman: Yes. Um THAT uh again, this is sort of beyond my expertise and there are a whole batch of new papers there that deal with the uh stature estimates using genome wide association studies to the extent that that will work uh to try to investigate that. Um So I don't know what the the going opinion on that is, but, you know, certainly that's, that's the type of thing that is entirely plausible that you could end up with uh in that. Um, YOU know, if you are a sedentary agriculturist who, agriculturist who lives in one area for a long time and you're surrounded by quite a few animals and quite a few other humans. Um Just the, the disease burden uh is going to be quite a bit higher and for a lot of these diseases that we uh think about causing problems for Children when they're young.

1:17:30 Ricardo Lopes: Yes. Uh So, uh I would like to ask you also before we move on to the last topic of our conversation, we've been talking about uh different kinds of mechanisms that operate in the evolution of uh trades complex traits and so on. But what about evil Devo approaches? I mean, what do we know about the role that developmental processes themselves might play in shaping evolution? And by the way, if they shape evolution in what ways does that happen?

1:18:07 Charles Roseman: So, uh the ways in which a developmental processes shape evolution has to do with the ways in which they um the ways in which they allow variation to be presented in a population. So, if you think about long bones, um the bones of your arms and legs and uh that sort of thing where that grow in length because we have growth plates and we know how growth plates work through uh through developmental biology and a number of other disciplines. And there are only so many ways you can get a growth plate to speed up its growth or slow down its growth. Um Those are limited and those tend at least in most mammals to say, be uh bilaterally symmetrical to one degree or another. And, and that type of thing. So if you uh depending on which mutations you introduce into the population in, in which genes you might end up with a situation where uh all of your limbs grow more quickly, you end up with longer limbs. Um um BUT in one circumstance, you uh are dealing with how quickly cells replicate in the growth plate as opposed to how big they get or how rapidly they become hypertrophy that is swell in size, which are two of the phases that are involved in growing a growth plate. All right. So what does this do? Um Well, if, if things grow together, they can end up being correlated with one another and correlated genetically like we were talking about earlier. So development can structure the ways in which organisms are prone to correlated responses to natural selection. So, um two characteristics might be highly correlated at one age and not so correlated at another age. So, depending on where natural selection is manifest in the life cycle, you could end up with very independent evolution of the two characteristics or a very tightly connected evolution of the two characteristics. So, um Evo devo is very important for understanding how variation gets produced in a population. Now, there's, there's a in addition to sort of figuring out why things are correlated, the way they are and how they'll respond to, uh, random genetic drift and natural selection. Um, ONE of the things to think about is that the, the variation that you see in a population today, um, is really not the variation that got the population there over the long term. All of that's been turned over by mutation and drift and selection and so on and so forth. Maybe there's been some gene flow or hybridization that sprinkles a little bit in there. It turns over and over and over again. And um even though that happens pretty regularly, you end up with a, you know, pretty much the same critter through time. And so what that means is that the uh um there, there's something robust about development in the evolutionary context that needs to be explained. Um And there, there is a, there are a couple of uh uh there are a couple of interesting biases because we typically only see organisms by the time that uh we know, say a mammal is pregnant or an egg has been laid or so on and so forth. And there's a lot of mortality that happens before that. So, um lots and lots of conceptions conceptus is uh in humans, just don't make it to the point where anyone knows someone that's pregnant. So, uh there's quite a lot of bias in terms of that. But still, even if you take that into consideration where we're not seeing all the really horrible mistakes that the development makes. Um THERE is something robust about it and it's robust to not just environmental differences, it's also robust to genetic differences in some ways. And so the ways in which variation can be manifest is very important for understanding how longer term evolution is going to take place. So if you at what kind of variation do you need to get from point A to point B in a space of possible morphology.

1:22:47 Ricardo Lopes: So getting then into the last topic of our conversation today, I would like to ask you about a very interesting scientific American article from last year that you wrote with Kara Obbo, who by the way, I'm going to interview later this year as well. So, and the title is to Understand Sex. We need to ask the right questions and I know that this article actually on social media and elsewhere generated a lot of controversy. But before we get into that, what was the main argument you were making there? Because I get, I guess that to avoid misconceptions here that probably lots of people laugh about it. What in your own words, what was the argument here?

1:23:35 Charles Roseman: So um uh to make sure that biology is more than stamp collecting, you know, just a recitation of facts, we have to think about how we relate different things in the world, together, world, together with theory. And this involves structuring questions and in general, that's kind of how II, I go at things. I, I like to assume that. Um, WELL, I don't know what this is. I'm going to research it. If I knew what it was, I wouldn't be doing research, I'd just be, you know, showing off how, how much I know. Um, AND that's not, that's not my job, that's not my point. My point is to figure interesting things out and that includes questioning things that people kind of take for granted. And so a lot of the discussions around sex seem to be blending together a whole bunch of different questions, a whole bunch of different goals, a whole bunch of different types of things that people want to explain. So the way that, you know, I look at sex as someone who studies genetics of complex traits is uh in, in, in, in mammals, um in terms of the, say the number of sexes. Well, the question I'm asking is, uh how do these mice reproduce? How, how does recombination work? It's very important when we're dealing with the genetics of complex traits. Um HOW uh you know, and, and a number of very, very basic things. So for me, in that context, two sexes, male and female probably work pretty well. And that's sort of where my expertise ends. I'm not much of a behavioral biologist. I don't do anything in the way of reproductive ecology and so on and so forth. Now there might be other questions for which you might want to divide up sex in a couple of different ways, you may not want to divide up sex at all. Now, that's beyond my expertise as, as a scientist. OK. So for me, two is fine and for my purposes of my question, no problem. Um So one of the uh so when one of the funny things is about the response was that people thought I was, I was trashing the, the, the sex binary. That's completely not the point that I was making. In fact, I, I rely on it to make a living. Um But in that context and this uh the article sprung out of a bunch of discussions that um Doctor Keach and I had about um uh about how people are talking about the spectrum, the spectrum of, of sex or many, many, many different categories. And the problem with looking at it in those ways is that say if you have a spectrum um and it's along one dimension, you still kind of have a binary, it's polar, right? And is that doing what these people wanted to do in, in the end? So the people who argue for that and then if you have a bunch of different categories, no, you don't really have a spectrum. Mm So, um ultimately, when it comes down to it, whether I think it's a, a binary, so I really don't have to worry about the mice that, that don't breed or don't make it or, you know, mom gets hungry after giving birth and eats one of them that happens. Um, AND, uh, I don't need to concern myself with that in my research. Uh, BUT, uh, other people may have to and there is, there are quite a few different questions out there. There are quite a few different ways of going at it. And, um, I'm inclined to see what happens but I would like to see questions be uh at, at the front and center and whether a binary works in a given situation really depends on what kinds of questions you're asking. No. So you might say, well, OK, there's spectrum, there's a spectrum, you're, you're really talking about gender when you should be talking about sex. OK. That I don't know, that's, that's beyond my expertise as a scientist, uh any number of other applications like that. And I think that there's a temptation the for scientists to say that the science is established and therefore social policy ought to be a certain thing. And I don't think that that's what science is for. And this is the second argument in the, in the article um as a citizen of a country. Um I'd, I have a, you know, I ought to have a voice uh in, in political decision making making. I, I certainly in favor of democracy and I think everybody should have that have that opportunity. Um But there's a difference between my opinion as a citizen and my expertise, as a scientist and um a lot of these decisions strike me as not being all that scientific. A lot of them have to do with the politics and the ethics and the morality of the situation, which is well beyond the purview of science, you know, if we're talking about competition in sports, well, I mean, why do we structure the competition in the way that we do in the first place? Right. You know, we think about fair competition um uh in the, where do our notions of fairness come from? Why? Why are we, you know, you know, is there something some other way that we might be able to do this that allows us to uh allows us to have fun in certain ways or you get the competitive bug out or, or, or whatever we might do um that, that, that are rather different, given the diversity of games that are out there and the way that they are played, it seems like there are um there are quite a few options. So um I think that the uh without the questions uh on one hand and without a little bit of scientific humility and a recognition that there's a larger political process that needs to be respected and it's important. Um Then the, it, it's very easy to get lost in a hashtag war and, and pick sites.

1:30:25 Ricardo Lopes: So uh about all of you, all of what you said there, I have three or four questions that I want to ask you before we go. So, first of all, um, are there questions that would be left unanswered if we did not consider how sex might vary across species? I mean, that is, if we might not consider that perhaps I, in certain species or in certain contexts, it would be better for us to consider more than two sexes, less than two sexes or any other variation of them. Yeah. Well,

1:31:05 Charles Roseman: uh, there are, yeah, if you're just interested in who has a big gamete and who has a small gamete, you know, eggs and sperm or, or whatnot. Um, YOU are missing out on just about the entire reproductive system. Uh, AND you will, the degree to which you can predict everything else about the organism based on the gametes, uh, including how sex determination works. Um, IS, uh, is, is kind of limited in many ways and on top of that, there are many organisms where there are, uh, individuals who don't necessarily reproduce. Um, SO halo deployed, uh, insects and that sort of thing. Typically you talk about the males and then queens and then, and then workers or something like that. And they're usually described as sisters of, of the queen or something like that. But they're really haploid or, uh, you know, you end up with a situation where, uh, no matter what you do, you have to do a lot of explaining to explain the particulars of the situation. And we can expect that in biology, uh what it comes down to when it, when it comes to sex, uh it really matters. Uh YOU know, kind of which questions we're asking. So, uh you know, our naked mole rats who, who help out their, their, their mother, the queen of the, of the uh the colony who um suppresses the reproduction of all the other females and so on and so forth. Uh, YOU know, how does, how do we want to talk about sex in that situation? Um I can see that there being, I can see there being a lot of complications and a lot of interesting things to talk about. But I'd like to see it linked to a theory linked to a question as opposed to people just saying these are the facts because, you know, if science has a, has a rough reputation with facts, they tend to turn on science pretty quickly. So,

1:33:20 Ricardo Lopes: yeah, and I was actually going to ask you to, to what extent does the question, how many sexes are there matter? Because I, I'm asking you that because many times we hear and of course, this is mostly politically motivated people that, but we hear that if there isn't a set number of sexes, usually they are referring to two sexes, then it, it's basically anarchy, scientifically and so on. But I, I mean, to, to what extent does answering that question really matter or having a definite answer to that question.

1:34:04 Charles Roseman: Um, WELL, I'm not sure. Um, IT mattered what context I guess is what I'd ask in the, in the sort of narrow explaining the world science type of thing or.

1:34:18 Ricardo Lopes: Yes. Yes. In that, in that sense. Yeah.

1:34:21 Charles Roseman: Well, um, the, so if you're a, say, a demographer or if you're breeding animals in a, in a, uh, um, in an experimental context or something like that, maybe uh it doesn't matter all that much and two will do. OK, let's say that you're a, you just are kind of interesting, interested in how many individuals there are to reproduce and that sort of thing. And the uh all you need to know are sort of uh basic properties of fertility and, and mortality in a population to extrapolate what's gonna happen over the next couple of generations. So, uh that's great. That doesn't really deal with properties of individual organisms all that much if you're interested in individual organisms and you're interested in uh sexuality, the expression of sex. Um Then maybe you don't want to tether it to gametes per se. Uh And we can certainly see this uh taking place in a number of different ways across the animal world. Uh But I would say that that uh whether clownfish change sex or whether there are different male morphs that are either defend a territory or sneak in on territory or mimic a female or something like that. Um, THAT matters very, very little for how we structure our society as humans. Uh, I really don't think that we ought to be looking to, uh, evolution and nature and all that sort of thing for, for moral guidance, we have to look, look to each other, uh, in terms of scientific anarchy. Um, YEAH, that's a, that's a bit of an overstatement. Um, uh, IN the sense that science is science is ideally a little bit anarchic. Um, IN that, you know, if you're supposed to be able to ask questions, answer them to the best of your ability and uh change your mind if things don't look, if your explanation doesn't look like it's working out terribly well. And ideally that shouldn't be driven by appeals to authority or appeals to tradition and that sort of thing, of course they are. But, you know, um, a little bit of, a little bit of free willing thinking does not hurt science and it's certainly not pseudoscience. So long as you're asking questions that will allow you to say, well, I was totally wrong on me to give up or, well, I might be right about this but it's a little bit over here doesn't seem to be working terribly well and I need to readjust it. So, um, that is, uh, that, that's the way that I'd put it. And again, um, I'm a, I'm a maybe a little bit vague here because this is outside of my realm of expertise as a, as a scientist for me, two is just fine for most of my work. Um I'm not going to dictate to other people what they ought to be doing, but I do expect them to come to me with a theory and uh and questions and not just tell me that these are facts and I need to shut up and go away.

1:37:51 Ricardo Lopes: And also, uh, I mean, of course, if I'm saying something stupid here, please correct me. But also when it comes to even definitions themselves, I mean, in this case, we're talking about sex and would, what would sex be or mean? But isn't it the case that people can still be doing very useful work and advancing science? Even if we, we have evolved definitions or sometimes even definitions themselves change as we uncover more about how things work. Like for example, definition of gene, the definition of species. And I guess that for sex it would be the same. And even, uh, I mean, sometimes, even without having any concrete definition at all, we can still progress science, right? At least that's how I look at the history of science when it comes to understanding what the gene is, what the species is. And I guess currently what the sex is. Yeah,

1:38:56 Charles Roseman: the I I think that the definition of gene and the definition of species are great examples, you know, um, you know, the the definition of gene seems to have wrapped back around to its original definition. Uh, AFTER it went through, you know, it used to be this factor on a chromosome and then, um, or they didn't really know about chromosomes then, or, you know how they were. Well, anyway, they, uh, and the, then it sort of became narrowly biochemical, then people realized, hm, this is not working and then looks like all traits are complex and it's kind of back to being a factor again, right? So that's a, there's a cycle there and species is a really interesting one. And, and this is the one that, uh, Doctor Oak and I did it used in the, in, in the article, in the sense that um, species concepts are useful in different situations. There isn't such a thing as a identifiable species. If you want to start a big fight amongst biologists, tell them to argue about species concepts. It, it's a disaster. It's just at each other's throats, you know, it's, it's crazy. But if you take the biological species concept and the nice thing about that is that, well, it's not applicable to the vast majority of life. It does come with a set of questions saying, OK, um, identifying those individuals with whom you can meet and produce a viable offspring or offspring that aren't uh pedal by uh hybrid uh inability or, um, and anything like that, um uh, you might need to evolve a set of mechanisms that allow you to discriminate on 11 level or another. And so that comes packaged with a whole set of ideas, a whole set of conceptual tools and theory to structure your questions. And it may be that well, these aren't biological species. Uh They may be two species on either side of them or two groups of organisms on either side of a mountain range. Um Well, they, they breed a breed just fine, but they never actually interbreed and they look really different and that occasionally happens. And in that case, you've answered a set of questions and you've generated a number of other questions. Maybe you want to talk about this in terms species, in terms of lineages. Now, how did the actual pattern of mating as opposed to the possible pattern of mating take place? And then that comes with another set of questions associated with it. And it's, this is, it's important to say that um just to throw up your hands and say that it's all very complex. There's so much stuff out there. We need to celebrate the complexity. OK. That's, but that's an aesthetic choice or a rhetorical choice. It's not conducive to develop, developing a theory that construct your questions.

1:42:12 Ricardo Lopes: Mhm So, uh since you mentioned earlier that uh in your case, for example, the sex binary tends to work quite well in the study of the evolution of complex traits. Let me ask you just one question. And I, again, I'm trying to avoid the politics here. I don't want to get into that. But many times I hear in on social media podcasts and elsewhere, people claiming and I'm bringing this claim to the table because it's a scientific one that you define the way you define sex is on the basis of a gamut size. Uh But I mean, it might not be or perhaps it's not reducible to just that. Right.

1:43:02 Charles Roseman: Yeah. And uh so again, this kind of gets to the question of how you relate gamete side to size to other things. Yeah. If you're just looking at game size and isolation, congratulations. You've noticed that one gamete is of a different size than another. Yeah. Yeah. This does not make you Einstein. Um It, it, what, what matters is the set of connections you can make to other things out there in the world. And a lot of times I don't really see that happening uh in a, in a careful way. I think that a lot of talk of spectra is not doing the kind of work that a lot of people think it is on the other side. Certainly not all that compatible with categories, many, many different categories of sex. Uh It, it, there a lot of questions need to be clarified and when those questions are clar clarified, when you clarify how you're interested in things relating to one another, then you can make progress. But if you just, if you're just counting, that's, that's not a particularly interesting scientific exercise.

1:44:23 Ricardo Lopes: So let me ask you just one last question and of course, I've alluded to the fact that you got different kinds of reactions to this article on social media and elsewhere. But I mean, looking at some of those reactions, what do you think are perhaps the things that people got wrong the most when it comes to interpreting what you were saying in your article? And what, what are perhaps some of the most interesting reactions you got to it?

1:44:55 Charles Roseman: Yeah. Um, uh, uh, PILE of hate mail. That was for sure.

1:45:04 Ricardo Lopes: I guess we all get a little bit of that now. And

1:45:08 Charles Roseman: yeah, it's a really, really thick envelopes that you gotta worry about. Um, uh, YEAH, the, um, uh, there's a tendency among the, um, people who are in favor of a sex binary and only sex binary to claim that any sort of, um, questioning of that is a, is a part of a, uh, is a part of a elaborate scheme to undermine western civilization and, and, you know,

1:45:46 Ricardo Lopes: it's, it's the woke mind virus,

1:45:49 Charles Roseman: right? The woke mind virus. And what's kind of interesting is that, um, you know, uh, and as, as you probably can tell, I'm much more sympathetic to sex binary in a lot of situations, perhaps a lot of other people would be. Uh, AND that's because I, I use it and I can show you how it works for those questions. Um uh I thought that I'd get a little bit of pushback for the, the part of the article where I do, you know where? Uh OK. And I do that, um I do say that the, the, the binary might do in certain situations. Um What I thought was interesting was the uh part where we talk about how um as scientists, we have a role in society. Uh, BUT that's secondary to our role as citizens and that secondary role, uh, uh, is an advisory one. YOU know, I can have my opinions. I've got lots and lots and lots of opinions. Uh, THEY, I, you know, I don't think that I am expert enough in everything in the world that I can offer an expert opinion about everything and that I need to be careful about that. So, uh, didn't really get much response to that part of the, uh, the article and that silence was kind of interesting saying that, you know, uh, the science matters. But, uh, it's, it's one of those things where it's a, in a constant state of negotiation. And as you pointed out, we, we seem to make progress even though we regularly revise the most basic things, uh, that we, that we, uh, that we think about but, or the way we think about very basic things and I, I thought that, uh, that would get a little bit more attention and it would seem to be completely ignored. Um, AND, uh, you know, I, I, I'm not precisely sure why, uh the, the, the statement about the binary being useful was completely ignored by every side there. So, um, but that's social media and, you know, that's, that's more about uh laying claim to being on a, a team. Um, AND, and that sort of thing as opposed to Twitter is not a very good place to, to figure things out in detailed argument. But yeah, and um, you know, it was, um it was fun to write and uh Doctor Keach and I disagree on a lot of things and um we, we, we agree on a number of things and this was sort of a kind of a uh a statement that we thought was, was a fair summary of, of both of our opinions on the matter and how they overlap and pointed to a few places where in which they, uh which they diverge. But, um then again, if you're inclined to write massive uh physical hate mail and send it to me at my work address, you're probably not doing a whole lot of deep reading and contemplation of it. But yeah, that's, it's a hazard, you know, that, that I'm aware of. And it's one that I one that I'm willing to

1:49:25 Ricardo Lopes: take. Right. So, uh apart from the article which I'm, of course, leaving a link to in the description of this interview? Where can people find you and your work on the internet?

1:49:38 Charles Roseman: Um, I have a Google scholar profile. Uh I have, I don't really have a professional website. Um, uh, AND uh I do have a Twitter account that I'm reasonably active on. Although most of my more scientific uh interactions take place on blue sky these days, but you can find me in both of those

1:50:01 Ricardo Lopes: places. Ok, great. So I'm leaving it uh that all in the description box of the interview and doctor Roseman, thank you so much again for taking the time to come on the show. It's been really a pleasure to talk with you.

1:50:16 Charles Roseman: Well, thank you very much. I appreciate it and I uh I look forward to seeing more of your interviews or uh you know, a real asset on the internet. So I appreciate it.

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