Death, Disease, and Politics | Dr. Randy Thornhill | EP 184

Is the tendency of an organism to evolve towards its childhood morphology? Yeah. And so, okay, so neoteny—averaged females are more attractive. Yeah. And so, now, just out of curiosity, do you think that the attractiveness of that neoteny is a consequence of the ability of the more childlike face to elicit care from a male? Yeah, illicit care and interest, and you know, attractiveness.

[Music]

Foreign

[Music]

Hello everybody! I'm pleased to have with me today one of the world's great biologists, Dr. Randy Thornhill. He's an evolutionary biologist and distinguished professor of biology Emeritus at the University of New Mexico, with a primary interest in animal behavior and psychology as well as human behavior and psychology. Dr. Thornhill and his colleagues have authored or co-authored about 250 scientific publications, including four research monographs or books. His publications have been cited in the scientific literature more than 35,000 times. A citation score is the number of times a reference to a given piece of research is cited by another researcher or in another publication by the same author. A scientific citation count in the tens of thousands clearly indicates that a researcher occupies a position in the upper echelons of scientific influence.

Dr. Thornhill is a founder of the research disciplines of behavioral ecology, evolutionary psychology, evolutionary aesthetics—that's the study of the experience of beauty from an evolutionary perspective—evolution and human behavior, the modern study of adaptation, and the study of sexual coercion.

Dr. Thornhill, thank you very much for agreeing to talk to me today.

Thank you for inviting me. It's a pleasure to be here.

Thank you! So, I've come across your research a number of times in my career and struck by its originality and its impact. I'd like to ask you first about something I probably ran into maybe it's 20 years ago, maybe it's 15, something like that. You did some work on the perception of attractiveness, bilateral symmetry, averageness, and sexual selection. Can you outline what you found and why?

Yes, I did work some years ago now on human attractiveness. That turned out to be very productive about attractiveness in general in animals, and one of the key traits that animals look at in judging physical attractiveness of partners or mates is bilateral symmetry. A colleague and I, in the early 90s, came up with a way to measure facial symmetry in humans. It had been worked on before, but the measurements that they used didn't work. So we came up with a method that did work measuring bilateral symmetry in the face, so that is the symmetry of the two sides of the face.

Why is that important and why is it a marker for attractiveness? It turns out that bilateral symmetry is a measure of developmental health. So the organism, when it starts developing, is designed by evolution, by selection, to achieve a bilaterally symmetric form. You can think of that this is the case. When I say organisms, I mean all forward-moving organisms. All forward-moving organisms have adaptations, developmental adaptations, to achieve a bilaterally symmetric body because, first of all, that reduces drag. So if you're moving forward and you're bilaterally symmetric, you don’t have any drag in your movement. You can think about a person with a leg a bit shorter than the other, and there's drag in the move, in the forward movement. The more of that asymmetry, the more drag. So you lose efficiency in movement; that's fundamental to what bilateral symmetry is about.

But next, bilateral symmetry is very hard—perfect bilateral symmetry is very hard to achieve by development, so it's a marker of quality of the individual pertaining to its developmental health. We see in many things that human beings design to move forward—bilateral symmetry. Cars or automobiles are bilaterally symmetrical, airplanes are bilaterally symmetrical. So we like our world to be that way. Yeah, we like the world to be that way. Actually, it turns out, and well, you're associating it if you had if you had one side of the car asymmetric compared to the other side of the car, then there’d be more drag. You know, it's not in a fish; you’d use more gas, think about it that way, in driving down the road with an asymmetric car.

But this, this is one component of physical attractiveness: bilateral symmetry. And we looked first when we developed this way to measure facial symmetry that became a very hot research topic. We did the first, and then others followed very quickly. Lots and lots of research has been done now, but there's, you know, symmetry of movement that's important in how fluid one's movement is and how attractive, therefore, one's movement is. You’re not dragging your foot or whatever, and all that is really a component of the importance of health in physical attractiveness.

So physical attractiveness fundamentally is a health certification. That's how we judge people's attractiveness. We don't think about it consciously; it's an unconscious calculation of the traits important in health and developmental health as bilateral symmetry is one of these. So you measure the symmetry of the two sides of the face, and we showed in our first study of this way back now that that measurement relates to how attractive faces are perceived—traffic is in the same sex or opposite sex. And then that research went on to look at kids looking at faces and different ethnic groups looking at faces. It works like a charm wherever you do it, lots and lots of preservatives.

So does it mean that if you show people symmetrical or asymmetrical faces, that they obviously have a preference for the symmetrical faces? Will they look longer at the symmetrical faces? Will infants look longer at symmetrical faces?

Yes, they do. Yeah, that's the way the infant beauty research is done. You just look at whether the baby—and they’ve got it down to almost newborns, you know, looking at faces and judging these faces basically on the basis of interest—how long they look at the face versus getting distracted to something else. And symmetry is one part of the beauty. Whether you’re talking about babies or kids or old people or young people or whatever, facial symmetry is very important. It's not the only beauty marker in the face we look at; we can talk about that in a moment too because that gets us into some other research we've done, but symmetry is a very important one.

Now that research went on to look at how symmetry plays out in the everyday lives of people, and we did the initial studies on that, but again that research bloomed, and lots of people have done it, and still, it's an active part of research. But the first thing we did—not just attractiveness—we did a bunch of that in relation to symmetry, but we looked at sex lives of people, romantically paired people. Studies of couples and looked at reports by men and women of sex partner numbers they've had in their lifetime; that was one component of them because that's a measure—in men in particular—of what biologists call mating success, the number of sexual partners one has.

And that research showed that for men, the more symmetric the man, the more sex partners he had. A technical tale there after we initially started with facial symmetry, but then we moved to the body of people and came up with a metric for body symmetry, measuring 11 traits on both sides of the body. These traits are ear length and ear width, and then we measure elbow—there's some elbow anatomy there that we measure, some bones, wrists, fingers, all those men measured of course on both sides, measure foot width, ankle width, trace like that. And we put that together in a composite as a measure of body bilateral symmetry that correlates highly with facial symmetry because the symmetry is a developmental health measure throughout the body, and that correlates with mating success of men. More symmetric men are physically more attractive and they have more sex partners.

We also got into looking at men's infidelities in their relationships and found that more symmetric men engage in more meetings outside the pair bond as well, so that's part of their mating success. We did the first study of a modern study we would call it of female orgasm in relation—in copulatory orgasm—in part looking at women, 200 romantically paired couples, and asking the women about their orgasm patterns during mating with their partner and separately asking the men. And we found that the men's reports and the women's reports of frequency of copulatory orgasm by the women were very highly correlated. So men are paying attention to this phenomenon of whether the female is sexually aroused to the zenith level of orgasm, of course, and more symmetric men were firing more copulatory orgasms too.

That was a very classic study in human. So I have a specific question about that. I've always wanted to ask a biologist interested in sexual behavior, but I know that there's been a lot of discussion about the hypothetical evolutionary purpose of female orgasm, and I was wondering if female orgasm is disproportionately likely to trigger male orgasm? I guess it could be an adaptation that's used to elicit pregnancy, essentially?

Yeah, I don't think it is. There's no evidence that females that orgasm very infrequently have fewer babies. And actually, women who don't ever orgasm can be quite fertile, so I don't think it's fundamentally that. I think what it is, it's part of female mate choice and more and more essentially sire choice of the female. Let me explain.

So when a female has an orgasm, she has uterine contraction, of course, and that works like a suction. It pulls the contents of the vagina up to the cervix, so it puts the content of the vagina in a good place. And if that content includes the male's ejaculate, then she's pulling the male's ejaculate up to the cervix where it's easier for him to get, you know, either for the ejaculate to get into the right place to conceive. So if she imagined a female who has two mating partners, she orgasms with one, pulling his ejaculate up to the cervix, and she skips orgasm with the other partner. So she, in effect, has mated with both men.

If you just look at mating success, but she's doing something more subtle that is differentially affecting the fertilizing capacity of the ejaculate of the two men. The ejaculate she pulls up has more potential for fertilization, and that's a component of cryptic female choice. In the 80s, I discovered what I labeled as cryptic female choice first in insects, and then it applied to female orgasm too in humans. Cryptic female choice is the kind of female choice that is invisible if you're only measuring mating success.

In the example we talked about, the two guys mating with this female had the same mating success—they both mated—but one was preferred over the other by the female's orgasmic capacity with him that pulled his ejaculate up. So females, by showing this differential orgasm pattern that I described with symmetry, are favoring symmetric partners over other men, and hypothetically healthier partners.

And yeah, with an advantage, that's right, higher genetic quality. And then that's an issue behind all this discussion so far is that female organisms are after high genetic quality partners when, you know, to be fathers of their offspring. So sire choice or the cryptic female choice is more of a sire choice than just a mate choice. And Darwin—Charles Darwin discovered female choice and did a lot with it for sure, and biologists had viewed female choice in a Darwinian framework up until very recently until the cryptic female choice came along. But females are far more sophisticated than just choosing one male over another as a mate. They do these subtle things and are involved in cryptic choice to prefer some sperm of some mates over the sperm of others—a whole suite of gnats.

That's a big area. Well, what other elements make up cryptic choice? You describe the orgasm—what else?

There was in some insects called scorpion flies, and what the females do there is they adjust mating duration and hence the amount of ejaculate that the male transfers. There's no orgasm in these insects, but the longer the male can mate, the larger the amount of sperm he transfers to the female. So females are adjusting ejaculate duration on the base of body size of the male. And about bigger males are more fit males and so forth, better growth and more resources growing up; the higher quality males. The females are receiving more sperm from bigger males.

That's one thing I did with these insects. Another was the female, after she mates with a male, makes a choice of whether to lay eggs or not. If she chooses to lay eggs, then she will fertilize, you know, from other research I’ve done, she will fertilize those eggs with the last male sperm she mated with. So if she makes the decision to lay eggs, she's going to use that last male sperm. And large males, again, are preferred and that component of cryptic female choice.

So cryptically, these female scorpion flies are preferring large-bodied males by both receiving more sperm from them and making decisions to lay eggs with them and not other males. So those kinds of subtle things that females do that aren't apparent if you're just measuring classical male mating success.

You know, and is symmetry in human beings associated—is it associated with longevity? Is it associated with decreased probability of disease in the future? Is it associated with higher general cognitive ability? Like are there other things that—

For cognitive ability, we did that research. And that's now—there have been three or four repetitions of our initial research. We did it on 200 subjects, similarly so—university students—the psych who will kind of study and measured IQ using a culture fair measure of IQ, a culture fair procedure and questionnaire measured that IQ and then measured the symmetry in it for both sexes. The higher the symmetry of the individual, the higher the IQ.

So do you remember the size of the relationship by any chance?

That one was about 0.3. It's a moderate relationship for IQ. You know, there's measurement error in measuring IQ; there's measurement error in measuring developmental stability as symmetry too. So, you know, we measure 10, 11 traits. If we measured 50 traits, presumably we would get a correlation of say 0.8 with IQ. You know what I mean? There's all that measurement, and the IQ relationship would exist hypothetically because the healthier individual would be prone to a more favorable pattern of neurological development over the course of life—that's the idea.

Exactly. Some colleagues went on to look at brain features in relation to developmental stability of the outer body. So they did imaging studies to look at certain brain parts. Some brain parts are bilaterally asymmetric by design, so I want bigger on one side than the corpus callosum. Well, the corpus callosum is a tube, you know, that connects the two hemispheres; that's just a size factor. But you can measure the size of that circumference of the corpus callosum as they did, and the bigger the bigger the tube, the higher the body symmetry of the person—the bigger the corpus callosum. They measured a couple of other brain parts too and showing that.

So you can talk about a modal directionality for an asymmetric trait. So there's a mode—the most common degree of asymmetry in an asymmetric trait. So like handedness and so forth, the average person or the modal person is 60% right, 40% left-hand use. You can measure deviation from that as another measure of developmental instability. And that was the kind of thing they did with the brain parts—these asymmetric brain parts, so that's deviation from averageness in a sense.

Now, you also did work on averageness and attractiveness.

Got some stuff on the averaging? This was really just to control it because you can do average facial features, you know, eye size, lip size, their measurements of the face, right? And people have built composites of faces to produce average faces and had people rate them. Average averageness—average faces—is more attractive than non-average. However, average is not the most attractive face; the most attractive faces deviate from average in predictable ways.

You want to talk about it?

Sure! Yes, okay. So I've seen averaged model faces, and they seem more attractive than averaged faces. And maybe that—

Yeah, well, you can take a model, and you can make her a knockdrop dead by the following computer manipulations. What you do, if she’s a female model—not a male model—if she’s a female model, you do the estrogen modifications on her face through computer techniques. So you reduce basically lower face size. She inside jaw size—those kinds of things that are under estrogen control during puberty and adolescence.

And for a male face, you manipulate in the opposite direction. So male faces are more attractive when they’re testosterone—not estrogenized—and female faces are more attractive when estrogenized. So the female model facial models get their job because they’re highly estrogenized faces.

And are they neotenous? The female attractive faces? Are they more neotenous?

Yeah, they’re more neotenous in a sense of—so a woman who makes her living with her face, her face is about the size—lower face is about the same size as a 10, 11-year-old girl, so neoteny in that sense.

So neoteny is the tendency of an organism to evolve towards its childhood morphology?

Yeah, and so okay. So neoteny—new yorkness—averaged females are more attractive, yeah?

And so now is that just out of curiosity? Do you think that the attractiveness of that neoteny is a consequence of the ability of the more childlike face to elicit care from a male?

Yeah, illicit care and interest, and you know, attractiveness.

So basically here’s the way we think it works. So the neoteny we’re talking about, we could talk about it just as degree of estrogenization of the face—that's what we measure. That is a marker of health in a different sense, hormonal health. So estrogen is fundamentally the fertility and reproductive capability hormone of the female mammal. The more estrogenized she is, the greater her fertility and reproductive capacity is, so that’s what we’re responding to in the physical attractiveness of a female.

Is there an association between average neotenous faces and optimal waist-hip ratio?

Yeah, well, yeah. The estrogenization affects not only the facial features; it affects bones and so forth. So, you know, petite people talk about petite women as attractive. She’s so petite and so forth. What they’re talking about is estrogenization of bones throughout the body, not just the face but—and that includes the waist-hip ratio.

Is really a marker of degree of estrogenization of the female body—a low waist-to-hip ratio. So a small waist relative to a more expanded hip—the smaller the waist relative to the hips is a marker of estrogenization of the female body. And that again is a marker of female reproductive capacity through the estrogen effect, and that's optimal at about 0.68.

Is that really research?

Yeah, you’re—you know—underwear models, female underwear models, they could go as low as 0.66 or 0.68. You can be a model.

Yeah, so what other elements are, what other elements make up attractiveness?

Okay, so a couple of things here. So the first thing that’s really quite interesting is that your work points to, or this entire line of work points to a profound biological basis for the experience of aesthetic attraction, at least in relationship to the perception of other people and, of course, the perception of ourselves.

You’re right! That’s a tremendous amount of thoughts grounded in instinct apparently, and it’s an instinct that’s manifest so early that you see the preference for attractive faces, say measured by averageness in newborns.

Do you see the same preference for testosteroneized males and estrogenized females among newborns? Has anyone looked at that?

Yeah, uh, yeah. Kids and down to very recently born kids have been looked at in terms of their judgment of men’s faces too. And that’s—they’re looking at testosterone features there, masculine, you know, you call it masculinity would be the common, but testosterone technically.

And these features that grow under the influence of testosterone during puberty and adolescence in the male. And then the female, they’re growing under the influence of estrogen—as basically estrogen just capping the growth of those facial bones and the other bones too in the testosterone along with growth hormone promotes the growth of the same bones in the face and body of the man. And so babies are judging men’s faces the same as you and I, or a person off the street. But, uh, that’s what the research shows.

Yeah, this was promoted—there’s a book called The Beauty Myth, for example, that purports to claim that conceptions of female beauty are, what would you say, arbitrary social constructions. What do you think about that idea? How powerful is the biological impulse towards aesthetic experience?

It’s the reality! The biological research I’m referring to has been so abundant since the—really starting in the 90s—that what really kicked it off was the stuff we did initially on symmetry. And then researchers got into the hormone markers, beauty markers involving hormonal health. And then most recently it has been—it’s been another drive to look at some pigment issues in terms of a beauty marker, a carotenoid pigment in particular, but it's all health.

It's all health?

Yeah, it's a—that’s—that's a—that's a good, good point. The beauty myth—yeah, I forgot her name?

Naomi Klein?

Yeah, right. Um, that was just a—just blank ideology—granting—yeah, had nothing to do with reality. And then there was enough known about sexual selection processes and animals to cast that idea in doubt. But since then, it's just—

That's right. Well, because you see these preferences that you’ve been describing. You see analogs of those invariants of them across the entire animal kingdom, and you see the preference in newborns. So it's pretty hard to construct a social constructionist view of the aesthetic experience of attractiveness given all that information, right?

Well, the first study on symmetry that I did, the role of symmetry in sexual selection, competition for mates, and mate choice, that was done on insects. At the same time, unknown to me, a Danish biologist was studying barn swallows and tail symmetry in barn swallows, and we co-discovered this role of symmetry in sexual selection independently.

He's working on barn swallows in Europe; I was working on scorpion flies, and then I got into humans too. But yeah, and then following that, biologists working on all kinds of critters, you know, looked at the symmetry paradigm in deer, in their favorite study animals. And I think by 1997-98, 75 species of animals had been shown in which symmetry plays an important role in the sexual selection system of the animals.

Yeah, so it's very robust, to say the least. So fundamentally, we find we use markers of attractiveness for across both sexes to indicate general health and more than health?

Is it also an indicator of general competence?

It's associated with general cognitive ability.

What about personality markers? Has anybody looked at that? Like, are people who are symmetrical less likely to be high in negative emotion, for example?

We looked for it. The guy who did most of the research on sex and symmetry in humans is a psychologist. And, you know, works in a psychology department. I'm a psychologist too, but I don't work in a psychology department. And we got right into looking at personality, thinking it might correlate with personality, and nothing. And others have tried it too.

So, symmetry is not a part of the personality paradigm?

Yeah, yeah. Well, it’s not obvious that there’s an optimal personality. Perhaps part of it is that there seems to be niches for personality that are useful for all sorts of different personalities. I mean, it looks all things considered like higher general cognitive ability is better across multiple domains, but it’s not so obvious with personality, so maybe that’s part of the reason that’s not so robust.

I was wondering more with sensitivity to negative emotion because I thought maybe that less healthy people would be higher in trait neuroticism, and that might show up with symmetry, but you haven't found anything like that?

Yeah, no, we didn’t; we didn’t find anything that was condensing there.

I see what you’re saying though—that would be a reasonable prediction too. You know, and then the personality domain, we can get into that when we start talking about the parasite stress.

Yeah, so let's move into the parasite stress theory now.

Before we do, let me just summarize the beauty thing in two minutes.

Great!

So the current knowledge—the reality about our judgments of physical attractiveness—empirically based knowledge, the only kind of knowledge there’s real knowledge, but empirically based knowledge of how we judge physical attractiveness in terms of facial and bodily attractiveness is we use health markers. And those health markers are developmental stability—that’s symmetry. Hormonal health, that’s another one. And senescence is a third.

So as we age, we lose attractiveness, of course, and we lose function too. And so we pay attention to age, and senescence affects when we judge attractiveness, of course. So symmetry, hormonal effects, and senescence, then the final one—the most recent marker of physical attractiveness that has been discovered is the carotenoid pigment thing, and it’s pretty wild.

So carotenoids—you can't make—animals don’t make carotenoids. You get them from diet. We eat carotenoid-based foods or—or animals that have eaten carotenoid-based foods. So you get all of our carotenoids, and the carotenoids are very important in metabolism. So, fundamental to metabolic—you gotta have a lot of carotenoids. If you’ve got a lot of carotenoids, and you’ve got excess carotenoids, you put those carotenoids in your skin, and then the yellow colors in skin and the yellow tints in skin doesn’t have anything to do with what your racial background is or whatever. You could—there's yellowness in the skin of African Americans, Caucasians, or whatever—Asians; there’s yellow pigment there. The degree of yellow is important and attractiveness.

We assess it when we look at faces. The more yellow, the more carotenoid the person has, the more excess carotenoid the person has can put it in their skin. And what carotenoids says is that you have to—you have to have a healthy gut to absorb carotenoid; it's fat-soluble. You can't absorb fat if your gut's sick. So it’s—the yellowness in skin is a marker, another marker of health that we use, and that's only been discovered in the last 15 years or so.

From what foods are carotenoids derived?

Your fruits and vegetables for the—you know, they’re full of carotenoids, so you want to eat a lot of those.

And is it also a marker of your ability to provision yourself well?

That too, but you can provision yourself in anything, and you know it doesn’t show up in your skin, right? So, but that's not a higher quality marker of provisioning; it's just—no, it's a sign of metabolic health.

Right, right.

Yeah, if you’re—you know, healthy body-looking and stuff—no, that’s a good indicator. But this is specifically related to your overall gut health and health, you know? So is it reasonable to say now that we know enough about the biology of attractiveness that we could build an optimally attractive form purely based on the scientific data pertaining to health markers?

Yeah, I can take a female model, famous facial model, and take that face, digitize that face into the computer like off the cover of Cosmopolitan or whatever, and I’ve done this, and I can make that, make her even more attractive through increasing the estrogenization components of her face. I could make her more attractive than she is.

So if I want to be particularly successful on Tinder, I’d put up a representation of my face, but I’d make it bilaterally symmetrical. So, I could duplicate maybe the left side of my face—I’d make my skin yellower!

Yeah, make your skin a little yellower.

Oh yeah, you can do it. I mean their last most recent research on the yellowness things—right on this thing. People would—do they did experiments where they put people on different diets, and they measure their, you know, take their facial picture before the experiment in six weeks after. In six weeks you can improve your facial attractiveness by carotenoid—increasing more carotenoids here in your diet. So it could be pretty quick. And students love this when we talk about it in class, of course, and tell them how to get prettier in a hurry.

Yeah, all right. So let’s move to the next major topic—I came across your work on parasite stress theory a few years ago. I started to get interest; there was a burgeoning literature on the role of disgust in political behavior, and I ran across your parasite stress theory. And so, and you were looking— to begin with—that the relationship between parasite stress and values and so maybe we could delve first of all into what parasite stress is and how you would study that in relationship to value and why you would ever think to do that because it’s by no means obvious.

Okay, so the parasite stress—what we call the parasite stress theory of values—we also call it the parasite stress theory of sociality—is a scientific theory about how people get their values. So the causes of people’s values and the theory is a theory about both proximate causation and ultimate causation.

So in biology, there are two general categories of causation: proximate and ultimate. Proximate causation has to do with causes of something that occurred during the lifetime of the animal—events during the lifetime that cause whatever effect you're looking at—that's proximate causes. Ultimate causation has to do with causes in the deep time past, evolutionary past. Ultimate equals evolutionary; proximate equals causes during the lifetime of the individual.

And this theory of parasite stress theory of values is both approximate ultimate theory about how we get our causes. So let's start with the approximate level of causation of our values and what I mean by values, so that’s—that's kind of a big topic.

If you look at the history of research on values, it is very large. But we could take and—and almost unbound it. What psychologists have called values—so value would be something like rank-ordered preference if we’re going to define value itself, right? Because we have to choose between things—that's value.

Okay, so we’re talking about the value people place on looking at one face versus another; that's a value—that's a preference, right? And they’ll donate more attentional resources to high-value faces because attention is a marker of value. Right?

But we can talk about what psychologists have called values and the study of values. And that's a big, big area of research. Values research and the history of it is really, really cool. But anyway, we could sort of bound this discussion of values in what political science refers to as values and what they refer to as values is the political dimension of highly conservative to highly liberal.

So it’s a continuum of values, and you can measure a person’s values. They worked hard to come up with ways to measure a person’s values. You measure a person’s values; you can put that person on that continuum somewhere. Everybody can be put on that continuum from psychometric procedure questionnaires that so the political scientists have done values that way.

Across cultural psychologists have done values in terms of collectivism and individualism, that dimension, with collectivism High collectivism being low individualism, individualism being low collectivism. And it turns out if you look at these two dimensions—one from psychology, collectivism versus individualism—one from political scientists, conservatism versus liberalism—they correspond.

So high collectivism is conservatism; high liberalism is individualism. And basically, as we show—that those measures, those dimensions are very, very similar, if not identical.

Could you take them apart a little bit and talk about collectivism, conservatism, and liberalism and individualism so everybody knows?

I will indeed. Yeah, excellent.

Yeah, so you measure these; you measure these—a person's collectivism, said differently, you measure his or her individualism. And you're measuring—so let's talk—let's start first with conservatism. So a conservative person has subcomponents of this value system.

So the person has beliefs—importantly—in traditional things, traditional things and parochial things, local. Also, the person is relatively xenophobic. Conservative people are relatively xenophobic. And xenophobia is fear, dislike, avoidance of stuff on the outside—foreigners, people—new ideas. So, xenophobia has a neophobia component.

Neophobia means phobia about the new. So you like traditional stuff; you don’t like new; you don’t like foreign. So conservatives have xenophobia, the traditionalism, parochialism. They also are high in ethnocentrism. Ethnocentrism is a preference for people like you. You're in-group. You define your in-group. That starts with your nuclear family, but then extends to extended family and others with like values, like you.

So that's your ethnocentric component. And another component of conservatism is liking to just stay home. So, Philip Patrick—love of where you’re born—you stay there your whole life and so forth. And in highly conservative and highly conservative cultures, you don’t know much.

So that's conservatism. And then the antipole of those values really characterizes individualism or liberalism. So instead of xenophobic, you’re xenophilic. You like people that are different from you. You're comfortable with other kinds of people, even if they have different values, even if they have a different color, even if they believe differently. You're more comfortable with those than you are if you’re conservative and, um, ethnocentric.

Ethnocentrism is low under individualism in, in the more nuclear family-oriented than extended family-oriented, and your in-group is really composed of people with all kinds of different beliefs and maybe colors and so forth—backgrounds—as an individualistic or a liberal, and you're more prone to moving around.

You’ve got a frontier spirit—movement and adventure and going to new places is a good idea. You got a passport if you're living. So those are some big differences between the two, and, you know, the two polls.

And is it—how much is that, do you suppose, is it preference for familiarity versus preference for novelty? Is that at the core?

No, that’s at the core. That’s that’s part of the neophobia. You could put that under the neophobia—so the fear, avoidance, dislike of new—and that can be new ideas; it can be new types of folks; it can be new discussions—all those kinds of things are avoided. And it just—it just, you know, most generally, it characterizes outsiders.

Okay, so let me ask you a really specific question about that because you could think about that two ways. You could think about that as avoidance of the unfamiliar and dislike of the unfamiliar, or you could think about it as marked preference for the familiar. And then, on the other side, you could think about it as marked preference for the novel. You know, rather than it being—is it against something or for something or is it both on both sides?

It’s both. I mean, against can go all the way to hate. You know, under high xenophobia, hate and even, you know, we get into how conservatism and traditional societies and so forth promote inner group aggression and warfare to the point where you not only hate those outsiders, you want to kill them. And so you have both components there—the out-group, the avoidance, as well as the interest in socializing with people that are like you.

Yeah. Okay.

Okay, so you know, we’ve got the values dimensions nailed down and so on to the parasite stress.

Yeah, so when you start looking at conservatism, let’s start there, and the connections to parasites jumped out at us, and let me try to explain. So with xenophobia, okay? You want to avoid those people over there that are different from you, okay? And that’s tied to a very fundamental part of host-parasite co-evolution.

So the way host-parasite co-evolution works is that it’s ongoing and it’s antagonistic, and the parasite is trying to evolve to eat the host. The host is evolving defenses against the parasite, and that continues in forever. You never get out of your host-parasite coalition race.

So you get this coalition race between hosts and parasites, and much research shows how localized those co-evolutionary races are—geographically localized. So you get different strains of TB in different neighborhoods in a big city in Morocco, for example. It’s geographically very localized, these host-parasite coalition races, which means that locally you’re relatively immune to the parasites, but the parasites on the outside—those people on the outside—in the out-groups, those parasites you’re not immune to.

So that’s why you have xenophobia; it is a way to avoid foreign parasites that you’re not evolved to deal with immunologically. That’s the xenophobia component. So that’s contamination; it’s avoidance of contamination, right?

Yeah, from parasites that you’re not immune to because you’re relatively immune to the local. The local—and you’re safe—you’re safe with people that are just like you, because they've got immunity like yours, and yours is relatively good against the local parasites but not the foreign parasites because of the foreign parasites, because of this localization of the host-parasite co-evolution.

Right. And so you’re saying that you don’t have to go very far away before you go—you don’t have trouble very far away?

No! All these new strains of COVID popping up—they're, you know, they're gonna be lots and lots and lots and lots of strains. And you hear about some of the strains now—they're eight or ten or something like that—but they’re popping up, and, you know, the surveillance on these new strains is pretty limited so far. They haven’t done a lot of that because they’ve been doing other things with the pandemic. But still, you get that occurring with the COVID too, this localization of the strains. You know, there’s a South African strain and so forth.

So, um, you don’t have to go very far, okay, for the localization of the immunity, you have to not work so well. And that’s where the Philip Patrick comes in, too. So Philip Patrick—you just stay home; you stay home; you interact with people that are immunologically like you, and therefore are safe, relatively safe—rather than dispersing to interact with foreigners in the habitats that may contain these parasites you’re not adapted to.

So that’s the Philip Patrick component. The ethnocentric component is related to, so when the diseases come, you want to have a lot of local social support. So you have all these ties with extended family and so forth. That’s your social support, and in ethnographic societies, traditional societies, anthropologists have done a lot of research on how important it is to have kin. That will help you when you get sick—that’s the only way you can make it. You have kin and kin and friends locally that that help you. That’s the ethnocentric part.

All right, so if there’s a high probability of illness occurring, then you’re more dependent in reality on your closest network, your kin, your friends, your close friends.

Exactly! The higher the parasite stress is in a region, the more likely it—those parasites are going to come eventually. And so you got to have that social support that’s important for dealing and getting through—you and your family, getting through the parasite crunch.

So that’s why the ethnocentrism, Philip Patrick, and xenophobia components—and those have—you know, the component—another part, you know, subparts of that, we talked about openness to experience, new experiences, and all that; that’s part of a part of really neophobia.

Right? So we okay, so there’s a personality, so in a couple of specific questions about that for you. So the best predictors of conservatism from a personality perspective are openness to experience—low—and one subaspect or one aspect of conscientiousness, which is orderliness.

Now I noticed in your research you looked at extroversion and openness together, and you saw that the more collectivist/conservative types who are protecting themselves according to parasite stress theory from contamination are likely to be more introverted and lower in openness, and that means less exploratory in general, because those two things together seem to maybe make up exploratory behavior.

But there is good personality data showing that the orderly part of conscientiousness is also a predictor of conservatism. And yeah, that I don’t know if I don’t know if there’s been any data because that’s a more microanalysis in relationships that nobody looked at that component.

But absolutely, orderliness is very fundamental to conservatism. Order, disorder is chaos from the standpoint of a conservative mind. You know, you want order in everything and chaos is—see, I've thought—and this is interesting too because maybe we could talk a little bit about the emotions that are elicited here.

So for the longest time I was— I had been thinking about the conservative collectivist viewpoint in relationship to novelty in two ways—two elements, two manners. One is that the more conservative mind doesn’t get as much of a positive emotional kick out of novelty and exploration, right? Because that’s fundamentally motivating if you have the personality type that’s associated with exploratory behavior.

But then there’s this idea of phobia too—like neophobia. But you know, conservatives aren’t higher in neuroticism, and so that’s a really striking finding because, if anything, it turns out that at least under some conditions, liberals seem to be higher in trait neuroticism.

But there’s a role of disgust that seems to be under-examined, and is it—is the neophobia a consequence of fear, or is it a consequence of disgust, which seems more tightly associated with immunity as opposed to, say, fear?

Yeah, well, yeah. I mean, you know, you can get prejudice toward an out-group that has fear components and discussed components. I mean, you can be absolutely disgusted, you know, how to—conservative person who has to interact with an out-group might even happen to disgust face—to face how to discuss it.

But it’s also—I think you see that with food, for example.

Yeah, right! You get it with food or, you know, any kind of pathogen threat can evoke disgust, this emotion of disgust in, you know, in a person. And the more conservative they are, the more likely they will get the actual disgust reaction.

Yeah, well, and discussion, you know, moral violation, food, rotten food, dirty toilet—all that stuff!

Yeah, so that's some account—like people have struggled for a long time to make sense of dietary prohibitions in religious contexts, for example. And, I mean, if you have dietary restrictions and markers for in-group identification, that's a good way of deciding or of determining consistently who's on your side and also marking who's on the other side.

Yeah, all kinds of things come into play to indicate boundary between boundaries.

Well, okay, so when I was looking at—thinking about the relationship—there's five basic personality dimensions and ten aspects, and so—but only two of them really strongly predict political affiliation, and that’s openness, so high openness is liberalism, and orderliness, which is less powerful predictor, but so the conservatives are low in openness and high in orderliness.

And I thought, why in the world do those two uncorrelated personality predictors co-vary to predict political belief? And then I thought, over a number of years, that it has to be—it has to do with borders. Is the fundamental political question is that the conservative likes thick borders between everything?

And the liberal wants thin borders?

And the liberal wants thin borders because their niche is the locale where information is transferred. But the counter tendency is the conservative tendency to say, yeah, but if you’re aware of the information is going to be transferred because the borders are thin, you’re probably going to get sick and die.

And they’re both right.

Yeah, seem reasonable.

Yeah, right in terms of what is—well, sometimes the conservatives are right that you’re going to die if you get exposed to what’s new, and sometimes the liberals are right in that you need what’s new to renew you, right?

Well, these values that we acquire are very strategic, and they’re— you know, they’re suitable for our understanding of the culture that we live in. They’re suitable for that. They’re optimal for that. So if you grow up—we haven't really talked about the evidence yet behind the parasite stress theory, but—and that'll give that—your comments.

Skip—get me into that. So we looked at—we looked at the theory in relation to what it predicts to test it. So it predicts that, you know, if you take measures of parasite stress across the world—countries or states of the United States or whatever—that that will correspond to conservative or collectivist values measured by political science—these measures have been put in the literature for countries and states.

Measures of psychologists of individualism-collectivism put into the literature. So we pulled those data and looked for the predictive relationship between parasite stress and conservatism and liberalism and found what we expected and strongly. So the more parasites, the more conservative, said differently the more parasites, the more collectivist.

And so does that broadly mean the more infectious diseases?

Yes, and so—yeah. More—there are two ways, basically. We’ve measured—or several ways now we’ve measured infectious disease levels.

So by parasite, I mean any infectious agent; it doesn’t mean just intestinal worms or something— it means any infectious agent. So virus, bacterium, worms, whatever level of parasites you’re talking about is a parasite—infectious disease synonymous with infectious disease.

So you can take number of infectious diseases per country, for example. You can take number of infectious diseases per state for the U.S. Or you can take the rate of infection—so that the proportion of the population that has each of these infectious diseases in an area.

So either number of infectious diseases are the prevalence of the infectious diseases in either of those very strongly and similarly predicts values with more infectious diseases, more conservatism.

That’s done on just geographic level, but then—and we did all that initially. And then others came along quickly, actually, once it got started. And it’s still really blooming out there—all the research on the parasite stress theory of values done by people all over the world now.

But, um, people started doing it at the individual level. So you take—bring a person into the lab, and you show them cues of immediate parasite danger. So these are just like a slideshow with disease cues in it—so dirty toilet, a person with skin pox, a person sneezing, those kinds of cues.

So they see these slots, and then you measure their values before and after seeing the slots, and you have an immediate effect! Amazing immediate effect!

So let me talk about the power of these relationships. So if I remember correctly, some of the data that your team generated showed that the correlation between infectious disease prevalence—so parasite stress and conservatism was as high as 0.7.

Yeah, so staggering, unprecedented strength! That’s stronger than the relationship between general cognitive ability or it’s as strong as the relationship between general cognitive ability and learning, which is the strongest association I’ve ever seen in social sciences.

Yeah, we get some big effects on—I mean, there’s variety—there’s variation in terms of what particular prediction we're looking at, and we’ve looked across so many domains of human life that, you know, there’s variation in effect size. But yeah, some of these effects are tremendous, and of course, we do standard statistical procedure—we do controls too of potential confounders in all these analyzes.

So that’s at the—you know—you do the regional stuff with countries of the world, states of the United States in relation to values and parasite level. But then this stuff coming along with looking at individuals really is nice too because you’ve got the— you got the same patterns and the reasons.

Yeah, and the individual level, right? So we should take that apart a little bit. So the problem with comparing nations is there’s lots of differences between nations that might be correlated with parasites. But then if you go to the state-by-state level within a country, you have—you control for lots of those variations.

You have to— you have to! And also in your analysis itself, you do statistical controls of things that potentially could be problematic confounds, whether you’re looking at between countries or between states. So we have data from all those levels.

Some of the more recent stuff—it’s coming out now; people are doing—they did a lot with the slideshow that I mentioned. There were 10 slides that were reliably will evoke greater conservatism, but then now they’re looking at like a short story about COVID.

Ah, COVID’s real serious in your neighborhood or something like that, you know, and that does it too!

So do you think there’ll be a swing towards conservative political belief across the world because of this pandemic? Will that shape the political beliefs of an Israel? Is there a crucial period for that to be shaped?

So, for example, will this have a bigger effect on, say, 14- to 16-year-olds or 16- to 18-year-olds who are catalyzing their identity? Would there be a cohort that would be most effective?

That’s a really interesting point, and I’ve thought a lot about it. There’s no data on that now.

So if you— I mean the way that you could empirically attack such a thing would be to look at—look at people of different ages in relation to, like, the effect of these experiments on them. Do you get a bigger effect size when you show slides—the disease slides to one age group versus another?

Yeah, or would it last longer? We don’t know how long it will last either. That research surprisingly has not been done. You bring people into the lab, and you’re showing these slots, and you get the effect.

Also, one nuance of that is if you measure what we call the perceived vulnerability to disease—that’s a—that’s a 14-item questionnaire that’s validated and measures a person's concern about infectious disease. And that’s an individually variable thing. More conservative people are the higher their score on that, of course, and worry about infectious disease.

So people that are high on this going into the experiment show a bigger effect when they see the slides; they shift more in terms of degree of conservatism.

Do you know if there are any effects of personality on that?

That hasn’t been looked at.

That hasn’t been done yet. But it would—there would be some covariance there because the people that are high in worry about infectious disease are basically conservative people.

So they’re going to have less openness to new things and more introversion and all that kind of stuff!

Oh, really?

Yeah.

So when I first came across your parasite stress hypothesis, I was reading a fair bit of the literature on disgust generated— a fair bit of it by Jonathan Haidt and his research team, because he was one of the first psychologists to look at disgust as an independent emotion. And, but I was reading a book called Hitler’s Table Talk, which was a collection of his spontaneous utterances at mealtimes collected over about three years.

And it really affected my reading of it because the number of times that he referred that he used parasite metaphors really stuck in my mind. And I started to look at all of the Nazi propaganda from before the Second World War in terms of parasite stress hypothesis, especially after I also realized that Hitler’s extermination campaign arguably had its origins in public health policy, because they started out with tuberculosis interventions and then they went to clean up the mental hospitals and so on.

And like the—the, you know, and Hitler went on a factory cleanup binge essentially after coming to power, and they used a variant of cyclone gas as an insecticide in the factory cleanups. So this was all quite terrifying, reading what you were writing and reading this at the same time.

And I don’t know what you—I mean, I’m going to ask you to comment about that—what do you think about that?

But yeah, the metaphor for parasites—that’s a fundamental—meta the Germans—the Nazis seem to view themselves as under assault by parasites.

Mussolini is the same way!

So you said Mussolini was the same way! Exactly the same way! He was a—he was just a replica, or Hitler a replica of him. Mussolini was, you know, his fascist dictator of Italy when Lily was passionate, and Hitler was—the fascist leader of the Nazi.

He doesn’t—but Mussolini—for example, outlawed handshaking in Italy. He thought it was the most disgusting thing to touch a person's hand. He was as much a germaphobe as Hitler, and Hitler bathed four times a day!

That's still going out in some parts of the world—these 30-minute showers in the Middle East, people talk about where you get the highly conservative people that really clean up.

But with regard to fascism, I’ve been very interested in fascism, of course, because it’s over there on the extreme pole of the conservative end of things. You know, it’s got all the components of conservatism in writ large.

And so I've been interested in the origin of fascism in Germany and in Italy and Japan about the same time—the three big fascisms have been—some other fascisms too. But a recent study—you’ll be interested to know—has looked at infectious disease in German regions, cities in relation to voting for the Nazi party, for Hitler’s party, the National Socialist Party.

And the more—the way it works is, so he had—he has data from 1918 to 1920—the number of Spanish flu cases. I never thought about Spanish flu as a contributor because that came right after World War I, of course.

Yeah, right after World War—it was one of the things that devastated an already devastated Germany.

Yeah, yeah, in the world in general!

Yep, yep. Germany was really hit hard by the Spanish flu, as Italy was too. And what this guy did, he got data—there’s a—there's a data collection managed by the University of Michigan on the Third Reich.

And these data include the number of cases, the deaths due to Spanish flu in all these German cities. And he also got the number of deaths from plague and tuberculosis and so forth too.

Tuberculosis was still a big problem by that point too. It wasn’t just—it wasn’t just Spanish flu, but it was fast food was the main killer. But tuberculosis was probably number two, like one, a bigger deal by that point.

So these data—these data have the number of votes in these different cities for the Nazi Party, the number of votes for the Communist Party, and the number of votes for various things.

So the Communist Party was considered extremist then, as was the Nazi Party. And the votes are from, let's see, the years 1930 to 1933, I think, so the critical years for the rise of—for really Nazism to get being there.

And the more— the more people dying from the Spanish flu in 1918 to 1920 in inner cities, the greater the vote for the Nazi party in 1930 to 1933.

So, that’s a connection—that was of interest to me. And this paper has just recently appeared.

Any idea about the size of the relationship, and what about economic? Are there confounds of economic well-being in the city?

Very important. He controlled—he was able to control through the same dataset for employment in those cities and for average wages in those cities. Two variables related to related to economic state.

I mean, that’s the traditional thing historians will tell you—well, the Germans were so economically distraught that they bought this stuff, you know, but the parasite stress theory of values adds a new mirror here, I think, for fascism.

In Italy, I’ve searched and searched for data on flu deaths in Italy, but I don’t think there’s going to be anything like it for some reason. The Third Reich is—you know—collected lots and lots of data.

Somehow, the University of Michigan—I don’t know the history of the acquisition by the University of Michigan of these data, but it is a reliable data source that is used now in sociological research.

Now, you studied other elements of parasite stress theory too—its relationship with altruism, its relationship with human cognitive abilities, yeah?

Yeah, we did a— a big study of IQ in relation to parasite stress and across the world and across the states in the U.S. And that worked out very well. The thinking was simply that if you’ve got—you know, you think about that human immune system—it is tremendous. It’s everywhere in the body, and it’s a very costly system in terms of the energy and in terms of tissue to make and maintain this immune system.

Humans have this huge brain too—a very sophisticated nervous system that is very costly. So we assumed that these two components of the body—immune system and nervous system—would trade off. And so, under high infectious disease, you’ve got to make a good immune system or you're going to die, but that's going to cost you in terms of neural development and so forth.

So we predicted that more infectious diseases, lower IQ. We predicted it across national predictions, about 0.8 between parasite stress and IQ—more parasites, lower IQ.

For the U.S., it’s about 0.7 across states.

Within states?

Yeah, between the 50 states you take average IQ.

Okay, so let’s pull back just a bit for everybody. I mean, it's important for everyone who's listening to realize just how important a role infectious disease actually plays in the shaping of human evolution, cultural evolution included.

So for example, there are estimates, correct me if I'm wrong Dr. Thornhill, but there are estimates that 90 to 95 percent of the Native inhabitants of North and South America died as a consequence of contact with Europeans because of the transmission of measles, smallpox, and mumps primarily.

Although they were also prone to many other diseases that were brought in by the Europeans who had lived in tight-packed cities, often with animals as close companions, had had, what would you say, exposure to a wide variety of extremely toxic diseases, developed immunity, but then brought those diseases to the new world and basically decimated the entire population.

Right, so this is a non-trivial event by any city. The Europeans, by the time they started moving out of Europe into the new world, had all their diseases, but they had relative immunity to lots of respiratory diseases, turns out.

And so they brought all that stuff over here and killed most of the Native new world people.

Yeah, I agree mostly!

So I had read that when the Pilgrims hit Plymouth, the natives were desperate to see them because they had lost so many people— they couldn’t harvest their crops!

Yeah, it was a mess! It continued to be a mess a long time!

Right, so when isolated populations of human beings have come into contact in the past, the upside is the trading of cultural resources essentially, and that can be a tremendous upside, but the downside is the exception of infectious diseases.

That’s right! And we’re caught between those two catastrophes, well those two—an opportunity and a catastrophe—which present themselves simultaneously.

Yes, openness and a little just liberalism is great in terms of its benefits. You got interaction with lots of different kinds of people; you get a bigger social network, got a bigger mating pool; you know, you don’t care if they’re different from you, you want to interact with them, and you can innovate out of catastrophe.

Yeah, new ideas, new ideas—innovations coming from the outside that you can use locally. But that’ll only work under low infectious disease because we get high infectious disease, all that out-group contact interaction—

Okay, yeah.

Yeah, yeah, well that’s exactly what we’ve seen in the last two and a half years too!

Yes! Absolutely!

So we’re right in the middle of it!

We’re right in the middle of it! And the mortality—and you know—the more human mortality from infectious disease before the pandemic was still greater than any other measured source!

So there's a recent work that's looked at—well, you can just sort of summarize it this way—you can look at—you can look at genes that have—that have—that play known roles in human life. So they're genes associated with immunity, and those have been described by immunologists, which genes are involved in their genes involved in diet, the genes involved in digesting protein—and all that kind of stuff—all these, you know, gene functions are known.

If you then—you look at where in the human genome there’s the most turnover of new alleles—new genes—those are genes that are evolutionarily very active.

It turns out that the immunity genes are the evolutionary hotspots in the human genome, and that says there’s more mortality from infectious disease than from other measured problems that humans face. Most mortality still is from infectious disease.

That was done at 50 sites—human science!

That provides evidence that that's actually the worst threat facing—

The worst threat! Absolutely!

Still?

Yeah! Hence its powerful effect on such things as values!

Yeah, absolutely! Absolutely! It’s the main mortality factor, and if you look at the anthropological evidence about the importance of infectious disease versus other things, there's a lot of evidence for that. A nice review recently that some people did, but infectious disease is the main killer of infants and older children in the ethnographic records of traditional societies.

Infectious disease is the big one; next is infanticide—that's number two, where parents kill their kids strategically because they can’t raise them under resource limitation or—or the kids are sick or whatever.

Infanticide is very common; that’s number two, but infectious disease is the main killer!

So, okay, here's some radical ideas I suppose because I mean reading all this—learning this—okay, let me say—before we go there, let’s do one other thing—main objections to the theory, practical and empirical—what’s—what I read a paper recently, and I'm afraid I can't cite it in detail, but it'll serve as an example claiming that with proper control for technological development, the causal or the effect of parasite stress on political belief vanished.

Now you cite many papers in your books and in your papers, so I'm by no means saying that this is a canonical study, but this is a very provocative theory. I mean, it upends, in some sense, my sense when I first encountered it was that it upend almost everything we think about politically. And so, and what’s the saying that that extraordinarily claims require extraordinary evidence? We’ve got to look at the counter-evidence too. So what do you think are the main weaknesses of the idea as far as you’re concerned, and how have you addressed them? And have they been successfully addressed?

Yeah, uh, we had—we addressed them as they have come out, and the parasite stress theory of values has gotten—when it first came out, I got so much attention that that attracted a lot of people to try to falsify, you know, and that’s the way that works in science.

Yeah, thank God we went through that—we went through that phase, and now all the research is looking at very interesting spin-offs in productive ways of the parasite stress theory, and no criticisms have come out recently.

But the kind of thing you’re talking about, where it’s really modernity and modern things and so forth—that controls our bed—that’s an old idea in the literature.

People just get more modern; they get more liberal, and so forth, and we take that on in a number of ways, and the one way I’d like to—you might be interested in—

We look at the cultural and social revolution of the 60s and 70s in the West.

So what happened—and I was there—you had a liberalization of values, basically, is the bottom line. But you had more, you know—more, you know—the women’s movement started then. There was a sexual revolution at the same time, right, which aids put a terrible crimp in other infectious agents!

And ethnic groups, minority groups that had been ostracized and so forth got more attention, positive attention. It was democratization of law, or voter laws and all that changed.

So you can—and it was—it was more than just people talk about that time as the sexual revolution time—60s and 70s—but really it was a—a much broader social revolution involving human rights—increasing human rights and liberties.

Basically liberalization. So what the hell happened?

Well here's what happened. It was infectious disease changes that began in the 20s that led to all these liberals in the West in the 1670s, and these infectious disease changes began in 1920 with fluorinated water.

That started in the West—we’re talking about the West; the East and the rest of the world didn’t change. They didn’t go through the social revolution; many places in the world still haven’t because of disease levels being high, and all of Africa basically, and much of Asia.

But 1920s chlorinated water started in the West and quickly spread throughout the Western world. By the Western world, I mean the U.S., Canada, Western Europe, Australia, New Zealand—those places.

So chlorinated water, and that knocked out lots and lots of infectious diseases. Put a little fluorine in public water also in the 20s began, some systematic garbage collection. Before, people just threw the garbage out there, howling, sewage treatment plants started then too.

There was more indoor plumbing starting in the 20s. Now let’s jump to the 40s. 40s—big, big changes with regard to emancipation from parasites had a child vaccination programs that began in the 40s, also antibiotics—first good antibiotics right after World War II, 1945.

In the 40s, so this was really by that point a new world in terms of lower infectious disease compared to the world that all generations of humans had experienced in the West prior to those 20s and 40s.

There were some antibiotics in the 30s, but sulfur drugs and so forth, but they had terrible side effects. So the real good antibiotics didn’t come along until the 40s and broad spectrum kind of antibiotics.

And, of course, that spread so rapidly, the use of antibiotics that they quickly saw a resistance to antibiotics popping up, you know, the evolution of resistance.

And parasites?

Yes, which is a serious problem we have now because we have diseases that are resistant to almost all the broad spectrum antibiotics, even in common!

That's a looming catastrophe!

Which we should obviously pay attention to.

Right! There’s an arms race between the parasites and the drug companies now—

With that, so up to the 40s, and then also in the 40s you had insecticides coming along—good insecticides—chlorinated hydrocarbons and organophosphates that killed pest species, including mosquitoes.

So, vectors—important vectors of disease in the West—mosquitoes. So that knocked out malaria, knocked out yellow fever with that, and all that was going on to emancipate people.

And then the generation two years later, you get the rise of liberalism throughout the West!

So all these liberal young people growing up in a relatively disease-free environment by all these health interventions became the hippies and so they were healthy enough to be free!

Yeah, and so that does really raise the question again of what COVID is going to do to the political temperament of the West or the world, for that matter. But, right, it’s a particular change in the West because we’re not accustomed to this sort of thing anymore!

So it’s so interesting because, of course, I’ve thought of the liberalism revolution being a secondary derivative of the birth control pill which is a biological revolution of immense magnitude.

But I hadn’t ever considered in depth even afterwards— I mean the use of birth control and all that—that takes some willingness to try new things, right?

Exactly!

Well, that's it. That might be dependent itself on one away from tradition, you know, taking birth control.

So there’s another perverse implication of the theory that you’ve developed too, which is that conservatism insistence upon hygiene and disease prevention is a precondition for liberalism if it's successful, right?

So it's in some sense—the conservatives are battling off the disease so that people can stay healthy, but the consequence of that is as soon as that they’re healthy, they become liberal!

Yeah, yeah! Isn’t that something?

Well, I think it's here—you can look at it like this. So if you’ve got high conservatism in a place, then those conservatives are doing things that promote—well, they’re, you know—they're not using modern technology; they’re not, you know, open to new ideas; they’re not open to science and all that.

So those are those attitudes that help the infectious disease really.

Right, right, right!

So the reliance on tradition—that’s a tremendous impediment!

It reduces their contact immediately!

So it works against them that way. I mean if you're not—you know—pro-science and open to new ideas and innovations and all that kind of stuff—that is tremendous limitations.

And so, you know, you don’t even put in septic tanks, and you think, or chlorinate the water or, okay, so another patient.

You don’t get a vaccination!

Right, well, okay, so let’s talk about two things then. One is I’ve been struck—didn't tell me what you think about this—the COVID has become a politicized issue in Canada and in the U.S.

But it doesn’t seem to have happened the way you might have predicted if you were relying on parasite stress theory because it seems to be that the conservative types are the ones who are objecting most strenuously to the lockdowns and to the inoculations, whereas the liberal types—I mean, and maybe I’m wrong about this— but seem to be more in favor of the restrictions of movement and so on.

And that actually—I don’t—I can’t get my head around that exactly.

Yeah, no, you’re right. That is the pattern, and that’s been studied now. And, you know, there's some papers on it.

And here's the way—here’s what’s going on. I think in the U.S. in particular, the conservative government at the time when COVID was getting off the ground—the Trump administration—was very negative about COVID. I mean, he called it a hoax and all that, didn’t believe it, and, uh, there’s no problem and, um, so that is the authority.

We need to talk about authoritarianism because here’s where it comes in. You have the King Donald Trump saying that it’s no problem, this disease is no problem, and it’s just going to go away; it’s a hoax and all that kind of stuff.

And that is the word from God, basically, to highly conservatives—conservative people.

And that’s the way authoritarianism works. People that are highly authoritarian and that conservatives—that's strong.

There’s a lot of evidence that authoritarianism is very highly correlated with conservatism, in fact, a component of it.

The more authoritarian the people are, the more likely they will follow these guys that they label as their leaders, and to the point that they’ll follow them anywhere—they'll follow them off a cliff, basically.

As they did in Germany, as they did in Italy, and as they did in the United States during this COVID tank.

So you believe that what happened was that the evidence that there was in fact a dangerous epidemic was rendered non-credible?

So that's right, exactly.

And do you think that’s a good prevented? It was the authoritarianism that conservatives are carrying, and had Trump acted another way, you know, said this disease is really important—I want you folks to wear a mask and be careful and distance and all that kind of stuff—then there would have been a different outcome.

Because that would have been the authority message.

So it’s one element of authoritarianism/conservatism interfering with another.

That’s right!

Okay, um, parasite stress and sex.

Yeah, there’s been some look at values in relation to sex. So conservatism—conservatives are conservative.

So, but there's old studies that—there's one paper I should send you—it’s got all kinds of correlations in there with everything under the sun in relation to conservatism and liberalism.

But, you know, interest in different positions, copulatory positions and all that; you did—the conservatives are more likely to stick to missionary style, and whereas the liberals are, uh, more adventurous with regard to position.

And is there a relationship between adventurousness and sexual position and the risk of transmitting sexually transmitted diseases?

Don’t know! I haven’t seen anything on that particular thing.

But, you know, liberals are more interested in—would be more interested in partners that are in different ethnic groups.

I mean that’s been studied. You don’t limit your sexual interests just to your in-group if you’re liberal; you’re happy with people of different color and different backgrounds and all that kind of stuff as sex partners.

So, those kinds of things have been done with regard to sexual behavior. We did a—we did the variable, social sexual orientation. It’s a—it’s a variable—it’s validated in psychology, and it measures really a person’s attitude about promiscuity or sex without commitment—you call it sex without commitment.

And that varies among individuals, their attitude about sex without commitment. And we looked—and there’s data on—I think it was about 120 countries, measures.

So we took those data and looked at them in relation to parasite stress and values. And the more parasites, the less interest that women show in non-committal sex.

So the more parasites—and that’s pro—that’s mediated, I presume, by a cultural response to the presence of the parasites?

Yeah, right, that's conservatism!

And I would have—any studies been done that are analogous to the political studies where people are shown images that are reminiscent of parasitic presence and then asked about their sexual preferences with regards to monogamy or uncommitted relationships?

No, that hadn’t been done.

No, there's a PhD thesis for someone!

Yeah, we just did the SOI data—social sexual orientation inventory data for men and women across these countries and looked at it in relation to parasite stress and values.

And, as I mentioned, infectious disease increases; women show more restriction, and as women specifically—women specifically—the effect for men is not reliable; this is not very big, and probably not even reliable; statistically significant, but for women, it’s highly significant.

The more parasites, the more restricted women are, and that goes along with conservatism. So conservatism is a sexual purity and protect the jewels kind of attitude that is instilled by a conservative culture in women.

So, but in women—in, well, so there's a question, okay? You know, it’s a double standard.

Well, when you get parasite stress increasing then is the conservative proclivity manifested to begin with in the women and then spread to the men? I mean because they’re more primarily concerned, let’s say, with sexual contamination?

I mean the role of the genders in determining—but the manner the men are changing—the men are changing, and other components, so they’re—the men are hot to trot regardless of—

Well, that’s what I was thinking, yeah. But the men are the men are changing in terms of becoming more androphilic and ethnocentric and those kinds of things.

You know, so they're the sexy changes don’t drive the rest of it?

No!

Okay!

Because, I mean changes in sexual behavior often drive changes in other phenomena, can be important!

Yeah, yeah.

You also write about parasite stress and religiosity.

Yeah! We did a big study of that looking at religion scholars—