Pathogens with Josh Ackerman
2026-06-02 12:00:00.000 +00:00

This is Evolutionary Psychology, the podcast. I'm David Pinsoff. I'm David Petrozowski. And this is Actual Evolutionary Psychology by Actual Evolutionary Psychologist. David, today we talked to Josh Ackerman. Yes. Uh this was a really fun conversation um about all things diseasey and immune system y. It wasn't a gross conversation at all though. I I would say because we've had these kinds of um you know, with like Josh Tiber, Deb Lieberman. I'm not saying those were gross either. Um but uh but this was I don't think there was too much gross in this. I think this was more uh That's true was fun and uh in a good way abstracted away from the the things that would elicit disgust, I would say. That's true.

And in fact, we get into the distinction between uh anxiety about disease and being grossed out and why they are different things. It's kind of an interesting question, you know. Like you could, you know, why are we why are we grossed out versus just afraid. You know, what what are these different emotional profiles doing for us? We get into that. We get into the the effects of disease concern on social life and social networks. Um it was yeah, we get into like picking up on sex ratios and population density, and just I like this is another example of people doing really cool work that is counterintuitive because it's not the kind of thing you would think that pathogens would have a big effect on human psychology, but of course they do.

They're huge selection pressure. And by doing an analysis of how pathogens affect our psychology from an evolutionary perspective, it suggests a whole area of research to look into. And as we talked about, pathogens are not a chapter in intro psych textbooks. But Josh is, for example, looking at how why people don't protect other people from disease and why why they, you know, and things like that that are really important that you wouldn't necessarily find out if you weren't studying the psychology of disease avoidance. Yeah, totally. And uh we even touch on reality TV a little bit. So if you're reality TV fans, this episode's sponsored by uh Survivor. David's proselytizing about the Please watch Survivor.

Do yourself a favor. It's it's fantastic. Survivor, please send us Survivor as if Survivor is an entity. Um I know. But anyway, I enjoyed this episode with Josh and uh it was lovely. It was nice. And David, it's nice to just be back to regular episodes. Yeah, good to great to be back. Josh Ackerman, thanks for being here. Um, Josh, um, we haven't always done origin stories lately, um, but I am curious about yours. Um, either in terms of in what order you came across evolution versus the subfield of behavioral science you apply evolution to. Which one came first? Yeah. Well, thanks for thanks for having me. And um in turn, I think evolution came first. I was one of those kids in high school that was reading like Stephen J.

Gould books, uh, those kind of things. I think really was one of the places that got me interested in just evolution as a concept. Um, but it it wasn't necessarily something that I, you know, knew what to do with, at least in terms of my um professional trajectory. Uh, but in college, I was undecided about what I was you know gonna do. And so I was taking uh psychology courses. I was also taking uh uh biological anthropology courses. And that's what really I think became that starting point for integrating kind of evolution and behavior. I took a course, and there really was one course that I think started it. It was a course on sociobiology, which I don't think was all that common in terms of like

course offerings at a lot of places at the time. But it was taught by Carl van Scheik, who was uh he has done a lot of work i think if i remember correctly with orangutans and looking at the evolution of behavior but it was really it was non-human behavior and so but at the same time it was really clear how this would start to apply to people and um so that's what really got me interested in like oh I like psychology. I like evolution. And so I was still undecided. Should I do some kind of primatology work or should I do people? But uh I think for many reasons people want out. Yeah, um, makes sense. Uh did you find, do you know what what about the class you that you found interesting? I think it was the uh it was it was several things but I think uh one of

it was just I mean evolution it evolution is just a fun idea uh in a lot of ways and it is so um universal in its application I think that it really was uh like sort of a lens through which to see not just a particular type of behavior but any aspect of what it means to be human. As well as having these real tools to use. So a lot of the sub theories that, you know, were sort of classic ones that were discussed, like inclusive fitness theory and so on, were things like, oh, I can really see how this is directly applied to non humans, but also human behavior. And so I think it was a sort of a combination of just sort of loving the biological world in general, but having a framework to organize all of that

into something coherent um with these with these tools that sort of show you where to go with this kind of thing. And it was, I don't know, it's sort of one of these it's a big picture theory. And it, you know, think about like how what what it means to be alive in the universe. And so you've got these different sort of major uh big perspectives on how you want to do that and you know in different fields, but in in behavior and biology, I think it's evolution. And so um it was just exciting. Yeah. I'm I'm curious what both of you think about this. And this is sort of fast forwarding to in your both of your experiences. Um and Josh, we should start with you. Um, but uh I I wonder, do you think that there's individual differences in how much people

like principles? Uh, in the sense of like you're describing like you're really attracted to principle. I think we're all here because of that. And anecdotally, I don't even know if I think this, but I will say it out loud as a hypothesis. There seems to be an individual difference where some people don't like principles because it sort of detracts from looking clever, um, or sort of being having unique knowledge. And there are aspects of human life that that makes sense, right? Like sort of it's a fashion um dynamic. Um, I don't know what do you guys think that that happens where some people dislike principles because of that, or am I reading into it too much? Um, yeah. Yeah, I mean, uh, there probably is.

I think that there's, you know, I guess principles can uh what what's ringing in my head is this um common refrain that you sometimes hear from people about like removing the mystery from uh from experience by applying principles, right? And so I think that if that's the take that you have, then I mean maybe it is an individual difference that you just you don't want to know the details about a lot of things and so but um on the other side it's just like well how do we actually grapple with these things uh I think is I would hope maybe it's not maybe it's not universal but I would hope is really just sort of an embedded fundamental part of like a scientific mindset. Yeah well put yeah Yeah, it's sort of like individual differences and whether you want the

magic trick to be explained at a magic show. I mean I mean me personally, I always like deeply want to know how the trick is pulled off. And like it's it's hard for me to enjoy a magic show because I'm just so curious about how they pulled off the trick. Um and I think some people really just don't want to know it. It just ruins the whole show if they if they know how the how the trick works. Um and I think there might be something similar when it comes to explaining psychological phenomena that it sort of demystifies the phenomenon. Um I've had that reaction to my work sometimes, but particularly with humor. Like when I explain sort of like the mundane, you know, uh game theoretic problem that that

hu the sense of humor evolved to solve, it sort of demystifies humor uh um in a way that uh is kind of unsatisfying for some people. Um that that probably is an individual difference variable. I don't know. If you have to explain the joke, then it's uh no that's true. That that's true, yeah. But if you have to explain why why jokes exist at all, you know, they could also have have have a different effect. It's kind of it's funny because it misunderstands the point of a joke, right? Which is your point, David. Yes, exactly. The theory explains why it's sort of funny. Yeah. Um I wonder there must be I I'm sure there's work on I mean, I know there's individual differences on curiosity. Um, but I wonder I like this idea of uh uh Joshua this idea of

um explaining something taking taking it as as sort of deflationary and tr understanding it that way. I would hope there's work on that as an individual difference as it would be worth looking. Um I'm curious I'm curious to see if that's part of the curiosity literature. Yeah. Yeah, exactly. for me uh it's almost like a kind of anger when something doesn't make sense. It's like I'm like frustrated. I'm like, no, it has to make sense. That doesn't make sense. Yeah, you can't tell me. Yeah, you're you're it's a secret. Yeah. It's sort of like I know, yeah, some people I know they're like it's angry because it's like it's keeping something away from you. It's like keeping it's uh it's a magician.

Um yeah. Uh maybe this need for uncertainty would be one of the individual differences that is that's there. Although I was thinking when you're talking about this, I I don't necessarily believe that understanding you know how something works removes the I'm gonna say mystery, I don't know if that's the right word, but the excitement about it. Yeah. Uh and you know I also this is I guess I'm just I essentially was a nerd as a kid, but I was also into magic. And uh I I think that understanding that there is a solution to how this works isn't necessarily the same thing as wanting to know the solution. So I didn't always want to know the solution to magic, but I got that there was a practical way of doing it.

Right. And so I think even when I understand aspects of principles or theories, whatever it is, it doesn't take away much like people often assume, it doesn't take away from that. Um that I guess the mystery of like how it came to be in the first place, what it means in the bigger picture, those kind of things. Yeah. Yeah. For me at least, like when I learned about how my visual system worked, it was more amazing because I was like, I can't believe that all those little doohickeys are all summing up to this thing I'm doing. And that seems even more incredible than just the thing I'm seeing. Yeah. Yeah, exactly. So PSA kids, don't um don't think that science explains away things. But yeah, it is an individual thing.

Okay. Anyway, so that that was great. Um uh you study, roughly speaking, um, illness. Uh or is that how would you characterize uh yeah, maybe that's completely the wrong way to no, I don't think that's wrong. Yeah yeah. Um I think that the major it wasn't always like this. I took a lot sort of a winding route to get to this uh topic area, But um I would say I'm interested in the role of infection in our psychology. Right. So illness can be broader, and there's a lot of overlap, I think, between infection and non-infection, but specifically how infection plays a role and uh who we are, sort of as what what it means to be human, is very much grounded in the history of infection uh and how we think these days and how we manage uh the

particular threats and opportunities that come along with infection. Yeah. No, it's it's uh a particularly important point reminds me of the episode we had with Dan Conroy Beam about how one of the most widely accepted theories for why we sexually reproduce at all as opposed to clonally reproducing is because of the risk of infection of pathogens just constantly evolving to hack our biological machinery and the need to throw out a lot of variation to make it harder for the pathogens to keep up with. So you know one of the most basic aspects of who we are as a species, the the fact that we have men and women and reproduce sexually, like that itself derives ultimately from the threat of pathogen.

So it really is, really does lie at the at the foundations of who we are. Yeah, exactly. I think it's true in our history, and it's true even in our current day-to-day life, in a sense. Um, there's this fact that I like to throw out with uh with evolutionary psych courses, um, where essentially if you just think about yourself right here sitting right now on this podcast, if you were to count up all the cells in your body, more than half of those are bacteria right now. So you're actually more bacteria than human, at least by number of cells in your body, which is suggesting that there's a very, and it's maybe not what we would call infection necessarily, but it is still the agents of infection are there, present at all times inside

us. Yeah, we talked to um uh Catherine White Whiteson about um uh the microbiome too which is mind blowing that was a great great episode yeah cool oh thanks yeah we'll pay you later um you you mentioned that the what it means to be human is is is is really driven by this can you unpack that because that sounds very intriguing. Uh what do you mean by that? Yeah um I mean essentially what at least the starting point is what David was was talking about. So this idea that much of how our physical form is set up, but also our behavioral tendencies are a response to the very, very long history of perfection. Right. So thinking everything about things like um yeah, the mating behaviors that we show, um, the fact that we have uh uh live births

is is related to infection. Um so I think it's something like that. I mean, there's an important theory, I think, around the placenta being a response to, or actually a both a response to infection, but also the the result of a particular infection. Um, and so those in combination with a lot of the I'm particularly interested in the social behavior, the ways in which people navigate various types of social behaviors and various instances of sociality as a sort of in terms of the trade-offs that people have to make with infection. And so I think that although it's not something that is top of mind for many people in day-to-day life, I think that it is something that is always either lurking beneath the

surface, or for some of us that are a little bit more germophobic. Um, it's a constant issue to navigate through our through our lives because every instance of interaction, whether it's with another person, um, some type of food or object, uh, is has the potential to create this kind of uh problem for us. And so it's it's just always there. Interesting. So it's kind of like gravity where it's a part of the design baked into the phenotype. But because gravity is constant, I mean, we we think about it, but we don't usually we think about like what objects are falling or could something fall in the same way, like could I get sick? But the fact of pathogens is invariable. So we it just sort of cancels out and we don't really think about it.

Yeah, I think that's a great analogy, right? It's something that's always affecting us, but it only sometimes comes to top of mind, you know. Uh maybe not often enough sometimes. Yeah. So it's an intellect interesting intellectual exercise aided presumably by thinking from an evolutionary perspective of how is our psychology shaped, given that this is really strong selection pressure, but at the same time there's instinct blindness because it's not maybe, I don't know, what what a psychology book 50 years ago did it have much much about infection? Probably not. I don't I don't know actually. I mean I think even today, most psychology books would have nothing about infection in them, um, unless they're taking this kind of either biological or evolutionary angle to

them. Um, yeah. I mean, I I just gave a talk to some people and they were like, oh, this is so interesting. It's stuff you would never think about. Like, well, we should be thinking about these kinds of things. Yeah. It reminds me of Annie Wirts's like plants where it's just like it's so foundational. It's like poison versus food, you know, like infection. So many people die. So many of our ancestors died from infection. We're very lucky uh to to not to take that for granted. And like we're I think we're like 1.5 point five or point seven five generation of taking that for granted and it's already biting us. Taking it for granted is already we're we're we're quickly eroding that taking for granted

issue. Um where like outbreak childhood diseases outbreaks. But yeah but yeah, so I mean it's really it's it's it's funny um to just interject that um people are like, Oh yeah, that's that's what a novelty, right? Uh yeah, exactly. Uh there's this it's not really evolutionary, I guess, but just essentially the taking it for granted, right? So if you look at the places that are showing the biggest spikes in vaccine hesitancy, so people who are, you know, not as interested in getting vaccinated, it's the places where vaccines have been the most effective. And you're just not, you just don't have the constant exposure. So you don't think that you need to worry about things like vaccines. Um, so yeah, that's uh definitely not top of mind for a lot of people.

But yeah, I mean, I think that's yeah, one of the things that I I thought was the most interesting about an evolutionary perspective with psychology is that you do have to kind of back away sometimes from the most complex kinds of thought patterns or behaviors that people you know might have been studying for a long time and really get down to the the core of what people what what is what are the key affordances or motivations or or uh inputs that are really out there. Hmm. Do you think the um our our infection or pathogen psychology could perversely play a role in driving vaccine skepticism? And that there is something kind of scary about stabbing yourself and putting a foreign substance into your body, you know, based on you know faith that the person who's

telling you to do this has your best interests at heart, uh and and knowing that the substance you're putting in your body is itself a a disease. Like it it seems like, you know, um uh you know people often talk about vaccine skeptics as you know being you know gullible or un unintelligent or something but it in many cases like the uh it is more counterintuitive to take the vaccine. It is it is uh it's kind of hard to wrap your head around like I feel like that's more psychologically mysterious is why so many people go along with vaccines than why so many people are are resistant to them. Because it takes a lot of you know uh overriding uh uh of your instincts of of what is you know a good idea absolutely i mean uh i think it might have been josh tiber

that's done some work on this idea of um what is i think in the field called body envelope violations uh yeah so the idea of like yeah stabbing yourself creating an open wound uh to protect yourself not not the most um And I don't know that I would be interested to know. I don't think that most of the people who are hesitant about vaccines are really thinking deeply about the idea that they're getting injected with bacteria or virus of some sort, even if it's inert. I think it's probably more the superficial, either don't want the needle, maybe it's something about the information that they're receiving around these things, whether it's historically from how certain parties have used vaccines and other kinds of injections in

the past, to you know, the messaging that's out there today around what vaccines mean, how what role they play in people's group identities, and so on. But certainly the sensory experience of it is really the opposite of what you would to help protect yourself. It certainly makes it easier for a bunch of people. Like if you got up on a soapbox and said, Hey, you know this thing where we all have to go through this painful thing at the doctor's office? Let's not do that anymore, versus like, hey, let's not eat candy anymore. You know, like one of those things is going to be easier to get people on board with on if they're not like burying their kids, right? Um because they're they died from some disease, which was happening, you know, two

generations ago. Yeah, it makes me think about most places, many places. Yeah, exactly. It makes me think about that whether there is a uh correlation with this kind of hesitancy around something like vaccines or other types of injections. And this tendency towards towards wanting to, like if you're a parent, I guess, not expose your children to any type of hardship, despite the fact that those kinds of experiences can produce better outcomes where our minds and our bodies are designed to, in some sense, expect some of those kinds of experiences. And when you don't trigger them, then you might have problematic downstream outcomes. I wonder how much there is that kind of sense that it's really about removing

all difficulty. That's interesting. Yeah. I also I would love to have somebody, and again, maybe I I haven't looked this up. I would, I would, I would love to have a cultural evolution person collaborate with like a developmental psychologist on this because the idea that you should um protect your kids from difficulty, I think Josh, that's like spot on. But it's clearly not universal. I mean, even German, Germany is very different than the US in that respect, and hunter-gatherer, like the the um uh Akka kids, for example, kind of, you know, like famously are very self-sufficient, you know, or you know, Schwar kids, you know, they're like using machetes and things like that. Um, you know, we talked to Shinalu Levy about, you know, they're keeping an eye on the

kids, the toddlers using the machete, but they're and it's not, you know, but they're still using a machete, you know. Um, but this idea, I wonder if it's just this thing of if there's a market for precaution and um combined with other things, you can just imagine this thing of there's always this appetite for easier things um or protective things for your kids. And it just creates this sort of bad dynamic where you um you overprotect yourself and kids from difficulty. Yeah. Yeah. Um to the detriment of their well-being sometimes. Yeah. Yeah. I mean it would be interesting to see. I mean, I uh it's probably a very complicated phenomenon, but I bet one factor is just the total fertility rate of the population.

Like if you have a smaller number of kids, you're gonna be more precious about each individual kid and try to minimize the risk. But if you have a lot of kids, then your your fitness interests are more distributed and you could be you could afford to be a little more risk prone uh uh in evolutionary terms but if your all of your fitness is bound up with one kid or two kids, like you really need to make sure that nothing bad happens to them because you know I don't know. Yeah that's also uh there's also a thing of like um if the kids get hurt is it going to be catastrophic so like just US versus Germany like I I'm much more worried about getting hurt just because there's like, you know, health insurance is worse here.

So um I'm sure that plays a part too, although that doesn't explain the hunter-gatherer thing. But I guess, David, the point would be then you're you've got multiple irons in the fire, as it were, in terms of the next generation. Yeah. Yeah. And I think the the culture evolution piece might be useful in thinking about whether some of this precautionary tendencies is forecasting potential blame that people might um might expect that if uh you know somebody gets your kid gets hurt, it's gonna come back to you. You are the bad parent, uh essentially. And so anything you can do to ward that off. Yeah, or like legal repercussions. I also think, you know, like just the structure of the society, right?

Like where if you're um yeah, if you have to be defensive, um, and you know, or like even as a school, right? Like if where you're worried you're gonna get sued, it just selects for an institution that isn't like, well, what's the way we're gonna expose most kids to good risk? It's what's the way we're gonna keep all kids as safe as possible so the one kid doesn't sue, you know, the one family doesn't sue us. Yeah. Yeah. How are we gonna reduce our own risk? Yeah, exactly. Exactly. Yeah, yeah. No, that's that would be a really great area for there's just all these unintended consequences. Really this the a lot of this is about risk, as you just put. Like I think that's really putting the the the heart at the heart of it.

It's really uh strategies for uh guarding against different risks. Yeah. Yeah. Interesting stuff. So you you I mean, speaking of how different features of the ecology might affect our this this parental overprotectiveness. I know you've done a lot of work on how different features of people's environments might affect their decision making. We've just talked about pathogens. What are some of the other ecological features that might push me to behave in a different way or make different decisions for myself or for my family? Yeah, I mean, some of them still relate to pathogen risk in some sense. So something like population density is a big one. And a lot of these are I'm I'm drawing to some extent on work from a former

postdoc of mine, Oliver Singh, who has done a lot of work like mapping some of the dimensions that are common in behavioral ecology work onto human ecology work, essentially. So population density being one of those. So if you live in these places where there's just a lot of people around, that does present an increased chance of infection transmission, pathogen transmission, but also a lot of other things in terms of competition for resources and what you have to do to navigate that. Another dimension that I've done probably more work on has to do with the sex ratio of the environment. So this is something that's widely known to have an effect, even at small scale increments of difference. And so, yeah, if the population or at least the local population that you're exposed to is

shifted or biased in one direction or the other in terms of women versus men, that has an impact on a variety of things that people think about and do, behave. So again, things related to, in some sense, resource competition, but at the heart of it is probably some connection to mating opportunities, or at least people's forecasted mating opportunities. And so yeah, so sex ratio is one where we've seen a wide variety of effects, everything from things related to changes in aggression or associations with aggression to decision making around risk again. So how much people are wanting to essentially uh be cautious about the kinds of decisions that they're making. We've looked at that often in sort of financial decisions, but I think it probably spreads

to other kinds of decisions. Um, versus kind of going all in. Uh, and these kind of patterns are things that we see again in non-human animals just as much as we see them in human animal uh humans. Uh, and so um those are probably some of the ones that we've looked the most at. But there's there's others like mortality risk, how dangerous is the environment that you're in, how much are people being aggressive towards each other? It's all that's coming to mind right now. Yeah. The the uh riskiness, can you unpack what the direction is? Is this with so unmated men acting risk? What can you unpack what the result is? Yeah. So um The influence of some of these uh dimensional factors is not always simple.

So it does we we sort of see different kinds of effects depending upon the um the type of question that you're looking at, but also the the sample that you're looking at. So sometimes we see, for instance, sex ratio effects on a whole population, sometimes it's only on, like, for instance, males. Um, But yeah, so if you have a male skewed uh population where there's more men than women, that means, you know, from the point of view of uh mating opportunities, it reduces the number of potential opportunities for any given man, you know, all else equal. Um, and so that can produce different outcomes like um a desire to essentially show off more, so to be competitive with other men, so to stand out from the crowd.

It can lead to things like feeling like, okay, well, if I don't have uh strong possibility of finding a partner, and I don't know that a lot of this is especially top of mind, but this is the logic anyway, um, That if you don't have a strong opportunity, well, you might need to really break out. And so what that means is taking more risks. And so doing things like we sometimes are doing studies where we're looking at financial decision making where people were having to make decisions between spreading out their investments essentially in finances into different options, which is essentially a form of bet hedging, and uh versus uh sort of putting everything into one risky option like where the payoff could be big but the risk is high um and in these male skewed environments or at

least when people were thinking about male skewed environments you see more risk-taking behavior so less bet hedging and that's not inconsistent with what we see and again some other species like birds will do this in terms of the number of eggs they lay depending on the environmental conditions or the sex ratio of that. So, but in terms of like larger scale work at like a population or a country level uh analysis, there's a lot of interesting work suggesting that when you have these kinds of shifts in a sex ratio, you get really wide-scale population level uh changes in behavior. So things like at least at the mating level, if you have a more female skewed environment, that means that it's always about the minority sex having more power on the mating market,

right? And so you see things like less um long-term relationships, people be more open to shorter-term relationships. Uh, whereas you get the opposite of that when in these male skewed environments, people want to stay the relationships if they find them. They want to, so men actually do more caregiving of children. Um, but there's a lot more people, a lot more men, I guess, left out, and those are the ones showing higher degrees of aggression and competition. Interesting. Uh it reminds me of um some work uh I saw at HBus uh by Pat Barclay on on risk taking, yeah, where he uh defines two different types of risk taking. One is where you would expect it to be higher among uh people with l in you know bad shape

or in in poor condition or in dire straits, where they're below some need threshold. Um you know, let's say you know they're they're not going to find a partner, they don't have adequate resources to survive uh or be healthy. Uh and in that case, they just want to do anything possible to get above that need threshold. And that means they're going to accept riskier uh decisions. And then there's the other type of risk taking where it's actually the opposite, where you're when you're in particularly good condition and in good shape. Uh you have a lot of resources. And in that case, the costs of risk taking are just going to be lower because you're going to be buffered against the downside, presumably, and you might have greater ability to to

show off by taking risks. If you're wealthier, you can afford to gamble more and show off your wealth. And so that predicts, you know, basically the opposite pattern based on, you know, where you're doing your best, where you're doing your worst. But it seems like if in a in a biased sex ratio environment, you know, both of those factors would be at play because you're going to have more, let's say, you know, it's a it's a male-biased sex ratio. You're gonna have more men who are below that need threshold where they uh it's looking to them like they're not gonna be able to find a mate and they're need to take whatever risk is necessary to get above that threshold. And then at the same time, um, the men who are doing better, they might want to show off

more uh and and and better outcompete uh other men. And so you might have both of those types of risk-taking increase. Yeah, exactly. I think what you're hitting is this idea that it's you're often when you're thinking about this idea of risk as a function of some of these ecological dimensions, you're it's often not going to be a linear relationship in terms of how those are connected, right? So um, and this will depend on you know other factors that come into play. But if it's like something around sex ratio and romantic intentions, well, so the people that are likely to want to take those risks are the people who are most relevant to romantic encounters in the first place, right? So if you are um thinking specifically about age.

So if you are somebody who's post-puberty and you don't have a lot of um resources or like you don't have a lot of uh ways of uh of breaking past that threshold, then you might need to take more risks to do that at the same time. As you're saying, David, people at the high end also have less less cost of taking those risks. You might see that. But if I'm pre puberty, then uh it might make sense actually to, and and I'm still in a in a biased sex ratio where there's a lot more of my same sex in that population. That does present a problem, but it's a problem where I might approach it differently. And so I might, instead of taking risks, I might use that opportunity. And again, a lot of I'm not intending to talk about this in a way that is a, you know,

conscious top of mind processing, but you might essentially uh want to build up your resources before you start taking risks, right? So you might start acting in a way that improves your own condition, right? Who you are, what are the skills that you have to show off, what are the, you know, what kind of maybe even what kind of job interests you have in terms of like, are you going to go for you know a career that's more exciting and sexy versus not? Um and we see those kinds of patterns with other ecological dimensions. So I mentioned Oliver Singh before he's got this interesting work on population density suggesting that if you were in a really population dense place, that inherently means there's competition for resources, right?

But what the consequence of that can be is essentially leading people to act in more, I don't love the slow, fast language of life history theory, but essentially in slower ways, where they instead of just going all out, they step back and they focus on building up their ability to obtain resources. So things like education, things like health and fitness, those kinds of things, which are a way of managing risk down the road, but not something that you're you would say is like an you're trying to achieve an immediate solution to the to the issue. So I think you're always going to get these kinds of interesting nonlinear relationships depending upon something could be like age or it could be other kinds of factors.

Um depending on the demand. Is that related to sort of like niche? I mean we we talked uh also about that like Patrick Durkey about you kind of look out in the world and you say, How can I make my living? This is also David's point about like choosing a status scheme. Um, is that related to this too? Where, you know, if you're in a higher density place, there may be more I mean, there's some evidence that, you know, with more with more density, essentially social capital. If you're in a place with higher social capital, there's more opportunities for different ways of making a living, maybe? I don't know. Yeah. I think so. Yeah. I think um, and I don't know how true this is just under general high levels of

competition, but I think in these situations, I think you would expect that it's uh you could try to go all in and take risks to outcompete the entire crowd, or you could break off and create new ditches um and try to specialize essentially uh in ways that it's easier, essentially it's the you know, the big fish in the small pond kind of approach. Um and so yeah, I think that that fits very well with that idea. It's not straightforward. It's quite complicated as you as you as you put it, because I mean if if your higher resource or your higher density, it might also be that externalities of lots of people around mean that there's roughly speaking more resources. So you don't have to discount the future.

Right. Um, so it is quite, I mean, it's it it as you're saying, it's not top of the mind, but it really suggests that there's these very smart systems that are detecting features in the world that we're not conscious of and they're having these weird effects. And it's it's weird. I mean, weird precisely in the sense of it's not intuitive, but it might be things like should I discount the future? Is the density such that I should or not? Or it affords delaying things. I mean, the even what those inputs are is not straightforward. Yeah, I mean, I think it is an incredibly complex problem. And it's it shows that you know we're not just paying attention to one particular type of input. But at the same time, there are people that make mistakes uh with these kinds of this this

complex decision making. Um, and they might go off down a path where things are not as beneficial to them. Uh, but it I think it just points to this idea that there's this a lot of machinery that's involved to have to have to manage all the variety of inputs that are there. Yeah. David, go ahead. Yeah. Uh so I'm curious, do you think the mind has systems for representing features of the ecology like sex ratio or population density, and that affects behavior? Or is it another possibility I can think of is that the mind isn't actually representing these features of the population. It's just looking at, you know, what's best for me, what are my options here right now. Like if the sex ratio is male biased, for example, I might not have a representation of

that fact. I might just be aware of the fact that, hey, uh, there aren't a lot of women who are interested in me. Uh most of the women are taken. Uh there are a lot of men out there who are also looking for relationships and they're pretty competitive. Like, uh, I don't know what I'm gonna do here. I better, you know, change my strategy, right? Uh and and I can do that without knowing that the sex ratio is male biased, right? Um, in the same way, you know, if I'm in a really population-dense area, I don't need to know. I I my mind doesn't need to calculate the population density of that area. I could just be aware of the fact that, hey, there aren't really a lot of opportunities for me to stand out or gain status.

And I have a lot of competitors who also want those limited positions of power or those limited jobs or or whatever. And uh, I better change the way I behave to really make sure I get those limited opportunities. And so do you view it as more just looking at at what is best for me in terms of my individual situation, or is the mind actually representing these population level variables? My take on it is probably the former, that it's it's not that people have some kind of holistic representation of each of these dimensions. I think that would be difficult for in a lot of situations for people to do, right? I mean, there are there are maybe some modern uh technologies that help people do this today.

If you're thinking about like an online dating pool, maybe people look up data on these kinds of questions. Yeah. But I think in general, um, it's really what you're exposed to and who you're seeing or around you. And um yeah, I don't think that it's I think these are just kind of convenient ways of carving up the the research space. Uh and but really it's about that that exposure that people have and like what their experiences are on the ground rather than that that that bigger uh representation. Yeah. I like that too, because I mean, like in behavioral ecology, so like Hannah Coco had some work on like the asymmetric or of attrition where there's decision thresholds for continuing or withdrawing from conflict.

And she had a paper that was amazing where she argued that there might even be tuning of that for an organism based on how often it encounters conflict. So it's a really nice example of this middle thing where it's it's sort of it's a consequence of the ecology or the population. But it's still this thing that David's pointing out, which is still it's sort of the local experience of how when I'm just motoring around in the world, how often as a squirrel do I see other squirrels fighting? How often do squirrels fight me? And that is a function of lots of population or or ecological level things, but the squirrel can't, you know, fly a drone to find out or like, you know, work with the local wildlife biologist to find out like what's the holding capacity of the of the land

I'm in. So it's got to use these on-the-ground cues. So I really like that, that even the description of the population density still requires this cue-based middle ground. Yeah. Yeah. And I think that if you think about the wide array of uh ecological factors that are really existing out there, right? It's like, am I as a squirrel or as a human, am I understanding like a long history of seasonal rainfall that's going to affect things? Or do I have to create, let's say, technologies to track that if I really care about it? Is it something that is just in my mind is designed to like track, or is it just whatever the, you know, the the current rainfall is is going to predict what I'm going to be doing

over the next season something like that. Yeah. Although I will say on the uh counter to what I'm saying also there are like well plants, you know, they have the variability in rainfall or season or temperature, they actually account for that to make good blooming decisions. So they actually do um aggregate um so it's not if you're too I I forget the statistical if you basically overfit or if you if you're too sensitive you can make the wrong decision and you actually want to aggregate over some noise because you know if it's spring maybe there's one warm day and if you just have a simple mechanism you bloom and then you freeze the next day. But if you average across some of the variability that's a smarter um system.

So so even plants, for example, have in their uh mRNA the ability to sort of track aggregate um temperature, for example. Yeah. So there's probably this like this this window and which uh or to subtract. And when I was talking about birds and and egg laying, they do the same thing in terms of a you know, a few seasons in terms of what the egg cache number should be, how you know how much to invest in a lot, just a single egg versus a few, those kind of things. And but it's a sh it's a short window. Yeah. Um, for um for sex ratio things, you mentioned they're shorter term things. So like, you know, uh anecdotally, like when a bunch of guys get together, typically, I mean, depending on, you know, what their what their status schemes are and what their, you

know, uh uh yeah, did their personal histories are. You know, a group of guys getting together versus a mixed sex group versus a bunch of women getting together, um, which I've never been because I'm, you know, not a woman, but you know, anecdotally or I I've been told, um, you know, typically these things are different. Do you think that really short time frame is that a sex ratio thing in the same way? Or is it just that, you know, the the the kind of way that we affiliate or the status games we play or what what counts as status or what's acceptable behavior um just changes real time? Like how have you thought about that? You know, because I'm sure there's studies where like you get five guys in a room and all

of a sudden they're more competitive. Does that is that analogize to like you have a high male ratio population where that's just a permanent feature when kids are growing up till the time they're 16, like that seems like a different situation. Yeah. Yeah, I agree. And I think in the sort of how uh how this type of work has progressed, I think there has been at least up until a point, uh, this idea that these really temporary changes are reflective of these longer scale uh behaviors. And I think, you know, this kind of just relates to a lot of the the uh I guess the meta science uh on on priming type work uh and so on. And so I think that people are a lot more hesitant to think that, okay, maybe these

short-term changes. And I and I know in the work that that we've done, those short-term effects are much less reliable than the ones that are associated with either individual differences or long, long time periods of exposure to environments. And so whether those are really reflective of something like the the sex ratio of a place you've been in for a a substantial period of time, I'm I'm less convinced about that. I think it's more these social dynamics that just might pop into play. Um and yeah so I would I would definitely not want to go out in the limb and say that uh yeah these short term things are um producing the same kinds of of calculations as the long term ones. Yeah. Which makes sense.

I mean as a uh evolved system that would that would make sense. It would make sense to have contingency based on who you're interacting with, right? Like just even the individual identity you interact with, if it's somebody different, you pull up what you know about them versus them. That makes sense. That's a real-time quick change. But yeah, that would be different than you know, um, the lifetime's experience. Yeah. Yeah, exactly. Exactly. And I think, you know, just in terms of like these groups of guys and groups of women that get together, um, throw out these social dynamics, whether it's the status competition or whether it's just um who else is around, right? If you're, you know, if it's just the guys who are by themselves versus guys in the room

with groups of women, you got different things going on there. Yeah, yeah. And and beyond sex too, right? Like a bunch of like 10-year-olds versus uh 16-year-olds versus 80-year-olds, a bunch of academics versus a bunch of firefighters versus a bunch of people sports fans. It's all different. Yeah, yeah. Right. Yeah. Absolutely. Um are you are you a fan of uh reality TV? Josh? I am not so edit this up. I feel like this is a test of an individual difference. Um I'm not so much. I my wife got me into Survivor. So I've watched quite a bit of Survivor. Nice. I am as well. I'm very much into it. And so I do like that. Um, but most reality TV, not so much. Um there was a period of time in in grad school where I was doing some work in the space of

romantic interactions, including on things like how people use groups of uh of same-sex others like friends to navigate some of the romantic goals that are out there. And I was doing a little bit of um work interacting with or consulting with one of one particular reality TV show. But um aside from that, you know It's a little too I think scripted, I think, than uh for me. That is fair. That is fair. Uh I do recommend Survivor for everyone listening in terms of just understanding the psychology of alliances. It's just it's one big alliance game. Uh and there's no better source of data for how humans make alliance decisions than just watching Survivor. Um in my sponsored by who does Survivor's MBC MBC MBC.

I think there it's on Paramount Plus now. It's been a minute. I'm so yeah. Yeah. Uh any but anyway, the reason I brought it up because is because you know the Bachelor or the Bachelorette is the most extreme possible sex ratio there is. There's one man or one woman and a bunch of different women competing for the man or a bunch of different men competing for the women. Uh and you might naively expect it to be a bloodbath between all the different uh same sex competitors. Uh and you know, there is, you know, obviously some some conflict and some bitterness uh in every season. But what's surprising to me is the deep friendships that form among the same sex competitors, despite the fact that they're literally in zero sum competition, uh you know,

for for the same mate. Um and that to me is is surprising and and kind of hard to explain that th you're in this intense zero sum competition and yet you have a deep friendship with this person that you're competing with. Uh and you know, you in some sense you might be heartbroken if you're, you know, let go, but you might also be happy for your friend that, you know, they ended up with this person. So I I I don't know how to explain that. I I find it very interesting. Yeah, I it's been a very long time since I've done this. But so it was it was the bachelor actually that I was uh working with a little bit about this kind of stuff because we were again doing this work on coalitions and friendship

coalitions and how they navigate how you navigate opposite sex romantic goals uh interactions. Um, and showing that people were not just competitive, right? So they were cooperative with each other. Sometimes they play different roles in terms of who is going to be essentially the lead or the target of the interaction. But it was interesting how, at least from our point of view, how men did it in a certain fashion and women did it in another fashion, both of which were complementary to each other. So it was sort of really directly showing this interface of different kinds of goals that each team in a sense was using. But we didn't go, I think, into the level of depth you're talking about, uh, David, in

terms of like how do people then continue to navigate those relationships uh among their those people who are part of their coalitions. I mean, David, a facile answer would be right, it's like, you know, whether or not you get the guy, you know, he might not be a good fit for you, but a friend is worth a lot too, yeah, if not more. Yeah, totally. Um Uh yeah, no, I just I I find that interesting. Um yeah. Uh so speaking of friendship, I I know you've done a little bit of work on that um a little bit. Uh is is friendship just a kind of fictive kinship, an extension of kinship psychology? Is it something more? How are you thinking of it? uh that's a that's a tough one um so we did a long time ago this was again

grad school uh have this work where we're trying to make a claim that uh men and women treat friendship differently and you might expect given a history of um um interaction among people and and individuals moving between their sort of home bases and their partners, home base in a sense, that you might expect differences in how women and men treat friends, uh, how they conceptualize them, how they interact with them. Um, and finding that women were essentially thinking about friends a little bit more like they were thinking about kin. So whether that's fictive kinship, I don't know that they actually think that there's probably more examples of men using things like fictive kinship terminology, but at least

in terms of the actual patterns of um of behavior, I think we found women were doing that more with their friends, essentially showing closer types of cooperative behaviors uh with friends than men were. Whereas men oftentimes in some of these kinds of game type environments were treating friends like strangers. So that was some of the early, early work we were doing on that. I've only kind of sporadically come back to friendship. It hasn't really been at the at the heart of things, although I was convinced early on by some of the um, I think it was a paper by uh martin and margo so martin daily and margot wilson where they were saying um actually they i think martin might have brought this up in the podcast he was on uh that uh kinship

was really an underrepresented uh type of concept in human psychology research and so was convinced by that, thinking like, we need to have have more of this. And so that was part of the motivation of trying to think, okay, how do people think about friends and kin? And are there is there overlap between these kinds of concepts? Do people think of friends as just fictive kin? Probably not. There's probably a lot of places where that would break down, I think, if people are pushed. To you know, is it the case that you're really going to be inspiring things like incest avoidance mechanisms with friends? Probably not. But yeah, so I I that's as probably as as deep as I can go in answering that particular question.

Um, but I think more recently we've been thinking about friends in terms of the the other kinds of uh dilemmas that they present to people, in terms of the uh both the opportunities and the threats that they uh provide to people. Because we often don't think about friends at the level of threat, although there's always you know competitive interactions that people have and so on but we've married that with things like the infection psychology that people are um are really concentrating on and so the more people you have that you're engaged with the more there's an infection risk possibility there and so we were interested in this question this is with a former grad student uh soyan choi who was really interested in this question of do people

alter or modify their friendship networks as a function of these types of things like infection threat? And they do apparently. Interesting. So what what is how are you measuring an an infection threat? Um so in that work, it was primarily thinking about individual differences in concern around infection. And there's all sorts of this is a sort of a whole other uh project area that uh that some people in our lab but also other labs are interested in these days. How do you measure these kinds of uh these kinds of factors? And some of these measures that exist out there have to do with um how concerned I actually am about infection. Do I pay attention to the idea that I could get sick from other people?

Others are more superficial in a way. That is just do I get grossed out easily? They're more having to do with these sensory inputs that have that are in some sense icky. And so, but these kinds of um these kinds of individual individual differences are what we looked at primarily to think about how people then might construct or construct a friendship network, or maybe even remove people from their friendship networks. So, what is essentially the threshold that we have for who is part of our networks? And we were finding things like the people who are most concerned about infection through these various measures, they tend to have smaller networks, generally speaking. And I think that makes logical sense in terms of just reducing the number of contacts that

you have. Those, that reduction was all happening at the um at the form that the layers of the network that were less close. So it's not like people had, they still had really close friends. They still had best friends to the same degree that people who didn't care about germs did. But they were just sort of not engaging as much with people, at least at a frequent regular level, with people that were just more distant in their in their environment. And that was really interesting, I think, because it could be there's like just sort of the one form of logic you could you could ask about that is um it may be that if I prioritize infection, of course I'm going to interact with with fewer people and I'm going

to be fine with that, right? Because I'm meeting my goal. But it turns out those people who are most concerned about infection who had the smaller networks were unhappy with their network, more so than the people who had the larger networks, because they weren't getting everything else that a you know somebody might get with from their friend. They weren't getting enough social support, they weren't getting enough emotional support, um, tangible support from like you know, what people are actually doing to help you out. And so it really showed the, I guess, the psychological dilemma of this trade-off where people couldn't these people who were really concerned about infection couldn't necessarily bring themselves to to start incorporating more people in their lives,

but also to the detriment of all the other stuff that that exists in life. That's interesting. I mean, uh so you've did you find uh correlations both with disgust sensitivity and with uh germophobia, uh for lack of a better term. So people who are explicitly trying to avoid disease and people who are just more easily grossed out. Both of those things are both predicting a smaller social networks? We did. And one I think was a little bit more reliable. We've this might get into the weeds a little too much, but there's the people who are the researchers who study a lot of this infection psychology work, however they wanted to label that, um, tend to gravitate towards certain measures more than others.

And but it just depends on who's doing the gravitating. Uh, and so we tend to do a little bit more work focusing on things like um the uh concerns that people have, the anxieties that are raised from uh the possibility of infection, whereas disgust sensitivity, I think, is a little bit more of a this kind of like sensory experience of something, there's a trigger that just creates this aversive reaction in me. And so, uh, which other other researchers tend to focus on a little bit more, but we've sometimes married those. And so in some of these studies, we had both of these measures, and we found, I think, a little bit more reliable uh effects with, in terms of everything I've just been talking

about, with something like germ aversion or something where it's a bit a little bit more, I'm gonna say cognitive in terms of how people are thinking about uh the risk of infection. But we still set we still saw the same pattern of effects with discuss sensitivity. Interesting. And I think like I I I imagine, you know, personal incredulity is not a scientific argument. I want to wear a t-shirt like that whenever I get a review. My personal incredulity is. Um, but uh, but let me unpack this because I think people listening might think this, and I want to hear what your response to this is. So the idea is that the more concerned I am about germs, the more I'm going to not extend sort of my zone of frequent interaction with people.

One one question I think people might have, and one question I have is that is it is it that you're restricting how many friends you have because you're worried about getting sick, or is it that if you're in a bad state for for different reasons, like you're you don't have a lot of um resources, you're just I mean different people are just more or less lucky or different paths in life, you might just be in a worse state. And so consequently you're both more worried about disease because compared to everyone else, when I get sick, it hurts me financially, physically more. And because of that, I also just have fewer social connections. So, in other words, um, it's it's the same point where they go together, but it's kind of

they they're combined because of the dynamics of the environment, as opposed to the psychology is sort of tying them together. I'm sure I'm sure you've thought of this. I'm just curious like what that what that is or if both are going on. Yeah. So it correct me if if if I'm characterizing this wrong. So the the first one is really about the the role of the individual who's concerned about this. And the second one is the role of the friends who are like I'm out of here because you're there's too much you're you're taking too much from me or asking too much for me. Uh one that's one way of putting it or even just that uh if I if I'm a low uh I'm gonna just be very like impolitic about this to just put it in like brass tacks

biological sense. If I'm a organism I'm I'm a human agent I have a certain social bargaining power or like what I can offer to the world you know and there's variation in that and if mine is lower it might mean uh that I have fewer resources to deal with problems that come up, including infection. But then it's also going to mean that as I just try out to be accepted by the social world, the degree to which the social world accepts me is just going to be shallower. Like so that's the brass tax way of putting it. Yeah. I think the possibility that somebody who has been chronically worried about infection over long periods of time are is going to develop a different set of strategies of social interaction, or maybe in some sense, maybe a less

complex or less uh well designed for actual social interaction set of strategies. I think that's a really interesting question. Um, not one we we've explored, but I think that would I think it would make a lot of sense. What the the factor that we were able to identify in a way with this was that it seemed to be that the people who are most concerned about infection also had the highest standards for their friends. So they were wanting people that also prioritized concern around infection. And so those people who are really concerned it's going to be more top of mind for them than somebody who's not concerned, right? They're going to be thinking about this at least more regularly. And so these standards were essentially a way of maybe

in inadvertently, but a way of essentially walling off that individual from a lot of opportunities, a lot of social opportunities. Yeah. And so I think it's at least what we found was that's more of that that that individual agent was causing something. Yeah, no, that's great. That would not what you just said would not be predicted by this alternative sort of fewer opportunities. That's really interesting. Is there a is there um do you know what predicts being worried about infection? Hmm that's a big question. Yeah. Uh so there's been um some obvious this is an important question. There's been some work in this space How how reliable I think the data are there, I'm not fully convinced. So I'll give you some some examples.

It does seem to be the case that having a history of infection across development is one of these. And I think that's that makes a lot of sense. That's pretty reasonable, right? And so the more you got sick, the more concerned you are about these things. And it actually that also predicts getting sick less in the future. People have looked at also other kinds of things like, well, what about something a little bit more physiological? Like maybe it's something around how um robust your physiological immune system is. And if that is really, and there's people have had these different models of how this could work. Maybe one is compensatory. So if your um If your immune system is compromised for some reason, you're going to be

really over the top about avoiding sickness cues psychologically. Or maybe they just kind of work together in a complementary way. My take on that literature is that it is just it's too messy to really draw strong conclusions right now. And so there was some really interesting initial work on this from people like Dan Fessler and Carlos Navaret and some other people like that. And then Sarah Hill has done some work in that space too. But I think that part of the issue is that the more that psychologists, I think, have gotten into studying the physiological immune system, The more I think we realize how complicated it is. And so it is there's just a lot of noise and a lot of unknowns about which particular markers of immune functioning we should be looking at.

And so it's, yeah, I I think we're very early in that process. There's still a lot more to be done. So I think that's those are some of the things that people have talked about as predicting this this kind of stuff. But I think there's probably some some other really interesting ones. I mean, obviously there's got to be cultural effects on this, right? There's just cultural differences in discuss sensitivity based on whatever the norms are that are common in those places. But yeah, I mean, I think a whole you could have a whole um body of work on this this very question. Yeah. There's something about this literature that confuses me. I'm hoping you can maybe clear up this confusion for me. So uh the idea is that disgust serves a pathogen avoidance function, and that makes

sense. It explains a lot of data in the discussed literature. Um, But then there's also this separate construct that has been developed, which is like fear of germs, like how consciously, you know, worried you are about getting sick. And disgust and explicit fear of disease are not actually very highly correlated with each other. They seem to be separate things. And also phenomenologically, they feel very different. When you're grossed out, that feels very different than being worried about getting sick. I mean, during COVID, I wasn't really feeling a lot of disgust or being grossed out by things. I was just worried about getting COVID. And I know Josh Tiber has data showing that disgust didn't really change throughout the

pandemic. It was more of this explicit worrying about disease. Um, and so my question would be: why does it seem to be the case that we have these two separate systems that are both phenomenologically distinct and to some extent take in different types of inputs. And yet they serve the same function. Why wouldn't we have just one system? Why wouldn't disgust just be applied to COVID? Right? Like why weren't people more grossed out during COVID? So why do we seem to have these two systems that serve the same function when we could just have one? Yeah, I mean, I think that's a it's a critical question, and one that I think early on there was some theorizing about this. I think there are people who are taking this more seriously now.

So I have a grad student who's working on something related to this. And I know there's some other uh labs that are doing some more trying to sort of pit these systems or models against each other and ask what is the what is the reason for this? And I think one of the explanations that I think makes a lot of sense is from Mark Schaller, who's uh big in the space. And he talked about this idea of a differentiation between reactive responses and proactive responses. And so disgust is a reactive system, right? You it's very difficult to get yourself to feel disgust, absent cues. Right. I can't just, unless I'm thinking about a cue in a really sort of very embodied way, then it's going to be really difficult for me to experience disgust.

But these proactive responses could help to, in some sense, prevent the disgust response in the first place, but really help me manage the situations that I engage with and the ways in which those various infection type of threats uh that are out there might be mitigated when there aren't cues that are relevant to the disgust system, right? So COVID is a great example because early on, um, there just weren't a lot of sensory cues that people were exhibiting that would trigger disgust. And so, in fact, if you think about diseases that are often spread um sort pre-symptomatically, which is a lot of them, there are no cues at all. And so unless you're taking in information from other sources, then you're just leaving

yourself exposed to that. Now that idea brings with it a lot of interesting implications. So that more proactive system is likely to have more be shaped more by cultural evolutionary forces. It's likely to be historically, I would assume historically less old. Depending on I think that some of the original, some of the work at least by some of the original people in psychology undiscussed, was really grounding that in the uh the the role of food, not actually a person to person interactions. So how do we avoid certain foods? They're going to make us sick. Obviously, that's a problem we've faced for for a very long period of time. Whereas things like communicable diseases between groups of people were

likely very rare up until a particular period in our history where we're able to maintain denser populations, right? Beyond that, we were before that, we were really getting sick from things like foods or animal transmission, where there are probably going to be or disgust related cues. And so I would say that the, at least my take on it is that this precautionary system, the prospective system, is probably more evolutionary novel to some extent, but it's still likely to be shaped by these forces. Like if I'm somebody who's chronically concerned about germs, I'm avoiding certain kinds of situations, even though I can't detect, I don't really know that there's an infection threat there. If there is, I'm safe, other people are not.

And so over time, you could imagine that there is uh the evolution of this kind of a system as well. Great response. Um that cleared up a lot of confusion on on my end. Um I wanted to ask you uh about the relationship between the behavioral immune system and um avoidance of outgroups or attitudes toward outgroups. I know we talked to Josh Tiber about this, um, and he expressed some skepticism about this hypothesis. Uh I'd like to get your take on this, whether whether you share that skepticism or whether you're more sympathetic to the idea and what you think the state of the evidence is there. Yeah. Um also a one of these topic areas that people have started to revisit, like Josh Tiber, to ask questions, which I think are really important ones, about um how

um careful, I guess, have we been about making predictions in this space? And I think, I mean, you can think about this in any kind of research space, where as soon as the topic area becomes popular in some sense, people make predictions about all sorts of things. Just how far can we push the boundaries of this idea? And then I think there's some scaling back and saying we went too far and so on. So when it comes to out groups, um I do agree with Josh uh Tiber that the types of interactions that really matter for presenting infection threats are probably going to be those in which people you're engaging with people who are practicing different kinds of behavioral X, cultural traditions, things that are

likely to essentially not have culturally evolved to prevent infection in the environment that you are in, right? Because different types of bacterial and even viral threats that exist in an ecology and cultures have developed in many ways, uh, many places, ways of at least minimizing some of that danger if you engage in the right kinds of acts for that location. So somebody who is an outsider who's bringing in new norms, new practices, That person is going to present a potential risk because they're not doing the behaviors that minimize that infection. So I think that makes a lot of sense. So it's like a particular type of outgroup number. Um, I think as a superficial feature of difference and a potential threat, I I do still believe that there's some

um Reaction, some essentially a cue. This is still a cue that I think people are reactive to to some extent. When there's any given threat that that is uh existing there. So that could be an infection threat. It could be another kind of threat. So I don't think it's outgroups are specific, like outgroup threat is specifically tied to infection. Oh sorry, David, go ahead. I mean, could it just be an extension of this social network idea that you're, you know, more restrictive about uh the people you spend time with more choosy and you're uh and you're less willing to have a you know a larger social network which could include quote unquote outgroups, uh but doesn't necessarily have to. Yeah, absolutely.

I mean, I think that that makes a lot of sense. Um so your if your standards are higher, that means that anybody who's you know not meeting those standards is going to be treated uh as somebody uh you need to be more cautious around, you're to keep them at a distance. And that could in some cases end up looking like prejudice, uh, depending upon what the kind of measure is that you're that you're looking at. So I think that makes a lot of sense. And I think um we see that a lot when it comes to large-scale events like COVID, where there are there can be these really explicit outgroup prejudices that emerge, right? Whether it's really a function of being prejudiced to all outgrowths, I don't think that's

necessarily the case, but it is probably an outgrowth of that same kind of a system. And and and at the same time, disgust uh and disease fears can be very profitably mobilized by political entrepreneurs and used uh to to to generate uh you know opposition to a particular group. Uh exactly. And there's a long history of using language uh to trigger disgust and create those kinds of um Barriers or conflicts with other groups. Yeah. I think one way of putting maybe how I'm hearing the answer to Josh is that, or one version of the hypothesis is that of all the group boundaries, when a group boundary involves differences in practices that evoke disgust or different hygiene practices. So if I'm in a culture and I go somewhere and everybody is even cleaner and and more

hygienic than me, I'm gonna notice that. And like I've crossed a norm, a culture boundary of hygiene, or like conversely, if it's less right. And so, I mean, thinking like Borat, like, you know, the humor of uh doing uh, you know, like bodily functions or cleaning differently, you know, like that really stands out. And so I I I one version of this hypothesis is that there's lots of group boundaries, but there's a particular noticing of the system when you cross any behavior that activates this sort of pathogen or hygiene practice or this open entry for like infection risk. And then that really that that's that's a very strong um detector that really draws that boundary in a unique way. It's sort of saying we're crossing a hygiene boundary.

And then as you said, that because that's true, then you can have demagogues using it to really reinforce a group boundary as well. Yeah. And I think something that's interesting with that idea is that people don't have a ready or at least a a um I will say evolved, I don't not gonna rest on that word, but uh evolved um understanding of what a good hygiene practice is. No, totally, yeah. Right? Yeah, and so you could have a group of people who is engaging in a behavior that's actually better than the one that your group is using to prevent infection, and you still might treat that as a problem. Yeah. So think about like mask wearing prior to COVID, right? That was often treated as some sort of weird thing that people did.

And even post-COVID, like even uh as COVID started, it was like, why? Why are we what's going on here? And so um even though though it's an effective strategy, uh people can still react negatively and and it's a useful one for, like you were saying, those demagogues to to leverage. Yeah. I think uh all the anthropologists listening are like thinking of all the examples in ethnographic history of colonialists going to a native population that had culturally evolved a really good way of making the living there. And then being like, no, that's the wrong way to do it, because in England we do it this way. And then it's a terrible idea and people die and get diseases or like it doesn't work. So yeah, no, totally like the the the sort of um the uh uh

parochialism of the way we do things is the right way everywhere uh is a very human thing to do. Exactly. Yeah, it is. And I guess that's suggesting that there's some ecological insensitivity that the events No. I mean there's a kernel of truth to that, which is as you said, like I think something Rob Boyd always said that it really stuck with me is that the world is opaque, right? Like we don't have a germ theory like until very recently. So there's this open slot for it seems like magic. We kind of do this thing, and it's like this proactive thing, right? It's like, you know, it's like we do this thing and somehow it keeps the spirits away. Or we're we're maybe dying less, but we don't know, you know.

So it's a really hard thing to get right, these like opaque things in the world. And that's why you get all these hitchhiking things of rituals um or spirit accusations, right? Um the this this open entry, like you said, this proactive thing it reminds me of Pascal Boe's work too about sort of like precautionary stuff with this issue of being precautionary about infections really hard to get right you know if you're not if you don't have like a lab to test pathogens and even that like that's not so reliable either. Yeah and you can't even rely on the cues of infection because they're so variable. Even within person the same disease could present differently different ways. So you just kind of have to gloss over a lot of those uh

things we can't really understand very well. Yeah. And in a in a world where there are lots of false positives because of you know error management logic where people are assumed to be unclean or unhygienic or impure or contamination risk for whatever reason, even though they're perfectly fine, you know, that itself can become a selection pressure. If that is a dynamic that exists in your social world where you run this risk of being perceived by others as a contamination risk or unclean or uh unhygienic, then you might have to actively perform certain rituals or send certain signals to minimize that risk that you're going to be uh excluded and and uh ganged up on and or treated as a as a pariah.

And you might want to, you know, incur lots of costs to really signal to people that um you're not a contamination risk. Yeah. I think that's a that's an excellent point, David. And it's really um we didn't set this up in advance, but that's that's sort of the direction that uh some of my work is going in these days. Oh, cool. Is um really interested in that question of how people manage those kinds of trade-offs or those kinds of dilemmas that they have uh with respect to this, you know, how they're going to be treated by other people, how they're going to manage uh the risks that they're seeing around infection versus versus social life, um, and then what are the strategies that people are taking to do that, right?

So are they having to go far in one direction in terms of showing something about themselves? Are they hiding cues to that that are gonna that could be used to ostracize them, those kinds of things? All right. Well, we're we're starting to to get up uh to uh a long time uh in this conversation so I mean I I think it might be s time to start zooming out a a little bit and um moving toward uh if there are any topics that you uh wish we had gotten to or any things that you're really excited about right now that that you'd love to delve into. Um is there anything Yeah. Um so I would say that one of the arms of work in this space that we've been doing for the past few years, um I I just think it's really a fun topic.

I I always hesitate to say fun when we're talking about sickness, but it's fun for me. Uh and is is one of the ways in which people manage these kinds of uh dilemmas or trade-offs, and that is through concealment of sickness. And so we've been doing a lot of our uh the work that I was doing early on in this space was more about kind of fitting in the behavioral immune system literature, really about how do we prevent infection. We've been doing a lot more about post infection psychology. So once you get sick, what do you what do you do about that? And uh specifically around social life. And so we have this whole series of projects where we're thinking about this idea that people hide signs of illness from others

because they are concerned about the reactions of other people, right? I don't want to trigger somebody else's behavioral immune system such that they're now going to react negatively to me, want to avoid me, you know, not allow me to engage in in social life in other ways. And so we were approaching that from the question of okay, there's lots of things that people could do to sort of alleviate that. But the the easiest, it's not in some ways, it would be to just not trigger those reactions in the first place. And so we have been studying that and uh asking people about how they uh engage in social life when they're sick. Uh and uh maybe good for us, bad for everybody else. Um, this is a really common behavior that that uh yeah people engage in.

That's super important. I mean, that's so useful to know because again, that's like another thing where like if I wear a mask, then everybody knows I'm sick, but then I could prevent people. But I but you want to that deal with that psychology. I love this idea, like the self-conscious emotions dealing with infection. You would imagine there's this this huge um thing. That's awesome that you're doing that. Yeah. Yeah. It's been really interesting. I'm sorry. I mean, I I would I would imagine that um anger or anticipated anger is also at play uh in addition to concerns about being the object of disgust or contamination fear. And that, you know, if I'm putting someone at risk of being sick, I'm inflicting a cost on

them uh for a particularly small benefit, just so I can have the pleasure of, you know, hanging out or being outside or or whatever. I'm you know, I'm inflicting cost on them for a comparatively low benefit to myself, Uh, and that could trigger anger. It could signal that I have a low welfare trade-off ratio toward other people. I'm not very concerned about other people and and their well being. And I might anticipate that and hide the fact that I'm sick to avoid eliciting other people's anger. It's sort of like I'm getting away with a a transgression of of putting people at at risk. So I I bet that is a part of it as well. So I can speak a little bit to that. Um where we've we so we've tried to collect data on the reasons that people give us, at

least for why they do these things. And what we've found so far, which I think so I had the same intuition that uh that you did. Um what we found so far in terms of the reasons that people give for why they would hide illness, this is specifically in face-to-face social interactions. There's about 20% of people that we've talked to say they do it specifically to avoid those reactions from other people. But it's only 20%. And there's some other reasons that seem to dominate this much more. In fact, when I when I tell people, like why would you engage in in social life when you're sick? The number one thing that people seem to to respond with is, well, if I'm thinking about like going to work when I'm sick, or if I'm a student going to class when I'm sick, it's

because I have to, right? It's because I don't have adequate sick leave or I have the, you know, there's a policies in place. But really, that one is also not uh leading the pack. That's only five percent of people. The majority of the reason why people say they do this is a combination of feeling like they are, they would burden other people. So if like if I I'm going to go to work when I'm sick because other people would have to take my work on if I wasn't there. And equally as strongly is basically just, I think, FOMO. They are just prioritizing their own goals. They don't want to stay home. They don't want, they don't, it's it's less about the reactions of other people. It's more about like my goals are what matter.

And that is a that is both in some ways maybe an expected uh uh behavior, but also a tough one to really deal with, right? Um it's and so I'm not saying that that I don't that that people are not worried about the anger of other people or the welfare trade-offs that they're they're expecting, um, that other people might calculate about them, but at least in terms of their top of mind explanations, it's really they're just prioritizing their own goals to some extent over those of other people. And we get that, I mean, I think that where that anger and concern for others would would probably rest is in when you have a pre-existing close relationship with other people. So we do see that people do this less with close others.

But there's a lot of places where they do it. They do it a lot, this kind of hiding behavior. And I think it was really interesting to find that it's really, as far as we can tell, so right now, it's really about this goal prioritization where it's just like either I'm just gonna go after my own goals, and it's partly it's because people believe that uh that it's everyone's gonna get sick. And so if you're out in the world and you get sick, maybe it's my fault, but you know, people can't see germs. So maybe you got to see somebody else. So there's some plausible deniability there. And it's like, oh, you're going into social life, you're, you're running the risk yourself. You know, you're interacting with me, uh, whether I'm sick or not.

And so you're just putting yourself out there as a possible infection target. And so I think there's a lot of ways that people can sort of navigate that that those those cognitions around that sounds like a rationalization. I think I think what we need to do is we need to get this subset of your population, Josh, that does this. And we need the David to sit down with them and explain to them. I feel like there's a there's an intervention for it. Yeah. Okay. So this the subset uh of people who actually hide illness in in our studies so far has been 75% of people. Yeah. Wow. And that included, we did some studies during COVID with healthcare workers, and that included people who work in hospital systems.

Um, and it was less, but it was still over 50% of people. And we have some recent data, like people we were presenting with some of this. A lot of this work has been led by by graduate students. I should shout out Wilson Merrill as being a lead on some of this work. Um he was doing some presentations, uh, he's a post hoc in Denmark right now with people in Europe, and they kept saying, Oh, it's an American thing, because Americans are just you know self-interested, and so we've done some international data collection, and the US is actually at the low end, one of the least frequent countries doing this behavior. So um it seems to be really common, seems to be really prevalent, and uh yeah, and it does seem to be the biggest predictor we found, I think, is exclusion concern.

So people who are worried about those those negative reactions from in terms of ostracism. I hope you're getting a tremendous amount of funding for this because like getting sick and illness is a huge uh uh harm to everybody. I mean, forget about a you know, they're just just yeah, like missing school, missing loved ones, missing social interaction. Uh I hope you're getting a lot of funding for this. They're laughs I just environment I'm not sure. Yeah, but this is super incredibly important. I mean, just yeah, this this idea that like missing out um is why uh people are getting each other sick is it makes sense, but it's it's it feels like there would be a way around all of this. Um yeah. Yeah, yeah.

Can you try an intervention where you just record me just yelling at these people? I really want to get this Tony. Yeah, this you self-entitled. Yeah, no, exactly. Yeah. Yeah. I actually one question is this is this what is the population? Is it is it undergrads at a convenience sample? Not as a duck uh a knock on it. I'm just curious, like what is the are these people with kids or not, or old people? Yeah. Right. So the first group of studies where we looked at this was a combination of undergrads. We we did some online samples with different different platforms. We did the healthcare workers. Um since then, we've been mostly doing various online platforms. Um international study was um with this platform that does a lot of different countries

around the world, focusing a lot of it on non weird uh uh populations. And so most of it is people, I would say, who are adults, you know, ranging from, you know, I think the average age is like 35 to 40. So I, you know, we haven't actually looked at the kids' question yet. Yeah. That is definitely an important one. But we've we have not explored it yet. So I think it would be um interesting to see what happens there. Anecdotally, we've been told many times that um people do this for their kids. So you know there's always the the question of kid like kids saying, oh, I'm sick mom, I don't want to go to school. But if your kids are young and you want to put them in daycare and go to work and they're sick, well now you're faced with that dilemma of like, do I hide

illness on the part of my child? Yeah. And we've been told that parents are not uncommonly doing that. Yeah. Yeah. Uh have you found any correlates of you said you looked at this in a bunch of different countries. Is there something that predicts the likelihood with which people are are um going to hide their disease cues? So I hope so. But what's really interesting uh in in where we've looked so far, we have found no country level factor that predicts this. Wow. Interesting. Not even collectivism or anything like that. I would expect naively expect that to be the case. No. Yeah, I know. We had a lot of predictions about these things, and we have found nothing so far. We have found individual level predictors that that have come within each country.

So exclusion concern is the biggest. Um, I think followed by psychopathy. Uh and that makes sense. All right. Yeah, that's that's I'm gonna include that. That's a group that David needs to talk to. That's yeah, I don't care. Get me all the psychopaths. It's opaque. Exactly. Yeah. Uh the last one is this is this disease avoidance motivation that people like. So if you're more concerned about illness yourself, like you're somebody who's germ averse or whatever, um, it turns out you actually are more pro-social in a sense. You hide it less from other people when you do miss it. So I think that's an interesting sort of benefit, I guess, to being um a little bit more, you know, uh germ concerned. Well it's yeah, it suggests that you know you perceive disease as a higher cost.

And presumably, you know, if it's a higher cost to you, then you translate that as a higher cost to other people and you're less willing to inflict those costs on them. Yeah. So long as you're not a sociopath or psychopath. Yeah. Yeah. Exactly. So I'll just mention one other project that's related to this that the sociopath thing triggers. But I it can't be all sociopaths in these samples. So what we've looked at also is not just the individual decision makers' behavior once you're sick, but third-party evaluations of this behavior. And so does this influence the judgments that you have about people engaging in this? Like, does it change your perception of their moral character or something like that?

Because they're being deceptive. Um, and what's really interesting is the answer is only sometimes. There are certain situations where most people excuse this behavior, Not just the person who's doing it, but like the observers. They're like, yeah, it doesn't change my judgment of them because it's something like if they're going to work or they're having to go to an obligation, I expect them to hide it. Yeah. Um, which is weird, right? Yeah, I think you, if you really cared about this stuff, you should expect them to admit to it and still do it. But I guess that they're the calculation is that if they did that, they would be somehow prevented from um engaging in that that behavioral I mean that suggests that,

you know, in order to avoid inflicting the cost on you, I would have to inflict an even bigger cost by like missing work when I'm really financially strapped or or missing, you know, important social obligation like missing that would be a huge cost to me and it it seems reasonable that we wouldn't expect people to incur those costs. Yeah. And so it doesn't translate into um any kind of knock on your your character, your moral your moral character. Yeah. It's a common knowledge problem. David, this is another thing you got to get on the common knowledge pathogen avoidance. So like is the chef going to wear like a mask and be like I have a cold and everybody thinks that's fine. You you know nobody's gonna knock the chef, but ideally uh everyone would have a norm of

well, if he has to work, he should do that. But there's not common knowledge. So we wouldn't we wouldn't expect the chef to do that because we know the chef would know that everyone would be think that's terrible. And what are you gonna do? I keep thinking of yeah, yeah. I keep thinking about the somebody just being like, excuse me, while I sneeze on your baby. This is Um I I I had one last question about this that that occurred to me. I'm curious about. It seems like um the psychology of um hiding a contagious temporary illness um is going to be very different from the psychology of hiding a chronic and a potentially uh non-contagious illness. And the reasons for doing so might be very different in in either of these cases.

Have you looked at at the different types of illnesses uh or or or and how that might be a factor here. Yeah. We have um not looked at comparisons with chronic illness, but we've looked at comparisons with uh hiding other types of information. So like um the chronic illnesses, I think the the major reason this these have been studied a fair amount. Uh the major reason people hide those is because they're anticipating some type of stigma to result. And but there's other types of information, people do this also because of the the stigma concern. So hiding something about your identity could be like sexual orientation, it could be like criminal history, it could be all sorts of things. We have done those comparisons and we find that people

who do, who are, who are hiding the contagious illnesses, they do anticipate some type of stigma associated with that. But even over and above that, they are still likely to engage in that behavior. So it I think that it is an appropriate comparison to make with something like chronic illness or identity concealment. But the major difference is those don't create the potential for direct harm. There's no transmitted harm just from interacting with somebody. Even if the deception was not uncovered, you still can have harm that results from that. And I think that's what makes this contagious illness concealment interesting. Cool. All right, Josh. I mean, this was a really fun conversation. I had a great time chatting with you.

I enjoyed it. Yeah, this is fun. Yeah. All right. Um yeah. And thank you for coming on. And yes, please, uh, if you are sick, uh what can we can we end on a PSA? If you're sick, what do you recommend people do? Like watch reality TV so they don't feel FOMO. Like can we wrap us all up in a watch survivor? Yeah. I probably shouldn't have mentioned that thing about people excusing it. Uh no, it's good. That's not helpful. No, it's it it reality is we should always accept the data and deal with the data. Yeah. Right. I would say just admit to it or prepare to be yelled at by David. Yeah, I I will find you. I will find you. Wear a mask. Wear a mask. Or, you know, just be on like if you're you have a social thing, just like tell your

friends that, you know, you have a cold and you know, if if if you don't want to risk getting sick, then you you understand. But if you know, leave put it in their hands. Like let them, you know, have the the full information and make an informed decision. Yeah. Everybody gets sick and there's always other stuff that's gonna happen. If you miss this one thing, so whatever. Yeah. Yeah, exactly. All right. Josh, that was awesome. Thank you so much. Okay. Great. Great to talk to you both. Uh David, do we think we still need to be doing these outros? I mean we're here anyway, so we should say something. Yeah, we we should say something. I really do like your um uh your song The Oh the this the music?

Can I ask you? It's called, can I tell people what it's called? Sure. It's Manafort. What is that? Uh it was totally random. I think I might have been like watching a documentary where Paul Manafort was mentioned and it was just on my head and I needed a title swift for it. It's a great, it's a great, it's a it's perfect. I love it. But in case you're wondering, it's called Manafort. Yeah. Yes. Um again not not enough Glockenspiel. Um David, what should we do in this uh outro other than remind people to um make comments? That's not the verb. Produce comments, excrete comments. That was a very excited, yeah. Yeah. Uh comment, like, uh subscribe. Yeah. Uh say nice things on social media. Patreon.

Uh Patreon. We do have a Patreon, yes. Yeah. We do. Has anyone we have? Yeah. Yeah. It's just it's just yeah. We I sh yeah we there we do. I mean we should actually figure out what we're gonna do with with those ten cents. But yes we do. Oh, all right. Yeah. Hmm. What can we spend that money on? Maybe we'll enjoy a a Snickers bar. Uh I was gonna say we could support a graduate a graduate student for a summer or something, you know, two people on MTurk. Or we can uh we can advertise the podcast to m we can we should advertise shorts um on YouTube and then because we do no advertising. That's true. So yeah maybe we could put that that money into some ads for yeah and then grow the grow the thing like a pyramid screen.

Um one of the comments people gave uh somebody was listening to one of the episodes on YouTube and they said, Oh, you guys could get a lot more hits and views if you had gotten on this like bandwagon cultural thing. I don't know. I'm just, you know, whatever. Um, it was something I think it was like the Colton Scrivener episode where they said, You you guys could have had a lot more. It was a great episode, and you guys could have had a lot more views if you had gotten on this, like, you know, people watching horror movie reaction bandwagon, if you had got on this. And I was just thinking, like, that assumes we uh what band the movie reaction band? What? You know how there's like YouTube videos of people like playing video games and people

watch people playing video games and I think it's like that where you like react to horror movies. I have no idea. I I I I only spent about four seconds looking into this. People watching people watching horror movies. Correct, correct. Which is actually kind of interesting. That is a recursive for sure. Okay. Um, yeah. So number one, that exists. Number two, this commentator on YouTube said if we had gotten into this, I guess, um uh we could have gotten a lot more views and likes. And so if we watched movies and videotaped us watching movies, I don't know. I don't know how we were gonna get out on the ground floor of the people watching people watching horror. I don't know. Maybe we can ask them what they meant.

Yeah, I think we need some clarification. Some guidance and how but what at my point in saying bringing the whole stuff is it assumes that we want to be like a viral podcast. Where we want more views. It assumes that. And I I don't know that's true. Yeah. I mean it's a reasonable assumption to make that you know we wouldn't want something. But I would I would poke on that like the idea that like numbers are what counts. Like if I I don't maybe this is a justification for not um being more Yeah, it sounds sounds like rationalization I I don't know, man. I I this is this thing of like I I I really question this modern assumption that like everything should be like entertaining and everybody should be putting content up for the

point of having as many people like it as possible. Maybe it's the um it it feels like very hollow to me. Like the point is you present stuff that you care about and that you're happy people are engaged with, but there's always a higher number, you know? That's true. Like what yeah, what hole in your soul are you trying to fill by having more people like your stuff? Yeah, that to I mean, I I totally get that. Yeah, I I don't you know, we don't need to have a massive following. Uh but at the same time. mom, I'm talking to you, Mom. You gotta listen. If you've got a neighbor, go knock on their door. No, I mean I I'm with you that we don't want to be too we don't want to water down um the science or or be too flashy.

Uh um but at the same time, numbers matter in the sense that we don't want it to be zero, in which case it would not be worth doing. No, that's they matter in the sense that it would be nice to have more a bigger audience. I wouldn't I wouldn't uh complain. Uh I'll have to think about that. But I appreciate if you're listening now, and especially if you're getting to the end of this nonsense. Thank you for listening. Uh David, this was really fun. Um, I'll see you next week. Next week we'll have another normal episode with a guest, I assume. Sounds good. Yeah. Uh good. All right. Thank you everybody for listening. And uh hey, your two. Ponton Pontin Do Pontum Pan Pontan Do Penton Ponton Pont Ponton Pon Ponton Do Pont Pontum

Pontan Do Pont Punning