Modern Wisdom - #632 - Ed Hagen - The Evolutionary Psychology Of Anxiety & Depression

Episode Date: May 25, 2023

Ed Hagen is an evolutionary anthropologist, Professor at Washington State University, a researcher and an author. Low mood, depression and anxiety are states we will all become familiar with at some point in our lives. But why did evolution create a creature that is able to contemplate so much complexity that sometimes it suffers psychologically? Why are we wired to feel this way and how are we able to pull ourselves out? Expect to learn the evolutionary reason why humans get depressed, how postpartum depression is adaptive, why being strong can lower your chances of depression, how evolutionary theory can improve all of medicine, why women are so much more depressed on average than men, why humans are even capable of suicide and much more... Sponsors: Get the Whoop 4.0 for free and get your first month for free at http://join.whoop.com/modernwisdom (discount automatically applied) Get a Free Sample Pack of all LMNT Flavours with your first box at https://www.drinklmnt.com/modernwisdom (automatically applied at checkout) Get 83% discount & 3 months free from Surfshark VPN at https://surfshark.deals/MODERNWISDOM (use code MODERNWISDOM) Extra Stuff: Follow Ed on Twitter - https://twitter.com/ed_hagen  Get my free Reading List of 100 books to read before you die → https://chriswillx.com/books/ To support me on Patreon (thank you): https://www.patreon.com/modernwisdom - Get in touch. Instagram: https://www.instagram.com/chriswillx Twitter: https://www.twitter.com/chriswillx YouTube: https://www.youtube.com/modernwisdompodcast Email: https://chriswillx.com/contact/  Learn more about your ad choices. Visit megaphone.fm/adchoices

Hello friends, welcome back to the show. My guest today is Ed Hagen. He's an evolutionary anthropologist, professor at Washington State University, a researcher, and an author. Low mood, depression, and anxiety are states we will all become familiar with at some point in our lives. But why did evolution create a creature that is able to contemplate so much complexity that sometimes it suffers psychologically? Why are we wired to feel this way? And how are we able to pull ourselves out? Expect to learn the evolutionary reason why humans get depressed, how postpartum depression is adaptive, why being strong can lower your chances of low mood, how evolutionary theory

can improve all of medicine, why women are so much more depressed on average than men, why humans are even capable of suicide, and much more. For the people who enjoyed the Randy Nessie episode about evolutionary psychiatry a couple of months ago, this is a great primer as well. It's really lovely to look at mental states that we are all very familiar with through an evolutionary lens. Why are they here? Why do we feel the things that we do? How are they useful? How were they adaptive and how are they mismatched with our modern world? I really find this stuff fascinating and I hope that you take tons away from today. In other news, this episode is brought to you by Woop. Woop helps individuals to unlock

their inner potential by providing personalized feedback around your lifestyle, training, sleep, and recovery. You can only manage what you measure. Woop helps you to understand the decisions that you have to make today so that you can be the best version of yourself tomorrow. It is more than just a tracker. It is a digital coach that helps you to understand

not just what you've done, but what you need to do. It's the own, like my barrier for new things in my life is incredibly high. It takes an awful lot. And I've stuck with this for four and a half, probably five years now. I'm a massive, massive fan. Also, you can join for free, pay nothing for the brand new Wootbe 4.0 strap. Plus, you get your first month for free and there's a 30-day money back guarantee. So you can buy it for free, try it for free and if you do not like it after 29 days they will give you your money back.

Head to join.woop.com slash modern wisdom. That's join.woop.com slash modern wisdom. In other, other news this episode is brought to you by Element. Element is a tasty electrolyte drink mix with everything that you need and nothing that you don't. It is a healthy alternative to sugary electrolyte drinks. Each grabbing girl's stick replaces essential electrolytes with no sugar, no coloring, no artificial ingredients or any other junk. It is formulated to help anyone with their electrolyte needs and is perfectly suited

no matter whether you're following a keto, low carb, paleo, or vegan diet. It contains a science-backed electrolyte ratio of sodium potassium is perfectly suited no matter whether you're following a keto, low carb, paleo, or vegan diet. It contains a science-backed electrolyte ratio of sodium potassium and magnesium with no junk, no sugar, no coloring, no artificial ingredients, gluten, fillers, or BS. It plays a critical role in reducing muscle cramps and fatigue while optimizing brain health, regulating appetite, and curbing cravings. But most of all, it just tastes fantastic. There is no BS, no questions asked, refund policy, so you can buy it 100% risk-free and you can get a free sample pack of all

eight flavors with your first box, head to drinklmnt.com slash modern wisdom. That's drinklmnt.com slash modern wisdom for a free sample pack with your first box. And in final news, this episode is brought to you by Surfshark VPN. You do not want to be browsing the internet without a VPN because it means that your internet service provider can see all the websites that you are accessing, then sell your data to advertisers who will target you with different ads and they will split test prices for products that you're already buying. If you're using a public Wi-Fi network, then the internet admin can see all of your data. So if you're working out of a cafeteria or a library, that is also Trez not good. But most of all, it means that you can access the entire world's Netflix library

from all of your devices. Surfshark is available across unlimited devices. You're laptop, your phone, your iPad, even your smart TV. And it means that you can change your territory and access things like HBO Max. When you're away from, and it means that you can change your territory and access things like HBO Max when you're away from home. It means that you can use Netflix in America or even if you're in the UK, which means you get access to tons more Marvel series and movies and a whole host of other things. And it secures your browsing. And you get an 83% discount, three months free, and a 30-day day money back guarantee. If you go to surfshark.dealsslashmodemism, that's surfshark.dealsslashmodemism. But now, ladies and gentlemen, please welcome Ed Hagen. One of the phenomena that I'm most interested in is depression. How should we understand depression through an evolutionarily adaptive lens? Yeah, well I think that if you look at depression, it's the most common mental health problem,

and it is a problem. Nothing I say should be construed as trying to diminish the fact that it is a very serious problem. But when we look at the causes of depression, it's very clear the evidence is overwhelming that it's adversity. Folks that experience adversity are much higher risk of experiencing depression.

And folks with depression have been much more likely to have experienced adversity. And there's quite a bit of evidence that that's a causal relationship that adversity causes depression. And rates are quite high in comparison to something like schizophrenia where the rates might be around 1%, rates of depression are at least 10 times higher than that if not more. So it's very common, it's caused by adversity and the symptoms, unlike the symptoms of schizophrenia,

which are kind of odd, including delusions and hallucinations, the symptoms of depression are things that we've all experienced. Sadness, loss of interest, inability to sleep, overeating, or lack of eating. Anxious movements like this when we're stressed out. So their symptoms are not strange or uncommon. There are things that we've all experienced in response to adversity. So I think these types of evidence suggest that we should really think of depression probably as an extreme form of sadness

or what Randy Thornehill and others have called psychic pain. And I think this is the best fundamental approach, an evolutionary approach to depression, is thinking about physical pain. It's unpleasant. We don't like it. It's costly. It prevents us from doing things. But we have special receptors for it and special neural circuits for it. And it is caused by physical injuries.

And you might say, why do we, why do we have to suffer physical pain? Well, we suffer it for a number of reasons. One is if you injure yourself, stop doing whatever you were doing to injure yourself. So it's a signal that you're doing something that is going to harm your biological fitness as we call it. And so that's one clear function of physical pain. And a second clear function is we begin to think about what did I do to get myself into the situation and learn how do I avoid this kind of situation in the future.

So that physical pain, when I broke my ankle, it hurt like hell, but it kept me off my feet. It made me think, don't do that stupid thing that you did to break your ankle. And I'm more or less avoided drinking my ankle subsequently. And so Thorne Hill and others have proposed. Psychic pain is very analogous to that. Something bad is happening to you, not physically, but socially, perhaps.

Your wife has left you, your boyfriend has left you, you've lost your job. That's bad for your biological fitness. And you need to think about it. So you need to, first of all, stop doing whatever it is that drove away your romantic partner or got you fired or causing your friends to disown you. And you need to think about that. And you really need to focus your attention on that. And then maybe learn, don't do whatever it was that you did. That may have caused your relationship to break up, or you to get fired. And it may turn out that you didn't do anything wrong, but you

need to think about it. You need to stop and say something really bad has happened. And I need to address this. And so psychic pain, sadness and even depression are probably very analogous to psychic pain as a way to stop furthering any problems that you have, perhaps cause or other people have caused you. And maybe somebody else has caused a problem and you kind of need to deal with them somehow. So I think this is the, sorry about that, my cat. Can't be out there.

Um, we all need attention, right? Um, so, and this, this work was, there's many people that have kind of put forward this idea, Randy Thornhill, Randy Nessie, Paul Andrews, as somebody that's been currently working on this. So I think this is is the kind of the most likely evolutionary explanation for why would being depressed cause us to act in the way that we do the symptoms of depression like low energy, like not wanting to get out of bed and go and do things like sometimes being anti-social? If I was to design a coping mechanism for psychological pain, some of the time if I went through something in the past that had happened with my relationship or with my friends, I might want to reach out

to them more. I won't want to go out there and try and do things to fix it, but it seems like depression causes people to be less mobile in that regard. Yeah, and you might even bring up the most mysterious symptom, which is suicidality. Why, if something bad has happened, would you ever want to kill yourself? That's a horrible way to increase your biological fitness. So not all adversity is going to cause depression. So in many cases, we do know how to deal with adversity.

We do know what to do. And for a second, give me the definition of adversity. What do you mean when you say adversity? So from an evolutionary perspective, it would be any situation or circumstance that's likely to decrease your biological fitness, i.e. decrease your ability to survive and reproduce. So losing a mate is obviously horrible for your reproduction. Getting sick or physical injury can often trigger depression, so that is obviously something that is bad for your biological fitness. Getting fired, that's your source of resources, that's what you need to

survive. So anything that would have a really dramatic negative impact on your ability to survive and reproduce is what I'm referring to as aversity and natural disasters. Things that are going to basically reduce your access to resources and mates and social partners, all the kinds of things that we needed to have access to on a daily basis over evolutionary history. So that's what I mean by adversity. And we've all, or death of a loved one, that's one of the most common ones. And if your parent dies, or your spouse dies, or a child dies, that can be really bad for your biological fitness because we really require our social partners to, and we always did, to survive and reproduce. We needed hunting partners and mates and folks

to share food with us and take care of us when we're sick. So if one of those folks dies, that's really horrible potentially for your own biological fitness. So that's what I mean by adversity. And what Paul Andrews argues, I think quite correctly, is when something like that happens, you really need to shift your cognitive resources to begin to think about these problems because they're not easy to solve. If a mate leaves you, what do you do? Or if someone dies, you can't bring them back to life. So these kinds of problems, this is where we think depression is going to really kick in is when you suffer adversity where the solution isn't obvious. You know, what you need to do to address that kind of adversity isn't clear. And you're going

to, it really takes a lot of thinking. So you're going to shift your attention to the problem and it's going to take a lot of thinking to figure out what you need to do. And when you're doing that, you can't be doing something else. So there's a trade-off. And that may just require you taking a lot of time to yourself to really think through these things. And the strongest piece of evidence for that

is that rumination, intense rumination is a really major component of depression for many people, not all, but it's a very common component of depression that when people get depressed, they really start thinking over and over and over about what happened. Why did you know something to leave me or did that? And I'll just give you a personal example when my dad died. He died of cancer and my mom became depressed and she was really withdrawn and what she was thinking about is could she have noticed something sooner and gotten him to the doctor sooner? Could she have noticed that something was wrong? And you might say, well, he's dead.

What could that help? And it's not going to help obviously bring back her husband. But it could help her when she's now interacting with other family members to really pay closer attention to things that might be indicating some health problem. And so all of that rumination about my dad's

cancer and the months leading up to it before it was diagnosed obviously wouldn't bring him back, but could have helped her potentially notice problems, other health problems in folks before they become untreatable. And in fact, because my dad died of colon cancer, that's highly heritable, she just started pestering me to go get checked out and get a colonoscopy, which is of course the last thing anybody wants to do. And so after months and months and months of pestering, I finally did it. And guess what? They found a huge polyp. So maybe she saved my life by becoming depressed and really thinking carefully

about what happened to my dad. Wow. So that would be an example of how this might work. Yeah. Oh my. So OK, I really like peeling a part of phenomenon that everybody that's listening to this will be familiar with, low mood, then getting across

into depression. Some people maybe even that have dealt with suicidal ideations and stuff like that. And actually looking at them from through a lens of, okay, why did this come about? Because especially if you are dealing with severe low mood, even more if it's chronic, if it's over an extended period of time, it feels like a personal curse. It feels like some evil God from Onhai has decided to hit you with an arrow, but it wasn't Kupens arrow, it was this depression arrow, and it's just the perfect storm of your thought loops,

poking you in exactly the place that it's going to hurt you, and it feels so curated, it feels so individualized for you. And I think that looking at it through this lens hopefully kind of helps to just, you know, relieve a little bit of that sense of, it's about me. Well, it seems like it's not about you, it's about the evolutionary pressures that would have made these kinds of emotions useful and sensually. And that story of you with your dad and your mum is, you know, it couldn't be more perfect of an example. Yeah, and again, depression is really immersive. It's just like physical pain. Nobody, if you break your ankle, you'll know that you won't be able to sleep. You won't be able to do all kinds of things that you can normally do.

And psychic pain is very analogous to that. Now I want to bring up a second possible function of these kinds of symptoms. I think the ones that I mentioned are probably the primary ones that hold across most, if not all, cases of depression. But just like when we suffer a physical injury, it hurts. That's our own personal experience of it. But in many cases, we're going to signal if we're a young kid, we're going to cry, we may yell out, we're going to be, we're going to have expressions of physical pain on our face. And those are likely signals and signals of need because when you suffer a physical injury or health problem, you often can't deal with it yourself. You need people to help you. If you break your ankle, you're not gonna be able to feed yourself.

You may not be able to do all kinds of things that you could normally do. And you may need to signal for help. And we have all kinds of evolved signals like tears and crying and screaming to signal that. And I think depression also involves a component of signaling. So psychic pain, just like physical pain,

often we can't address adversity completely by ourselves. And so there's going to be facial expressions. And I think some of that, those physical manifestations of depression where you're not doing anything, our social partners are gonna pick up on that. And they're gonna make inferences about our state of mind. It's something's wrong. And I think that's another evolutionary reason why depression

does involve some of these impacts on our behavior that they are also to signal our social partners that we are suffering adversity and we do need help in addressing some of these things. So that's probably a second reason for some of these symptoms is that signaling component. Why is there a sex difference in depression? Why do men and women get it at different rates and in differing intensities? Yeah, we don't know. So this has been a huge area of research. It's one of the biggest sex differences out there. Women are about twice as likely to be depressed as men. And there's been all kinds of, is it different rates of adversity or women There's been all kinds of, is it different rates of adversity or women experiencing adversity at high rates than men?

Are they somehow more vulnerable to a given level of adversity having these emotions trigger? I mean, there's some support for all these ideas. One factor that we highlight that I think is really, it's very well established empirically, but it's not really part of the national conversation about depression and that is the depression is really intertwined with social conflict. That there's a lot of anger involved, typically. And you think about it if your partner leaves you, you're

going to be sad, but you may also be angry. And of course, that person is leaving you probably because there's some conflict between you and your relationship. And or if you get fired from your job, again, that suggests social conflict or you're having some kind of family situation, social conflict. And so the evidence for this is really overwhelming that social conflict and anger are deeply intertwined with depression in many, many cases. And so that's kind of our, the angle of my research group, this taking on depression is really looking at this aspect of conflict because that's an area where evolutionary Thinking where evolutionary theorists have pretty much spent

ever since dark conflict and the struggle for existence has been part of evolutionary theory from the beginning and it's really striking How important a theme that is in depression? So how might that explain the sex difference? well one way that we all deal with conflict often, not just us humans, but across the animal kingdom, is physical aggression. And so when there's conflict between males, there's physical aggression or female,

intersexual conflict often involves male coercion. So the way that many, many animals, including humans, deal with conflict is physical contests. And in physical contests, in animals and in humans, individuals who are physically stronger will often prevail in those conflicts. So our hypothesis was that males are physically stronger than females, and that's actually an extremely dramatic sex difference. There's almost no overlap in upper body strength between males and females. Almost all males are greater upper body strength than almost all females.

And that means in many, many conflicts, especially between men and women, men are going to prevail due to that physical advantage. And that means that if you're in a situation where you might be experiencing depression, if you can prevail due to your physical advantages, then you're not going to get depressed. And so what we did to test this idea is we have a huge nationally representative database of upper body strength as well as depression levels.

And our hypothesis was that the sex difference in depression is really a strength difference, not a sex difference. And so what we found is that when we controlled for upper body strength, the sex difference in depression, diminished and actually went away in some of our analyses, suggesting that once you control for the differences in strength between the sexes, there is no longer a sex difference in depression. And our hypothesis for that is that stronger people. And that's exactly what we see that stronger people are less likely to become depressed and physically weaker people are more likely to

be depressed in our data. And that presumably tracks within the sexes as well that weaker men, compared to stronger men, have greater propensity to depression. Okay, which direction is the arrow of causation going? Can I make myself less depressed by becoming stronger? Yeah, we don't. So there is a quite a bit of evidence that physical exercise does help with depression. But whether that is because it's increasing some sense of an ability to deal with adversity, we don't know. But you're absolutely right. Those are the right questions to ask always with these correlational studies, which ours

is as well. What is the direction of causality here or is there some third confounding variable? Now, in our study, we control for everything we could think of to control for, and we still see this dramatic effect of strength on depression, this negative association, despite controlling for all kinds of, I think, socioeconomic status, age, hormones, health status, all kinds of things. It looks like there's still this very clear negative association between upper body strength and depression. But yeah, could you go to the gym and get rid

of that depression? I don't know, maybe something that we should do. I wonder what it is about strength. What was the measure of strength that you used? Was it hand grip? Hand grip, yeah. That's right. Yeah, okay. I wonder what it is about strength, because that's not the only measure of physical fitness, you know, where persistence hunters, and cesterly, why is it not your VO2 max?

Why is it not your level of zone two fitness or your lactate threshold or some other measure of fitness because there are multiple ways that you could measure this, right? You know, cardio, why is it not your flexibility, your ability to get into the box splits or whether you can do a good lunch without getting into pain or something like that. Presumably hand grip strength. It's not about the fact that the person that can grip the stone or the piece of wood, the hardest has something. That is an indicator downstream for a bunch of other things.

So hand grip strength is a very good index of upper body strength. An upper body strength is a very good index of prevailing in physical fights. So we think, given the clear evidence that social conflicts are deeply intertwined with depression, and given the evidence that upper body strength is one of the best predictors of prevailing in physical aggression and physical conflicts that this is the key index. So it's not these other aspects of health. It's not a health thing. It's a physical fighting thing to resolve conflicts in your interest.

So that is so interesting. MMA fighters should be the least depressed people on the planet by this. Yeah, unless they got beaten by somebody else. But yes, these guys, we would expect, I mean, that's what our data show, at least. We don't obviously have in our data anyway, you know, fight outcomes. But we do, it's very clear that the folks with the greatest upper body strength are the least likely to be depressed. And it's not necessarily because they had to get in a physical fight, but they just, when

there's a social conflict, that conflict, at least our hypothesis is, and this is going to require a lot of additional testing, is that there are the ones that are going to more often than not prevail. And by prevailing, that means that the conflict resolved in their interest, and there's no need to get depressed, things worked out their way. Does this get flipped on its head a little bit when we talk about people who commit suicide? Because I think I'm writing saying that women commit suicide, or attempt suicide, sorry, at a significantly higher rate than men do, but presumably one of the reasons why men are able to be successful, if that's the right way to put

it, with their suicide attempt is that they do have this extra degree of lethality. They do have this extra amount of physical strength, which perhaps can mean they can carry through with this. How do you conceptualize the fact that women attempt suicide more, but men are commit suicide more? Yeah, that's definitely true in the United States. It's true in a lot of populations. It's not true in every population, but it is a pretty good way.

Where is it not true? I have to check to make sure I had my stats right in this. But I think in China, we see really high rates of female successful suicides. But I want to double check that to be sure. But I think that's one of the major exceptions with the little astros, because I have to go back and look at my notes.

And what most people think and what I think seems really plausible is that men are more likely to use lethal methods like guns. And that's one of the major reasons why the suicide rate for men is much higher than for women, but you're right, the attempt rate for women is much higher. I think the key thing here is that the attempt rate for both sexes is dramatically higher than the success rate. So for men, there's about 10 suicide attempts per completion in, let's say, young to middle age adults.

And women, especially in young women, it may be as high as a hundred or more attempts per completion. So what we argue, is that really the phenomenon of interest here is the attempt, not the success. And what we are arguing is that for the vast majority of suicidal behavior, the phenomenon of interest is the suicide attempt and that the successful quote-unquote or the suicide deaths are the unintended accidental consequences of making an attempt that is serious but hopefully won't actually succeed. And our argument here is similar to what I was mentioning before that there's a signaling component to depression. You need to signal that you're in need, that you've suffered adversity.

But if there's conflict, as I've emphasized, people may not believe you. And so we all know situations where, for example, women are experiencing sexual harassment or sexual abuse, and they're not believed. And the reason they're not believed is there's conflict. Do they have some incentive to lie? Or, and that's of course what everybody immediately will say on social media, oh, she's just trying to manipulate the situation. So how do you can, and it's a kind of behavior that's often private, it's, you know, he said, she said, how can you convince other people that you're telling the truth? Again, this is where evolutionary theory comes in.

There's a whole area of research called credible signaling because in animals, within species and between species, there's often conflicts of interest between predators and prey, between males and females, between two males of the same species. And yet there's a big cost of actually fighting or chasing down the prey. So there's all kinds of signaling going on in non-human animals. And biologists for a long time wondered,

why are those signals honest? Why should, if there's a huge conflict of interest, between the signal sender and the signal receiver, why should the receivers believe the sender? Why aren't they just exaggerating their qualities? If it's a mating situation or their form of ability, if it's a aggressive situation. And so there's a body of research on ways

that credible signals can evolve. And one of them is that credible signals can evolve. One of them is that the signals have to have some cost or more accurately that the benefit of signaling has to outweigh the cost for the sender, but the cost of the signal have to outweigh the benefits for potential cheaters. Cheaters can't actually send the signal because they can't afford to do it. What we're arguing is that suicidality might be exactly one of these honest signals of need and how it would work is if your life is going really well,

you can't afford to actually do something that puts your life at risk. You can't take that 1% or 10% chance of killing yourself to get whatever benefit you might get from social partners because your life is already going really, really well. But if your life is not going well, if your mate has just left you, your potential fitness is really taking a huge hit. And in that case, the benefits that you might get from social partners by convincing them that you genuinely are in need might outweigh the cost of taking a 1% chance of actually killing

yourself or a 10% chance of killing yourself. So we're arguing that suicideality is a credible signal of need in situations of adversity that can convince skeptical social partners that you're telling the truth that you really do need their help. And what you hope is you'll engage in this kind of behavior where you put yourself at real risk of actually killing yourself. truth that you really do need their help. And what you hope is you'll engage in this kind of behavior where you put yourself at real risk of actually killing yourself. But most of the time you won't, you'll survive. And then social partners will believe, yes, that person really doesn't need my help. And you'll get the help you need. But unfortunately, because the signal has to have those, it has to take a genuine risk of death at the margins.

So that, in our view, explains these tremendously high rates of suicide attempts to completions in both men and women. And then the sex difference in those may be because in our society we have guns, it's an extremely efficient way to kill yourself unfortunately and men are much more likely to use those than women maybe for cultural reasons. How did natural selection create an animal with the capacity to willfully kill itself? How is it that suicide hasn't been selected out of the population? I don't understand how something can be adaptive and on top of all of that, suicide is moderately

heritable as well. What the fuck does that mean? Yeah. So let's think about the case of a young woman who's experiencing sexual harassment or sexual abuse. That's enormously costly to her biological fitness is going to prevent her from, you know, may physically injure her, it may infect her with a serious disease that could sterilize her, it may get her pregnant by some person who's not going to invest in her. So it's an enormous, enormous cost to her fitness and he's to stop. But because of that physical form of ability difference that

I talked about, she may not have the ability to stop her abuser by herself. She needs help. And yet, due to the privacy of those kinds of behaviors. He said, she said, situation, she may not get that help. People may be skeptical. The man's friends and family may back him up. And so what can she do? She can't easily physically resist him. She's not getting the social. She may have married into his family

and be physically removed from her own family in evolutionary contexts or many traditional contexts today. So she just doesn't have the social partners in backup and yet she's suffering a huge and maybe worth the 1% or even 10% chance of killing herself if in the 90 to 90% number of times that this kind of behavior would happen. She convinces people that she's telling the truth and that actually stops the abuse. So it's the potential benefits of convincing social partners that you really do need to help that would outweigh the cost that you might actually end up killing yourself. It's that benefit that explains in our view, at least in our theory, why people are willing

to take that extreme kind of action. It's a way to convince people that you really need help. Yes, I understand. Have you got any idea about whether, ancestrally, men were more successful at suicide attempts than women. I'm wondering whether this is, this signaling is the same. Ancestraly and we have an evolutionary mismatch between the tools that men now have access to that means that they can be more successful at attempts.

I think that's a reasonable hypothesis. We have with my former student and collaborator, Kristen Sime, we've come through in Decker field. We've come through the ethnographic record on suicidal behaviors. Now these are modern groups, but modern groups, many of whom are living in ways that are similar to the way we think were, our ancestors lived traditional societies, hunter-gatherer societies. And we've scoured the ethnographic record for every example of suicidal behavior. And these records are not systematic, so they don't allow us to estimate rates of lethal versus non-lethal behavior or anything like that. What they do is what we do see in some of these societies that almost all of the cases are female, in other cases almost all of the cases are female, and other cases

almost all of the cases are male, and others it's kind of a mix. So we can't, if men, ancestral, actually, tuck up riskier, engage in riskier kinds of suicidal behavior, that would have led to their deaths. That's just something that I think we can't see in the ethnographic record. But we do see all the other things that our theory would predict. We see social conflict, we see adversity.

We see that if you survive, you do get help in most cases. You do get social benefits, often somebody's being abused by their parent and they attempt suicide and then the whole village realizes and they start pressuring the family to treat this person better. Or they engage in a suicide attempt and they get their mate to return. Somebody who had left them comes back or they get their husband to leave his, you know, conkybine or mistress and come back to the family.

So it's all the kinds of things that we see today that trigger suicide attempts. We see in the ethnographic record and we also see that these often, if the person does survive, they do generate benefits. But yeah, the sex difference is not something we can address with the data that we have access to. Maybe somebody will more clever than I am, won't figure out a way to do it, but I haven't figured out a way to do it. But we could. Well, what I was just going to say is maybe by studying some of the few hunter-gatherer

societies and small-scale societies that is yesterday, if we study them more systematically, for suicidal behaviors, we might be able to begin to address that. Question the problem is it's an incredibly stigmatized behavior, and so it's incredibly difficult to study this. And we have tried, Kristen, has made several efforts to try and collect these data and just the resistance of the community to actually talk about the stuff is we haven't been able to overcome that challenge yet.

One of the other things that I've been considering, sex differences, one of them, but age as well as another one, what can we learn from the onset of suicide in relation to age? So what we see is that both depression and suicide begin to really onset in kind of middle adolescence to early adulthood. And that's when they really peak the suicide behaviors. And then they gradually decline with age. We see the successful suicide rate actually increasing with age, but it's always much, much lower than the suicide, suicidal behaviorism until you get up to about age 70 or so. And what's striking to us is that these

behaviors are on setting as people are transitioning from the juvenile phase to the adult reproductive phase of life. And of course, in the juvenile phase, typically, most of us have protection from our family and our parents. We're not engaged in inter or intrasexual mating competition. We're not competing for mates. We're not competing for resources. sexual mating competition, we're not competing for mates, we're not competing for resources. And when we see these behaviors onset is right when we're transitioning from that juvenile phase when we aren't engaged in all these kinds of competition, to the adult reproductive phase when competition can become very, very intense, so mating competition, resource competition.

So our hypothesis for the onset of depression and suicidality in adolescence is that this is when individuals are transitioning to mating competition and resource competition. And they kind of peak in early adulthood when that competition is probably most intense and then it seems to gradually decrease over the lifespan as mating competition is probably decreasing as well. Isn't the current highest risk group in the US for suicide men aged 40 to 45 or something like that. I think white men are... So the risk of... The risk of completions goes up with age. But the risk, the frequency of suicide of behaviors is going down.

So you've got this kind of... Suicide of behaviors really just spiking incredibly in adolescence or in early adulthood into your sort of mid-20s or so, and actual suicide deaths very, very low. And then the suicidal behavior begins to decrease as you go into middle-age and older-age, but the actual rates of actual completions are going are climbing. But they're still well below. And climbing, but climbing presumably at a rate, if the number of attempts is lower, but the percentage of successes is higher, given the fact that

we have, I think it's five times more men in middle age commit suicide successfully than girls who are adolescents, given the fact that we have a mental health crisis around young girls at the moment in the US, but it is 60% of teenage girls in America say that they have persistent feelings of hopelessness and doom or something like that, their ability to be successful in this regard has to more than compensate for the fact that you have significantly lower numbers of attempts. That's right.

And so we don't have a great explanation for that yet, but what we look at, and we look at just mortality rates from any kind of cause, they kind of follow the same kind of pattern. And so something about, so if you actually fit the curves, they're very, very similar. So it could be, and we really don't know. So is it the case that maybe older individuals have to engage in cost-leaders signals to convince folks that they need help for some reason, so they're engaging in riskier behaviors, but also as we get older, we're more vulnerable to dying from any kind of cause. And so it might be the case that it's kind of a combination of engaging in maybe costlier signals, if you will, riskier kinds of behaviors to actually

get that signal across to other people, but also being more physically vulnerable to having something going wrong. Fascinating. Yeah, yeah. Fascinating. Yeah. So, so interesting. Is there a link between suicide and intelligence?

So intelligence is not, so I look at intelligence from humans compared to other species. And we've obviously got these huge brains, but I don't really, I've never really looked at variation intelligence within species. So I can't say too much. It's not a variable that we have a very good, sort of the proxy for intelligence

in most studies of evolution is kind of species level brain size. So if we look at us versus chimps and other apes and other primates and other mammals, there's lots of good work in that area. but we try to think about what does it mean for differences in intelligence within species. It's not an area that I'm an expert in, but I haven't really seen any great operationalization or evolutionary rationale for within species variation. So I can't really answer your question on that one, unfortunately. One other kind of weird, to me at least, phenomenon is postpartum depression.

So women who have given birth and then after that they have this onset of depression. Have you looked at that through an evolutionary lens? Could you give some potential adaptive explanations for that? Yeah, so that's actually, it was my dissertation research and that was kind of entry point into this whole area. And from an evolutionary perspective, on the one hand, postpartum depression is really odd. You've just had reproductive success.

That is, as we've learned from day one, is the whole physiology and psychology is organized to reproduce. And so you've now successfully reproduced. You, in most cases, have a nice, healthy baby. You are a mom in one of the richest countries that has ever existed. You have more resources in one of the richest countries that has ever existed. You have more resources than anybody in the past could ever imagine.

Your baby is very likely, the probability that it's going to die from an infectious disease is vanishingly small these days, at least if you are lucky enough to live in a high income region. So what the heck is going on? You are feeling miserable, you don't love your baby, you may not be able to eat, you may not be able to care for your other children. It seems like just the most incredibly paradoxical kind of experience you could imagine. kind of experience you could imagine. And so what I started to do is look into what are the circumstances that seem to be associated with postpartum depression. And the big one is lack of social support, lack of social support from your husband, lack

of social support from your husband, lack of social support from your family. And we know that we humans are cooperative breeders. We really, you know, takes a village. We never buy ourselves. We were always reproducing in family units where husbands and siblings and older children and grandparents were helping us and we were hanging out with the other moms and the other parents and we were helping them take care of their kids and they were helping us take care of our kids. And if you didn't have that, there was no way that you were going to be successful in raising that kid ancestral. And what I found in the evidence for this is overwhelming is that many, not all cases,

but many, many, many cases of postpartum depression are occurring in contexts where mothers feel they don't have social support, often from the husband or maybe from their other family members. And that would have been a cue ancestralally that this child isn't gonna make it. And so what I have argued is it's exactly this kind of adversity where we should be experiencing psychic pain.

We should really start thinking, what is wrong, why am I not getting this social support I need to help raise this kid? And what can I do about it? Can I get that social support somehow? Can I juggle responsibilities? And if I can't, then I really should just stop caring for this kid.

And we know in kinds of populations that approximate our ancestral past, if you didn't have the resources, you might just not take care of that kid to begin with. And we often see very high infanticide rates in situations where there is extreme, extremely limited access to resources. But you shouldn't commit infanticide immediately. You should start signaling that you are genuinely in need and access to resources. But you shouldn't commit in fantasy immediately. You should start signaling that you are genuinely in need and you really can't raise this kid in the circumstances the way they are.

Something's got to change. And so I'm arguing that a lot of the postpartum depression symptoms are a form of psychic pain. You're not getting what you need. And we also see it when the kid is unhealthy. If it's if there's pregnancy problems, if there's health problems in the child, if the mother has health problems,

these kinds of things are also strongly associated and probably causes of postpartum depression. And then you should signal. And you should use one of these costly signals that is going to convince people that you're not just trying to manipulate them and get more help than you deserve that you really are in need

and you really do need extra help. Or you're gonna stop taking care of this kid. And that kid is not just your kid, it's your husband's kid, it's your grandparents, grand kid, it's your siblings, niece or nephew. And biologically, if you don't take care of that kid, it's going to, niece or nephew. And biologically, if you don't take care of that kid, it's going to have a negative impact on their fitness. So they have an incentive if you really are in need to step in and help you get what you need to successfully raise

the child. Seeing suicidality and depression through a lens of signaling. There is something going on, please give help. Having, especially suicide attempts, be something which is a very costly signal to try and do it if you're just fucking about and you just want some attention but you don't actually feel that bad is, you're flying pretty close to the wire.

I love the idea of in older age it being a combination of perhaps the signal needs to be more reliable, i.e. more costly, which means that you fly closer to the wire of mortality with your signal and the fact that maybe your physiology is just a little bit more fragile in some way, you're a little bit more vulnerable to this. I don't know if I would think that a 45-year-old man would be more vulnerable than a 16-year-old girl. They both seem, I don't know, there's some pretty robust 45-year-old guys out there. I don't know, that's interesting to me. But I just, this conceptions very, very fascinating. And I think hopefully should help people to feel, yeah, a little bit less sort of

personally cursed. One of the other topics that I saw you get into on Twitter recently was a discussion about whether or not race science is deeply embedded in evolutionary psychology. Where did this come from? Is it true that race science is a foundational part of evolutionary psychology? Is evolutionary psychology racist? Yeah, I would argue it's probably the least racist discipline in the social sciences. Because the social sciences for decades have really foregrounded race

is this fundamental aspect of our psychology that we code everyone by race immediately. And there's quite a bit of evidence that people do and code as soon as you see somebody that one of the first things you're gonna think of is Black guy or White guy or, you know, Mexican or Asian, you're going to code race really quick. It's going to influence all kinds of decisions and behaviors.

And that's been part of, you know, non-evolutionary social science forever. So, what evolutionary psychology has proposed is that we humans have evolved in Africa. And if we go back two to and a half million years ago, our brains were about the size of chimp brains, about one third of the human size that we have today. So 400 cubic centimeters versus about 12 to 1300 cubic centimeters. So it's a tripling over that two million years. And that all occurred in Africa. And then very, very, very recently, modern humans with modern human size brains and modern behaviors and modern capabilities, expanded out of Africa and colonized the rest of the world. So all of us just a few minutes ago in evolutionary time were big brain modern humans in Africa. And what we argue is that that massive brain expansion we evolved a unique human cognitive abilities that are shared by everybody today because we all came from that same population of Africans just a few tens of thousands of years ago.

So as you'll may notice here, there's no race anywhere in that conception. And the races, quote-unquote, come about because in that very, very recent expansion of modern humans out of Africa, of course, you're colonizing Asia and Europe and the Americas. And in that relatively short time frame, some very, very minor physical differences have evolved skin color. You're actually really hard, you can put almost all of the differences on, you know, a little infographic. There are a few things where there's really strong selection pressures like solar radiation or pathogens or diet or if you're at high altitude oxygen levels or things like malaria resistance. But they're very, very, very, very minor in the scheme of things. And what we argue is in that very narrow sliver of time, there just wasn't time for much

of any evolution of complex psychological differences. Any differences that might exist between populations would be bad as significant as having a little bit more versus a little bit less melanin in your melanocytes, so your skin cells. And so that's been the perspective of evolutionary psychology for sensitive inception. However, there is a real problem. I don't want to diminish this. have folks who have kind of latched on to the evolutionary psychology label, who are very interested in the possibility that just as there are physiological population differences,

there might be psychological population differences. And that's never been part of mainstream evolutionary psychology, but some folks are really interested in that. It's obviously a hugely controversial topic. Some of the evolutionary psychology journals have accepted papers that have been purporting to provide evidence for that. Those papers have relied on a national IQ database that is extremely problematic and has really no claim to have accurate numbers on nation level IQ for many, many nations. Getting basically

nation, boiling a whole nation down to a single number, we can do it, but it's, it takes, you know, literally might take a million dollars to do it right. And that kind of money was not put into this research. I can tell you that. And that'd be for one nation. To get that one accurate number for that one nation on any one number that you wanted is a very, very expensive thing to do. And this dataset doesn't do that at all. So, yes, there is a problem now that some evolutionary psychology journals are publishing some very suspect papers promoting the idea that there are population differences in intelligence. And that's going to take some work to deal with that to begin to counter some of those narratives with much better research and much better reviewing. I think there's quite a bit of evidence that the quality of reviews that are going on subpar.

So, we're working on that. Is it part of what has inspired literally hundreds of social scientists who adopt evolutionary ideas? No, it's really not been the inspiration. The inspiration has been this kind of vision of a psychic unity of mankind that we all have a common repertoire of psychological mechanisms that unite us. What do you say to the people that accused evolutionary psychology of being just so stories? Well, you could say I'm a fan of just so stories, the more the better. All science starts off with a just so story that we have some phenomenon in nature that

we find interesting and we come up with a story about it, what explains that phenomenon. And so we evolutionary psychologists are as liable to do that as everybody else and all the other scientists and all the other scientists and all the other disciplines. But then you gotta test it. And just as every scientist and every other discipline does, we begin to design experiments to test these ideas and some of them hand out and some don't.

So yeah, we love our just-so stories, but we also love science and the scientific method and empirical research. And if you look at any evolutionary psychologists, they have a very robust empirical research program to test their ideas and Some of them have been panned out and some haven't I'll give you one that that didn't pan out or doesn't seem to There's the beta still there, but

There's a lot of there were a lot of very interesting. I thought just so stories that Mating preferences might for women might vary across the menstrual cycle And there were some preliminary empirical evidence and favor of that, but much bigger and more controlled studies have really failed to find that mating preferences change across the menstrual cycle. So that's an example of a great theory. It was one that suggested empirical tests.

It was amenable to empirical testing. There's empirical tests have been done and have not found support for the theory and that's how science works. It's hard to figure out how the world works. So we're going to have many, many just stories that just don't pan out and we have to be okay with that. That's the only way we're going to make progress if we rule out telling stories, then science dies. It's such a shame that the ovulatory shift hypothesis didn't end up being true because it's just so interesting. There was so much cool.

Yeah, and maybe it will. You know, it is very cool, but maybe there'll be some new twist on it. I don't know that we've heard the last word, but yeah, right now I don't know. Oh, not dead yet. Yeah, it may not be dead yet. Who knows? Who knows? There may be some new twist on it.

We'll see. But yeah, for right now, it's not looking good. One of the other things that you've studied is music and, ancestrally, evolutionarily, the role that music and dance and other actions had. How does that fit into anything resembling an evolutionary or adaptive story for humans? So my career, I thought, when I first introduced to evolutionary psychology, I thought, well, if this is right, it should be able to answer questions that nobody's been able to answer. It really makes some progress on some of the big mysteries, things like depression and

suicide. And music is one of those big mysteries that Darwin himself puzzled over. It seems, if we look at food and mating, these are all behaviors that have clear evolutionary utility and you look at something like music and it's just what could be the utility with that kind of behavior. It's not at all obvious. So if evolutionary approaches are going to prove their worth, they should be able to begin to give us insights.

And it won't be any surprise based on everything that I've said that I kind of take a approaches are going to prove their worth, they should be able to begin to give us insights. And it won't be any surprise based on everything that I've said that I kind of take a signaling approach here, an incredible signaling approach because a lot of the strange things that we see in animals and being signals of some sort, and often costly, or the kinds of signals that you can't fake. And so when I began thinking about music and what the heck is going on there, I thought, well, what's really distinctive about it? And there are, of course, many distinctive features when we compare it to language or other kinds of auditory signals that we know are signals.

But the thing I decided to tackle was the joint performances that, and they're incredibly well synchronized. In fact, the way I was driving to work one day as a grad student and an old song came on the radio that I hadn't heard in, you know, since my high school days. And I was able to immediately sing along with the song in perfect synchrony. The lyrics just came back effortlessly. And if this had been a, you know, a verbal account, you know, linguistic, just a normal, I would never, I wouldn't be able to remember anything. And yet I could remember this thing and not only remember, but just engage with precise

synchrony. And so that's what really fascinated me that precise synchronization is this key element of music. It's not the only thing, obviously, but it's really critical to the whole experience. And I thought, what could be the function of precise synchronization and this musical memory? I thought, you know, the only way I could remember this is if I had a specialized psychological adaptation to remember music. And I thought that precise synchrony could be a signal of coalition quality, that the only way that you can achieve that precise synchrony is with a lot of practice.

It's really hard to learn a song and get everything synchronized. And so when we learn music, we've got a practice to master our instruments and then we practice songs together. And so receivers, if they might take, and in fact, when I began to look in the ethnographic record, sure enough, folks would be spending weeks and months practicing songs and dances for an upcoming feast. in the ethnographic record sure enough folks would be spending weeks and months practicing songs and dances for an upcoming feast but they're going to give that song they're going to present it

in just a few minutes or maybe an hour in a very short amount of time so it would allow observers to observe something that would be very very difficult to assess otherwise how much of these people how willing are they to cooperate with each other, how long have they known each other, are they a really highly coordinated coalition? And if you observe a group of musicians and dancers, you can tell very, very quickly whether or not they have been practicing together for a long time or not. And that would have been critical in our evolution because humans are quite unique in that we cooperate not just at other for a long time or not. And that would have been critical in our evolution, because

humans are quite unique in that we cooperate not just at the individual level, but at the group level. Groups cooperate with other groups. So groups really need to assess the coalition quality of the folks that they made allied with, because they may depend on them for their lives and military conflicts and battles, or if they're sharing food, those guys better be good hunters. So hypothesis is that these joint musical performances may signal to potential allies that yeah, we are a really high quality coalition and you guys should ally with us.

That would explain why I remember songs from 14, 15, 16 years ago. And yeah, I, you're totally right. I can't remember. I can barely remember anything from my entire university degree. But if you play me any emo slash pop punk song from 2003 to 2009, I can recite it pitch perfect. I can tell you what the lyrics were because I looked up the lyrics online and then went back and updated my programming around that word that

sounded like another word and I used to go, ah, ah, instead of actually saying what the word was. Yeah, I, it's very interesting that, that we almost have this purpose-built circuitry for it is, what's the reason that music, have you considered a reason for why music makes us feel good or why it can create a psychological state change within us? Yeah, I don't have a, and I think it's just the kind of obvious thing that anything that we do that increases our biological fitness, we're going to probably feel good to encourage us to do that thing and anything that decreases our biological fitness is going to probably feel good to encourage us to do that thing. And anything that decreases our biological fitness is going to probably make us feel bad. So practicing music and you know,

when I was in the jazz band in high school, nothing was more fun than just playing gigs and having people kind of rock out or dance to the thing. It just was this infusion of good feelings. And the argument would be because you're doing things that actually are going to increase your fitness. You are learning how to send a signal that you've got a really strong coalition and other folks would benefit by cooperating with you instead of those guys in the other valley. So yeah, it's in our fitness to master these things and do well at them and we feel good when we

when we do that. Ed Hagen, ladies and gentlemen, if people want to keep up to date with the stuff that you do online, why should they go? Just Google me, Google Ed Hagen, and you'll find me real quick on Google, you'll find my faculty page and also at Hagen on Twitter. If you want to see me rant about evolutionary just those stories that I love. I do, I do indeed. Ed, I really appreciate you. Thank you for today. Thanks for having me on. Thank you very much for tuning in. I really hope that that helped to give you a new perspective on mental health, depression, anxiety, a good reason for the ladies and the gentlemen to become stronger, to work on your grip strength, perhaps, because it is going to improve your

mood. In some bizarre roundabout way, the stronger that you are, the less likely you are to suffer with mental health problems. So, off to the gym, you go. I really hope that you enjoyed that one. I really love these evolutionary psychology episodes. We've got a fantastic one coming up with a guy called Tony Volk over the next couple of weeks about the evolutionary psychology underpinnings of bullying. Can't wait to drop that.

Anyway, as always, I appreciate you for listening. And I'll see you next time. couple of weeks about the evolutionary psychology underpinnings of bullying can't wait to drop that. Anyway, as always, I appreciate you for listening. And I'll see you next time.