Rationally speaking, is a presentation of New York City skeptics dedicated to promoting critical thinking, skeptical inquiry and science education. For more information, please visit us at NYC Skeptic's Doug. Welcome to, rationally speaking, the podcast, where we explore the borderlands between reason and nonsense, I'm your host, Masimo on YouTube, and with me, as always, is my co-host, Julia Gillard. Julia, what are we going to talk about today?

Masimo, today, we're going to talk about the field of evolutionary psychology, which, in the words of two of the field's founders to be an Kosmidis, is simply psychology, informed by the fact that the inherited architecture of the human mind is the product of the evolutionary process. But that innocuous sounding statement hides a mountain of controversy. The field has more than its fair share of critics who charge that evolutionary psychology is unscientific, inventing all too convenient explanations for human behavior that they either don't test rigorously or can't test at all, even in principle.

Right.

I think we should clear the air right at the beginning from a couple of misconceptions. I think that, for instance, although I count myself among the critics of evolutionary psychology, broadly speaking, the statement you read by two Kosmidis is in fact very reasonable. I mean, there is it would be unreasonable to imagine that of all things, human behavioral traits are the only things that didn't involve since evolutionary biology, evolutionary theory in general is the the way we explain the characteristics of modern day living forms.

It seems bizarre to say that something like at least partial aspects of human behavior did not evolve. And it would be even strange to claim that they didn't have all by natural selection. And surely some aspects of human behavior evolved by natural selection. The course the problem is in the details. The devil is in the details. You which particular aspects and how do we test that as an empirical scientific hypothesis as opposed to just the general possibility?

OK, so now that we're clarifying things, could you articulate whether for yourself and also for other philosophers of biology who I understand are frequently critical of evolutionary psychology as well, is the claim that it's not possible, even in principle, to tease out these evolutionary causes of human behavior or that it is, but it's just done poorly usually?

Well, actually, neither really, because I don't know of any philosopher who claims that evolutionary psychological explanations are impossible to test in principle. And in fact, we should also say that it's not just philosophers of science who are critical evolutionary psychology. A lot of biologists, evolutionary biologists also are right.

You know, there's no reason in principle why human behavior or traits are any different than any other animal behavioral trait or for that matter, any characteristic whatsoever, including physical ones that are living organisms have. And it's not necessarily the case that evolutionary psychological research is done sloppily. Some of it is. There's no question about that. And, you know, let's let's not get into specific examples. But but there is plenty in the literature of claims that have been thrown out there with very little empirical support.

But even that is not necessarily unusual within the sciences. There is these a range of reliability of scientific findings. Now, I think that the main problem is that evolutionary psychologists typically, although there are there is an increasing number of exceptions, but typically they tend to focus on precisely the worst examples from the point of view of testability because they seem to be interested in what they consider, you know, the fundamentals to human nature, which means traits that are uniquely human and universally human among humans.

So these are things these are behaviours that are not shared by any other animal and their behaviors that are universal in all human populations across history and across geography. And that's what makes those those those claims particularly difficult to detach, because that means that your sample size is exactly one. There's no variation either across species or within species.

OK, so what's wrong with the reasoning that, well, we we know what the environment was like for our ancestors in the Pleistocene era 10000 to two million years ago.

And we understand what the selection pressures would have been. And we can extrapolate from that to predict what kinds of behaviors we would see now as as being adaptations that, you know, became ingrained in our brains. What's wrong with that?

Well, the first thing that is disputable is not wrong with that is that we actually don't know much about the ancestral environment of the places. But incidentally, it's not clear to me why evolutionary psychologists are fixated with the plasticine. I mean, evolution. I mean, most of their their reasoning is in terms of the place, the seen environment. But in fact, human beings evolved, you know, much earlier than the place the seen and kept evolving after the.

So it's not really clear to me why the Pleistocene is supposed to be this crucial moment in human evolution, but that when we when we sort of finished our evolution into humans and. Well, evolution is is a continuous. Process and it's not really clear, I mean, even even the dates that actually separate homosapiens from close related species are not really that clear. They keep moving all over because a new fossil findings and in fact, again, it's not clear that what we today find to be exclusively human behaviors, they may have evolved actually, among other hominids, which are now extinct.

Right. So we don't know if some of our behaviors were not actually shared by our mirabilis or activists or other species of of of the dinosaur.

And, you know, they're extinct. So there's no way to tell. And so but the first part the first thing that is, in fact, problematic is that we don't know a lot about the ancestral human environment, especially in terms of the societal, ancestral human environment, which is really what it's more important for, for behavioral traits is not just the physical environment, obviously. And we don't know anything or much at all about the selective pressures.

I mean, we can we can postulate things. We can speculate. There's no question about that. But we certainly have no measure of selective pressures. So it's difficult. You know, it's easy to come up with scenarios, but it's difficult to actually quantitatively do a test for those scenarios.

But there are some things that seem like surely we must be able to conclude that this must be true.

Like humans who are attracted to other humans with traits that that are correlated with sickness are not going to their genes, are not going to do as well as the humans who are attracted to humans with traits that are correlated with health.

So but see, that's an example where it's not really no longer do evolutionary psychology. You're actually doing standard evolutionary behavioral ecology because those traits are actually shared. Those countries you're talking about are shared by others, by many other species. So we know across a large number of species that there is whenever there is a demonstrable correlation between certain behaviors and reproductive traits, those behaviors tend to be selected for by sexual selection.

That's exactly what I was saying earlier, that the problem is for uniquely human behaviors. Nobody really disputes seriously that certain other kinds of behavior. For instance, if a response, a fear response to danger, I mean, there's no question that evolved and evolved by natural selection. But the reason we can claim that with a fairly high degree of confidence is because that kind of behavior is widespread across a large number of organisms.

First of all, we know the physiology very well, but we also know we can do the the necessary tests in terms of natural selection and field ecology outside of human beings.

OK, so let's look let's take an example of an evolutionary psychology, as you're talking about it, a trait that's unique to humans and universal among humans. What would be an example that evolutionary psychologists have in your mind unwisely tried to?

Well, let's start with the basic one, which is why don't we have big brain, right? I mean, before we even get to specific behavioral traits, the fact the thing that we still don't know is why we have such big brains. I think very few biologists would deny that that is the must be the result of some kind of selective pressure simply because, first of all, it's hard to imagine then that a large brain will come across by come by, by, by chance, but also because the brain actually consumes a lot of metabolic energy.

It's a very expensive thing to keep going. And so it seems like if there is no natural selection favoring the action of a of a large brain, then clearly not G.S. would have favored saving energy, essentially, and not having a large brain. So there must be a reason why we have a large brain.

That reason probably easiest to reason, but even there, there is plenty of different theories and there is no particular reason to think that one is better than the other. I mean, there is a sexual selection theory. For instance, it says that big brains evolved in a way analogous to the peacock's dale male started getting intelligent and females started liking the intelligence of the males and so on and so forth. Although, of course, that does not explain why female humans have a large brain.

You know, the female the female of species where there is sexual selection don't necessarily show the the customary traits.

So there's that one.

There is there is the idea, of course, that has been around for a long time that perhaps it's got to do with the ability of manipulating tools. Well, yes, but it's not clear there which one came first. Is it that we started manipulating tools and then that created selective pressure for the brain, for a large brain or perhaps a large brain came about for other reasons. And one of the byproducts was that all of us and we were able to manipulate tools.

So all of these things, even even the basic question of why we have such a large brain to begin with is far from being settled.

And the reason is far from itself is not because there is anything magical about it or because anybody seriously doubt that there was a selective pressure, but because we just don't have enough information.

So this wouldn't be the case in other species, because I know that I read studies of explaining why certain traits evolved in.

Other species, yes, absolutely. So, for instance, let's take the same example, the same brain size, it's very well known and has been well known for a long time that predator animals, animals that are predators have larger brains than than herbivores. And this is this cuts across the board in a bunch of different groups. And it does it makes sense because a predator has to be smarter, a predator has to to stalk the prey and has to be able to implement sophisticated behaviors to go after the prey.

Yeah, the the herbivore just have to find a large field and start grazing.

So this is very well known and it's pretty obvious that it is a result of natural selection and it cuts across a large number of species. So so even the same. Is this a good example of how the same exact trait can be easily understood in terms of natural selection when it comes to a large number of species? But when it comes to human beings, we really don't know and we are fairly exception among primates.

Now, that's not to say, you know, some sometimes critics of evolutionary psychology go a little too far and essentially imply that we can't say anything about human evolution, which is certainly not the case. So, for instance, until several years ago, one of the big issues in the evolution of human behavior characteristics was the question of whether the big brain evolved first or the bipedal posture. Did we start walking Iraq before we we had a big brain or vice versa.

We started developing larger brains and then started changing our behavior in terms of posture.

Well, it's quite clear at this point that bipedalism came first, and that's because of the fossil record. You know, once we found astroparticle severances, you know, the Lucy skeletons and a bunch of others, then it's pretty clear that what happened was that the bipedalism came first, in fact, came much, much earlier than Big Brains, which means, incidentally, that the shift to a bipedal posture cannot explain the evolution of a large brain because it happened way later.

OK, so it seems like one of the fundamental requirements for a scientific approach is to have your theory generate new testable predictions, which you can then use to to confirm or disconfirm the theory. And the evolutionary psychologists that I've talked to will readily admit that there are plenty of bad and untestable evolutionary psych theories out there.

But there are nevertheless some evolutionary psychological theories that have given rise to testable predictions. So, for example, a lot of sexual selection theories about how people choose their mates predict that females would need to balance various qualities against each other when they're choosing a mate, such as genetic health against, say, trustworthiness and reliability.

And so then based on that theory, we would expect to see that genetic health would become relatively more important than the other positive qualities in a mate when a woman is most fertile and most able to conceive.

So and dozens of studies based on that theory have found that women are more attracted to masculine looking faces and bodies, which is a sign of health and dominant acting men, again, a sign of good genes when they're in the most fertile stages of their menstrual cycle.

So would you not consider that moderate support for the sexual selection theories or what's wrong with that, that sort of set of reasoning that I've laid out?

Well, the any itself, there's nothing wrong with the question. Again, the issue, I think is is in the details. So if we're talking about the general claim that certain characteristics are attracted to females, for instance, let's assume that having a symmetric face, a symmetric face is known to be an indicator of health.

You know, if you have a certain number of a large number of defective genes that cause problems, you've courteousness become less symmetrical or I should say the other way around. If your characteristics are less and less symmetric, that means often that you have a problem with your genetic background.

So that would work. But again, that is actually the case of something that is not typical of humans, is not as you need a human uniqueness situation because a lot of other animals show the same thing. And in fact, we can measure the even the amount of selection for symmetrical characteristics among males. The other characteristics that you're talking about are also common among other primates. So, yes, all those things we can do. And but but but if you're talking about those kind of traits, then there is nothing new about evolutionary psychology because those kind of things have been done by Darwin, you know, since the late 19th century.

I mean, Darwin's book on the origin of human evolution was exactly about those kinds of traits where you can do comparative analysis.

So I think that we should discuss briefly the fundamental issue here, which is. How do evolutionary biologists go about testing adaptive hypotheses normally so in general and then once again they said that then we can say, well, does that apply to evolutionary psychology or not? And probably there are only three ways in which you can do that. Either you can measure natural selection as it's happening so you can go into the field and measure and demonstrate that there is, in fact, selective pressure.

There is there is a set of standard techniques that you can do that. That's the first the first option.

The second option is you look at the fossil record and you make reasonable inferences on the evolution of certain traits based on the fossil record. Again, there are statistical techniques there to tell you how likely it is that a trait evolved by selection as opposed to by stochastic processes and so on.

And the third one is by doing a thorough genetic comparative analysis. You pick a bunch of species that are known to be closely related in a particular fashion, and you examine how the trait of interest evolved across these pieces.

Those are three standard ways. Now, the problem with humans is that although it's as I said earlier, no one should think that this is impossible, but it is particularly difficult and it's difficult because, A, we can't measure natural selection really today because the I mean, we can in human beings. But today's environment is significantly different from the ancestral environment. I mean, for other species, that's not a problem. A lot of species of plants or animals that we study today live in a similar environment to what was historically their environment.

That's not true for human beings. If there is anything that is different by modern humans and engine Youmans is precisely the environment, particularly the social environment. So clearly, if you measure selective pressures today, that doesn't tell you much necessarily about ancient selective pressure so that one is difficult to implement. The second one is the fossil record. We've seen an example when we talked about bipedalism versus large brains. Yes, there are some things you can tell about the fossil record of humans, but very little unfortunate in terms of behavior behaviours, notoriously dumb, fossilized, or certainly not directly.

And then the third one is the comparative analysis, comparative genetic analysis. And again, there we are. It's just a matter of bad luck.

We don't have a lot of relatives or close relatives who are alive, a lot of other species. In fact, every other species have gone extinct, possibly because we clubbed to death.

But that's another story.

And we have to consider this species of chimpanzees, right? The chimpanzee and the bonobos. The problem with that is, A, they're not really that close related. They're actually separated by several million years from the human lineage. And second, they're very different between themselves. So if you make any comparison, in any case, you can you can you're going to start making about, for instance, that human beings are aggressive because chimpanzee aggressive.

The bonobos will give you the counterexample and at that point, you're stuck. So those are the reasons why it's difficult. Again, I wouldn't go as far to say it's important, but it's really difficult to do that sort of analysis that otherwise in other areas of evolution, evolutionary biology are pretty straightforward.

So what do evolutionary psychologists try to do to reach some explanation of of unique human behavior that you think is flawed? Well, try something.

They must try something. Right. So, first of all, there are a lot of there's a lot of research in that area that it's not that doesn't go under the heading of evolutionary psychology. A lot of the best paper is actually on the evolution. Human Behavior are published by in the general field of behavioral ecology and evolution.

And those are the cases that, as I was mentioning earlier, of behaviors that are actually compared across a large number of species. So that's privileged.

That's right. Tell me about the knowledge and the knowledge. It is the stuff that, again, that again is is is both unique to humans and universal among humans. About those. I think that honestly, one can say very, very little, precisely because there is essentially no comparison you can make and in the modern environment, a significant difference from for the old ones. So, you know, the classic example of that is this book that came out a few years ago on the natural history of rape.

And there are two authors, Tony Thornhill and Palmer. One of them is an evolutionary psychologist. The other one is an anthropologist, actually a physical anthropologist. And, you know, they published a whole book about obviously an interesting human behavior. But but even they couldn't agree whether that behavior was a result of natural selection or was a byproduct of something else. And because so one possibility is that rape is a so-called secondary sexual strategy. That is a male who is at a disadvantage cannot get the female by the by the regular standard way of buying flowers or driving Ferraris, then tries to second the other alternative.

That's one possibility. I mean, it's certainly not impossible. As a matter of principle, it's a possibility. The other the scenario one can easily imagine, however, is that rape. Is a byproduct of certain kinds of aggressive human behavior that are typical and are present in human males for a variety of reasons and have to do with self-defense the ability to hunt, and they can be explained by certain physiological characteristics, such as surges in testosterone levels and so on and so forth.

So is it a byproduct or is it a result of natural selection? Even the two evolutionary psychologists couldn't agree on that. And the reason for that is because we know nothing about the pertinent selective pressures when the trait allegedly evolved. Now, we should say one thing. I should add one thing just just to make clear about how controversial this whole area is.

That book got vilified in by some reviewers simply for opening up and out the possibility that despicable behavior such as rape evolved, even though the authors were very clear that the fact that something involves absolutely doesn't license anything about moral permissibility of certain behavior in philosophy.

As you know, we talked about this in the past. There is a there's a distinction between is and art. There's a distinction between matters of fact, the matter of value. And so even even even if you can show that, say rape is an adaptive behavior favored by natural selection, well, so too bad for natural selection. We live in a society where we don't want to condone that sort of that sort of behavior. And the others were very clear about that.

And despite that, they got attacked essentially to imply for implying that somehow that was if a behavior evolves, there is a past that one can get it out of natural selection. That's certainly not the case. But it is, unfortunately, the case that a lot of pop, evolutionary psychology, evolution, psychology that gets published in magazines or books for the conception, for general public consumption, they don't make that distinction quite that clear.

And they you know, we read constantly things like, well, you know, no wonder men cheat on women. That's because it's it's a natural thing to do. Is the result the natural selection for these or that kind of behavior? Well, first of all, we don't know. And second of all, it doesn't license that conclusion. I mean, that the major problem with evolutionary psychology in terms of the general public is precisely that very few of the evolutionary psychologists who write for the general public make clear that these are just hypotheticals and that they do not have, you know, moral consequences for Masimo.

One of our commenters named Lulla Walwa argued that your criticisms of evolutionary psychology apply equally to regular psychology. Would you agree with that?

No, because the reverse psychology does not actually it does not propose a theory of the historical origin of human behaviors. Regular psychology deals with current human behavior, and it's its description, the possibility of predicting human behavior under certain conditions. And when we're talking about cognitive science is more broadly, it's concerned with the physiological basis of that behavior. So, you know, what kind of brain structures are involved in? What kind of hormones are linked causally to do what kind of behavior?

There is no overall theory of in psychology these days that tells us why human beings do things in a certain way rather than another.

This is this wasn't always the case. I mean, psychology started out at the end of the 19th century and the beginning of the 20th century with the idea that there must be an overall overarching theory.

Of course, Freudian psychoanalysis is one of the best known examples, but those theories failed. Very few modern psychologists you take seriously anything like Freudian or Jungian psychoanalysis as a psychological theory, as an overarching duty of psychology. So the idea is that right now psychology doesn't really have an overarching theory, which, of course, is why a lot of people are so interested in evolutionary psychology, because evolution might, in fact provide psychology with sort of the overarching theory that has been missing for the better part of the 20th century.

But that possibility in itself, it's it's not enough to make evolutionary psychology viable.

So, Masimo, based on your criticisms of evolutionary psychology, I think it's probably appropriate to quote the geneticist, Richard Lewontin, who said, I must say that the best lesson our readers can learn is to give up the childish notion that everything that is interesting about nature can be understood. It might be interesting to know how cognition, whatever that is, arose and spread and changed, but we cannot know.

Tough luck. Yeah, that's that's the one thing. All right. He was actually a major influence in my early career. I started as a biologist focusing on gene interactions precisely because that's the field where what he works is a geneticist, a molecular biologist. I think he's just retired recently from Harvard, but he was one of the most influential figures in evolution and genetics over the.

Part of the second half of the 20th century and yeah, that sounds like vintage, they want them. And on that cheerful note, we're going to wrap up this section of the podcast and move on to the rationally speaking, PEX.

Welcome back every episode, Julie, and I think a couple of our favorite books, movies, websites or whatever tickles our irrational fancy. Let's start with Julia Spik.

Thanks, Massimo. My pick is a book called Stumbling on Happiness by Daniel Gilbert. I picked it up because in a recent episode of the podcast, we were talking to Jennifer Michael Hecht about research on happiness. And she mentioned that she is skeptical of some of the research by people like Daniel Gilbert, which shows that people in seemingly miserable life situations are actually happy.

So what I found in reading Gilbert's own book is that he's actually very forthright about how profoundly problematic it is to try to study happiness.

And one example that he uses is a pair of conjoined twins joined at the head, I believe, which is a life that most of us imagine would be horrible. And yet the twins in question claimed to be quite happy with their lives. So, first off, we might be tempted to say that, well, they only think they're happy because they don't know what they're missing.

They've never had a normal life. Well, on the one hand, maybe not knowing what you're missing does actually allow you to be genuinely happy in situations where the rest of us who who would know what we're missing could not be happy, in which case we would be wrong to doubt their claims of happiness.

But then, on the other hand, it could be that they actually are less happy than non conjoined people and they just don't know it.

So even if they report their happiness level to be they are seven out of 10 and I report my happiness to be a seven out of 10, it could be that their seven represents a lower actual level of happiness than my seven. So in other words, the scale of possible happiness that they're envisioning when they answer the question is like a squished version of mine. So it's just really hard to make these comparisons. There's a lot more on this example, and I encourage you to pick up the book.

But I'll just conclude by saying that I left the book with the impression that I'm not sure whether it is even conceivably possible to compare to people's happiness reliably or even one person's happiness at different points in their life.

So I don't know exactly what Jennifer's reasons were for dismissing Gilbert's research, but at the very least, I should say that it is far from straightforward how we should think about this field.

And what is your level of happiness right now? Oh, I'm nine point seven thirty four. That's good enough. Roughly.

My pick is a book also. It's by a Canadian researcher and philosopher, Norman Balagan. The title of the book is A Short Course Intellectual Self-Defence, and it is actually the book that I use for my critical thinking class, which I teach every fall semester at the university. The phrase, the title, of course, an intellectual self defense comes from a famous phrase by Noam Chomsky, who said that My personal feeling is that citizens of the democratic societies should undertake a course of intellectual self-defence to protect themselves from manipulation and control and to lay the basis for more meaningful democracy.

Or, as I tell my students, they're about to start a course in bullshit detection. And you know who who doesn't want to do that. So it's a great book. It's a it's a short introduction to critical thinking.

It goes through the logical fallacies, both formal and informal. It talks about mathematical terrorism, which is the way in which we're terrorized by numbers and statistics because we can't wrap our minds around them. And it gives the reader a lot of interesting suggestions for basically cutting numbers to size so that we can understand what it is that we read in newspapers or watch on TV. It's a it's a very nice read, so I highly recommend it. Again, the title is A Short Course, Intellectual Self-Defence.

I love the way this guy has framed skepticism and critical thinking and sort of like a gangster terrorist fighting movie. This is really the lesson from this is that is that for the rationalist skeptic movement to succeed, we need to to frame it as like a high stakes gunfight.

It is. That's a good idea. All right.

We're running out of time. So I'll just remind all of our listeners that the rationally speaking podcast is brought to you by the New York City skeptic's. And we invite you to show your support by visiting our website, NYC Skeptic's Doug, and to consider becoming a member for now. This concludes another episode of rationally speaking. Join us next time for more explorations on the borderlands between reason and nonsense.

The rationally speaking podcast is presented by New York City skeptics for program notes, links, and to get involved in an online conversation about this and other episodes, please visit rationally speaking podcast Dog. This podcast is produced by Benny Pollack and recorded in the heart of Greenwich Village, New York. Our theme, Truth by Todd Rundgren, is used by permission. Thank you for listening.