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In my seemingly endless writing on multilevel selection (my first article was published in 1975), I often lament that the general public lags so far behind the peer-reviewed literature. The former still thinks that group selection has been rejected in favor of kin selection and all that, whereas the latter has embraced the concept of equivalence.

Equivalence notes that theories can differ, not by invoking different causal processes, but by offering different perspectives on the same causal processes. Three metaphors can make the concept of equivalence clear (see my book Does Altruism Exist? for a fuller treatment). Imagine a graph that shows the distribution of a variable (such as body weight) and calculating a mean and variance from this data. The two summary statistics look different from the distribution but they are based on the same numbers and there is a way to translate between them. Actually, the translation only flows one way, because the summary statistics can be calculated from the distribution but the distribution cannot be recovered from the summary statistics. Many distributions can result in the same mean and variance; a fact to which I will return below. 

Second, imagine two people who speak different languages—say, English and Spanish—declaring that each other’s languages are confusing and wrong. Maybe they’d change their minds if they became bilingual. Then they might appreciate the different perspectives offered by different languages.

Third, imagine that you decide to climb a mountain with a friend and are standing together to plan your ascent. You decide that it would be better to view the mountain from different locations to get a better sense of its contours. It’s the same mountain, but it can usefully be seen from different vantages.

These three metaphors illustrate the concept of theories that invoke the same causal processes but deserve to coexist by virtue of their different perspectives. The controversy over group selection that emerged in the 1960’s seemed as if one theory could be rejected in favor of another, but it was really more like monolingual people declaring each other to be confusing and wrong. Thankfully, the scientists closest to the subject, who contribute to the peer-review literature, have become more multi-lingual. If only the general public would catch up!

Jonathan Birch is definitely a scientist close to the subject, but in a recent academic article titled “Are Kin and Group Selection Rivals or Friends?” he offers an account of equivalence quite different from my own. Yes, equivalence has become the consensus among the cognoscenti, but it hasn’t really drawn the two sides closer together. Moreover, equivalence has become “a purely statistical formulation” that isn’t really worth wanting. Perhaps we should be drawing distinctions between kin selection and group selection after all, in what Birch calls a “K-G space”.

I agree with about half of Birch’s analysis but disagree substantively with the rest. Rather than debating the issues by trading articles in the peer-reviewed literature (a process that can require years), I invited him to have a conversation on TVOL and he graciously accepted. TVOL readers can think of it as a Master class in kin selection, group selection, and all that. The best way to prepare is by reading Jonathan’s academic article, which is open access.  

David Sloan Wilson (DSW): Welcome Jonathan! I admire your work and look forward to taking a deep dive with you. Please introduce yourself to our audience. What is your academic background and what drew you to the study of social evolution?

Jonathan Birch (JB): I started with an undergraduate degree in Natural Sciences at Cambridge, gravitated towards the excellent History & Philosophy of Science Department they have there, and then took a PhD in philosophy of science.

At first, my main motivation was to understand what an organism is. Bacteria, trees and elephants are organisms, whereas biofilms, forests and herds of elephants are not. Organisms, though, are themselves groups of lower-level entities (cells, organelles, etc.). So what does it take for something to constitute an organism rather than a group? Obviously, it has something to do with “integration”, but this is just restating the problem: what kind of integration does the job and why? And what should we say about really integrated groups like ant colonies—the kind of groups many (including you, I think!) want to call “superorganisms”?

I still don’t have a good answer to these questions. But they’re the questions that led me towards social evolution theory. I came across the idea (in a paper by Dave Queller and Joan Strassmann) that organisms are literally nothing more than social groups with very high levels of cooperation and very low levels of conflict. That led to a lasting interest in trying to understanding social evolution theory—and in seeing whether it can help explain the origins and nature of organisms.

DSW: Thanks! Let me begin by outlining what I see as our zone of agreement. I think it’s safe to say the we are both multi-lingual and can speak the “languages” of not just two but a whole family of theories of social evolution—group selection, kin selection (aka inclusive fitness), evolutionary game theory (aka reciprocity), selfish gene theory, extended phenotypes. New terms continue to be coined, such as “social selection”. Why these perspectives proliferate is an interesting question, suited for sociologists, historians, and philosophers of science as much as practicing scientists.

We agree that something called equivalence has become the consensus view among the cognoscenti. But I’d like to push back on the impression you give in your article that the two camps are as far apart as before. When I was a graduate student in the 1970’s, it was almost mandatory for authors to assure their readers that group selection was not being invoked. Now it is almost mandatory to acknowledge equivalence. That’s a huge difference! I, for one, always acknowledge that the gene-centered view is insightful, as long as it’s not used as an argument against group selection. To pick someone from the “other side”, Andy Gardner has made a useful contribution to MLS theory which includes the statement “social evolution theorists now widely agree that a covariance between group trait and group fitness may arise in the natural world, resulting in a response to group selection.”  Please—let’s acknowledge the progress that has occurred!

JB: This is progress! And yet, I’m still troubled by the divisions that clearly exist.

Andy Gardner’s paper is an example: although he acknowledges that group selection can happen, and acknowledges a form of equivalence, he goes on to claim that “there can be kin selection in the absence of group selection, as defined above, even in populations that are structured into clearly defined kin groups.”

Gardner’s argument is that, although kin and group selection (or multi-level selection, MLS) theory are “equivalent” when applicable, kin selection theory is the mathematically richer of the two, and the one that is better able to handle complexities like class structure (i.e. populations where you have distinct classes of organism such as “worker” and “queen” that differ in their reproductive value). This point about methodology is then taken to imply that group selection is “absent” when you have class structure.

The other side of the divide is well illustrated by the last sentence of your 2007 paper with E. O. Wilson. This paper too acknowledges equivalence, but ends with the line: “Selfishness beats altruism within groups. Altruistic groups beat selfish groups. Everything else is commentary.”

The sentiment being expressed here, if I’m reading it correctly, is that, equivalence notwithstanding, the group selection tradition has latched on to the fundamental causal explanation of why altruism evolves. All the kin selection tradition has done is develop a unhelpful way of expressing that insight that buries it deep in a superficially group-free formalism.

To return to your linguistic analogy, both sides seem to regard the other as a bit like Pig Latin, where you move the first letter of each word to the end. Yes, all the same claims can be expressed in that language, but why on earth do you think that’s a good idea?

DSW: There is a lot to unpack here. I think it is important to distinguish between two debates taking place in parallel and—being debates–both have two sides.  The first debate is about the virtues of different mathematical and statistical formalisms, which you describe in your article. This is what Gardner means when he describes his model of kin selection as “mathematically richer”. On the other side we have the infamous Nature paper by Martin Nowak, Corina Tarnita, and Ed Wilson asserting that their mathematical formalism is better than inclusive fitness theory.

The second debate is about causal processes that can be described in words, graphs, computer simulations, or any number of formal analytical models. Darwin’s theory of natural selection is like this. It is a series of three causal claims that can be described in words: 1) Individuals vary; 2) Their differences make a difference in terms of survival and reproduction; and 3) Offspring resemble their parents. Therefore…

Of course, the verbal description can be enhanced with models of various sorts, which have the virtue of precision but also the limitation of their simplifying assumptions. The more complex the real world being modelled, the greater the limitations of the models. The physics of celestial bodies rotating in space hits a complexity wall going from two bodies to three bodies. Population genetic theory hits a similar complexity wall going from two-locus to three-locus models, not to speak of the whole genome!

Against this background, the need for group selection can be seen as an addendum to Darwin’s theory of natural selection that can be described in words: 4) Prosocial behaviors oriented toward the welfare of others usually require time, energy, and risk on the part of the individual actors; 5) In the absence of other reinforcing behaviors such as rewards and punishments, this places prosocial individuals at a direct fitness disadvantage, compared to more self-oriented individuals with whom they interact, who receive social benefits without providing them;  6) Social behaviors are almost always expressed among sets of individuals (groups) that are small compared to the total evolving population; 7) To find the direct relative fitness advantage of prosocial behaviors, it is necessary to go up in scale. Groups (as defined above) with a higher frequency of prosocial individuals collectively survive and reproduce better than groups with a lower frequency of prosocial individuals. This is what Ed Wilson and I summarized with our pithy “Selfishness beats altruism within groups. Altruistic groups beat selfish groups. Everything else is commentary.”

Against this background, equivalence in the causal sense of the term asserts that most theories of social evolution reflect claims 4-7. Notice that this generality requires a certain definition of groups. Define groups another way, and the generality goes away. Also, I have been careful to use the term “direct fitness” and added the caveat “in the absence of reinforcing behaviors such as rewards and punishments”. I will elaborate on these points below. For now, the main point I want to make is this one:  Like the theory of natural selection described in statements 1-3, MLS theory is a series of causal claims that can be stated in words (statements 4-7) without requiring mathematical or statistical formalisms at all. This is the second debate that takes place in parallel to debates about whose mathematical formalism is the best. Are we in agreement on these points?

JB: I think so! I agree that the core commitments of MLS theory can be stated verbally, and the theory doesn’t need to be wedded to any specific formalism.

Your claims 4-7 raise the question of what constitutes a group, and this seems like a crucial question to me. Your claims, as you note, rely on a very broad definition of group. And you assume that, even when group is defined in this very broad way, it still makes sense to talk about groups “collectively surviving and reproducing”. There is room for debate here. I think it might be a more substantial notion of a group, one requiring really tight integration, that gives rise to genuinely collective reproduction.

I talk in my Current Biology essay about the “quest for generality”. Both the kin selection modelling tradition and the multi-level tradition have sought, over the years, to cover as wide a range of cases as they possibly can. On the kin selection side, this has led to a broadening of the concepts of “relatedness”, “cost” and “benefit”. For example, relatedness is understood to encompass any kind of genetic assortment. It sometimes seems as though little importance is attached to the question of whether social partners are close genetic kin.

On the group selection side, the quest for generality has led to a remarkably broad definition of “group”, as captured in your “trait-group” concept. Trait-groups can be very ephemeral, very unstable, and they can be “continuous” rather than discrete: the groups can blur into one another, without sharp boundaries where one group ends the other begins.

“Group” has to be defined in this very broad way for it to be the case that groups are present wherever altruism evolves. They have to be defined in this broad way for your slogan to be true. An example that brings this out is a “one-shot” two-player game where the players interact once, then disappear back into the population and never meet again. Altruism can evolve in such a model if the players’ genotypes are correlated. For your slogan to be true, you have to say that these two organisms, who interact once during their entire lifetime, form a “group”. That’s a broad definition of “group”.

In the essay, I push back against this a little bit. I suggest that it may be more helpful to reserve the term “group selection” for those cases where reasonably enduring, stable, well-bounded groups can be identified. (I call the degree of well-bounded and stable group structure “G”). On the other side, I suggest it may be more helpful to reserve the term “kin selection” for those cases where there is whole-genome relatedness between real genetic kin (I call the degree of whole-genome relatedness “K”). That makes it possible to have an empirically-driven debate about the relative importance of these causal factors.

If you think about the distinction my way (and perhaps we’ll come back to this), there will be some evolutionary processes that are clearly kin selection and not group selection at all, some that are clearly group selection and not kin selection at all, some that are both, and some that are neither. They are neither equivalent nor mutually exclusive. Instead, we think about them as things that come in degrees. A given process has a degree of “kin selection character” and a degree of “group selection character”. In the article, I explain how we can plot these variables in what I call a “K–G space”.

DSW: I will come back to this, but first I’d like to unpack the caveat “in the absence of reinforcing behaviors such as rewards and punishments”. It is intuitively obvious that altruism can beat selfishness within groups if altruism is rewarded and selfishness is punished by other members of the same group. To understand what is going on in detail, we must think about rewarding and punishing as separate traits that coevolve with the altruistic trait being reinforced. For example, punishing selfishness requires time, energy, and risk on the part of the punisher, which creates a direct relative fitness disadvantage compared to non-punishers within the same group. Invoking punishment to explain the evolution of altruism doesn’t change the problem, but merely relocates it to the punishing trait. Ditto for time, energy, and risk required to reward altruists. Agreed?

JB: That’s right—punishment itself calls for explanation, and it sometimes leads to “second-order free rider problems”, if individuals stand to gain from leaving all the punishment to others.

The exceptions are cases where the punishment is directly beneficial to the punisher in some way. For example, worker ants in many species are not fully sterile, but they will “police” each other’s egg-laying, eating any eggs they find. Eating the egg may be directly beneficial to the eater—at the very least, it offsets the energy cost.

DSW: Agreed. As for the distinction between direct vs. indirect fitness, this is worth spending time on to get it right. I said that we would be taking a deep dive! The concept of indirect fitness is the hallmark of inclusive fitness theory and requires calculating the effect of a behavior on the gene influencing the behavior in both the actor and the recipients of the behavior. To see how this works in a model of social interactions among full siblings, imagine a mutant dominant gene for altruism (A) in a large population of selfish individuals (a). Because it is the only one, the mutant gene exists as a heterozygote (Aa) that mates with a selfish homozygote (aa) and produces a clutch of offspring that socially interact with each other. It doesn’t matter whether the siblings confine their interactions to each other because they are spatially isolated or because they are capable of recognizing each other. It is the social interactions, and not the physical appearance of a group to our eyes, that counts.

In the sibling group, the altruists (Aa) exist at a frequency of about 50% (there will be sampling error around this mean). Altruists deliver a benefit (b) to their siblings at a cost (c) to themselves. They always bear the cost and the recipient shares the altruistic gene 50% of the time, so there is a net increase in copies of the altruistic gene (A) when c-(0.5)b>0. This is the inclusive fitness of the altruist, compared to its direct fitness of -c. However, we have not yet calculated relative fitness within the sibling group. There is an even larger increase in the copies of the selfish gene because selfish siblings are the recipients of altruism the other 50% of the time and they never bear the cost. Hence, calculating indirect fitness rather than direct fitness does not alter the conclusion that the altruistic gene is less fit than the selfish gene within every sibling group containing both genes.

To know whether the altruistic gene evolves in the total population, we need to compare the fitness of the two genes averaged across all of the sibling groups. The altruistic gene exists in only one group so its fitness is c-(0.5)b. In a large population, almost all of the selfish genes exist in sibling groups comprised entirely of selfish individuals. The lucky few selfish genes that exist in the sibling group with altruists are such a small proportion of all the selfish genes that they can be ignored. Hence, the altruistic gene increases in frequency in the total population when (0.5)b-c>0. This is Hamilton’s rule. It correctly predicts when altruism evolves in the total population, but obscures the fact that altruism evolves only by virtue of a fitness difference between groups and not a fitness difference among individuals within the group of socially interacting individuals.

It is important to stress to our readers, and to agree between ourselves, that everyone at the time, from Hamilton on down, thought that inclusive fitness theory explained the evolution of altruism without invoking group selection. It was only by encountering the Price equation that Hamilton realized that altruism is selectively disadvantageous within each and every kin group containing both types (the negative within-group component of the Price equation) and requires the differential contribution of groups to the evolving populations to evolve (the positive between-group component of the Price equation). Whatever we might say about the failings of a statistical partitioning method such as the Price equation, it did deliver this fundamental insight to Hamilton. And Hamilton was happy to embrace the conclusion! This makes it especially intriguing why so many of his followers couldn’t follow him in this particular respect.

To summarize, equivalence can be argued in causal terms, so it need not be an argument about mathematical formalisms or statistical abstractions. In addition, once we appreciate the limitations of formal models (their need for simplifying assumptions) in addition to their strengths (precision), then there will always be a diversity of formal models addressing complex topic in physics, biology, or the human social sciences. The idea that one formalism is superior to all the others emerges as wrongheaded.

JB: Yes—I support a genuine pluralism in this area, where researchers make free use of kin and group selectionist methodologies and “speak both languages”, as it were.

And one the goals of my Current Biology essay is to encourage people to read Bill Hamilton’s 1975 paper on “Innate Social Aptitudes of Man”, in which an argument for equivalence based on the Price equation is made for the first time. Hamilton, I think, has a nuanced and appealing way of thinking about the concepts of kin and group selection, and my “K–G space” is inspired by a quotation from the paper.

I don’t agree with everything you said, however. When you say that the inclusive fitness approach “obscures the fact that altruism evolves only by virtue of a fitness difference between groups”, that sounds like the type of “Pig Latin” accusation I mentioned earlier. Hamilton says: altruism evolves by virtue of an inclusive fitness difference between individuals. You say: altruism evolves by virtue of fitness differences between groups. Both are correct descriptions in different languages, so why say that one “obscures” and the other reveals?

DSW: I think that I can say this based on the history of the subject. We have to remember that the main context for thinking about group selection, starting with Darwin, was not the evolution of cohesive groups that we associate with major evolutionary transitions, but the problem explaining the evolution of single prosocial behaviors, despite their local relative fitness disadvantage. When modelers such as Sewall Wright, Ronald Fisher, and J.B.S. Haldane tackled this problem (which they did only briefly), each made different specific assumptions about the groups, since the purpose of their models was to capture the gist of the problem, similar to Darwin talking about “tribes” and “communities” in words.  V.C. Wynne Edwards was not a modeler. He gestured toward Sewall Wright for that kind of authority and proceeded to describe a diversity of population structures, including some that did not have sharp group boundaries. Gregory Pollock has written an important article on this subject that deserves to be widely read. Discrete group boundaries are prominent in the theoretical literature because they are mathematically tractable, not because naturalists such as Wynne Edwards thought that they must be important.

Despite their diversity, what all of these models and verbal descriptions shared in..

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The Federalist Papers explained how a UNION formed by the 13 states would provide collective benefits that the states could never achieve on their own. Not just defense, but many other collective benefits. It’s right there in the Constitution, which defines “promote the general welfare” along with “provide for the common defense” as critical roles of government.

But those benefits weren’t possible without a central government with the power to constrain and regulate the states. The Federalist’s authors understood that any political UNION must constrain lower-level interests; not only each state wanting to preserve its autonomy, but also commercial interests and indeed anyone who sought to profit from undermining, rather than contributing to the common good.

All nations have the same problem, which is why the influence of the Federalist Papers extends far beyond the USA. But 200+ years of refined thought since the Enlightenment allows us to generalize the main theme of the Federalist Papers beyond anything imagined by its authors, extending to all animal societies and indeed all living processes.

Every animal society experiences the same tension between the need to cooperate to achieve collective benefits and the disruptive pursuit of lower-level interests. In most cases, evolution results in what America would have been like if the Constitution had not been ratified: a degree of cooperation but also a lot of internal strife. In chimpanzees, one of our closest primate relatives, violent clashes to assert self-interest are over 100 time more common than in small-scale human societies. Even cooperation usually takes the form of tiny alliances clashing with other alliances. We would hate to live in such a society, just as we hate to live in human societies riven by internal conflict.

But in some animal societies, evolution results in what America became thanks to the Constitution: A well-regulated higher-level UNION that succeeds by suppressing the potential for disruptive competition and exploitation within its ranks. Examples include the social insects—the bees, wasps, ants, and termites–whose colonies invite comparison to a single organism (or super-organism). We might not want to live in these societies either—who wants to be a worker bee?—but we cannot help but admire their industry and internal harmony and to wish some of the same for our own societies. That’s why “Industry” is the official motto of the State of Utah, accompanied by the symbol of a bee hive.

Astonishingly, every entity that we call an organism, from a single-celled amoeba to the trillions of cells in your body, is a society of lower-level entities that live in harmony because evolution resulted in something like the American Constitution—a set of mechanisms that suppresses disruptive lower-level competition so that the whole can function as a cooperative unit. Life itself likely began as social groups of cooperative molecular interactions.

Although biology confirms the Federalist’s logic in politics, it is ignored by modern-day politicians and economists who portray regulation as categorically bad. Biology teaches us that an unregulated organism is a dead organism.

This is what 200+ years of refined thought adds to the Enlightenment values that informed the American forefathers. The multilevel governance needed to form higher-level, more perfect UNIONS in human society can be understood against the background of evolutionary forces that explain the presence and absence of cooperation in all living processes.

Read the full series “Darwinizing the Federalist Papers” below:

  1. Preamble
  2. On the Origin of Socialist Darwinism
  3. More Perfect UNIONS Must Regulate Their Parts

Image: “Cooperators vs. Self-Maximizers” by Julia Suits

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Socialist Darwinism is the idea that natural selection promotes societies that cooperate as moral communities. This concept actually predates Social Darwinism, which later emphasized competition and individualism. Socialists throughout the 1860s-70s praised Darwin’s theory as promoting progressive social change.

As Eric Michael Johnson has documented in The Struggle for Coexistence (pdf here), the earliest consistent application of Darwin’s ideas for human society can be classified as Socialist Darwinism. For these authors, evolution demonstrated that the inequality maintained by institutions of God and State were not facts of nature but were imposed by power and privilege. It was therefore necessary for society to be redesigned from the bottom-up following scientific principles.

“I am a Socialist because I am a believer in Evolution,” wrote the women’s rights activist Annie Besant. She saw in Darwin’s work the clearest evidence yet that the status quo was not divinely ordained. Social species had evolved traits for cooperative behavior and humans, the most social of all animals, displayed the most elaborate moral instincts. Because evolution had shaped human physiology, behavior, and mind, Besant concluded, “it was not possible that Evolution should leave Sociology untouched.” Like Besant, many nineteenth-century socialist scholars, scientists, and activists quickly deployed Darwin to challenge the status quo.

The most prominent advocate for Socialist Darwinism was the Russian prince and naturalist Peter Kropotkin. His 1890 papers on “Mutual Aid Among Animals” (later published as the book Mutual Aid: A Factor of Evolution in 1902) synthesized the argument promoted by the “Darwinian Left” over the previous thirty years. In the process, Kropotkin closely hewed to Darwin’s theory of natural selection and demonstrated how the feeling of sympathy could evolve to form the basis of human morality.

The one factor that united diverse Socialist Darwinists across England, Europe, and Russia was a commitment to building on Darwin’s “moral sense.” For group-living species, natural selection had promoted traits that emphasized sympathy and cooperation. They believed it was wrong to ignore what Darwin called “the noblest part of our nature” in our efforts to improve human society.

In contrast, those who would later be called Social Darwinists (the term did not become widely used until the 1940s) claimed that the state of nature was nothing but brutal competition. Thomas Henry Huxley called nature a “gladiator’s show” and denied that morality had evolved in humans. Huxley, Herbert Spencer, and Francis Galton differed in their views in important ways, but all believed that natural selection was purely competitive and that society should be organized to ensure that the best rose to the top so the privileged could be protected against the supposed “unfit.”

Modern evolutionary science shows that cooperation is just as important in nature as competition. In group-living species, those traits promoting mutual aid often succeeded over traits promoting individualism. The first advocates of Socialist Darwinism were correct about this aspect of Darwin’s science. Solidarity is a fact of life—even between species. We could not live without our microbiomes, for example.

The first Socialist Darwinists didn’t get everything right. Today we know much more about how cooperation and competition can be blended in the right way. However, the origin of Socialist Darwinism reveals that seeing society through a Darwinian lens does not mean an endorsement of brutal competition. By taking Darwin seriously about “the noblest part of our nature,” we can complete the Darwinian revolution and build upon that which is best in ourselves. 

Read the full series “Darwinizing the Federalist Papers” below:

  1. Preamble
  2. On the Origin of Socialist Darwinism

Image: “AOC Reads Mutual Aid” by Julia Suits

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Routine infant circumcision is a common practice in the US today. Opinions on the practice are highly polarized, from those who advocate it as merely cosmetic and a parent’s choice to those who see it as a human rights violation and an assault against bodily integrity and healthy sexuality. The rationale culturally used to justify the procedure include “medical benefits” and “low risks;” these arguments disregard foreskin as a functionless, vestigial remnant of our primitive past. An ancestral perspective, on the other hand, suggests that we should give nature the benefit of the doubt: first, we should consider the possibility that foreskin serves valuable functions and that its loss may be felt not only in the short term, but also the long term, before we assume that no essential harm is done in removing it.

Circumcision, as a US cultural phenomenon, is not primarily Jewish in origin but traces back to the late 19th century. Medical theories of the time credited excessive levels of bodily “irritation” with producing countless ailments: from paralysis to kidney dysfunction to epilepsy. Removal of the foreskin (as the object of irritation) was deemed a cure. [1] In addition, during late Victorian times when masturbation and sexual excitement were given similar attribution for illnesses of all sorts, foreskin removal was recommended as a preventative measure [2]. The crusade against sexual excitement applied to women as well as men; only in 1996 did it first become illegal to excise portions of the genitals of female minors [3] (before which, many American women were subjected to the such excisions [4]).

Male foreskin, like female foreskin (the latter more familiarly known as the clitoral hood), is highly specialized tissue which cannot be interpreted simply as an excess of skin. [5] At birth, male foreskin is fused to the penile glans by the balanopreputial membrane to barricade against foreign bodies and to resist infection. [6] Infant circumcision destroys this membrane, leaving the glans a large, open wound. Left intact, the membrane dissolves naturally by adolescence, facilitated by the boy’s natural exploration of his own genitals without any caregiver intervention [7].

Circumcision is cogently described by one internet meme as “the only surgery where amputation is performed before treatment, for a problem that hasn’t even arisen.” There is no extant medical parallel. Each time a supposed medical benefit has been disproven, another has been suggested in its place. The American Academy of Pediatrics currently cites “benefits” as reduced rates of three medical pathologies: urinary tract infections (UTIs), penile cancer, and sexually transmitted disease (STD) transmissions (specifically including HIV) [8]. With regard to these supposed benefits:

  • UTI risk is very low for boys overall (between 1-2% by age 10 [9], compared to as many as 1 in 3 women by age 24 [10]). UTIs are readily treatable through less invasive means. Because reduction in male UTI rates is confined to the first year of life, it is worth considering the possibility (and perhaps likelihood) that the higher rates of UTIs in intact boys aged less than one year could result from caregiver errors, such as misguided attempts to prematurely retract and clean under the foreskin (which is painful, unnecessary, and damages the balanopreputial membrane) or from the introduction of soap under the foreskin which becomes trapped and disrupts the natural microbiome of the penis.

  • Penile cancer is extremely rare, affecting as few as 0.58 in 100,000 men per year (and declining) as of 2002. [11] While evidence has shown that penile cancer appears more frequently in uncircumcised men, a 2005 study reported that “When we restricted our analysis to men who did not have phimosis, the risk of invasive penile cancer associated with not having been circumcised in childhood was not elevated.” [12] This again suggests that considering circumcision status alone may not be as pertinent as to consider the factors surrounding and contributing to phimosis — such as forcible retraction of the foreskin before it is fully retractable and the long-term damage that such improper care may inflict.

  • Questions of sexually transmitted infections are both irrelevant to infants and highly speculative about an individual’s future adult sex life. Given that safe sex practices such as condom usage are known to be highly effective against STDs (more so than circumcision status) and that any STD protection inherent in circumcision can be achieved when the individual is an adult (studies which have suggested circumcision efficacy have primarily been performed on adults), the only rationale for promoting infant circumcision for this purpose relies on the dual assumptions of being able to predict the child’s future preferences and the idea that a neonatal circumcision is substantially preferable to one elected as an adult.

All of these benefits are of very limited application and none justify a non-therapeutic procedure which inflicts extreme pain, carries risks (which, even if “rare,” can be extreme in their outcomes), permanently impedes function, and unnecessarily denies the individual the right to their whole body. A standard of “first, do[ing] no harm” requires taking these factors into consideration.

With regard to pain, when anesthesia is used at all (many physicians regard it as unwarranted), infant circumcision is performed only with local anaesthetic, not general. [13] The dorsal penile nerve block is seen as most effective, though not fully effective (and does not last during the days or weeks of subsequent healing for a procedure that inherently creates an open wound over the entire glans surface). [14] This may represent an underestimated infant trauma (a risk factor for many future adverse conditions) on the part of a high percentage of American males.

While the medical community describes the risks of circumcision as low, these risks do include death, bleeding, suture sinus tracts, infections, phimosis, concealed penis, adhesions, meatitis, meatal stenosis, fistulas, necrosis, and amputation of the glans or entire penis. [15] Even if rare, serious risks such as these are never justified for a non-therapeutic procedure.

Besides benefits and risks, however, entirely absent from informed consent discussions are the inherent costs to the male from removal of the foreskin. The following seven functions are permanently inhibited:

  • Protection: Intact, the foreskin is attached to the shaft by the sensitive frenulum while the dartos fascia provides tension to keep the opening closed to prevent introduction of microorganisms and debris. [16] The Langerhans cells and microbiome of the penis provide immune function help to combat infections. [17] [18] Removal of these leaves the glans and the urethral opening exposed and more vulnerable.

  • Sensation: Removal of the foreskin fully eliminates the “ridged band” at the distal tip of the (flaccid) foreskin, along the mucocutaneous junction. This area is populated by Meissner’s corpuscles, the fine touch sensors found in only specialized places such as the lips and fingertips. With their loss, sexual sensory input from the penis relies on free nerve endings found in the glans, which predominantly register sensations of pain and irritation. [19] As a result, sexual sensations can feel uncomfortable and excessively intense rather than being co-mitigated by the combination of these two types of sensations. [20]

  • Lubrication: Becoming an external structure causes the glans to become keratinized rather than maintaining its natural state as an internal, lubricated, mucosal structure. [21] This leaves it up to the female partner to provide 100% of lubrication, which is further challenged by the alteration in mechanical action (next).

  • Mechanical action: The retraction of the foreskin allows the penis to function as a rolling bearing in which the male and female mucosal tissue can come in direct contact while the epithelial tissue remains outside (and lubrication stays inside). This reduces the force needed for intromission by 90%. [22] Loss of this function also leads to every stroke drawing moisture out of the vagina, contributing to dryness and friction during sex (often then attributed to dysfunction in the female partner). [23]

  • Partner stimulation: The ridged band provides texture; the additional tissue of the foreskin increases the contact area between partners. Additionally, the male’s stimulation along the foreskin as it rolls back and forth encourages a shorter thrust length than when the glans is the primary locus of stimulation. [24] This shorter thrust style maximizes contact and pressure which stimulates a greater percentage of the female erogenous area.

  • Erectile stimulation: The foreskin contains stretch receptors whose function is to help maintain erections during stimulation and intercourse. Loss of these receptors likely contributes to reduced erectile function later in life as hormonal contributions decrease. [25]

  • Penis size: As the corpus cavernosa engorge, the penile tissue stretches out to accommodate the erection. If there is insufficient capacity, the skin surrounding the base of the penis will be pulled up onto the shaft (evidenced by hair appearing to reside on the shaft) or the erection will be compressed into the abdomen. Both reduce the effective external volume of the penis. Taylor (1996) notes that “The amount of tissue loss estimated in the present study is more than most parents envisage from pre-operative counselling.” [26]

Ultimately, the human right to bodily integrity, especially such that would promote the celebration of full sexual expression, should be enough on its own to discourage the practice of infant circumcision. In the meantime, we can hope that better education about the true costs associated with loss of one’s foreskin will encourage more doctors and parents to resist this unnecessary and detrimental practice.


[1] Gollaher, D.L., 2000. Circumcision: A History Of The World’s Most Controversial Surgery. Basic Books, New York, NY, pp. 73-101.

[2] Wallerstein, E., 1985. Circumcision: the uniquely American medical enigma. Urol Clin North Am, 12(1), pp.123-132.

[3] Legal Information Institute. 1996. 18 U.S. Code § 116 – Female genital mutilation.  Accessed December 6, 2016.

[4] Webber, S. and Schonfeld, T., 2003. Cutting History, Cutting Culture: Female Circumcision in the United States. The American Journal of Bioethics, 3(2), pp. 65-66.

[5] Cold, C.J. and Taylor, J.R., 1999. The prepuce. BJU international, 83(S1), pp.34-44.

[6] Denniston, G.C., Hodges, F.M. and Milos, M.F. eds., 1999. Male and Female Circumcision: Medical, Legal, and Ethical Considerations in Pediatric Practice. Springer Science & Business Media pp. 11-12.

[7] Agarwal, A., Mohta, A. and Anand, R.K., 2005. Preputial retraction in children. Journal of Indian Association of Pediatric Surgeons, 10(2), p.89.

[8] American Academy of Pediatrics Task Force on Circumcision, 2012. Circumcision Policy Statement. Pediatrics. September 2012, 130(3).

[9] Singh-Grewal, D., Macdessi, J. and Craig, J., 2005. Circumcision for the prevention of urinary tract infection in boys: a systematic review of randomised trials and observational studies. Archives of Disease in Childhood, 90(8), pp.853-858.

[10] Foxman, B., 2002. Epidemiology of urinary tract infections: incidence, morbidity, and economic costs. The American Journal of Medicine, 113(1), pp.5-13.

[11] Barnholtz-Sloan, J.S., Maldonado, J.L., Pow-Sang, J. and Guiliano, A.R., 2007, September. Incidence trends in primary malignant penile cancer. In Urologic Oncology: Seminars and Original Investigations (Vol. 25, No. 5, pp. 361-367). Elsevier.

[12] Daling, J.R., Madeleine, M.M., Johnson, L.G., Schwartz, S.M., Shera, K.A., Wurscher, M.A., Carter, J.J., Porter, P.L., Galloway, D.A., McDougall, J.K. and Krieger, J.N., 2005. Penile cancer: importance of circumcision, human papillomavirus and smoking in in situ and invasive disease. International Journal of Cancer, 116(4), pp.606-616.

[13] Stang, H.J. and Snellman, L.W., 1998. Circumcision practice patterns in the United States. Pediatrics, 101(6), pp.e5-e5. 

[14] Brady‐Fryer, B., Wiebe, N. and Lander, J.A., 2004. Pain relief for neonatal circumcision. Cochrane Database of Systematic Reviews, (3).

[15] Hutcheson, Joel C., 2004. Male neonatal circumcision: indications, controversies and complications. Urologic Clinics, 31(3), pp.461-467.

[16] Denniston, G.C., Hodges, F.M. and Milos, M.F. eds., 1999. Male and Female Circumcision: Medical, Legal, and Ethical Considerations in Pediatric Practice. Springer Science & Business Media, p.12.

[17] de Witte, L., Nabatov, A., Pion, M., Fluitsma, D., De Jong, M.A., de Gruijl, T., Piguet, V., van Kooyk, Y. and Geijtenbeek, T.B., 2007. Langerin is a natural barrier to HIV-1 transmission by Langerhans cells. Nature medicine, 13(3), p.367.

[18] Cold, C.J. and McGrath, K.A., 1999. Anatomy and histology of the penile and clitoral prepuce in primates. In Male and female circumcision (pp. 19-29). Springer, Boston, MA.

[19] Ibid.

[20] Bonobo3D, 2011. Interview with Dr. Ken McGrath on Anatomy of the Penis: Penile and Foreskin Neurology. [online video] Available at: https://www.youtube.com/watch?v=DD2yW7AaZFw [Accessed Jan 26, 2019]

[21] Cold, C.J. and Taylor, J.R., 1999. The prepuce. BJU international, 83(S1), pp.34-44.

[22] Taves, D.R., 2002. The intromission function of the foreskin. Medical Hypotheses, 59(2), pp.180-182.

[23] O’Hara, K. and O’Hara, J., 1999. The effect of male circumcision on the sexual enjoyment of the female partner. BJU International, 83(S1), pp.79-84.

[24] Ibid.

[25] Fink, K.S., Carson, C.C. and DeVellis, R.F., 2002. Adult circumcision outcomes study: effect on erectile function, penile sensitivity, sexual activity and satisfaction. The Journal of urology, 167(5), pp.2113-2116.

[26] Taylor, J.R., Lockwood, A.P. and Taylor, A.J., 1996. The prepuce: specialized mucosa of the penis and its loss to circumcision. British Journal of Urology, 77(2), pp.291-295.

For Further Reading:

Boyle, G.J., Goldman, R., Svoboda, J.S. and Fernandez, E., 2002. Male circumcision: pain, trauma and psychosexual sequelae. Journal of Health Psychology, 7(3), pp.329-343.

DeMaria, J., Abdulla, A., Pemberton, J., Raees, A. and Braga, L.H., 2013. Are Physicians Performing Neonatal Circumcisions Well Trained? Canadian Urological Association Journal, 7(7-8), pp.260-4.

Favorito, L.A., Balassiano, C.M., Costa, W.S. and Sampaio, F.J.B., 2012. Development of the human foreskin during the fetal period. Histology and histopathology, 27(7), p.1041.

Gairdner, D., 1949. Fate of the Foreskin. British Medical Journal, 2(4642), pp.1433-1437.

Halata, Z. and Spaethe, A., 1997. Sensory innervation of the human penis. In The Fate of the Male Germ Cell (pp. 265-266). Springer, Boston, MA.

Hammond, T., 1999. A preliminary poll of men circumcised in infancy or childhood. BJU international, 83(S1), pp.85-92.

Harryman, G.L., 2004. An analysis of the accuracy of the presentation of the human penis in anatomical source materials. In Flesh and Blood (pp. 17-26). Springer, Boston, MA.

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The Federalist Papers sought to convince the citizens of New York to adopt the newly written American Constitution. This would create a UNION (a word that they capitalized) capable of accomplishing more than any state alone and would showcase America’s Enlightenment experiment as an example for the rest of the world.

Today, that UNION is in such disarray that effectiveness of democracy itself is being doubted. Everyone knows the system is broken but no one seems to know how to do better. 

Until now, and from an unexpected source: The current incarnation of Darwin’s theory of evolution.

Many people link evolution with Social Darwinism, the idea that competition is the law of nature and deserves to shape human society. This view misses the point that cooperation is often the fittest strategy. In The Descent of Man, Darwin described how we, as a social species, survived only in interdependent cooperative groups, not as individuals. He wrote: “Selfish and contentious people will not cohere, and without coherence, nothing can be effected.”

A science of society built on the biological necessity of cooperation can be called “socialism” in the truest sense of embodying our inalienable social nature. Hence, we call the toolkit of ideas outlined in these papers “Socialist Darwinism”. Historically, the Socialist Darwinian focus on cooperation actually preceded the Social Darwinist focus on competition, and the former fits the latest evolutionary science better.

Socialist Darwinism, suitably updated, provides a practical toolkit for democratic UNIONS, at all scales, from small groups to the planet.  We can confidently say that these tools can help you become a better capitalist, or economist, or centrist, or socialist, or whatever–ist, because no -ist or -ism can work well with a false or partial description of human nature and social systems.

This toolkit doesn’t fit current political categories. It isn’t left, right, center or libertarian. It recognizes that markets are powerful engines of coordination but clarifies when self-interest, rightly understood, can robustly benefit the common good. It focuses directly on the welfare of society while recognizing the limitations of top-down planning and regulations that get in the way. Using the latest science to refine the logic of these two main policy narratives, Socialist Darwinism describes what canwork.

One key insight is that societies must function as moral communities. As Darwin knew, without a strong moral system, a human group cannot “cohere” or function well. He called our evolved moral sense our “highest faculty”. The great failing of moral systems, of course, is that they are seldom all-inclusive. But we’ll provide examples of multi-level moral systems that can —in principle—be extended planet-wide.

And evolutionary science can upgrade the old “society is an organism” metaphor invoked by great thinkers such as Hobbes and Aristotle. Today we know that human societies truly can qualify as organisms in the benign sense of cooperative wholes that are more than the sum of their parts (UNIONS) and that nurture their parts—but only under special conditions.

Difficult? Of course. Possible? Yes, with the right toolkit.

These short essays will lay out the history, principles, and applications of Socialist Darwinism’s toolkit. The Federalist Papers argued for the creation of a more perfect UNION based on Enlightenment values that predated Darwin. Here we add 200+ years of scientifically refined thought.

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Humans rely on their eyes to give them clues about their environment. A complex network of ocular and cerebral neurons work in concert to provide us with four basic pieces of information: where we are, where an object is, what an object is, and how to get it.1 This is as true today as it was 10,000 years ago. However, the environment in which we operate today is radically different. The fact that you’re reading these words on a computer, tablet, phone, etc. illustrates that fact.

As hunter gatherers, our survival was dependent on identifying resources and threats, usually at a distance, in an outdoor setting. Native populations around the world that most closely mimic our ancestral groups (traditional diet and work) maintain a rate of nearsightedness (myopia) of less than 5%.2 However, the visual skills and ocular anatomical variations best suited for meeting the vision demands of the ancestral world are completely different from those many of us face today. Nearly every single person in the developed world spends some amount of their time extracting information from written words on either paper or an electronic device. And often, this takes place indoors under artificial lighting. We have gone from a species which habitual views distant objects in a relatively uncrowded visual space filled with natural light to one that spends the majority of its time viewing objects within hand’s reach while being surrounded walls and artificial light sources. Not surprisingly, the rate of nearsightedness has skyrocketed in the last century and is projected to reach 50% worldwide by the year 2050.3

The huge increase in such a short period of time suggests that genetics are not the primary driver of the phenomenon. Certain genetic makeups may predispose an individual to become nearsighted in a specific environment but it is not guaranteed. Myopia is not a destiny, it is an adaptation. So, what kind of environment is responsible for the huge increase in myopia across the globe? The answer, not surprisingly, is multifactorial. Near work, lighting, diet, crowded visual spaces, and sleep/wake cycles likely all play a role influencing development of nearsightedness. While we don’t know the exact biochemical cascades that cause myopia, we do know the end result: eye elongation. The longer the eye grows, the longer the axial length, the higher the degree of myopia.

Today, our goal as vision care providers is to slow down, stop or better yet, prevent excessive eye growth. Our primary target is children. Unfortunately, it’s likely too late for you and I. Myopia typically begins to develop around the age of 7 to 13 and stabilizes before the age of 25 (though cases of adult onset and progression of myopia are becoming more frequent).4 But, there is plenty we can do for our children.

  1. Remove excess refined carbohydrates and sugars from the diet. There is evidence that insulin and IGF may play a role in eye growth. A diet that maintains proper insulin sensitivity reduces the risk of myopia development among many other health benefits.5,6
  2. Take breaks from near work in outdoor environments. Viewing a near target (phone, book, etc.) causes a significant increase in axial length as a result of vascular changes within the eye. These changes can persist for up to 10 minutes after the cessation of the task.7 It is important for children to take breaks of at least 10 to 15 minutes every hour and view distant targets in an uncrowded (open space) outdoor environment to ensure their axial lengths returns to baseline.
  3. Spend at least an hour outside every day. Light from sun is significantly more intense than indoor lighting, no matter how bright the lights inside may seem. The spectrum of light provided by the sun is also more complete. Both intensity and spectral properties have been shown to alter dopamine levels within the eye and reduce the rate of eye growth.8,9 Additionally, keep light exposure consistent with natural daylight hours. Too much light after the sun goes down can affect dopamine levels as well.

There are also optical and pharmaceutical interventions we can provide if lifestyle modifications are not enough but should remain second line treatment. Putting our children (and ourselves) in environments that mimic the visual space of our past, providing food that mimic meals of our past, and using the sun as the guide to when lights should be on and off is first step halting the rapidly increasing myopia epidemic.


  1. Shayler G. The Use of Models to Help Our Understanding of Vision. Optometry and Visual Performance 2015;3:138–50.
  2. Garner L, Owens H, Kinnear R, Frith M. Prevalence of Myopia in Sherpa and Tibetan Children in Nepal. Optom Vis Sci 1999;76:282–5.
  3. Holden BA, Fricke TR, Wilson DA, Jong M, Naidoo KS, Sankaridurg P, Wong TY, Naduvilath TJ, Resnikoff S. Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Ophthalmology 2016;123:1036–42.
  4. Zadnik K, Sinnott LT, Cotter SA, Jones-Jordan LA, Kleinstein RN, Manny RE, Twelker JD, Mutti DO, Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study Group. Prediction of Juvenile-Onset Myopia. JAMA Ophthalmol 2015;133:683–9.
  5. Cordain L, Eaton SB, Brand Miller J, Lindeberg S, Jensen C. An evolutionary analysis of the aetiology and pathogenesis of juvenile-onset myopia. Acta Ophthalmol Scand 2002;80:125–35.
  6. Galvis V, López-Jaramillo P, Tello A, Castellanos-Castellanos YA, Camacho PA, Cohen DD, Gómez-Arbeláez D, Merayo-Lloves J. Is myopia another clinical manifestation of insulin resistance? Med Hypotheses 2016;90:32–40.
  7. Woodman EC, Read SA, Collins MJ. Axial length and choroidal thickness changes accompanying prolonged accommodation in myopes and emmetropes. Vision Res 2012;72:34–41.
  8. Read SA, Collins MJ, Vincent SJ. Light Exposure and Eye Growth in Childhood.
  9. Feldkaemper M, Schaeffel F. An updated view on the role of dopamine in myopia. Exp Eye Res 2013;114:106–19.
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As a clinical psychologist I collaborate with people facing problems that are sometimes practical but also of an emotional nature. Emotions evolved to motivate us, to “motion” us into action — and sometimes those emotions are involuntary, that is to say, not chosen. Some, are unwanted. Take shame, for example, one of many social emotions that allow us to navigate relationships.

The emotion of shame doesn’t garner as much research attention as do other painful emotions, but clinically, it undergirds many instances of depression and anxiety. My mentor, Albert Ellis saw shame as a driver of much emotional pain and devised “shame-attacking” exercises to rid us of all shame. He saw shame as a bug, not a feature of our cognitive software. The approach yielded mixed results, but today we have a better understanding of shame.1

A clue that shame has evolutionary roots is that it feels involuntary.2 Morality and a sense of shame served the needs of our place among kin and group. The inclusive tent for conscientiousness raised the possibility of falling short of our tribe’s expectations.

Understanding evolution helps us gain an “ancestral awareness,” to contrast the modern challenges that face us — mismatches between those natural mechanisms and the novel current environment. As a cognitive behavioral therapy practitioner for many years, this perspective fits into best practices because it aids us in understanding dysfunctional emotions and how to augment our thinking.

For example, many of us avoid potentially embarrassing adventures (to our long-term detriment), because of the risk of incurring scorn. Clinging to an “appropriate” facade feels natural but can also activate anxiety, “What if I look foolish? That would be horrible.” That’s a common premise entertained (sometimes semi-consciously) by anxious people. I’ve often seen versions of this phenomenon in a clinical setting, with consequent anxiety and depression.

Self-recrimination and depression can follow a self-described “shameful” performance. Anxiety often occurs in anticipation of one. In both cases, shame is at the root. A possible shameful event is looming in the future and we feel anxiety. Shameful event in the past and we feel depression.

We want to survive, mate, contribute to our group, offer resources, and command positive attention. Here, shame may be a trade-off between goals as a signal to oneself and as a signal to others, that we are trustworthy and well-meaning. An evolutionary perspective can help us keep conscientiousness while challenging crippling shame. 4

Shame may have helped us to maintain conscientious behavior, but our current self-messages such as, “I absolutely must be approved and loved by important allies” may trigger unwanted modern effects such as avoidance and isolation.

Shame seems to have two separate components. One, the corrective feedback for us by which to monitor social behavior. The other, the more troublesome one, is putting oneself down as an incompetent person. Huge difference! My job is to help clients keep the first, while changing the second of those. And evolutionary thinking helps us do that.

Today, the entire world seems like our village. Social media can fool us into taking our reputations not just seriously, which is good, but too seriously, which is harmful. You see, for most of human history our reputations would stratify us in the entirety of our social options. Our minds still read it that way. But a few screwups today do not have to sully our relationships to any hardened degree. Our long lives and multiple opportunities to connect with new people has never been greater.

Our ancestors did not have electronic social media, iPhones, police, air travel, cities, Tinder, vodka, running water, Starbucks or delis. These may seem obvious, but its profundity gets clearer with a few thought experiments. Mismatch insights are revelatory in reframing our modern experiences. Not a cure — a perspective helping to distinguish emotional features from emotional bugs, and how the experience of shame can reflect both. Evolutionary context and purposes matter — and understanding ancestral mismatch can provide a ready rosetta stone.

An ancestral awareness can provide some perspective on our propensity to feel overly ashamed about our errors, either the ones we’ve made, or the ones we’re endlessly committing—in our imaginings only.


  1. Gilbert, P. (2003). Evolution, social roles, and differences in shame and guilt. Social Research: An International Quarterly of the Social Sciences 70, 1205-1230
  2. Gilbert, P., & McGuire, M. T. (1998). Shame, status, and social roles: Psychobiology and evolution. In P. Gilbert & B. Andrews (Eds.), Series in affective science. Shame: Interpersonal behavior, psychopathology, and culture (pp. 99-125). New York, NY, US: Oxford University Press.
  3. Gilbert, P. (2006). Compassionate mind training for people with high shame and self-criticism: overview and pilot study of a group therapy approach. Clinical Psychology & Psychotherapy, 353-379.
  4. Pelusi, N. (2008) No shame on you. Psychology Today: https://www.psychologytoday.com/articles/200801/neanderthink-no-shame-you
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The world continues to wait for a conversation between Brett Weinstein and myself on the topic of group selection. It began with Weinstein’s conversation with Richard Dawkins, where he tried and failed to get the great master to admit that religions might be adaptations rather than mind viruses. That led me to look up what Weinstein has written on the subject. There wasn’t much [1], but it was enough for me to tweet that he was invoking group selection. Weinstein didn’t see it that way, so we both started to tweet about having our own conversation. It would be punchy but respectful, in keeping with the ethos of the so-called Intellectual Dark Web.

Alas, the event has yet to materialize so the world continues to wait. Fortunately, a lengthy conversation between Weinstein and Joseph Walker [2] provides all the information needed to justify my original hunch. Brett Weinstein invokes group selection in every way except using the words.

If this phrase sounds familiar to some readers, it is because I have written a similar critique of Richard Wrangham [3], based on his new book The Goodness Paradox. As an old guy (I turn 70 in July), I even critiqued Richard Alexander, Weinstein’s mentor and PhD advisor, way back in 1999 [4]!

Lest you think that I’m trying to nuke the entire establishment of evolutionary thinkers who traffic in ideas such as selfish genes, kin selection, reciprocal altruism, indirect reciprocity, and extended phenotypes, let me be clear about the nature of my complaint. Imagine that you are fluent in two languages—say, English and Spanish–and you enter into conversation with someone who speaks English fluently and Spanish hardly at all. To your surprise, this person tells you that English is a superior language and that much of what is said in Spanish is flat out wrong. What an incredible boor!

That is my complaint against the establishment of evolutionary thinkers who reject group selection in their own minds when they can barely speak its language. Why can’t they become bilingual, for heaven’s sake! I can speak and appreciate what is said in their language–why can’t they do the same in mine?

Actually, the peer-reviewed literature has become more bilingual over the decades, I am happy to report. Here is what two highly respected researchers, Jonathan Birch and Samir Okasha, write in a 2014 article titled “Kin Selection and Its Critics” [5, p. 28].

In earlier debates, biologists tended to regard kin and multilevel selection as rival empirical hypotheses, but many contemporary biologists regard them as ultimately equivalent, on the grounds that gene frequency change can be correctly computed using either approach. Although dissenters from this equivalence claim can be found, the majority of social evolutionists appear to endorse it.

A 2014 survey of anthropologists from PhD granting departments found that the majority accepted group selection as an important force in human cultural evolution and understood the concept of equivalence described in the passage quoted above [6]. Unfortunately, the majority of social evolutionists contributing to the peer-review literature aren’t very active on the internet. In addition, there are generational effects. The adage “science progresses funeral by funeral” doesn’t hold for everyone, but it does hold for some, who will go to their graves proclaiming that English is superior to Spanish and that things said in Spanish are just plain wrong.


Weinstein laments Dawkins’ inflexibility on the subject of religion, but he himself is a seed that has fallen close to the tree of his mentors, Robert Trivers and Richard Alexander, in his portrayal of group selection. At least he is fluent in the language that he knows, so his interview with Walker provides all of the background needed on the core concepts of selfish genes, kin selection, reciprocal altruism, indirect reciprocity, and extended phenotypes, which became established during the second half of the 20th century, along with the stock argument for why group selection doesn’t work. Let’s take these in turn.

What all the core concepts share in common is the appearance of selfishness, or self-interest if you prefer. Everything that evolves boils down to selfish genes. Inclusive fitness is about maximizing the copies of your genes in the bodies of others in addition to yourself. Reciprocity is about helping others in expectation of return benefits to yourself. Extended phenotypes are about your genes reaching beyond your body, such as a beaver dam as the phenotype of a beaver. Indirect reciprocity notes that the return benefits from helping others need not be restricted to the individual that you helped. In all cases, the explanation ends up being all about you.

The stock argument against group selection is that in any group containing both altruistic and selfish individuals, it is inevitable that the latter will replace the former. Hence group selection won’t work. This is what Dawkins says about group selection in The Selfish Gene and what Weinstein says in his interview with Walker—over four decades later—hasn’t changed a bit. There’s an enduring meme for you!

I have always marvelled at how this argument against group selection could ever have been taken seriously when it doesn’t even acknowledge the solution offered by group selection theory. The reason that altruism can evolve, despite declining in frequency in each and every group also containing selfish individuals, is because groups with a higher frequency of altruists contribute more to the total gene pool than groups with a lower frequency of altruists. What evolves in the total population reflects a balance between the opposing forces of selection among individuals within groups (favoring selfishness) and selection among groups in a multi-group population (favoring altruism). You can’t dismiss the evolution of altruism by focusing only on the negative within-group component!

Allow me to illustrate this point with one of the most influential models of group selection—the haystack model of John Maynard Smith [7]. The advantage of a model is that it makes everything precise. Maynard Smith fancifully imagined a population of mice that lives in haystacks. At a single genetic locus, one allele codes for aggressiveness (a form of selfishness) and its alternate codes for docility (a form of altruism). Each haystack is colonized by a single female fertilized at random by a single male—therefore a sample of four alleles drawn at random from the total population. The population in each haystack grows for a number of generations without any migration between haystacks. Then all of the mice disperse, mate randomly, and colonize a new set of haystacks to repeat the cycle. During the period of time spent in isolation, the selfish gene completely replaces the altruistic gene in all haystacks that were colonized by both alleles. In haystacks that were colonized only by the altruistic allele, however, the mouse population grows larger and contributes more to the total gene pool than the selfish populations.

Unlike the stock dismissal of group selection, the haystack model includes both within-group selection (favoring selfishness) and between-group selection (favoring altruism) in accounting for what evolves in the total population. Given the assumptions of the model, within-group selection is by far the strongest force, so altruism goes extinct not only within each haystack, but in the total population. When the haystack model was published in Nature magazine in 1964, it was regarded as a drop-dead argument against group selection as a whole.

But wait! Looking back, the assumptions of the model are highly unrealistic. In particular, the assumption that altruistic genes are completely replaced by selfish genes within each haystack before dispersal occurs makes within-group selection as strong as it can possibly be. In fairness to Maynard Smith, 1964 was before the advent of desktop computers and many of his assumptions were made to simplify the math. But what if we were to revisit the model with more realistic assumptions? For example, what if we use the same benefit and cost terms that Hamilton used in his model of inclusive fitness? In other words, in every haystack containing both types, altruists deliver benefits (b) to others in their group at a cost (c) to themselves, while selfish individuals accept the benefits without paying any costs. Let’s also alter the number of generations spent within each haystack (e.g., 5,10,15) as a variable of the model. What happens then?

This is the question that I asked in a 1987 article published in the journal Evolution [8]. What happens is that the altruistic gene declines in frequency in each group colonized by both types, but it doesn’t entirely go extinct. Take the extreme case of a single altruistic mutation in a population of selfish genes. The mutant allele finds itself in a haystack with three selfish alleles, or an initial frequency of 25%. Depending upon the values that we assign to the b’s and c’s, its frequency might decline to 19% after 5 generations, 14% after 10 generations, and 9% after 15 generations. That’s the bad news. The good news is that the single haystack containing the altruists might grow 20%, 45%, and 80% larger than the entirely selfish haystacks during the same period. Thanks to this fitness difference at the group level, the frequency of the altruistic gene can increase in the total population, despite decreasing within the haystack. A thorough exploration of the parameter space, made possible by the advent of desktop computing, showed that altruism can robustly evolve in the haystack model, given assumptions that are more reasonable than Maynard Smith’s original model.

This was only one of many computer simulation models, laboratory studies, and field studies demonstrating that between-group selection cannot be dismissed as invariably weak. Instead, the balance between levels of selection must be evaluated on a case-by-case basis. One of the most general and elegant theoretical formulations of multilevel selection is the Price equation, which convinced Hamilton that his theory of inclusive fitness had been invoking group selection all along [9]. None of this is reflected in Weinstein’s perpetuation of the stock argument against group selection, which only takes note of within-group selection.


Something else that Weinstein gets wrong in his interview with Walker is that group selection models are confined to interactions among non-relatives. I wish I could say otherwise, but this simply reflects ignorance of the literature, including everything that W.D. Hamilton wrote from 1975 onward. If Weinstein was bilingual, he would realize that the coefficient of relationship (r) in Hamilton’s rule translates into an index of genetic variation among groups in a group selection model. When r=0, individuals are randomly distributed into the groups. When r=1, group members are genetically identical and all of the variation is between groups. Throughout the entire range of r values, what evolves in the total population reflects a balance between levels of selection. In all of the classic group selection models, groups are colonized by small numbers of individuals, which are therefore related to each other compared to the total population. In the case of the haystack model, the mice within each haystack start out as full siblings, but this did not prevent Maynard Smith from calling it a group selection model and contrasting it with Hamilton’s model of kin selection. Years were required to reveal that not only is between-group selection a potent evolutionary force, but that it is implicitly invoked by all of the theories that were developed as alternatives.

Perhaps the best way to make this point is for me to present my fantasy version of a conversation with Weinstein.

David Sloan Wilson (DSW): Brett, do you agree with me that evolutionary models are based on relative fitness? It doesn’t matter how well an individual survives and reproduces in absolute terms, only that it does so better than others in its vicinity—right?

Brett Weinstein (BW): Of course!

DSW: Then doesn’t it strike you as curious that all of the models framed in terms of self-interest don’t calculate relative fitness?

BW: What do you mean?

DSW: They all assume that individuals or genes evolve to maximize their absolute fitness. For example, an individual that follows Hamilton’s rule will make more copies of its genes than if it doesn’t follow Hamilton’s rule. The reciprocal altruist gets a larger net benefit than if she doesn’t reciprocate. They all take the form of “what’s my payoff if I behave this way, compared to my payoff if I behave that way”. That’s the maximization of an individual’s (or gene’s) absolute fitness, not its relative fitness compared to others in its vicinity.

BW: But the models show that these behaviors evolve in the total population, compared to those who don’t maximize their absolute fitness. Isn’t that relative fitness?

DSW: Yes, but it’s relative fitness all things considered. By “in the vicinity,” I mean within the groups where the social interactions are taking place. Let’s take the concept of extended phenotypes, for example, which notes that a beaver dam can be regarded as part of the phenotype of a beaver.

BW: Yes—that’s one of Dawkins’ concepts that I like, even though I disagree with him about religion.

DSW: Ok, but now let’s look more closely at a beaver pond. Does it contain only one beaver?

BW: No, typically it contains more than one.

DSW: What if the beavers in a single pond vary in the amount of work they put into building a dam? Which have the highest relative fitness?

BW: Well…..

DSW: Spit it out, Brett! The free-riding beavers have the highest relative fitness! Calling the dam an extended phenotype of beavers doesn’t alter this fact!

BW: But what if the beavers are related?

DSW: That doesn’t matter either! In every pond containing both types, the free-riders will have the relative fitness advantage. Genetic relatedness is important because it clusters the dam-builders and free-riders into different ponds more than if they were distributed at random. So-called kin selection increases variation among groups, therefore the importance of between-group selection compared to within-group selection. Partner choice among genetically unrelated individuals would do the same thing. It’s variation among groups that’s important, not genealogical relatedness per se. Hamilton got that in 1975. Where have you been all these years?

BW: Hey! We of the Intellectual Dark Web like to keep the conversation respectful!

DSW: So do I, but I am cordially telling you that there are academic standards to maintain. Our reading public deserves to know that we are both experts in the topic that we are discussing. But, to lighten up on you a bit, I know that there is a weird dynamic in which some experts aren’t bilingual when it comes to theories of social evolution. They only think in terms of the individualistic perspective, only read that literature, and therefore dismiss group selection and can’t see it in their own models when it is front of their faces. Here’s an example from Richard Wrangham’s new book The Goodness Paradox, which is just like the beaver example. Instead of beavers in their dams, we have chimps in their communities. The counterpart of dam-building beavers is male chimps that kill or harass members of neighboring territories. The cost of doing this might not be large, but it is still an individual cost, while the benefit of expanding the territory over a period of years goes to the whole community. This is by Wrangham’s own account, but he can’t see the role of between-group selection any more than you can. The same goes for your mentor, Richard Alexander, but you should have the flexibility to learn what has become the consensus in the peer-review literature.

BW: Well, gosh, David! Thanks for enlightening me! I’m really beginning to see it your way now!

Ok, that last line was total fantasy, but this is the conversation that I will attempt to have with Weinstein, if it ever materializes, and I don’t see how he can evade the conclusion. His stock dismissal of group selection—selection against altruists within groups—takes place in every model of social evolution framed in terms of self-interest and can be seen merely by comparing the relative fitness of individuals in the groups where the social interactions are taking place.


Much of the conversation between Walker and Weinstein is framed in terms of the study of religion. For Weinstein, it is a no-brainer that religions are adaptations, not mind viruses. They are also “memeplexes”—whole complexes of cultural traits that evolve as a package—not atomistic memes. Weinstein wishes that Dawkins could be flexible enough to get beyond mind viruses. I wish that Weinstein could be flexible enough to realize that possibly—just possibly—the evolution of religions as adaptive memeplexes might require a process of selection among alternative memeplexes and cannot be explained entirely in terms of selection among alternative memes within memeplexes. That should also be a no-brainer.

I also hope, respectfully, that in future conversations with myself or anyone else on the subject, Weinstein displays a grasp of the peer-reviewed literature on religion from an evolutionary perspective. As far as I can tell, he remains mostly within the bubble of the New Atheist community, which for the most part does not conduct serious research on the subject. When was the last time that Richard Dawkins, Daniel Dennett, or Sam Harris contributed to the peer-review literature? How familiar is Weinstein with the likes of Candice Alcorta, Scott Atran, Robert Bellah, Pascal Boyer, Joseph Bulbulia, Michele Geland, Joseph Henrich, Dominic Johnson, Ara Norenzayan, Richard Sosis, Peter Turchin, and Harvey Whitehouse in addition to my own scholarly work? Go here [10,11] for recent overviews.

To pick an example central to New Atheist concerns, consider the concept of the resurrection associated with Christianity [what follows is distilled from a chapter of my book The Neighborhood Project titled “The Natural History of the Afterlife”]. When did it arise in human history and what caused its spread, compared to alternative beliefs? Historical scholarship is sufficiently detailed to answer this question [12]. In the Hebrew Bible, death is mentioned about a thousand times. In most cases, people just die and nothing is said about an afterlife of any kind. Judaism is centered around establishing the nation of Israel on earth, not in an afterlife.

In about seventy cases, an afterlife is mentioned in the Hebrew Bible, but it is not the heaven associated with Christianity. Instead it is Sheol, a gloomy place similar to Hades in Greek mythology, where everyone goes regardless of whether they have been good or bad.

Sheol is mentioned in a specific context—when people face the prospect of dying without having achieved much of anything during their time on earth. Their gloomy thoughts about the afterlife mirror their gloomy thoughts about their lives. So much for the concept of heaven as an individual-level adaptation for allaying anxiety about death!

The concept of the resurrection associated with Christianity doesn’t unambiguously appear until the Book of Daniel. Scholarship of the period is so detailed that the Book of Daniel can be dated to the time of the Seleucid persecution of 167-164 B.C.E., which makes it one of the latest texts of the Hebrew Bible. The challenge to Judaism at that time was assimilation: many Jews were attracted to Hellenic culture. According to the Book of Daniel, eternal life would be granted to Jews who maintained their traditional ways and all other Jews would suffer everlasting abhorrence. Belief in the resurrection was arguably a key factor that enabled the Maccabees, the traditionalist faction, to resist the Hellenist monarch Antiochus in a victory that is still celebrated in the festival of Hanukkah. Here is how two eminent scholars of the period put it [12].

The Jewish expectation of a resurrection of the dead is always and inextricably associated with the restoration of the people of Israel; it is not, in the first instance, focused on individual destiny. The question it answer is not the familiar, self-interested on “Will I have life after death?” but rather a more profound and encompassing one, ‘Will God honor his promises to his people?’

In other words, the concept of the resurrection originated as a cultural mutation that increased solidarity in the context of between-group competition within Judaism. The belief did not increase the fitness of individuals, compared to other individuals in the same group who did not believe. It increased the fitness of the groups that believed, compared to the groups that didn’t believe.

The religion that formed around Jesus was initially a twig on a branch of this cultural tree that sprouted several centuries previously. The idea of a Messiah who would die and return to signal the end of days was by then thoroughly familiar. The followers of Jesus thought that he was the Messiah, that he had indeed risen three days after his crucifixion, and that the end time had begun. The Jesus sect would probably have remained a footnote in religious history were it not for a key difference that had nothing to do with its otherwise standard (for its time) afterlife beliefs: Gentiles could now become the chosen people. A belief system that previously had been restricted to one ethnic group could now spread throughout the world. The same dynamic would result in the origin and spread of Islam centuries later.

But wait! There’s more! Have you ever wondered why the four gospels of the New Testament are so different from each other, not to speak of the gospels that weren’t included in the New Testament? Was it simply because of faulty memory and the passage of time, which in evolutionary terms would be a form of cultural drift? Not according to the distinguished scholar of religion Elaine Pagels. In The Origin of Satan and other books, she interprets each gospel as a sacred story that became locally adapted to a particular Christian community in the context of its specific challenges. The gospels that made it into the New Testament were the ones that did the best job of creating strong communities.

There is much, much more, but perhaps I have said enough to make my general point: Human history provides a fossil record of cultural evolution so detailed that it puts the biological fossil record to shame. It isn’t necessary to speculate about whether religions are adaptations or..

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It is well known to most that physical activity and exercise can exert positive effects upon our health and wellbeing. The fields of epidemiology and exercise physiology have yielded insights into the amount of physical activity we should be performing, with more typically being better; and that the harder the physical activity is, the greater the benefit received independently of the amount. Many have argued that the benefits received from physical activity and exercise come from our evolutionary history where we were typically far more active than we are today. That our bodies evolved to be active. Some have even gone so far as to offering recommendations for how to achieve ‘evolutionary’ or ‘paleo’ fitness (Cordain et al., 1998; O’Keefe & Cordain, 2004; O’Keefe et al., 2010; 2011).

These recommendations consider ‘what should we do?’ based upon the evolved traits in humans that determine our physical activity capacities and limitations (i.e. ‘what can we do?’), and with respect to emulating the physical activity patterns of extinct or extant hunter gatherers (i.e. ‘what did we do?’).

But, are narratives regarding evolutionary rationales and recommendations for physical activity and exercise a convenient ‘just so’ story?

Paleo-archaeology has given us considerable insight into the types of activity Homo sapiens are adapted for and what we are capable of. We have numerous features that indicate we evolved to be able endurance athletes, particularly with respect to bipedal locomotion, and which conferred several adaptive advantages (Bramble & Lieberman, 2004). Further, although we have lost much of the upper body locomotor specialization from our ancestors (Lovejoy, 2009) studies indicate our ancestors likely had well developed upper body musculature and thus physical capacity (Trinkaus et al., 2002). Lastly, as is evident from the field of exercise physiology, our bodies have adapted to be highly plastic with the ability to adapt towards the demands placed upon it (Lieberman, 2012).

Clearly, with respect to the question of ‘what can we do?’, Homo sapiens evolved to be physically capable and able to perform quite a repertoire of physical activity patterns. But, this doesn’t necessarily answer the question of ‘what did we do?’ when it comes to the physical activity patterns of our evolutionary past.

We can learn a lot from our close relatives, other extant primate species, who interestingly (though with obvious variation across species) are probably not as physically active as many would expect. They spend the vast majority of their time resting, typically sitting, and relatively little being what we would consider to be ‘physically active’ (Rose, 1973). It could be argued that primates are actually quite sedentary.

However, the reconstruction of physical activity patterns of extinct Homo sapiens is what some have termed ‘Bio-archaeology’s Holy Grail’ (Jurmain et al., 2012). Understanding the volume, frequency, intensity of effort, and types/modalities of activities performed by extinct humans is not a simple endeavor. Studies of articular modifications, musculoskeletal stress markers, and skeletal robusticity and geometry, though informative, are certainly not something we can reliably use to answer the question of ‘what should we do?’ in order to enhance our longevity and health in the modern world. Indeed, some research would perhaps suggest we should avoid the types of activities our ancestors likely engaged in (Berger & Trinkaus, 1995).

That last point is worth expanding upon. In our evolutionary past our physical activity was directed towards, and evolved enabling, things that would maximize our reproductive success; our evolutionary ‘fitness’ though not in the sense that many of paleo fitness proponents use it. Not all ancestral adaptions are good for us, and many involve trade-offs. Some novel modern behaviors not selected for are not necessarily bad for us either.

With a lack of ability to truly understand the physical activity patterns of our extinct ancestors, studies of extant hunter gatherers perhaps offer the most valuable insight into what physical activity patterns we should be following. Indeed, they typically are more active on the whole than people in modern industrialised populations (Eaton & Eaton, 2003) and spend at least some of their time performing more vigorous intensity of effort activities (Gurven et al., 2013). However, when it comes to the types and modalities of physical activity, these are highly variable and influenced by sexual division of labour, occupation duration, habitat quality, and hunting and logistical mobility (Grove, 2009).

Physical activity recommendations from national and international guidelines have historically been ‘volume-centrique’ with a focus upon how much we should be doing. However, it has recently been argued that perhaps we should be focusing more on how hard the activity we perform is (Steele et al., 2017). We can’t know what our physical activity patterns truly were in our evolutionary past. But, this approach perhaps best matches the physical activity patterns of modern hunter gatherers who have highly variable activity patterns, undulating both within and between days. Indeed, there are poor relationships between physical activity levels and physical fitness in many cases (Lightfoot, 2013) making it unclear from an evolutionary perspective as to whether adaptations drove increased physical activity, or vice versa. In considering the variation in physical activity types and modalities it’s clear that recommendations to engage in any particular one may be folly. Yet, it may not even matter as long as such activities are of a sufficient intensity of effort as recent work suggests the physiological response, and perhaps then the stimulus, to differing modalities differs little (Steele et al., 2018).

It’s highly likely that some degree of mismatch exists between our modern environment and the physical activity levels we have evolved to perform. Yet, despite the lack of clarity as to exactly what the physical activity patterns of our past, what kinds of recommendations could we broadly offer that fit with modern understandings of exercise science:

  1. Select a modality based upon personal preference (or sporting requirement) whilst considering the potential injury risks associated with it; consider the risk-reward ratio.
  2. Focus upon utilising a high intensity of effort (preferably maximal or near maximal) at least some of the time whilst performing low intensity of effort activity the majority of the time.

In all likelihood, it’s probably as simple as that.


  1. Cordain L, et al. Physical activity, energy expenditure, and fitness: An evolutionary perspective. In J Sports Med 1998;19:328-335
  2. O’Keefe J, & Cordain L. Cardiovascular disease resulting from a diet and lifestyle at odds with our Paleolithic genome: How to become a 21st-Century hunter-gatherer. Mayo Clin Proc 2004;79:101-108
  3. O’Keefe J, et al. Organic fitness: Physical activity consistent with our hunter-gatherer heritage. Phys Sportsmed 2010;37:11-18
  4. O’Keefe J, et al. Exercise like a hunter-gatherer: A prescription for organic physical fitness. Prog Cardiovasc Dis 2011;53:471-479
  5. Bramble DM, & Lieberman DE. Endurance running and the evolution of Homo. Nature 2004;432:345-352
  6. Lovejoy CO. Reexamining human origins in light of Ardipithecus ramidus. Science 2009;326:e1-8
  7. Trinkaus E, et al. Upper limb versus lower limb loading patterns among near eartern middle Paleolithic hominds. In: Akazawa T, et al. Neanderthals and modern humans in western Asia. Springer: Boston, MA, 2002
  8. Lieberman DE. What are humans adapted for? Presented at the Ancestral Health Symposium 2012 – https://www.youtube.com/watch?v=Txrs-FLz64Y&t
  9. Rose MD. Quadrupedalism in primates. Primates 1973;14:334-357
  10. Jurmain R et al. Chapter 29. Bioarchaeology’s Holy Grail: The reconstruction of activity. In: Grauer AL. A Companion to Paleopathology, Blackwell 2012
  11. Berger TD, & Trinkaus E. Patterns of trauma among the Neandertals. J Archaeol Sci 1995;22:841-852
  12. Eaton SB, & Eaton SB. An evolutionary perspective on human physical activity: implications for health. Comp Biochem Physiol A Mol Integr Physiol 2003;136:153-159
  13. Gurven M et al. Physical activity and modernization among Bolivian Amerindians. PLoS One 2013;8:e55679
  14. Grove M. Hunter-gatherer movement patterns: Causes and constraints. J Anthropol Archaeol 2009;28:222-233
  15. Steele J et al. A higher effort-based paradigm in physical activity and exercise for public health: making the case for a greater emphasis on resistance training. BMC Public Health 201717:300
  16. Lightfoot JT. Why control activity? Evolutionary selection pressures affecting the development of physical activity genetic and biological regulation. BioMed Res Int 2013;821678:1-10
  17. Steele J et al. Similar acute physiological responses from effort and duration matched leg press and recumbent cycling tasks. PeerJ 2018;6:e4403
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Evolutionary mismatch is now recognized as affecting many aspects of modern life; examples include diet, exercise, light exposure, chronic stress, sleep deprivation, electronic technology, drug abuse, mental health, spousal abuse, climate change, social inequity, politics, and economics1, 2, 3, 4, 5, 6, 7, 8, 9. It also has many implications for Public Health, often resulting in unnecessary suffering and death. The controversy surrounding vaccination is just one such example.

Vaccines have been undeniably successful at preventing many of the most dreaded and fatal diseases and represent one of the most important health discoveries ever made. One has to look no further than the eradication of smallpox, protection against polio, and the dramatically lower rates of many previously common diseases (e.g., measles, mumps, rubella, cholera, yellow fever) to appreciate their importance.

I hypothesize that the current anti-vaccination movement is a result, in part, of the innate cognitive biases inherent in our nervous systems that evolved to deal with problems in a very different premodern world. While such largely unconscious biases worked well for our distant ancestors in their environmental context, they are ill-suited to novel modern circumstances. Two such biases that today result in people making objectively irrational decisions are “discounting the future” and “loss aversion.”

“Discounting the future” makes us more likely to value immediate rewards over future benefits, and was on average beneficial to hunter-gatherers (e.g., it was best to drink and eat while water and food were available). However, today humans are faced with longer lives complicated by rapid cultural evolution. Ignoring Public Health interventions such as vaccinations (or stopping smoking, etc.) that greatly reduce future morbidity and mortality can only be described as irrational.

“Loss aversion” (the tendency to strongly prefer avoiding losses relative to acquiring gains) made sense in the ancestral context because it was better to err on the side of caution when dealing with predators, since a loss might mean death. Today this bias results in irrational decisions with people often avoiding even very minor “risks” (e.g., low probability of allergic reactions or slight inconvenience such as minor pain of an injection) rather than opting for a far greater likely gain (protection from serious disease).

Likewise, humans evolved to respond most strongly to immediate threats or clear and present danger (e.g., predator attack) but not so strongly to something more remote that might or might not occur (e.g., infection by a fatal disease). Considering this perspective, vaccines that protect against potentially catastrophic but temporally or spatially remote and unfamiliar illnesses often do not generate a response proportional to their true benefit. In the modern context such biases predispose us to irrational decisions that can result in individuals or their loved ones having higher rates of avoidable disease or death.

Cognitive biases also interact with cultural mismatches in the anti-vaccine movement. Consider the opposition by some religious groups and politicians to vaccination against human papillomavirus (HPV) because of the fear of promiscuity. People can easily fall into the trap of “in-group” versus “out-group” or “us versus them” cognitive bias. Subsequently, once a party or religion or other group “decides” what is “correct,” there are psychological and social consequences (e.g., ostracism, expulsion from the group, loss of reputation) for individuals that go against the group mentality. This can lead to individuals making choices that ultimately cause harm to themselves and others. Thus, affiliation with a religion or political party that advocates ideas harmful to group members becomes an example of cultural mismatch. This is especially tragic in the case of HPV where the vaccine is now known to reduce cervical cancer risk (as well as the risk of throat and mouth cancer) and those not taking the vaccine have a much greater risk of unnecessary suffering and death.

How does one address these types of mismatch? The only approaches likely to succeed are those that consider both our inherent strengths and innate weaknesses, and that apply appropriate techniques to change minds and ultimately policies. Such strategies that have been suggested and sometimes applied in other fields (e.g., Behavioral Economics or in countering climate change denial) include: increasing awareness of our cognitive biases; improving choice architecture (i.e., design ways in which choices are presented to increase the probability of desirable outcomes); framing topics differently (e.g., focusing on what can be gained versus lost); encouraging people to contemplate the question, “What if I’m wrong?”; leveraging relevant social group norms; and minimizing time discounting and present bias (e.g., help people connect with their future selves or descendants)10, 11.


  1. Lloyd, E., Wilson, D.S., & Sober, E. (2011). Evolutionary mismatch and what to do about it: A basic tutorial. Available at: https://evolution-institute.org/wp-content/uploads/2015/08/Mismatch-Sept-24-2011.pdf.
  2. Eaton, S.B., Konner, M., & Shostak, M. (1988). Stone agers in the fast lane: Chronic degenerative diseases in evolutionary perspective. American Journal of Medicine 84(4):739-749.
  3. Lieberman, D.E. (2013). The story of the human body: Evolution, health, and disease. New York: Pantheon Books Inc.
  4. Logan, A.C. & Jacka, F.N. (2014). Nutritional psychiatry research: An emerging discipline and its intersection with global urbanization, environmental challenges and the evolutionary mismatch. Journal of Physiological Anthropology. 33(1):22. doi: 10.1186/1880-6805-33-22.
  5. Pani, L. (2000). Is there an evolutionary mismatch between the normal physiology of the human dopaminergic system and current environmental conditions in industrialized countries? Molecular Psychiatry 5(5):467-475.
  6. Diggs, G.M. (2017). Evolutionary mismatch: Implications far beyond diet and exercise. Journal of Evolution and Heath 2(1):3. doi: 10.15310/2334-3591.1057.
  7. Thaler, R.H. & Sustein, C.R. (2008). Nudge: Improving decisions about health, wealth, and happiness. New Haven: Yale Univ. Press.
  8. Kahneman, D. (2011). Thinking, fast and slow. New York: Farrar, Straus & Giroux.
  9. Gifford, R. (2011). The dragons of inaction: Psychological barriers that limit climate change mitigation and adaptation. American Psychologist 66(4):290-302.
  10. van der Linden, S., Maibach, E., & Leiserowitz, A. (2015). Improving public engagement with climate change: Five “best practice” insights from psychological science. Perspectives on Psychological Science 10:758-763.
  11. Ross, L., Arrow, K., Cialdini, R., Diamond-Smith, N., Diamond, J., Dunne, J., Feldman, M., Horn, R., Kennedy, D., Murphy, C., Pirages, D., Smith, K., York, R., & Ehrlich, P. (2016). The climate change challenge and barriers to the exercise of foresight intelligence. BioScience 66(5):363-370.

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