scilogs Biology of Religion

Religions and Fertility in the US - GSS-Data

from Michael Blume, 03. June 2010, 19:23
There are many high-fertile religious communities out there - as, for example, the Old Order Amish. Other religious groups, as the Shakers, who didn't manage (or chose) to have enough children, succumbed to (bio-)cultural evolution. In contrast, we still don't know about a single, non-religious population, movement or group that was able to retain more than two births per woman (the so-called replacement level) throughout subsequent generations. This is relevant from a sociocultural perspective: Secularization is taking place (especially among wealthy and secure populations) - but running into demographic dead ends, followed by religious-demographic revivals (through births and immigration). And it is relevant from the perspective of evolutionary studies: Intergenerational reproductive success is "the" benchmark of evolutionary fitness, promoting biocultural traits as speech, musicality - or religiosity.

A range of data sources as e.g. the Swiss Census and the World Value Surveys showed the reproductive potential of various religious communities. Vegard Skirbekk, Anne Goujon and Eric Kaufmann did another study in religious demography at the Vienna Institute of Demography, based on post-millennia General Social Surveys in the USA. Their findings are fully congruent: Most religious communities are showing higher fertility rates than the religiously non-Affiliated, whose birth rates are far below replacement level.

Please note that fundamentalist Protestants do have more children (on average) than moderate and liberal ones. An interesting case is US-Judaism: While Swiss Jews performed near the top of the Swiss birth table -together with the highest portions of academics, leading professionals and urban dwellers-, Jews come out below the non-Affiliated in the USA. The reason is: regional religious history. While there are strong conservative, orthodox and some ultra-orthodox (Haredim) communities among the Swiss Jews, most US-American Jews are (yet) liberal, although the Orthodox share is growing quickly - most importantly due to its higher fertility. 

Transition rates

Another interesting set of data explored the transition rates between the various religious groups.

The results seem to be pretty conclusive. There IS secularization: From 7.3% of former Catholic Hispanics to 19.7% of former Hindus and Buddhists, almost all religious groups are losing members to the category of the Non-affiliated (which includes various ranges of individual religiosity and spirituality). But then, nearly half (44.1%) of those raised without religious affiliation chosed to join one later - according to the study, especially women.

Together with the low birth rates of seculars, these data sets explain how waves of secularization and religious revivals progress simultaneously. Neither secularization nor religion may win entire populations - especially among the free and educated, there will be ups and downs driven by demography and culture.

Evolutionary Final 

The reproductive advantage of religiosity, which was -according to my knowledge- at first assumed by nobel laureate Friedrich August von Hayek, is observable in the USA, too. Religious communities don't need State funding to raise the average reproductive success of their adherents. And Twin-studies are strongly supporting the - expectable - assumption of partial, genetic heritability. As this wonderful video-clip from Tuebingen University is showing: Darwin rocks! Religiosity and religions are part of the great, evolutionary story.

  Share on ResearchGATE




Biology of Religion: Is Hans Rosling right? Religion and Fertility between and within Nations
Biology of Religion: Missionaries or Parents? How are religions growing?
Biology of Religion: Why Religion is not going to die - The Quiverfull Example of Religious Fertility
Biology of Religion: Charles Darwin about the Evolution of Religiosity and Religion(s)


  1. Corneel Two questions
    04.06.2010 | 15:08

    For the sake of scientific inquiry ;-)

    1. But then, nearly half (44.9%) of those raised without religious affiliation chosed to join one later - according to the study, especially among women.
    It is hard to say without the absolute numbers, but the influx of apostates seems to be way higher than the loss. Isn't there a net gain of the unaffiliated based on these transition probabilities? (Nothing a bit of matrix algebra can't solve :-)

    2. The reproductive advantage of religiosity... In the context of your research, how is "religiosity" defined and measured? Is it just the tendency to believe in the supernatural? Or does it also involve social/ behavioral aspects? I ask this because I see no connection between belief in a supernatural agent and having lotsa kids.

  2. Michael Blume @ Corneel
    04.06.2010 | 18:04

    You are very welcome! :-)

    It is hard to say without the absolute numbers, but the influx of apostates seems to be way higher than the loss. Isn't there a net gain of the unaffiliated based on these transition probabilities?

    Yes, that's the point! Secularization is taking place among all educated and wealthy strata, with more people leaving religions than (re-)joining them. But then, those secular populations are running into demographic dead ends, while the religious tend to have more children. Therefore, we are observing ups and downs without any side winning the entire share...

    In the context of your research, how is "religiosity" defined and measured? Is it just the tendency to believe in the supernatural? Or does it also involve social/ behavioral aspects? I ask this because I see no connection between belief in a supernatural agent and having lotsa kids.

    Darwin defined religiosity as "belief in supernatural agents". But today, some of us (including me) would rather use "behavior towards supernatural agents", because it is hard to observe und quantify beliefs per se.
    As to the proximate mechanisms linking religiosity and fertility, you might be interested in my Amish-case study discussing this very topic:

    And, what a coincidence, I just did a review about an entire tome about "The Biology of Religious Behavior" in the Marburg Journal of Religion:

    Evolutionary studies especially in the complex field of human biology and culture(s) are teamwork, indeed...

  3. Maciano New method: measure by ethno-religious fertility rates
    05.06.2010 | 19:42

    I disagree with the numbers on the Jews here. A religious evolutionary perspective should look at difference within (religious) ethnic groups. Jews are an ethnicity and a religion. If you'd look at all White Americans, and presumed they were all Christian, the birth rate would be low as well. The low birth rate of American Jews means only this: secular Jews have very few children, religious Jews a lot. This doesn't mean that Jews have a low birth rate, it means secular Jews are being replaced with Orthodox Jews. If this goes on long enough, their birth rate will bounce back with a vengeance. In Israel this is already the case, according to Eric Kaufmann.

    I've become more and more convinced that low birth rates in modern societies do not necessarily reflect a decreased will for having children. Think about it: why do many young people not have children? They have to study until their early-mid 20s, after that they have to work hard in crowded cities in low status jobs and find a mate. If there's even a grain of truth to the reality of Sex and the City-type cliques existing, is it any wonder that these people are dying out? They're self-obsessed, obsessed with status, self-centered and they endless talk about men and meaningless side-shows like labels, while their red state sisters are having the kids. This is nothing new either, urbanites have been replaced with peasants in history constantly; cities are a fertility drain -- high house prices, expensive living, complicated problems, competitive environements at work, etc.

    They say that liberal democracy creates a society where a lot is permitted as long as you don't hurt others. OK, fair enough. But this also means that the modern world is in itself a fundamental different ecology than the pre-modern Christian conservative world where a lot was forbidden, locally organized and many passions controlled, especially among the young. (I refer to Jonathan Haidt's distinctions on morality differences between conservatives and Christians for this.) To put people in this different environment leads to natural selection for pronatalist instincts. After all, the people who have kids these days have them because of their (innate?) religiosity, ethnocentrism, sense of motherhood and/or high time preference urge them do so.

  4. Michael Blume @ Maciano
    05.06.2010 | 19:56

    I agree with you, especially with regards to the fertility differences "within" Judaism! For this very reason, I included a study of mine about the fertility differentials according to the Swiss Census, where Jews showed high birth rates:

    The reason is the historically higher share of conservative, orthodox and (in small numbers) even ultra-orthodox (Haredim) Jews among the Swiss, in comparison to the (yet) mostly liberal (or outright secular) American Jews. But even in the USA, there is a demographically growing orthodox minority with impressive fertility rates, cp. a case:

    Before publishing "Shall the Religious inherit the Earth?" (review here:)

    Eric Kaufmann conducted demographic studies comparing birth rates among Jews of various religiosity in Europe:

    Thanks for your insightfull post, I would love to read more from you, @Maciano!

  5. J. A. Le Fevre Religious Fitness
    06.06.2010 | 00:05

    Dr. Blume:

    I have browsed your blog here with some amusement. There seems to be much fixation on this ‘fertility advantage’ theme. It just looks like you (collectively) are focusing your microscope on just one part of the elephant. I have been troubling over the question of ‘religious fitness’ since stumbling onto the Dawkins website a few years back, and came to some very different conclusions than you have been presenting or discussing, and think they are worthy of review. I wanted to start with the elephant, not one part of it, so tried to look back at where it all began, and found two very distinct ‘starting’ points, with very different impacts on the respective human populations.

    I chose to take the ‘adaptation’ perspective, needed two definitions to differentiate the periods, and settled on:
    Spiritual – Behavior or artifacts indicating a deference to supernatural agents, and
    Religious – a spiritual community that supports dedicated structures for ceremonies or services (i.e.: temples) and professional religious practitioners (as priests or monks).

    ‘Archaic Man’, to borrow the archeological parlance, lived in caves, under trees, etc. like a tool wielding ape who knew also to control fire (I am borrowing here from Jarred Diamonds description in ‘The Third Chimpanzee’).
    The Spiritual adaptation led to what is referred to as ‘fully modern’ man because of his greatly advanced technologies and lifestyle – he lived and behaved in a fashion we see as human. The introduction of the spiritual adaptation is known to archeology as the ‘Upper Paleolithic Revolution’ for the large, rapid advances in the human condition.
    The Religious adaptation led to an even more dramatic acceleration in the advance of humanity as it allowed the formation of cities, states and empires. In the ten thousand years that cities have been built, close to or isolated from other civilizations, colonies or independently formed, historic or pre-historic: All have temples, all have priests.

    From a strictly demographic perspective, archaic man reached and estimated population maximum of (very roughly) 50,000 individuals throughout Africa, the Middle East, and the temperate regions of Europe and Asia. With spirituality, habitat expanded to include the arctic and the America’s, and population expanded to (still very roughly) two million.

    Humans with the advantage of Religion have usurped the prime habitat of the globe and pushed the population past 6 billion. Humans with religion have launched men to the moon, human populations without religion (and not on reservations) still live much as they did 10,000 years ago, illiterate and with stone age technology. Human populations without spirituality went extinct 30,000 years ago - they simply could not compete.

    The significance of religion in the human community goes way beyond differential reproductive rates.

  6. Michael Blume @ J.A. Le Fevre
    06.06.2010 | 10:26

    You might be surprised - but I would agree with you!

    In fact, my magisterial thesis has been about the identity formation of young muslims in Germany and my dissertation has been about religion & brain sciences. But in the wide and diverse range of evolutionary religious studies, I started to concentrate on religion(s) & demography, as this correlation is very important from a biological and cultural perspective. But I would agree absolutely that this is only a part of the great jigsaw - it's just the part I have been exploring scientifically these last years. And as there are increasing numbers of scientific blogs about the evolution of religion available, I thought it might be interesting for others to find informations, links and downloads about this specific topic here.

  7. Corneel @ J. A. Le Fevre
    07.06.2010 | 10:33

    I am glad that you amused yourself, but I am afraid that I find your hypothesis not as convincing as Michael's.
    Michael carefully backs up his claims with data demonstrating that religious communities have higher growth rates than secular ones, which makes his premise plausible.
    All you provide is the anecdote that modern humans started practicing organised religion at the same time that there came some "technological" advancements. You present absolutely no proof whatsoever that one thing caused the other. In fact, several of the most technologically advanced modern socities are highly secular. This clearly demonstrates that religion is not a prerequisite for the development of technological sophistication. I am sorry, but your elephant remains unexplained.

  8. Tom Rees Intersting analysis
    07.06.2010 | 22:51

    Hi Michael, looks like an interesting analysis. What I would love to see is something that looks at intensity of belief, rather than affiliation, and controls for potential mediators like conservative ideology, social status, immigrant status, etc.

    FOr example, Muslims are the most fertile in this study, but is this because they are the most devout, or because they tend to be recent immigrants fro countries where high fertility is the norm, or because they are poor? Does the high levels of liberalism (i.e. a lack of social conservatism) help explain the low fertility of jews, 'others', buddhists and liberal protestants (as well as 'nones'). Many questions. Few (as yet) answers!

  9. Tom Rees By the way...
    07.06.2010 | 22:52

    Kaufmann's paper on this has just been published in JSSR.

  10. Michael Blume @ Tom Rees
    07.06.2010 | 23:11

    Yes, I would agree. In a very early study I did together with two colleagues, we explored the fertility-relationship based on religious self-identification and pryer frequency:

    See especially chapter 3. But of course, there remains much to be done and explored!

  11. Michael Blume @ Tom Rees II.
    09.06.2010 | 17:56

    Yes, you are right! Here is the link to the new article by Eric & colleagues:

    And as I am a member of the SSSR, I am looking forward to receiving this issue! :-)

  12. Balanus @Corneel / Two Questions
    11.06.2010 | 10:05
    For the sake of scientific inquiry ;-)

    1. But then, nearly half (44.9%) of those raised without religious affiliation chosed to join one later - according to the study, especially among women.

    It is hard to say without the absolute numbers, but the influx of apostates seems to be way higher than the loss. Isn't there a net gain of the unaffiliated based on these transition probabilities?

    In the JSSR paper of Skirbekk, Kaufmann and Goujon, the net flow is given with 24,7%.

    Obviously, secularisation has clearly outweighed religious revivals.

  13. Balanus No ups and downs
    11.06.2010 | 14:33

    Michael Blume said (04.06.2010 | 18:04):

    Secularization is taking place among all educated and wealthy strata, with more people leaving religions than (re-)joining them. But then, those secular populations are running into demographic dead ends, while the religious tend to have more children. Therefore, we are observing ups and downs without any side winning the entire share...

    Based on the fertility and transition rates as given by Skirbekk, Kaufmann and Goujon in their new paper, the number of US-people with no religious affiliation will steadily increase in the near future (up to 2040). Therefore, there will be no significant "ups and downs".

  14. J. A. Le Fevre @ Corneel
    14.06.2010 | 04:12

    No argument offered. It was not my intent to derail this discussion. On other forums, Michael weighs in on many loosely related topics, I found it curious that his forum was so focused. (Yes, its because he wants to.)

  15. Corneel response
    14.06.2010 | 16:49


    Thanks for the information. I wonder whether demographic processes can counterbalance such massive secularisation.

    @J. A. Le Fevre

    you said:
    No argument offered. It was not my intent to derail this discussion.

    I didn't think you were, and you are welcome to offer your own views. I don't mind a scientific argument (in fact, I enjoy them). It's just that when you criticise another person's viewpoint, you should also be able to defend your own.

  16. Michael Blume @Cornell & Balanus
    16.06.2010 | 07:42

    Thank you for the good debate! Corneel wrote: I wonder whether demographic processes can counterbalance such massive secularisation.

    Yes, I am wondering about that one, too. According to Eric's new (and very recommendable!) book, it will and the "religious shall inherit the Earth":

    But I would like to point out that evolutionary studies are not primarily about projections in the future, but about exploring history. There could be numerous factors (e.g. economics, diseases, immigration, new techniques or scientific findings etc.) complicating the upcoming demographic picture. Thus, I would just remark that the reproductive advantage of religiosity is an observable fact, that we don't know about intergenerationally fertile secular movements and that secularization has never "won out" in the observable past. Such facts can be tested and falsified empirically, while we will have to wait regarding demographic projections into the future.

  17. J. A. Le Fevre @Cornell
    16.06.2010 | 21:40

    I had no intention of criticizing any viewpoints in that post (hence no defense appropriate), I was simply asking Michael about his focus on this, ‘his’ forum, when his posts on other forums suggested a wide interest in the overall question of adaptive qualities in religion. I understood from his answer that he recognized the question.

  18. J. A. Le Fevre On Secularization
    17.06.2010 | 03:19

    The climate (or environment) drives adaptation throughout nature – a basic premise of evolution. If religion is adaptive, a condition in the ‘climate’ could explain the rise in secularism. Religion is, after all, expensive. 10 percent of your time, 10 percent of your money – A secular individual ‘gains’ an instant advantage over the religious, all else being equal. To be an adaptation within a community, religion would have to solve some ‘problems’ that were ‘worth’ more than 10 percent of the communities resources to have solved, or people would not be rational to keep paying for it, and communities which gave it up would out-perform those which did not. I will suggest that the current rise in secularization is the result of changes in the social climate and/or new or improved community institutions (such as better public schools, better trained teachers, police and politicians – or better formed governments) that serve some of the functions traditionally served by religions.

  19. Corneel @J. A. Le Fevre
    18.06.2010 | 00:24

    I had no intention of criticizing any viewpoints in that post (hence no defense appropriate)

    Fair enough, but I still think your ideas about "religious fitness" are flawed, and you might want to consider the following.

    You said:
    If religion is adaptive, a condition in the ‘climate’ could explain the rise in secularism. Religion is, after all, expensive.

    That didn´t make sense to me. If you are correct that religion is expensive, than you have established that it is MALadaptive, and the trait cannot evolve by natural selection. Thus, you ought to consider evolutionary forces that can fix nonadaptive traits: genetic drift, genetic hitchhiking and pleiotropy.
    Since you reject Michael´s premise of a reproductive advantage (or think it is too narrow a view), why do you still think religion is adaptive?

  20. J. A. Le Fevre @ Corneel
    19.06.2010 | 17:58

    You said:
    ‘I still think your ideas . . . are flawed’. I’ll give them a 50-50. I am, alas, only human. However, from your questions I do not think you are really reading my posts. Perhaps I am being too cryptic?

    I really do not think there is any argument that religion is expensive. You might argue that it is more or less than my estimate of 10%, but I think that is a reasonable estimate, if only for discussion purposes. Our large (human) brains are also expensive. I have seen estimates that 30% of our food intake goes to support our brains. Expensive is only mal-adaptive if the return (the benefit we get back) is not greater than the cost. Most of us believe our brains are worth feeding. Nature, by promoting us to the top of the food chain, and the dominant species on the planet, seems to agree.

    Let’s be clear though: Religion is strictly voluntary, and history has many examples of whole populations giving up their religions, as did France in the nineteenth century. Jarred Diamond, in ‘Collapse’ recounts several civilizations in the archeological record which abandoned their religions (and ate the priests), Mayan and the Anasazi among them. Our brains we pay for or else - nature, not us, decides if they are worth the price.
    This ‘voluntary’ quality, along with the high price of religion leads me to the adaptive conclusion. We can (and have at times) give religion up and save ourselves the cost. Should that have proven an advantage, no community would ever have held to (and paid for) religion in the past – for they would have faced competition from their more efficient secular rivals.

    History, I think, clearly shows that communities with religion dramatically out perform communities lacking religion (see my first post) and that the differential reproductive advantage of religious believers chronicled by Michael explains only some of that advantage. (The French, by the way, may have beheaded a few priests, but are not suspected of eating any.)

  21. Balanus @J. A. Le Fevre
    20.06.2010 | 13:51

    » History, I think, clearly shows that communities with religion dramatically out perform communities lacking religion... «

    I think, history clearly shows that communities with science dramatically out perform communities lacking science.

    In addition, secularisation is mainly a cultural phenomenon that occurs in those individuals who are not genetically determined to believe in supernatural beings.

  22. Corneel @J. A. Le Fevre
    21.06.2010 | 10:33

    from your questions I do not think you are really reading my posts.

    I am sorry. I'll do my best. You said:

    Expensive is only mal-adaptive if the return (the benefit we get back) is not greater than the cost. Most of us believe our brains are worth feeding.

    ..and traits are only adaptive, if the return IS greater than the cost. If both are equally large, a trait is considered NEUTRAL. There are numerous examples of neutral traits in nature, and neutral evolution is considered as important as natural selection in modern evolutionary thinking. Neutral traits can be gained and lost (and go to fixation) without any fitness effect, exactly like in the examples you mentioned. My point is that it is highly unscientific to assume a priori that a behaviour is adaptive. The onus is on you to demonstrate a fitness advantage. As demonstrated by the comment you have already received from Balanus (and I agree), history does *not* unambiguously show any such an advantage.

    and finally something that irks me as a biologist:

    Nature, by promoting us to the top of the food chain, and the dominant species on the planet, seems to agree.

    Humans are NOT the dominant species on the planet by any objective means of evolutionary success. Nature likes beetles (sorry).

  23. Corneel Corneel
    21.06.2010 | 10:56 any objective MEASURES of evolutionary success.

    See what happens when I get worked up?

  24. J. A. Le Fevre Apologies to Michael
    22.06.2010 | 03:49

    @ Corneel

    I new that would get me in trouble as I posted it, but I’ll bet even money if you water-board any reputable entomologist you abduct from a near by institute you could force a confession out of him that a beetle is: a fun car to drive, a reputable rock band from back in the day, or one of half a million to 100 million species of beetles (estimates vary). Not to diminish their 300 odd million years of success, as a homo-centric thinker (and I think I speak for most of homo): I still think we dominate the earth today more than any 10 species of bugs. Lacking, however, a clear and mutually agreeable definition of dominate, I suspect this is not a productive direction to argue.

    @ All

    Please indulge me a bit of your attention, as your comments still baffle a bit. It has been suggested that human communities with deliberate science programs out perform communities without such programs. While that may be true, it is off track. Identify for me, as an exercise, all of the countries conducting anything you would consider science which have a history of less that 5,000 years of religious heritage. If (a big if) science requires religion, religion still out performs no-religion. This makes the assumption that religion is a community level ‘adaptation’ (not yet demonstrated, but I think you see my direction), not an individual level, so secular individuals within a ‘has religion’ community still receive advantage (at a reduced cost).

    If I could, I would like to redirect this discussion in what I hope is a more productive direction (if at least for my interests). Over decades of (rather casual) research into archeology and anthropology, I never saw religion addressed as more than a curiosity. Upon reading Dawkins’ ‘God Delusion’, it struck me that perhaps there was more to it than science was giving credit for. I thought about spots on guppies – some biologist found a bunch of guppies living in a shady spot in the river with spots. Then found a bunch more living in a sunny area of the same river, but these had no spots, concluding that this coloration was adaptive, spots helping fish to hide from predation in shady waters, where no-spots would help better in sunny waters.

    What if religion in communities was like spots on guppies. How would you assess its effects? First I divided the populations of the world, over the last 2.5 million years, into three groups (I started with two, but it quickly became apparent that three was more appropriate): No religion, Spiritual Beliefs, and Religion.

    Cutting to the chase, the ‘no religion’ group went extinct 30,000 years ago, the ‘spiritual beliefs’ survive mainly on reservations, often living as they have for the last 10,000 years, the communities which developed religion went on to build moon rockets and the internet. That last ‘experiment of nature’ is still ongoing, but the ‘advantage’ of religion is space+information age to stone age.

    Gotta run. I think I can explain the more basic mechanisms when I have a bit more time.

  25. Corneel Michael won't mind (I hope)
    22.06.2010 | 10:17

    @ J. A. Le Fevre

    What if religion in communities was like spots on guppies. How would you assess its effects?

    I am reading your posts, and I think I understand what you're saying, but you can't just ignore one-and-a-half century of evolutionary research.
    We know that humans developed a tendency to believe in supernatural agents. Good, what now? First, we need to establish that this has a genetic component, and isn't just a cultural adaptation. If not, then it cannot evolve in the Darwinian sense.
    Once we have established that, we need to consider all mechanisms of evolutionary change: natural selection, genetic dift, mutation and migration. We can safely ignore the latter two for our purposes, but that still leaves genetic drift as a valid alternative. Most adaptive explanations for the evolution of religiosity (including yours and Michael's) invoke group selection. This is a notoriously weak selective mechanism, that is easily overrun by selection at the individual level and genetic drift. Therefore, these explanations require thorough empirical confirmation.
    Finally, once we have established that natural selection was the agent of evolutionary change, we still need to verify that it was acting on the trait itself, and not on genetically or pleiotropically linked traits.

    So you see, there are many alternative explanations. This is the reason why it is incorrect to just assume that any behaviour is adaptive, and why I am sceptical of adaptive explanations of religious behaviour.

    Oh and,

    I still think we dominate the earth today more than any 10 species of bugs.

    Whatever works for you, lowly vertebrate ;-)

  26. J. A. Le Fevre @ Corneel
    22.06.2010 | 17:16

    Excellent. We are on the same page, but no time to write at the moment.

  27. J. A. Le Fevre @Corneel – Part 1
    24.06.2010 | 03:16

    I am going to ask you to step a bit outside your comfort zone here, as this is an issue of anthropology, not biology. I plan not to ignore any research, but to propose concrete mechanisms for long standing issues in human development: The Upper Paleolithic and the Neolithic revolutions.

    A few background tidbits to start. It is politically correct to make the claim that all living humans are closely related and of (nominally at least) equally capable, regardless of region of origin. Experiments have been run in the past and (unofficially at least) continue into the present of integrating individuals from aboriginal communities successfully into modern communities and vice-versa. While all variety of studies document innumerable minor distinctions between peoples, I feel that the integration experiments render any noted differences irrelevant to our investigation.

    My research further suggests that religion has defiantly not been genetically selected for in the human population, as whenever the environment is favorable (peace and prosperity), atheists come out like ants at a picnic. When peace and prosperity strike a population (rare in the human experience), widespread disrespect for the communities religious traditions show up within a generation. This cannot be explained by genetic drift nor adaptation, but opportunism, and seems to be followed by purges and repression once the peace is broken. My sample set is woefully small here: Athens and the Delian League (as witnessed by Socrates), Rome through the Pax Romana (preserved for us in Pompeii) and the current Pax Americana. We may soon learn if the pattern of purges and repression holds as this current state of peace is challenged by the waning of US military dominance. Two samples over 70,000 years of supernatural scenarios is probably no reason to panic, but I would like to reemphasize that today's rapid rise in religious non-observance is not due to any recent mutations of a ‘religious gene’ but rather a clear mark that religion has never been genetically selected for.

    Later, if Michael’s patience and my attention hold, I will argue that modifications in religious behaviors during the iron age (and on) encouraged ever greater ‘genetic tolerance’, that is we can see religion adapting to include greater personal preferences and personalities. I posit no genetic component to religious beliefs, rather I suggest that Dawkins’ ‘Blind Watchmaker’ took an already evolved large-brained primate and crafted a behavior modifying cultural adaption for it that has been getting further refinements ever since. This is ‘group selection’, but cognitive, not genetic. I fully agree that group selection at a genetic level is, shall we say, challenged (to prove itself). I will attempt to argue that group level cognitive adaption is the ‘best fit’ answer to human socialization.

    An experiment some time back had subjects wired into an EEG, given a set of buttons to push and a series of multiple choice questions. The researchers were able to determine the specific brain response for each button (which in turn corresponded to an answer). The ‘decisions’ showed up on the screen almost instantly as the subjects were given a question, but the subject would take up to several seconds to push the button. As an aside, the researcher suggested that the results may suggest a lack of free will. A lack of free will would have rendered the researcher incapable of designing the experiment, but this does highlight a very significant ‘feature’ of our predator rich environment evolved brains: We jump to conclusions, we respond to our ‘gut’. And we are prone to respond as if our lives depended upon it.

    Chimps, our nearest ‘relative’ (as well as other social mammal species) have social groups organized under an ‘alpha dominant’ system, where the ‘big guy’ calls the shots and gets first pick of the mates . . . until that is, he gets successfully challenged.

    I think it was Jane Goodall, but it could have been another, who witnessed several male chimps ambush another from a neighboring troop. They took turns beating the tar out of him for several hours, until they all went back home exhausted. The victim limped back towards his own habitat. Put a spear in the hand of a young adult male Erectus (Neanderthal or Cro-Magnon it really makes no difference), let him catch the biggest, strongest human in the district unawares, and a fatal injury could be seconds away. Alpha dominancy, among humans, is a non-starter. Lawrence H. Keeley in ‘War Before Civilization’ recounted estimates of a 40% homicide rate among Neanderthals (forensics from bone damage). Archaic humans did not play well together, populations were scattered, lives were short 25 – 35 years peak.

    The ‘Modern’ populations which replaced them would typically have individuals 60 – 70 years old, which for most anthropologists, explains their greatly advanced technologies in weapons, food collection, clothing and housing – advances could be carried across generations and children could be much more effectively educated. We infer from artifacts that they had spiritual beliefs and we deduce from the modern populations of Australia and New Zeeland, some 50,000 years separated from mainland humans, that their language was fully developed by the time they (moderns) first left Africa. The majority opinion among archeologists is that ‘language is somehow responsible’ for the improved socialization, but I suggest it was the development of spirituality, a trait also attributed to all ‘modern’ populations. The behavioral ‘improvement’ (the ability of the group to grow larger, nurture grandparents and the resultant technological improvements) was coincident with spiritual artifacts, yet the development of a spiritual belief system requires all of the related myths and legends that are possible only with a developed language. Spirituality could have been introduced in a single generation, language required a long dependence on vocal communication to evolve our throats and brains – likely millions of years.

    Spiritualism, I propose, allowed the first ‘men’ to behave like men rather than like armed, carnivorous primates by allowing them to suppress their instinct to ‘take charge’, or ‘assert dominancy’ ie: posture or compete for the ‘alpha’ position and to form egalitarian, leaderless bands. By introducing shaman, rituals and legends, they were able to form communities of reverence to the Great Spirit that were free of the instinctive primate alpha-dominance feature.

    Testing this hypothesis poses a challenge – it happened long ago with scant records left. This happened once, allowing no ‘tests’, no cross correlations with any other variables. It involved a founding population estimated to be a few thousand individuals from the same region of SE Africa. This ‘social’ feature was apparently developed by a fairly small group of interacting communities of neighbors some 70 to 100 thousand years ago, and we cannot really see how it developed nor how long they spent working out all of the bugs until it became a well functioning ‘system’. All that we can really tell from the fossil record is how well it was working once they began expanding, began their great diaspora, leaving us as their legacy.

    Next: The Neolithic Revolution, and how I justify my Paleolithic claims (everyone’s patience permitting)

  28. Michael Blume @Corneel & J.A. Le Fevre
    24.06.2010 | 10:38

    I don't want to interrupt your very fascinating discussion! Thank you for that one, I read every post with interest and delight. And I got new ideas for a whole bunch of upcoming blog posts! :-)

    And I would like to offer the possibility of a guest post to you, if you would like to have the chance to present a special argument for broader discussion.

  29. J. A. Le Fevre Thank you Michael.
    24.06.2010 | 21:46

    I think this is much easier for you to recognize and comprehend as you have fairly deliberately sensitized your self to my ‘answer’. I suspect that the last ‘century and a half’ of scientists have been just as determined to not see things my way either because they wanted to purge God from all thought, or to avoid accusations of allowing ‘miracles’ into their conclusions. As such, I’ve had to ‘re-interpret’ the last hundred years of data for what was overlooked and missed. When I first argued my UPR hypothesis I phrased it: ‘they nominated a ‘virtual alpha’ as their leader, one who could not be killed for succession’. A couple vocal theists in the group rather objected to this characterization of ‘spirituality’, so I rephrased it: That’s just science talk for ‘God revealed himself to the community, and they accepted him as their leader, which allowed them to stop living like animals by breaking their ‘alpha-dominance pattern violence’ and begin living like humans (as we have come to understand humanity)’. Mollified, but not altogether satisfied, I suspect. Perhaps it’s a bit too odd for the experience of most. (I haven’t written pt. 2 yet – mayhaps this weekend)

  30. Michael Blume @ J.A. Le Fevre: Alpha Female!
    25.06.2010 | 10:36

    Dear J.A.,

    as I prefer to work empirically, I tend to be somewhat reluctant to as-if stories, which may be too closely related to mythologies. But then, they may make fascinating ways to new ideas and avenues of testing hypotheses.

    If we would assume the compelling narrative that early religious groups managed to reorganize adaptively along religious claims, I would prefer the assumption that Alpha Females took the lead, for a range of reasons, e.g. the rather egalitarian structures among contemporary hunters and gatherers, the almost exclusive dominance of female figurines in long stretches pre-historic artwork, the (on average) stronger religious motivations of women and the reproductive effects delineated in this (and other) posts. I already did a related blog post on that one:

    And I hope to find the time to do a special one about the fascinating topic this summer!

    Thanks for your evolutionary creativity! It's kind of infectious! :-)

  31. J. A. Le Fevre From the clouds . . .
    25.06.2010 | 23:14

    Too free (wild eyed?) thinkers rely on empiricists to drag their feet back to the ground on occasion, but a very relevant lament popular in the circle is that if you gather all the bones of all the Neanderthals we have collected from the entire span of their existence, you could not fill a boxcar. Little evidence exists, but I contend that my claims are very consistent with the existing data. My post was written to illuminate, not educate (for space if not for my convenience). For a more educational piece, I should take you up on a dedicated spot.

    As to your suggestion that ‘that early religious groups managed to reorganize adaptively along religious claims’, I lean away from that notion, if for no other reason than modern humans, by all evidence I have seen, routinely, hold contradictory beliefs simultaneously, and it is rare that any two people uniquely agree upon just what it is they both believe in.
    I take a very mechanistic approach: No beast under the sun has ever prevailed nor failed based on belief, but behavior. Beliefs are only significant (in my thinking) by how they motivate behavior, how beliefs express themselves in the behaviors of the population. It is also tough to assess the claims of the pre-literate or the beliefs of the deceased.

    It was the Bronze Age that saw the rise of the Patriarchies. I’ve started a piece on ‘The three tribes of Able’ in defense of the honor of Cain. This story of the violent farmer was just political spin from one of the three pastoral tribes whose descendants have been terrorizing the world (and spreading their language families) from the time they first learned to craft bronze weapons and to lash chariots to their domesticated steeds. The Semitic, though winning much of the worlds’ hearts and minds with their religions, were much less successful in conquest than the Altaic (Turks and Mongols) or the Indo-Europeans (which would include the empires of Greece, Rome, Persia, Spain and England + USA of course). Life was much more peaceful with men in the fields and women in charge, before the men started playing with swords and horses.

  32. J. A. Le Fevre The Neolithic Revolution and development of religion
    26.06.2010 | 20:04

    Once again – to keep this short I must jut touch on the main points (illuminate, not educate) – there are many ready resources for parties interested in more details. About 10,000 BCE, hunter-gatherers turned to agriculture and settled into villages with larger populations. This required more complex administration – Chiefs and staff which evolved into kings and aristocracy. Villages which expanded their populations beyond the administrative limits would split, with a group going off to form a new village (populations grew much faster than the ability to govern the crowds could evolve). Once populated regions began to exceed several hundreds of individuals, new features had emerged in the communities, particularly specialists – pottery and brick fabricating shops, artisans of various sorts, and priests. The only universal were the priests (and kings – can’t run a city without a leader) – other specialists would vary over time and place. Unlike the Upper Paleolithic, which happened once and spread around the world, city development occurred independently thousands of times through the Middle East, Asia, India, Europe and Americas. To assess the significance of having priests in a community, I contrasted the behaviors in villages with out priests to those in cities with them. The most commonly noted difference is that people in cities pay taxes. Many have suggested that priests were required to initiate the taxation required to support a complex city/state style government. To look beyond that one feature, I turned to my most referenced tome (in this series of posts at least, but I have read other books, honest) Lawrence H. Keeley, ‘War Before Civilization’: Violent deaths in pre-state societies, about 30%. In the wars and purges of the twentieth century ‘state’ societies, about 3% (a rough estimate, mine, not Keeley’s – the body count is estimated at 200 million (Keely and others) for the two world wars, commi purges, etc. Total deaths include a string of pandemics and famines along with the usual infant mortality, accidents and ‘natural’ causes). For the Twenty first century we are coming in at about 0.1% violent deaths (my calculation: 10 of 100,000 violent vs. over 1,000/100,000 total deaths), so excluding wars and purges, ‘in group’ violence within state societies is dramatically reduced. I do not have a number for in-group vs. out group for pre-state societies. Incidence of war between pre-state societies: ave. once per year. State societies, once per three years.
    How is it that state societies can so dramatically improve the socialization of their subjects? I propose it was priests, the one common denominator of early state societies, and that their principal, functional role was ‘professional life-coach’. In my earlier post I recounted how our brains evolved to reach decisions very rapidly, as if our life depended upon it. But the ‘conclusion’ it is going to jump to will be its most recent similar ‘event’, possibly add a correction or two, and execute like response for like stimulus. That is why solders drill and athletes and artists train. Practice and rehearsal polishes our mental responses, optimize our performance. That allows us to jump to pre-decided conclusions without a second thought, conclusions considered in advance, not the panic of the moment. In chimp as well as pre-state societies, it has been widely noted that coming in sight of an unknown individual induces high anxiety, often a ‘fight or flight’ response, and virtually always ‘dominance posturing’ – effecting a threatening or defensive warning posture. Such behavior would be debilitating in a state society where many ‘in-group’ individuals could never be known to all and encounters with strangers would be common. The priests, their rituals and the stories served as constant reminders to the people who they were, who they served (God and king or country) and how to behave towards strangers (love thy neighbor).

    To tie this back to the Upper Paleolithic, as religion has been correlated 100% to cities and the improved socialization required to form them, it is reasonable to postulate that spirituality (ie: religion-lite) could have provided the socialization necessary for the first bands and tribes that they could nurture their parents into grandparents, and reap the benefits of accumulated wisdom. This, I propose, is a best-fit evaluation of the evidence. If you want proof, stick to math. In these other sciences, we do the best we can – not myths, but best fits to the data.

  33. J. A. Le Fevre Back on track: Religions and Fertility
    28.06.2010 | 01:37

    Having a penchant for mechanized solutions, I propose a mechanism akin to gene activation (via environmental triggers). This should be testable for the empirically minded: Religion (perhaps) nurtures an ‘environment’ of safety and security that encourages couples to choose (or increases the desire) to have children. This proposal, however, also opens a less cheery back door – this can also be stress induced. I see no suggestion of the ages of the females in this study, if they are under 18, it suggests a seriously stressed community, marrying off their daughters before maturity.

  34. Corneel short reply
    29.06.2010 | 17:04

    Michael said:
    And I would like to offer the possibility of a guest post to you...

    Thank you. I'll consider it, but -darn- I am a dreadful writer.

    @J.A. Le Fevre

    I don't believe I will be able to comment on your entire opus, so I'll just note a few points in passing:

    You said:'s rapid rise in religious non-observance is not due to any recent mutations of a ‘religious gene’ but rather a clear mark that religion has never been genetically selected for.

    That's nonsense. The fact that some of the variation in religiosity is not genetical does not prove that none of it is. In fact, Michael already blogged about a significant heritable component of this behaviour. That doesn't mean there has been no scope for cultural evolution, but if you are correct that religion is adaptive, than it has also evolved in the Darwinian sense.

    I posit no genetic component to religious beliefs, rather I suggest that Dawkins’ ‘Blind Watchmaker’ took an already evolved large-brained primate and crafted a behavior modifying cultural adaption for it that has been getting further refinements ever since.

    Dawkin's "blind Watchmaker" is a metaphor for natural selection. If it didn't act on genetic factors, than how did it "craft" an adaptation? Even if I would accept your "cognitive selection" mechanism, that still leaves the question why humans were receptive to religious ideas in the first place. Wouldn't that have been by some chance process, according to your scenario?

  35. Michael Blume @Corneel
    29.06.2010 | 22:41

    You wrote: I'll consider it, but -darn- I am a dreadful writer.

    Well, I disagree on this one! I am enjoying every post of yours, for sure!

  36. Balanus Reproductive fitness and religion /@all
    30.06.2010 | 22:21

    In a study on natural selection and quantitative genetics of life-history traits in western women it was found that religion only accounted for 1% of variance in fitness. I do not exactly know what that means, but I think, that finding may indicate that the effect of religious affiliation on fecundity (fitness) is not very pronounced.

    Here is an exerpt of the abtract:

    "In this study, data from a large twin cohort were used to assess whether selection will cause a change among women in a contemporary Western population for three life-history traits: age at menarche, age at first reproduction, and age at menopause. We control for temporal variation in fecundity (the ‘‘baby boom’’ phenomenon) and differences between women in educational background and religious affiliation. University-educated women have 35% lower fitness than those with less than seven years education, and Roman Catholic women have about 20% higher fitness than those of other religions. Although these differences were significant, education and religion only accounted for 2% and 1% of variance in fitness, respectively."

    Kirk et al.. Evolution, 55(2), 2001, pp. 423–435

  37. J. A. Le Fevre @ Corneel
    01.07.2010 | 01:30

    Back in the seventies, with the Hare Krishna movement sweeping California, if not the civilized world, our youth group devised an experiment: Do a random ‘dance’ of hopping around and clapping in a fashion to mimic the ceremonial revelry witnessed at many an airport in the day, and chanting nonsensical rhymes. Most participants reported mild euphoric sensations. I had an opportunity to visit Kenya in the eighties and spend a few weeks with the Kikuyu in a village outside Nairobi. Every full moon the young men of the village, with a few older men as well, gather about midnight with drums, kettles and various implements of percussion for fairly loud and raucous ritual dancing. Great fun, much energy, adrenalin and, of course, endorphins. In monks and mystics, this reaction has been achieved through prayer and meditation – the physical activity appears helpful but not necessary. I have not looked into other religion/gene phenomenon yet, but this one sure looks to be real. My problem with attributing this to a genetic adaptation of religion is that the physical behavior is too similar to the ‘rain dances’ Goodall found in chimps, and other animal behaviors. If you wire up one of the students at your local primate language institute and integrate them into a mosh pit at a rock show, I’ll bet even money you get the same psychochemical response.

    More significantly, I see no selective pressure on the Human to have this trait – these were all male dances, so no mate selection, and was no appearance of improving status within the tribe – just recreation. Not all selective pressures are obvious of course, but this appears to be selective for the belief system (humans will be happier with, and therefore more likely to continue practicing a ritual set that gives them lots of fun endorphins than one that doesn’t - at least in many situations).

    I have a strong suspicion that if you look closely to any such ‘biological’ adaptation, you will find a pre-existing genetic ‘condition’ that spiritual or religious rituals or practices have discovered and learned to take advantage of. Hence, my ‘blind watchmaker’ analogy. The early humans, time and gathered foodstuffs permitting, developed a series of stories, myths and rituals – just because they could. No plan nor goal, just what in their heart they felt was right. Until something they did managed to stay their worst reactive habits and allowed larger groups to accumulate (before the stress and violence drove the group to split), consistently allowed some to grow old before dying, allowing those groups to benefit from the extra generational wisdom and education opportunities. They could now learn more and remember more, allowing other discoveries to accumulate across generations, giving them a competitive advantage over the archaic groups.

    I think this would only apply to ‘spiritual’ rites and rituals, as it appears to me that by the time religion was developed, the humans in the loop appear to know their roles and were making very deliberate decisions on how to craft the institutions. There was surly a very random element to the things they tried, and some were clearly self motivated (there are aspects of religions clearly for the benefit of the priests, and aspects of benefit for the king), but the overall selective pressure was to develop religions which would motivate and propel the host community to out compete its neighbors, or succumb to the neighbors dominance and, of course, religion. The most effective religion would prevail – that is the evolutionary process. The pressures on the human communities from the advent of religion, appears to me to be to select for the most effective leaders and institutions, not the ‘best’ genetic humans.

  38. Michael Blume @Balanus
    01.07.2010 | 07:25

    Thanks for the hint, I will take a look at it. But it seems that they didn't even take a look at the number of children born but only at the age of the first one... A very, well, special definition of fitness! :-) And even then, they found religiosity to be adaptive! Wow! :-)

  39. Michael Blume @ J.A.: Hare Krishna
    01.07.2010 | 07:29

    If you are interested in the Hare Krishna-movement, you might like this blog post! :-)

  40. J. A. Le Fevre @ Michael
    01.07.2010 | 22:09

    Thank you, yes. I did enjoy that, but at the end you promised 'to do a special post on biocultural evolution (or Gene-Culture-Coevolution) in the near future! :-)'

    Is that available?

  41. Balanus Fitness /@Michael Blume
    01.07.2010 | 22:40

    » But it seems that they didn't even take a look at the number of children born but only at the age of the first one... A very, well, special definition of fitness! :-).«.

    No, that's not correct. In "Materials and Methods" you will find:

    "To estimate fitness (measured as r) of individual twins, we needed to be confident that each twin who we studied had completed their reproduction."

    "Age at first reproduction" was only one of the life-history traits assessed.

    And they did not found religiosity to be adaptive, because this was not investigated in the study.

  42. Michael Blume @ J.A. & @Balanus
    02.07.2010 | 12:10

    Thanks for the comments.

    @J.A., yes, I fulfilled that promise:

    @Balanus: Sounds interesting. Do you have the cited study? Or just the abstracts? I would be very interested in reading the whole text.

  43. J. A. Le Fevre Chapter 8
    03.07.2010 | 04:35

    Thank you for the link – liked your paper, agree with the data, but I do not agree with aspects of your analysis. I have two issues with the ‘genetic’ analysis. The big issue is that the problem at hand, man’s inhumanity to man, dwarfs your solution of ‘religion adds more kids’. Religion addresses many problems, but the biggest was civility in my analysis.

    My small issue with your ‘religious heritability’ postulate is that it just does not ‘feel’ right. It looks at the surface to make bad predictions: Religious beliefs have dominated the human landscape for 50,000 years, and have been ubiquitous for 30,000 years, twice as long as we have had projectile weapons. This ‘gene’ should be firmly fixed in the human genome. I can accept Socrates and his nefarious cohorts as victim to some retro virus which attacked only philosophers of Greek disposition, and leaving them with a rare mutation in their religious gene, and to Pompeii we can grant the presence of too much lead in their water pipes and wine goblets. Hundreds of millions of secular ‘conversions’ in the last two generations of northern hemisphere humans, though, defy my ability to concoct semi-plausible levity. I have witnessed mass abandonment of religious practice, and faced the frothing minions at ‘’. Just don’t sense a real strong ‘we all love religion’ throughout the population. If that is what we have after 70,000 years of ‘belief’, I have to assume that same ambivalence throughout the ages. I can only conclude that we humans have willingly paid the high cost of religion these eons is that we recognized some advantage: That seemed the best way to effectively compete, the best chance to prevail, and that something in the competitive environment has recently changed in many advanced communities.

    I can accept without reservation that ‘religious people’ are having more kids, but there just seem to be too many over-night conversions away from religion to accept that there is much in-born desire for it. I think the decision must carry a fair consideration, which gets re-considered time to time as conditions change. Dawkins, quoted from ‘The God Delusion’: ‘When I pressed him, he said he found that Judaism provided a good discipline to help him structure his life and lead a good one.’ I suspect this individual is not unique. Religion has evolved to address many problems, but there is a lot of deliberate, rational thought (as your text clearly demonstrated) in choosing to believe, not at all ‘moths to a flame’ as evolved instinct (or Richard Dawkins) would conclude.

  44. David Yamane Terminology
    10.08.2010 | 02:44

    I stumbled into this post, and enjoyed it very much. Very interesting. My only suggestion is that, when writing about the US context, you refer to religious "nones" as "nones" or "unaffiliated" rather than "non-denominational." You may know that in the American context, nondenominational has a particular relationship to Protestant Christianity and increasingly to a particular cultural orientation to religious tradition on the part of both individuals and congregations.

    Good luck!

  45. Michael Blume @David Yamane
    19.08.2010 | 14:46

    Thank you for your feedback! And, yes, you are right: The German term of "Konfessionslos" and the US-term of "non-denominational" are not exactly synonymous. I shall use "unaffiliated" (or "non-affiliated"?) in the future.

    Thanks & best wishes!

  46. single mothers grants Statistics are sometimes right
    30.03.2011 | 03:37

    We've also had a similar case study about religion and ethnicity during my Psychology classes a couple of years back and I think this was the chart that was shown by my professor.

    All in all, I wouldn't be surprised if the number of Muslim people would double a couple of years from now... Maybe even a little earlier than most predictions.

  47. Michael Blume @culinary scholarships
    08.04.2011 | 07:44

    Yes, I agree. The statistical correlation of religious affiliation and fertility is the result of numerous specific cases of religious traditions, with those endorsing and supporting families enjoying a competitive edge.

    After case studies i.e. concerning the Old Order Amish, I just wrote a piece about the emerging Quiverfull-Movement in the USA.

    Thanks for your interest & best wishes!

  48. Michael Blume @jet charter
    18.04.2011 | 09:55

    Thanks for your interest! When you think about it, it's fairly obvious. Some religious movements manage to attain extremely high fertility levels throughout subsequent generations, i.e. the Old Order Amish:

    Or the Quiverfull-network:

    In contrast, we didn't find a single comparable case among the non-religious.

    A lot of ressources and articles from various colleagues in the field are on my homepage:

    Enjoy the science! :-)

  49. Michael Blume @customized running shorts
    21.04.2011 | 10:02

    I do agree in full. And that's the very reason we are enriching the statistical (quantitative) data with (qualitative) case studies. See, for example, the Amish:

    Or the recent Quiverfull movement:

  50. MIchelle Dough Subject
    09.06.2011 | 15:27

    Good day! I'm Michelle and I would just like to say that your articles are incredible. You are a really talented writer and it's very honorable of you to share your gift by providing high quality articles to everyone.
    Aside from your writing skills, you also have great researching skills; it's very evident in your articles that you do ample research for the information or idea you are trying to convey in your articles.

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