scilogs Biology of Religion

Religiosity Genes (again) confirmed by (another) Twin Study

from Michael Blume, 12. March 2011, 21:45

For decades, religiosity (defined as beliefs or behaviors towards superempirical agents) has been explored like other traits such as musicality, intelligence or skin color by Twin Studies - which conclusively found it to be partially inherited by genes and partially dependend on environmental (cultural) clues. In fact, religion turns out to be fully comparable to other biocultural traits such as speech or music.

Now, Kenneth S. Kendler, Hermine H. Maes and Todd Vance from the Virginia Commonwealth University in Richmond, VA, presented another Twin Study with rather large sample of 1106 monozygotic twins and 1501 dizygotic twins on "Genetic and Environmental Influences on Multiple Dimensions of Religiosity" (J Nerv Ment Dis 2010; 198: 755-761), DOI: 10.1097/NMD.0b013e3181f4ao7c.

Religious behaviors are partly inherited by genes. 

Building on lots of earlier Twin Studies, they selected 78 religion-related items for their questionnaire, which were organized (by way of a statistical VARIMAX rotation) into 7 factors: General Religiosity, Social Religiosity, Involved God, Forgiveness, God as Judge, Unvengefulness and Thankfulness.

And as those (many) earlier studies (e.g. Bouchard and Koenigs), they found the correlations among monozygotic twins to be far stronger than among dizygotic twins, strongly supporting the notion of genetic heritability of the trait. For illustration, I chose the five strongest correlations from among the female twins.

All the seven religiosity factors were found to be largely influenced by additive genetic and unique environmental effects, with surprisingly little influence from common environmental effects. At first, this seemed to conflict with other studies which found a strong role of family environment in the passing on of religious values. But the sample used in the present study had been comprised entirely of adults (with an average age of 43.06 years), leaving open the possibility that the common environment could be important in the development of religiosity in early life, whereas individual genetic and environmental effects are gaining importance later on.

Religion & Demography, Enste

Religiosity is part of our nature. And as religious demography is showing and as Robert Rowthorn has emphasized recently, the evolution of homo religiosus is still going on...

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Natur des Glaubens: Evolutionäre Fitness und Religiosität
Natur des Glaubens: Kognitive Archäologie und die Naturgeschichte des Glaubens
Biology of Religion: Why Religion is not going to die - The Quiverfull Example of Religious Fertility


  1. Sebastian R. Subject
    13.03.2011 | 14:23

    I have enough of those hypothetical studies with their statistical results. They may be nice to look at, but in the end it´s just statistics. So how about you try to get some hard evidence in the sense of real genetic studies. For example: It would be very significant to compare the genome of religious people with non-religious ones. Through that, you could choose your candidate-genes that would be responsable for religiousness and get a closer look at them. But no, nothing like that happens and people still calculate and calculate. I don´t understand it or did I miss those papers where they really tried to do that?

  2. Clay Farris Naff All very well, but...
    13.03.2011 | 14:29

    I don't necessarily dispute the data, but unless you assume a nonrandom distribution of the relevant genes, how can it account for the great disparities in religiosity from region to region?

  3. Michael Blume @Sebastian R.
    13.03.2011 | 16:47

    In fact, that's what scientists tried all along - and found the genome to be far more complex than anyone thought possible. Even for undisputedly "cultural" abilities such as reading and writing, numerous alleles tend to play a role in complex interactions. And then, it seems that divergent cultural traditions (such as various alphabets, Chinese scriptures etc.) seem to build on a variety of neuronal foundations - indicating that any (upcoming) generalizations about "reading and writing" will have to be adjusted to various aspects. Epigenetic effects added further dimensions of complexity. And religion is probably even more complex than reading & writing alone! Thus, although I do agree with your insistence on more studies in the field, I think we had enough of preliminary "God gene"-headlines. As with music or speech, I think there's still a long way before us.

    Cp. the slow progress of psychiatric genetics:

  4. Michael Blume @Clay Farris Naff
    13.03.2011 | 16:54

    Thanks for your interest!

    The very thing about biocultural traits is their ability to bring about dynamic variety quickly adapting to various circumstances. For example, we might compare how we manage to adapt "speech" not only into literally thousands of different forms, but also in signs, scriptures and internet codes (which we are using this very minute). In order to get an overview over to evolutionary potentials of religiosity, case studies are absolutely necessary. For example, I did one about the Amish:

    And another one about the atheist Raelians (which is in German, but I plan to do an English translation in the near future):

    And note that both of these religious variants are thriving in the same region of Northern America (including Canada)!

  5. Sebastian R. Subject
    13.03.2011 | 17:28

    @Michael: Okay, then we agree, that the headline of this article is a little misleading ;-)

  6. Michael Blume @Sebastian R.
    13.03.2011 | 18:55

    Well, I am ready to agree that it should "lead" to more scientific work on the subject! That religiosity and spirituality do have a genetic base as any other biocultural trait has been found for many years, now it's time to go ahead! And I am looking forward to reading and reviewing the very studies you envisioned! :-)

  7. Balanus Another study?
    13.03.2011 | 21:38

    Hi Michael,

    I think, the term "another study" is somewhat misleading.

    Now, Kenneth S. Kendler, Hermine H. Maes and Todd Vance from the Virginia Commonwealth University in Richmond, VA, presented another Twin Study with rather large sample of 1106 monzygotic twins and 1501 dizygotic twins...

    In fact, the present study is based on the data of a previous study by Kendler et al. (2003). Here is an excerpt of the new study (page 756):

    "In the present study, using the same data and the same sample, we recreated the 7 factors reported by Kendler et al. (2003) and sought to answer the following research questions: What is the magnitude of genetic and environmental effects on multiple dimensions of religiosity?."

    Nevertheless, religiosity is based on the functional structure of the brain, which in turn is created according to the instructions of the genes in response to environmental influences.

    So we are entitled to use the term "religiosity genes" ;-)

  8. Michael Blume @Balanus
    14.03.2011 | 07:31

    Thanks for the comment! In fact, Kendler et al. are citing various old and new Twin Studies about the subject of religiosity. Even some years ago, there were several of them available, I linked a paper with respective citations here (cp. p. 50):

    But alas, I perfectly agree with your conclusions. It would have been an absolute sensation if there would have been "no" genetic-neuronal bases of religiosity - as there are concerning about all complex personality traits. We might use the term of "religiosity genes" the same way we speak about "genes for reading and writing", indicating those alleles encoding for neuronal potentials of the trait.

  9. Dutch Bieber Break it down, break it down
    17.03.2011 | 03:10

    Religiosity? as a trait? I recently discovered your blog, Michael. I am interested in these studies. I believe there is something(s) having to do with religion that is selected for, but I don't think we will find it if we are looking for "religiosity". Recently I read a book on language. Researchers break language acquisition down into many parts. John Dow (laying his bias aside) suggests

    a preliminary hypothesis consisting of three stages in the evolution of religion:

    (1) a cognizer of unobservable agents,

    (2) a sacred category classifier, and

    (3) a motivator for public sacrifice.

    I don't think these are the right pieces or the right definition but religiosity needs to be broken into constitutive elements. "Religion" itself is so big - mystic, deist, theist - just what kind of believer are we proving is genetically selected for?

  10. Michael Blume @Dutch Bieber
    17.03.2011 | 08:04

    Thanks for your interest!

    And yes, the idea that religion should be explored from the perspective of evolutionary theory is not new, but rather classic: It has been started by Charles Darwin himself, see:

    And of course, about all of us working in the field are assuming underlying modules such as Hyperdetection of Agency, Theory of Mind, Reputation Management etc., which evolved into the new, emergent trait. I featured two very recent books on the matter, discussing respective theses - one is "The Nature of God"

    and the other is
    "The Biological Evolution of Religious Mind and Behaviour";_knv_dok_nr=090501574

    A more popular overview has also been presented by Jesse Bering in his new "The God Instinct":

    There's much empirical work available and some more on the way - keeping up your interest might be a good way of contributing!

  11. corneel Subject
    18.03.2011 | 16:39

    @Sebastian R said
    I have enough of those hypothetical studies with their statistical results. [..] you could choose your candidate-genes that would be responsable for religiousness and get a closer look at them.

    and how would you establish an association between genetic variants and religiosity, if not with statistics?

    There is no discipine that is so dependent on statistical routines as genomic association research.

  12. Dutch Bieber Definition inadequate
    19.03.2011 | 13:21

    "religiosity (defined as beliefs or behaviors towards super-empirical agents) has been explored like other traits such as musicality, intelligence or skin color"

    Yeah, I know I am new to this area.

    I read David Wilson's follow-up article to his book in which he examines criticism of his book and offers further evidence. His discussion of Jainism reveals a complex of cultural and religious behaviors and communal relations that can't be contained by the term "religiosity." Religiosity is inadequate as a measurable category for what is going on in these communities.

    As categories, musicality or intelligence or skin color are not equivalent to that claimed for religiosity. To make musicality equivalent you would have to add audiences, school funding for teaching, marching bands and parades. To test intelligence you might have to add soduku. To test skin color you would have to add racism.

    Supernatural is insufficient to be the center of a definition of religiosity. I think it must be something like "a unfalsifiable supernatural 'authority'." That, to me, is the center of the argument for Jainism. If it was not about this unassailable authority, the ascetic would not be welcomed in a ritual manner.

    If supernatural alone is central to a definition of religiosity you have to include measurements the of the following

    People who believe in
    Ghosts 34%
    UFOs 34%
    Astrology 29%
    Reincarnation 25%
    Witches 24%
    (Fox News)

    I believe in something inheritable within the idea of religion but religiosity is too clumsy of a category.

    Take Care

  13. Michael Blume @Durch Bieber
    19.03.2011 | 22:20

    Thanks for your thoughtful comment. But you seem to have misread my quote: I wrote about superempirical, not supernatural agencies. Aliens from outer space, ghosts, souls and star gods fully conform to this definition.

    And if you would like to explore the Evolution of musicality or speech, you would have to include the (social) forms, functions and effects as well. Please keep up your lively interest, there is much to be discovered!

  14. Dutch Bieber evolutionary process as a cruciform process
    20.03.2011 | 02:43

    "You can, then, see the whole evolutionary process as a cruciform process, the cross spread out over fourteen billion years of evolution" - Ilia Delio

    Having participated in Michael Dowd's Evolutionary Christianity I returned to the web searching for other voices. When I saw your blog I had expectations. But I am discouraged.

    Superficially, yes, I did mistakenly use supernatural instead of your super-empirical. But super-empirical is a screen, a pretense that it is not the supernatural we are talking about.

    Maybe your definition of superempirical does not include conceptual simplicity, explanatory unity - one source defined this as the search for the "one and only first cause" - and relative coherence, but I suspect it does. I understand these concepts to be comments about the set of beliefs not the focus of the beliefs. So, for me the definition is not nested correctly.

    From Levi-Strauss quoted in Masks of the spirit: image and metaphor in Mesoamerica By Peter T. Markman, Roberta H. Markman

    "The mind thus passes from empirical diversity to conceptual simplicity and then from conceptual simplicity to meaningful synthesis."

    This is a summary of

    "Speaking of the natural source of images man combines to make the supernatural meaningful and accessible, [Levi-Strauss] says,'even when raised to that human level which alone can make them intelligible, man's relations with his natural environment remain objects of thought: man never perceives them passively, having reduced them to concepts, he compounds them in order to arrive at a system.'"

    To not fully recognize and acknowledge human agency is to miss the mystery and miracluousness of evolution. The Linkean thesis makes a wonderful sermon illustration - perhaps for process christians anyway - in that the consonants on the scroll can be seen as God, always there, waiting, offering the divine self for human participation and it is only when the scroll is read and the human inserts the vowels does the scripture spring to life and claim meaning.

    Humans evolve so religion must have evolved. I do not hear you talk about change in religion. How does religion evolve?

    The clumsy "religiosity" seems to assume that religion is fixed and you conclude from your studies and others that this fixed container of beliefs and behaviors is successful over time but nothing in the container seems to change - how does that work in evolution? The other problem with this clumsy religiosity is that you must respond to studies that show that increased religiosity correlates with decreases in intelligence and wealth. If that is battle you are prepared for then go for it.

    But in evolution all things evolve, even religion. The treasures of the Evolutionary Christianity teleseries are the language and the metaphors which give us words to express our gratitude and awe.

    Again Ilia Delio-

    "In that word of God spoken in love is the world. From the very beginning of that spoken word is Christ. The whole evolutionary creation, from its beginning, is intended for Christ. By that, I mean that it’s intended to be a personalized unity in God, in love. When we speak about Christ, we’re talking about the word of God in love, our word in flesh, the word of love enfleshed. That’s what we mean by Christ—or what I mean by Christ. If we think about love incarnated all along, then from the Big Bang onward, in every quark and every photon in every hydrogen atom and in everything that’s emerging, the whole evolutionary universe is that word of love being incarnated.

    Take Care


  15. Michael Blume @Dutch Bieber: Legwork
    20.03.2011 | 10:15

    Wow, these are deep thoughts! In a sense, your disappointment seems to be understandable to me. Although I am interested in the great and last questions as you are, I try to keep my scientific work down to earth. For example, all definitions of religion used in empirical studies may at best be approximative working definitions. I do agree that "Religion" is evolving in itself, but see my task in bringing up "just" more empirical data and studies - in doing the legwork, so to speak.

  16. J. A. Le Fevre Dutch –Cognitive vs. biological evolution
    22.03.2011 | 17:27

    Michael is addressing biological evolution with ‘religiosity’ as a phenotype, in its most general form: The practice of or ritual participation in religion, or expressed belief in super-empirical agents. The evolution OF religion is really more a theological exercise. Your observation of ‘seems to be fixed’ is because each study is of a ‘fixed' generation. The consistency of the data suggests a trend that will drive evolution, but does not yet document an evolutionary path.

    To my reading, Michael directly addresses the challenge of studies that show that increased religiosity correlates with decreases in intelligence and wealth, a 'great irony' to borrow his words.

  17. J. A. Le Fevre The need for religious evolution
    23.03.2011 | 02:18

    Religion, as ‘belief’ has been practiced for the last 70,000 or so years. Organized religion, as an institution within human community, identified by the existence of temples and/or priests may have begun about 11,000 years ago, and has been an integral component of civil society from the beginning of city formation. Archeology and history document the evolving states of society and religion through the ages. One way to view the current spread of atheism is a failure of religion to evolve adequately to hold the hearts and imaginations of many in the most successful modern states. Richard Dawkins and Dan Dennett have waxed on of religions’ evolved ability to ‘engage’ the human mind, but that, like biological immunity, minds also develop resistance to being so engaged. In the developed world, the resistance appears to be gaining ground over religious engagement, the most successful and most intelligent being most resistant. The ultimate irony in the success of resisting the allure of religion is that those individuals also loose interest in sustaining their own genetic legacy.

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