Cultural diversity of religion across 117 countries

Domain: neuroscience
Published: 2026-01-12
Editorial outcome: major_revision

Abstract
Humans show marked diversity in cultural values, beliefs, and preferences. Here, we analyze survey responses from 640,110 individuals in 117 countries (representing 89% of the World’s population), and 2,333 sub-national districts, surveyed in the World Values Survey and the European Values Study. Across multiple sets of comparable cultural traits, we find that religion consistently emerges as the cultural trait that exhibits the largest cross-country divergence (measured by the Cultural Fixation Index or simple variances). For example, personal emphasis on religion varies 5-10 times more across countries than emphasis on family, politics, or work effort, and religion is the most divergent quality valued for raising children. Likewise, differences in religious group membership across countries exceed those in other voluntary affiliations. These cross-country differences in religiosity stem partly from differences between religious traditions, but mostly from individual differences in religious involvement intensity. Our findings underscore the importance of religion in shaping cultural differences across societies.

Introduction
Worldwide, there is considerable population variability in human values, beliefs, and preferences, and this diversity in cultural traits is orders of magnitude larger than diversity in genetic traits1–3. The nature of this diversity, and its persistence over time, remain a scientific puzzle that continues to occupy the social sciences.

Of the myriad ways in which cultural traditions may sustain global divergence in values and preferences, people’s relationship with religion is particularly important. People affiliated with distinct religious traditions differ in their attitudes and preferences4–6. For instance, religion galvanizes beliefs, rituals, and sacred commitments as means of creating a moral community7–9. This key feature of world religions consolidates values, beliefs and preferences within a superordinate identity6,10–12. In addition, secularization has spread in some parts of the world such as Europe, North America, Australia, and East Asia, altering moral values and other social preferences, further increasing differences in levels of religiosity across the globe13,14. Based on this, we hypothesize that global diversity in religiosity is high. We aim to estimate the magnitude of this global diversity, relative to the diversity of other cultural traits.

Our focus on religion is motivated by evidence that both the strength of religiosity and affiliation with different religious traditions shape important outcomes, including education, income, crime, well-being, conservatism, and prosociality4,11,15–19. However, attempts to quantify the relative contribution of religion compared to other cultural traits have been few12. In this study, we investigate religion as one domain of worldwide cultural diversity, and compare to other domains of cultural life, such as family, work, politics, and leisure. This allows us to assess the relative contributions of each domain to overall cultural diversity. Moreover, we distinguish between the intensity of individual religiosity and affiliation with specific religious traditions, in order to evaluate their respective contributions to cultural variation across the 640,110 individuals from 117 countries in our sample.

Previous research has examined the development of cultural diversity over time. Using data for 76 countries available in up to seven waves of the WVS, Jackson and Medvedev examined 40 cultural values and documented increased divergence in emancipative values (defined as a favorable stance on issues such as homosexuality, euthanasia, divorce, prostitution, suicide, abortion), but convergence in values across countries in the same region14. They attribute this mainly to the widening gap between high-income Western countries and the rest of the world. Comparing 18 countries in 1990 and 2010, other research finds convergence in cultural traits typical for Western rich individualistic countries20. Research analyzing preferences for 80,000 individuals in 76 countries reaches similar conclusions: preferences—such as patience, willingness to take risk, altruism, trust, positive and negative reciprocity—are becoming more similar across countries21. Most relevant to the main question we address here is the study by White et al. (2021), which used three waves of the World Values Survey (WVS) across 88 countries to document that individuals who share the same religious tradition and level of religious commitment also tend to share similar cultural values and preferences both within and between countries12.

In the current study we build on this research but also extend it in several important respects. First, we restrict the analyses across values based on groups of questions that are directly comparable across cultural domains. This enables us to compare cultural traits for the same individual, thus removing confounds related to individual differences and features of survey questions. Second, by exploiting information on the subnational districts of the interviews (instead of countries), we are able to argue that the analysis exclusively captures cultural diversity within countries, such as differences in geography, national culture, or institutions. Third, we are equipped with a much larger sample than previous research, which means that our sample is much more representative of the full global sample and that we can analyze changes over time. This method allows us to assess cultural change in a balanced sample over 60 years. Balancing the sample is crucial, as the inclusion of different countries at different points in time would otherwise distort the computation of diversity. Taken together, these steps increase our confidence that it is religious diversity that we detect, rather than other variables associated with it.

Results
To identify which cultural values differ most across our sample of 640,110 individuals from 117 countries, we compute the Cultural Fixation Index (CF st), which is commonly used to measure cultural diversity and differentiation12,24. It is adapted from the Genetic Fixation Index (F st), which compares the genetic variability within and between any populations23,25. The CF st ranges from 0 to 1, where 0 corresponds to the lowest diversity, indicating that the cultural variations across examined populations are identical and 1 indicates the highest diversity, where the populations do not share any cultural traits. We extend beyond standard usage in three respects: We compute the CF st for each cultural value separately, allow the population to comprise either countries or sub-national districts, and treat the CF st as a measure of the total existing between-population variance for each cultural trait. We compute:

CF st,i = var b,i / (var b,i + var w,i) (1)

for each of the cultural values i examined. var b,i is the cross-population variance in cultural value i. The population is either a country or a sub-national district. var w,i is the within-population variance for cultural value i. The index ranges between 0 and 1 with 0 indicating that countries (or sub-national districts) in the sample are similar in terms of cultural value i and 1 indicating that countries (or sub-national districts) differ completely in terms of value i.

Comparability
We ensure comparability of each measure of cultural values i by selecting subsets of questions that are asked within one group of questions, such as “important child qualities" or “values important in your own life." We choose these groups of questions based on the criteria that they i) include a question related to religion and ii) are available for at least 350,000 respondents.

Figure 1 shows the CF st for each of the cultural values within each of the four comparable value sets. The left panels show the CF st for the full sample and the right panels show the development in CF st over time, where time indicates the birth-cohorts of the respondents.

Personal values
The first group of comparable values includes answers to the question: “For each of the following aspects, indicate how important it is in your life." The list of qualities includes family, friends, leisure, politics, work, and religion. These questions are answered by 599,313 individuals from 117 countries in six waves (1989–2022). The upper panel of Fig. 1 reveals that values regarding religion differ much more across the 117 countries, compared to any of the other dimensions. The cultural diversity in personal emphasis on religion is 3.4 times larger than the value with the second-largest diversity–emphasis on leisure–or 9.7 times larger than the value exhibiting least diversity–emphasis on family. This pattern persists across cohorts from the 1930s to the 1990s (as shown in the right panel of Fig. 1). If anything, countries are becoming more different over time in terms of individuals’ personal emphasis on religion (i.e., religiosity). Differences based on the other cultural dimensions have not changed much during the past 100 years. These patterns are not due to great changes in the mean values of these cultural dimensions. For instance, the average person has regarded religion as rather important (score 2) throughout the past 100 years, while the average person has regarded family as very important (score 3) throughout the period (Supplementary Fig. S1 in Supplementary Information). The lack of a change in the average emphasis on religion covers declines in some parts of the world and increases in others. For instance, if we had focused the analysis on Europe, we would have seen a decline in the average emphasis on religion, as expected.

Child qualities
Our second set of values includes answers to the question: “Here is a list of qualities that children can be encouraged to learn at home. Which, if any, do you consider to be especially important? Please choose up to five." The listed qualities are: Independence, hard work, feeling of responsibility, imagination, tolerance and respect for other people, thrift (saving money and things), determination and perseverance, religious faith, unselfishness, and obedience. These questions are answered by 640,110 individuals from 117 countries in seven waves (1981–2022). These are depicted in the second panel of Fig. 1 (Child qualities). Again, these 640,110 individuals from 117 countries differ more in their emphasis on the importance of religion, compared to any of the other dimensions considered. The variation in the emphasis on the importance of religion is 49% larger than the value exhibiting the second-largest diversity–emphasis on hard work–and 5.2 times larger than the value exhibiting the least diversity–emphasis on determination. The pattern has not changed much over time, except that countries have become more similar in terms of their emphasis on the importance of hard work.

Self-reported values
Surveys are sometimes criticized for their exclusive reliance on self-reported values, which may not always accurately reflect individuals’ true beliefs. We have no a priori reason to believe that the biases inherent in self-reports significantly impact the results. Moreover, studies have shown that values and preferences in surveys spanning multiple countries do predict relevant behaviors in laboratory experiments as well as institutional features of societies3,26. Nevertheless, we proceed with two groups of questions that—although they are still self-reported—are more likely to reflect the respondents’ actual behaviors, not only their self-reported values.

Voluntary membership
Our third values set includes answers to the question: “Please look carefully at the following list of voluntary organisations and activities and say which, if any, do you belong to?" The list of organization types includes religious or church organisations (we term this group Religious); education, arts, music or cultural activities (Culture), labour unions (Labour); political parties or groups (Political); professional associations (Professional); sports or recreation (Sports). Corroborating our previous results, countries differ more in terms of individuals’ memberships of religious organizations than any other voluntary memberships. The pattern is visible in the aggregated data and in every decade of the past 100 years. The pattern is even more pronounced with regard to whether respondents are active members of these organizations (the lower panel of Fig. 1). Interestingly, there is a slight tendency for convergence in membership in religious organizations, but a divergence in personal values. This signifies that the reason for the divergence has more to do with differences in actual personal religious beliefs, rather than differences in membership of religious organizations across the 100 countries in this sample.

Religiosity vs. affiliation with religious denominations
We test the extent to which religious divergence constitutes divergence in the intensity of religiosity, or affiliation to different religious denominations. To examine this question, we remove variation due to religious denominations from the measures of cultural values before computing the CF st. Unsurprisingly, cultural diversity declines, particularly for values regarding religion (Supplementary Fig. S10 in Supplementary Information). For instance, diversity declines by 25% for Personal values and 9% for Child qualities. The difference between diversity in religiosity relative to the remaining values declines by 35% for Personal values, 44% for Child qualities, 2% for Membership, and 26% for Active membership. This indicates that around one-third of the observed diversity in religiosity can be attributed to differences between denominations, while the majority of the variation is not due to differences across religious denominations.

To further examine the differential contribution of religiosity relative to religious denominations, we perform the analysis separately within each major religion. Specifically, we divide respondents into four religious affiliation categories: “None," “Christianity," “Islam," and “Other" (which includes Judaism, Hinduism, Buddhism, and Other religion) and compute the CF st separately within each group. We find the greatest divergence in religiosity within each religious group, with the exception of child-rearing values among Christians, where “Hard Work" shows greater diversity (Supplementary Figs. S11–S14 in Supplementary Information). Notably, even among individuals who do not identify with any religion, their stance towards religion remains the most culturally diverse dimension.

These findings suggest that differences in religiosity take up a larger share of cultural diversity than affiliation with different religious denominations. This aligns with previous research indicating that religious affiliation explains only a minor share of the global variation in religiosity27.

Within vs. between variance
The CF st,i statistic implicitly accounts for differences in within-country variation. Consequently, for a given level of variance across countries, the index will increase as within-country variance decreases. Computing instead the within and between country variances (var w,i and var b,i) separately, we find that the results are driven by a higher variance across countries for religiosity (Supplementary Figs. S2, S3 in Supplementary Information). Indeed, the pattern of between-country variance is very similar to the pattern of the Cultural Fixation Index, whereas the within-country variances do not differ much across the cultural dimensions and do not follow a similar pattern across the four groups considered. This corroborates that religiosity differs more across the 640,110 individuals from 117 countries than any of the other values considered and that this is not a byproduct of more homogenization within countries.

Diversity across sub-national districts
A potential caveat of the above analysis—and any other analysis of cross-country differences—is that countries differ from each other in countless ways. A concern is that these cross-country differences may be the true drivers of the identified associations. By restricting our comparisons to answers by the same person, we limit the potential bias caused by this substantially. Only if these cross-country differences influence, say, values regarding work and religion differently would they matter for our results. In theory, however, such cross-country within-individual influences pose a concern.

To address this, we leverage information provided by the WVS and EVS on the sub-national district where each survey was conducted. This information is available for 467,690 individuals in 2333 sub-national districts in 109 countries for the child qualities and 435,241 individuals in 2252 sub-national districts in 109 countries for the personal values. We then remove cross-country variation in each of the values before computing the CF st measures in order to investigate cultural diversity across sub-national districts within countries. This accounts for variation in national-level factors such as religious majority, Western influence, national institutions, national culture, and geographic features.

Although this exercise reduces the variation in all values considered and narrows the difference between religion and the remaining dimensions, it does not change the conclusion: religion remains the cultural dimension along which these sub-national districts differ the most for all four groups of cultural dimensions considered (cf. Fig. 2). For an analysis of diversity across sub-national districts without removing cross-country variation, see Supplementary Fig. S4 in Supplementary Information.

Accounting for age and gender of respondents
Another potential concern is that the observed diversity over time may reflect demographic changes in the sample, such as age and gender. For instance, respondents born in the 1930s were on average older at the time of interview than those from younger cohorts during the survey period (1981–2022). Age and gender could influence the self-reported cultural values, affecting the observed diversity across countries.

To address this, we first remove variation due to age and gender before calculating CF st over time. This approach allows us to disentangle demographic effects from broader cultural trends. The patterns in CF st are virtually unchanged (Supplementary Fig. S5), suggesting that the temporal trends are not driven by demographic differences. Applying this approach to the full sample, without considering changes over time, yields the same result: religion remains the cultural dimension along which countries differ the most (cf. Supplementary Figs. S6, S7).

Alternative balancing
When analyzing changes over time (cf. the right panels in Fig. 1), we restrict the main sample by respondents’ birth year so that each country is represented in each of the 13 half-decades. This balancing is crucial for analyzing variation in cultural diversity over time, since later waves of the WVS and EVS include countries that differ more from the first waves. For instance, developed nations were more represented in the first waves than their actual global representation. If this is not accounted for, measures of cultural diversity will mechanically rise over time due to a more diverse sample of countries over time. We show that conclusions are unaltered if we instead balance the sample by interview decade. In Supplementary Fig. S8, we restrict the sample to countries with respondents interviewed in each of the 1990s, 2000s, and 2010s. This results in samples of 61 countries for Personal values, 61 countries for Child qualities, 35 countries for Membership, and 25 countries for Active membership.

Additional robustness checks
We conduct various additional robustness checks.

Cross-country differences
The examination across sub-national districts within countries rules out that country-level factors explain the results. Nevertheless, we include another measure of cross-country differences as an additional robustness check. A substantial part of differences across countries occurs across continents. If such differences explain results, we should see results change if we account for differences across continents. Removing variation across continents before computing the CF st does not change results (Supplementary Fig. S9).

Socioeconomic status
To account for socioeconomic differences, we consider the highest educational attainment and income of respondents. We account for this variation by removing variation caused by 8 different education levels and 10 different income levels before computing the CF st. The results are unchanged (Supplementary Figs. S15, S16).

Excluding invalid responses
As an additional robustness check, we exclude respondents who selected more than five qualities in the Child qualities question group. Although the survey explicitly instructs respondents to mark up to five qualities, some individuals select more. This means dropping 22,658 respondents in the full sample and 18,133 respondents in the cohort-based sample. Dropping these responses has no impact on the results (Supplementary Fig. S17 in Supplementary Information).

We conclude that results are not sensitive to differences across countries or individual-level differences in religious denominations, socioeconomic status or demographics. This includes the fact that we compare values for the same individual. Thus, all factors that influence the individual values similarly are implicitly accounted for.

Methods
Here we describe our data and outline the main aspects of our methodology. Further details are provided in the Supplementary Information.

Exemption from ethics approval
This study used anonymous and publicly available data. No additional ethical approval was required. This was confirmed by the Research Ethics Committee at the Department of Economics, University of Copenhagen.

Data source
To measure cultural values across as many countries or subnational regions as possible, we use the pooled World Values Survey and European Values Study49. We use all available seven waves (1981–2022) of the World Values Survey (WVS) and all available five waves (1981–2021) of the European Values Study (EVS). The surveys are representative of the full population at the country-level, and hold numerous questions on cultural values on trust, individualism, and religiosity, for instance.

Cultural values
To ensure comparability of the different dimensions of culture, we only compare within values that are asked within the same set of questions. We restrict to sets of questions that include at least one question on religion and that are answered by at least 350,000 respondents. The 350,000 limit is chosen to keep the task manageable and to ensure representation across countries (maximum N=117), birth decades (T=13), and sub-national districts (maximum N=2333). We have checked results for questions available for fewer respondents and conclusions are unaltered; religion clearly dominates cultural diversity. We arrive at four sets of values. Two sets include respondents’ stated values, two sets include memberships of voluntary organizations and thus reflect respondents’ revealed values.

Our first set of values–Personal values–includes answers to the question: “For each of the following aspects, indicate how important it is in your life" (Questions A001–A006). The list of qualities are family, friends, leisure, politics, work, and religion. The original variables took values 1 (Very important), 2 (Rather important), 3 (Not very important), and 4 (Not at all important). We recoded the variables to 0 (Not at all important), 1 (Not very important), 2 (Rather important), 3 (Very important).

Our second set of values–Child qualities–consists of answers to the question: “Here is a list of qualities that children can be encouraged to learn at home. Which, if any, do you consider to be especially important? Please choose up to five" (Questions A027–A043). The listed qualities are: Independence, hard work, feeling of responsibility, imagination, tolerance and respect for other people, thrift (saving money and things), determination and perseverance, religious faith, unselfishness, and obedience. The variables take on values 1 if the particular quality was mentioned, 0 if not.

Our third set of values–Member–includes answers to the question: “Please look carefully at the following list of voluntary organisations and activities and say...which, if any, do you belong to?" Questions include A065, A066, A067, A068, A072, and A074. The questions in between are not asked in all waves and thus include answers by fewer than 350,000 respondents. These omitted organization types are “Local community action on issues like poverty, employment, housing, racial equality," “Third world development or human rights," “Conservation, environment, animal rights groups," and “Youth work (e.g. scouts, guides, youth clubs etc.)." The conclusion is unaltered if we include these questions. The list of organization types includes religious or church organisations (we term this group Religious); education, arts, music or cultural activities (Culture), labour unions (Labour); political parties or groups (Political); professional associations (Professional); sports or recreation (Sports). The variables take on values 1 if the particular membership was mentioned, 0 if not.

Our fourth set of values–Active member–includes answers to the question of whether the respondents are active or inactive members of the same organizations. Questions include A098–A105. In addition to the organizations in the third group, this set also includes environmental organizations, as this is answered by more than 350,000 respondents. The variables take on values 0 if the person is not a member, 1 if he/she reports being a member, and 2 if he/she reports being an active member.

Within each group, we remove respondents who do not answer all questions within the particular group.

Time-variation and balanced samples
To analyze the diversity in cultural values over time, we attach a survey response to the respondent’s birth year. We hereby assume that an individual’s cultural values are closely correlated with the predominant values of his or her birth year. This assumption is based on a literature that documents how attitudes, preferences, and beliefs to a large extent are formed in childhood and early adulthood50–52. Our main sample is restricted to respondents with birth years between 1930 and 1994. This timespan is chosen to maximize the length of time studied and the number of countries with information for each half-decade.

When analyzing variation across time, we balance the sample so that the same countries are represented (by at least 10 respondents) in each half-decade within the timespan. The average country-half-decade has 450 respondents. In Supplementary Fig. S8, we restrict the sample based on interview year instead. In this analysis, we restrict to countries with respondents interviewed in every decade of the 1990s, 2000s, and 2010s. To group respondents by decade, we take the first year of each wave’s time interval and include 2020 in the 2010s14.

Cultural diversity
We examine cultural diversity using two different measures: the Cultural Fixation Index described in Eq. (1) and simple between-country or between-sub-national district variances.

The CF st index was originally designed to capture cultural distances between specific populations, such as countries or religious groups12,24. This dyadic approach focuses on measuring how much two populations differ in their cultural values. In contrast, we compute the variance across individual responses. This variance captures how much individuals within the entire sample differ from each other in their cultural values and can be decomposed into between-group and within-group variances based on countries or sub-national districts. By structuring the data at the individual level and using the xtsum command in Stata, we can calculate the relevant variances for each cultural value across different population definitions without needing to structure the data into specific dyads.

Sub-national analysis
To construct Fig. 2, we remove cross-country variation from each of the cultural dimensions before computing the variance within and across sub-national districts. We do so by the following procedure. We regress each of the cultural values on a full set of country dummies and save the residuals. The variation in these residuals equals the variation in the cultural values, excluding the variation from cross-country differences. Thereafter, we compute the variance across and within sub-national districts for these residuals.

Individual-level controls
We use information on the socioeconomic status of the respondent, which includes self-reported education levels (variable X025) and income levels (variables X047_WVS and X047_EVS), and their demographics, including gender (X001) and age (X003). To account for variation at the individual-level, such as religious denominations, educational attainment, and income, we follow the same procedure as described for removing cross-country variation. For instance, to account for variation in religious denominations, we first regress each of the cultural values on a full set of dummies for religious denominations, save the residuals, and compute the CF st for the residuals. These estimations include accounting for dummies for 10 religious denominations, 8 levels of educational attainment, 10 income groups, 92 age levels, and 2 genders.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "I really enjoyed reading the paper “Religion and global cultural diversity.” The paper convincingly shows that people are more culturally divided over the value of religion than the value of many other personal qualities and qualities in children. The analyses are extensive and contribute to a growing body of research on the persistence of cultural variation in the contemporary world. I think this paper will make an important contribution. Although some of my feedback might seem critical, I want to emphasize the fact that I think this is an important, clear, and creative paper!\n\nCONCEPTUAL FEEDBACK\nMy major point of conceptual feedback to the authors is to be clearer about cause and effect. Currently, the authors interpret their results as evidence that religion causes cultural variation. Here are some quotes to this effect, with stars around causal language:\n(Abstract) “Of the many cultural traits, which ones **generate** the most global diversity across countries?”\n(Abstract) “The results reveal the pervasive **role** of religion and secularization in the cultural evolution of societies”\n(Introduction) “The root **causes** of this diversity…are a scientific puzzle”\n(Introduction) “There are reasons to believe that religious affiliation and engagement is a deep **root** of a broad array of cultural traits”\nIn principle, I am OK with developing causal theories and testing them in the World Values Survey. But in this case, I believe the paper is conflating the nature of cultural variation with the causes of cultural variation. Just because people are divided over the value of religion (the nature of variation), this does not mean that religion is causing cultural variation. To take an analogy, consider that countries are polarized over the justifiability of being gay. This does not mean that gay people are causing cultural polarization.\n\nIn my view, this paper does not say anything about the causes of cultural polarization over the value of religion. Nor does it need to. The question has already been covered (using WVS data) by White and Norenzayan and by Jackson and Medvedev, who are both cited prominently here. These teams conducted analyses of “who” is polarized, which can tell us something about the roots of cultural polarization, whereas this paper is testing “what” people are polarized over, which cannot tell us about the roots of polarization.\n\nNow, I do not think this misinterpretation is a fatal flaw, because the results of the paper stand on their own. It is genuinely interesting and useful to see just how much people are culturally polarized over religion compared to other domains of culture. However, I believe this issue does require a major reframing of the paper’s introduction and interpretation. All language about the sources of cultural variation should be removed from the abstract and introduction, including the paragraph on the “three broad factors” causing cultural variation, the paragraph on moralizing gods as sources of cultural convergence within groups and variation between groups, and any claims that the paper is discovering “global diversity attributable to religion” when setting up the value of the paper. As I mentioned before, showing that people are polarized over some topic does not mean that cultural polarization is attributable to that topic. To take one more example, American partisans are polarized over abortion rights, but polarization across regions of the US is not attributable to abortion, it is attributable to a complex array of exogenous factors.\n\nFor what it’s worth, here is how I would interpret your results: They suggest that the religion is currently a prominent (perhaps the most prominent) form of cultural diversity, and that it is becoming even more prominent over time. Relatedly, secularization in the 20th and 21st-century seems to be characterized by more polarization in religion (at least when you consider people’s personal values) in addition to declines in the overall value of religion. We saw something similar in our recent paper “Exposure to automation explains religious declines.” In that paper, we find that many of the most religious countries are becoming even more religious, whereas the least religious countries are becoming less religious (see Fig 1). In the 21st century, religious polarization is actually growing at a faster rate than religion is declining, and this religious polarization is clearly visible in your data.\n\nOf course, you have no obligation to use any of my interpretation. And, if you think that I have seriously misunderstood something about the conceptual interpretation of your findings, I would be happy to reconsider my feedback.\n\nEMPIRICAL COMMENTS\nApart from my conceptual feedback, I have some more concrete empirical suggestions:\n1. The paper claims that “We develop a method to compute global diversity attributable to religion and compare it to other cultural traits for the same individual.” However, I’m not sure what this “method” is. Is it the process of calculating CFst at the item level? If so, then I don’t think that this is necessarily novel. The procedure was explained in the original Muthukrishna paper, and measures of creating item-level cultural polarization scores has been published before (e.g., Jackson & Medvedev, Fig 1 presents one such method). Perhaps it is something else, like the process of combining EVS and WVS data, or dividing findings by birth cohort? Whatever the method is, I would be more specific about what you mean here.\n2. I was not sure what the role of “commitment” is here. I understand that you replicate the results when removing variance associated with denomination (in the “Additional robustness checks” section), but I don’t see analyses where you look at CFst scores from people of different levels of religious commitment. In fact, I do not see the word “commitment” appear in the results section, even though it appears repeatedly in the introduction and discussion sections when setting up and interpreting the results. Is the idea that anything that isn’t reducible to religious denominations must reflect religious commitment?\n3. I would actually have recommended doing the religious denomination analyses a little differently. Rather than just removing denomination variance, why not do this: (1) subset the WVS and EVS to just people from a single religion, (2) remove the countries where there aren’t enough people from that religion to get stable estimates of values, and (3) then calculate the CFst scores. If you do this for each religion, then you can see which religions have cultural diversity in religious values across cultures. For example, it might be that Muslims around the world do not vary widely in their value of religion, but Christians do. If you replicated your main finding within each religion, this would also show the pervasiveness of your result.\n4. You may already know this, but there were problems in many countries (especially India) with the “child qualities” items. Although people were also supposed to select only up to 5 from the list of 10 socialization goals for children, this rule was not followed very strictly in most countries and some respondents chose up to 10. In some countries, the majority of respondents chose more items than they were supposed to. I bring this up just to make sure that you have adjusted for this in your analyses.\n5. What is your interpretation of why birth cohorts are converging on membership in religious organizations, but diverging on personal values? One thought that occurred to me is the “credibility enhancing displays” argument that declines in religious practice foreshadow declines in religious belief. It could be that, around the world, people are declining in their rate of religious participation, and that this is foreshadowing a global around the personal value of religion in the future (see Langston, Speed, & Coleman, 2020; Gervais et al., 2021). In general, I would have liked to see some interpretation of why the birth cohort trends look different across the different questions.\n\nVERY MINOR POINTS\nNone of the y-axes in the paper are labeled.\nSome claims need citations, like the claim that “most studies have sampled from single country” when you speak about the limitations of past research on cultural variation and religion. I think that claim in particular is a bit disingenuous because every paper about religion that uses the WVS, of which there are many, samples from many countries.\nI hope these comments are helpful, and best of luck with the research!\nJoshua Conrad Jackson", "reviewer_2": "## Summary\nThis study examines how much religion contributes to global cultural diversity, using combined data from the World Values Survey (WVS) and European Values Study (EVS). The sample includes 640,110 individuals from 117 countries, 2,333 sub-national districts, and 13 birth cohorts. The authors measure cultural diversity with the Cultural Fixation Index CF_st. Their main question: which surveyed cultural traits vary the most within and across groups?\nThey find religious traits vary more than traits related to family, work, politics, or leisure. This remains true for personal values, child-rearing values, and memberships in voluntary organisations. Decomposing this effect, about two-thirds of the diversity stems from differences in religious commitment (from secular to devout). The remaining one-third reflects broad denominational affiliation (Christianity, Islam, Buddhism, etc.). Thus, even nations sharing the same religious heritage diverge sharply if one is more secularised. The result holds across sub-national districts, controls for demographics, and multiple cohorts.\n\n## Contribution\nThis study's main contribution is identifying which cultural domain differs the most worldwide. Past cross-cultural work (e.g., the WVS \"cultural map\") emphasises secular vs. traditional values. However, the WVS culture map does not quantify how much more religion varies compared with other traits. By combining multiple sets of related questions (personal, child-rearing, memberships) and using CF_st at the individual level, the authors give a more precise and flexible estimate of how much each cultural domain contributes to global diversity. The findings extend prior research (e.g., White et al. 2021) by showing that religious identity and intensity can bridge or cross-cut national boundaries. Recent evidence (e.g. . https://doi.org/10.1038/s41467-024-46581-5) on global divergences also supports religion's substantial variability.\n\n## Support for the authors' claims\nThe data and analyses support the conclusions. Religion outstrips other domains in between-group variation, confirmed by comparisons of religion vs. family, work, or other values. The authors decompose this variation further to show that the strength of religiosity (secular vs. devout) explains more diversity than denominational labels alone. Robustness checks that adjust for demographics and examining sub-national districts support core findings. Effect sizes are large, and significance tests suggest the findings are unlikely to be artifacts of sampling.\n\n## Limitations\nAlternative analyses: the authors rely on CF_st estimates, which are appropriate for comparing relative between-group vs. within-group variance. But other analytic approaches—such as Latent Profile Analysis (LPA) of different religious and paranormal orientations—might reveal subtler patterns that CF_st cannot detect (e.g. https://doi.org/10.1080/2153599X.2019.1678516, or https://doi.org/10.1080/2153599X.2013.779934).\nComparison to other dimensions: religion appears uniquely variable compared to family or work values. However, the differences might shrink if we included other major cultural factors (e.g., language). For instance, linguistic diversity could outstrip religious diversity when measured on a global scale, depending, of course, on how we measure such diversity (see: https://doi.org/10.1163/1570068054305619). The authors note this, but nevertheless, measures of cultural diversity seem inevitably linked to our interests in dimensions of diversity. Similar points have been made about genetic diversity (e.g. https://www.science.org/doi/10.1126/science.298.5594.824), and some functions-based methods have been applied to culture (e.g.: https://doi.org/10.1101/263905)\nTheoretical Explanations: the authors emphasise secularisation. Yet drift, recognition signalling, or competition between religious groups could also drive global religious variation (e.g. https://link.springer.com/article/10.1007/s12110-012-9138-8, and, as the authors are no doubt aware, the author's considerable work in this area, e.g., especially https://doi.org/10.1146/annurev-psych-122414-033426, https://doi.org/10.1017/S0140525X14001356). The current data cannot fully disentangle these mechanisms. Future work might incorporate historical or phylogenetic approaches to test competing theories of religious change and diversity, which the authors note, but might state more clearly in relation to cultural evolutionary work (e.g.: https://doi.org/10.1163/1570068054305619) and/or to sociological theories of diversification (e.g.: Wuthnow, R. (1994). Producing the sacred: An essay on public religion. University of Illinois Press).\nThese limitations and avenues for explanation do not undermine the study's central findings. The authors acknowledge limitations and conduct supplementary checks/sensitivity analyses relevant to *their* method and data.\n\n## Methodological soundness\nThis study's design is sound. The sample is large and diverse. Using CF_st to quantify between - vs. within-group variance fits the research question, and their methodological innovations in developing CF_st for generic group comparisons (not merely pairwise between countries) is interesting and valuable. Comparing religion and other domains within the same individuals guards against many confounds. Robustness checks (demographic controls, sub-national analyses) increase confidence. The authors provide replication materials for Stata users.\n\n## Broader Implications and Future Directions\nThe results imply that religion (including degrees of religiosity) is a considerable cultural fault line worldwide, at least compared to other WVS/EVS values domains. As the authors note, future work might examine the historical/causal mechanisms that give rise to these patterns. Such future work might also determine whether other domains (e.g., language or moral norms) rival religion. The present study opens many doors to future inquiries.\nOverall, I find the paper compelling and well-executed. The methodological choices are appropriate, and the authors address possible concerns through careful controls and decomposition analysis. Although the authors might consider more clearly linking the observations of this study to their earlier work, most especially their https://doi.org/10.1146/annurev-psych-122414-033426 because causality cannot be established, such an extension might distract from the interest of the study's methods and findings. I would leave any decision about expanding the to them. It reads well as it is.\n\n## Recommendation\nI recommend publication."}, "author_response": "Response:\nThis is a very good point, and we agree that establishing that religion is a prominent source of cultural divergence is a different point than identifying the root causes of this diversity. We have edited the text throughout the manuscript to reflect the idea that religion constitutes the most prominent form of cultural polarization instead of saying that religion causes polarization. We kept the “three broad factors” causing cultural variation paragraph, to address a point that Reviewer 2 made, and also because it points to an important area of research related to this topic. But we put it in the Discussion at the end, clarifying that this paper does not directly address, but contributes to future discussions of these factors.\n\nWe now have a sharper interpretation of the results that more clearly convey the key contribution of the paper without overstating the main conclusions.\n***\nResponse:\nAnother good point. We have revised the text to better reflect what we meant by this. We rephrased the particular paragraph into the following:\n“In the current study we build on this research but also extend it in several important respects. First, to examine cultural values that are directly comparable, we restrict analysis to values based on questions that are grouped by the survey producers. This enables us to compare cultural traits for the same individual, thus removing confounds related to individual differences and features of survey questions. Second, by exploiting information on the subnational districts of the interviews (instead of just the country), we are able to conduct the analysis exclusively within countries, thus accounting for a large pool of confounders that vary across countries, such as differences in geography, national culture, or institutions. Third, we are equipped with a much larger sample than previous research, which means that we can analyze changes over time. This method allows us to assess cultural change in a balanced sample over 60 years. Balancing the sample is crucial, as the inclusion of different countries at different points in time would otherwise distort the computation of diversity. Taken together, these steps increase our confidence that it is religion, rather than other variables associated with it, that is the source of global cultural diversity.”\n***\nResponse:\nSorry for this confusion and thanks for pointing it out. We have used the terms “religiosity” and “religious commitment” interchangeably. However, we realize that “religious commitment” signals a much more behavioral dedication to religion, while “religiosity” captures rather a felt centrality of religion. Our reading of the literature is that most use the term “religiosity” as the broader category of the two, which seems more appropriate for our analysis as well. We have therefore harmonized the text to use exclusively “religiosity”, explaining in the introduction how this relates to the term “religious commitment”.\nWhen we compute CFst scores for people answering differently to the questions, such as “How important is religion in your life?”, our intention is that this reflects exactly differences in religiosity, as we now term it throughout.\nWe have also clarified the text to indicate that religiosity and affiliation with religious denominations are distinct aspects of religion that could independently account for global diversity (and indeed we find that they do). Our approach, consistent with previous work (e.g., White et al. 2021), allows us to check whether the differences we find in religiosity are indeed due to the strength of religiosity, or due to differences across religious denominations (for instance, on average, Muslim populations are more religious than Christian populations).\n***\nResponse:\nWe agree this is a valuable addition. We have added Figures S11-S14, which show the estimates across countries computed within four broad religious denominations: \"None\", \"Christian\", \"Muslim\", and \"Other\" (Jewish, Hindu, Buddhist, and Other religions). These figures demonstrate that religiosity remains the most divergent cultural dimension even among individuals who share the same religious background.\nInterestingly, one exception emerges in the Christian sample: \"Hard work\" shows slightly greater cultural diversity than religiosity; a finding that may reflect Weber's classic hypothesis on the Protestant work ethic. We thank the reviewer for prompting this valuable extension. Please note that the “Other” group consists of 17,000-46,000 respondents and dividing it into its separate denominations would yield much fewer respondents spread across rather few countries. For example, for “Child Qualities”, which is the set of questions with most responses, we would get 2,202 Jews in 31 countries, 12,747 Hindus in 21 countries, 16,449 Buddhists in 33 countries, and 14,669 Others in 84 countries. Therefore, we did not decompose this grouping further.\n***\nResponse:\nWe have added Figure S17, which presents a robustness check that excludes 22,658 respondents (of the original full sample of 640,110 respondents) and 18,133 respondents (in the original cohort-based sample of 535,540 respondents) who selected more than five qualities in the Child Qualities questions, in violation of the survey instruction. This exclusion indeed includes mainly the 2012 India wave. Despite this adjustment, the results remain unchanged. The figures are nearly completely unchanged. This confirms that the main findings are not driven by respondent error in this particular battery.\n***\nResponse:\nThanks for noting this and thank you so much for your attempt at explaining. Figure S1 shows the development in mean values, which reveals that the mean is quite stable over time, which speaks against the idea that the difference between the patterns is caused by declining participation. Instead, we added the following: “Interestingly, there is a slight tendency for convergence in membership of religious organizations, but a divergence in personal values. This signifies that the reason for the divergence has more to do with differences in personal religious beliefs, rather than differences in membership of religious organizations across the globe.”\n***\nResponse:\nOur judgement is that if we label the y-axes, the text in the figures will become too small to read. Throughout, it will just say “CFst” on all y-axes (except some of the appendix figures when we show robustness to using the variance and show the means of the variables). To clarify, we have now re-arranged so that “Overall CFst” and “CFst over time” occurs in the top of Figure 1 instead of the bottom and included CFst in the subtitles of the figures as well.\n***\nResponse:\nWe agree and have removed the claim. Furthermore, we have gone through the document to limit such unclear language.\n***\nResponse:\nThey certainly were. Thank you once more for your kind and thoughtful comments!\n***\nResponse:\nThank you for pointing out these important limitations. We agree, and have included these limitations in our discussion, and added some of the relevant sources cited by the reviewer. We emphasize that the current study does not address another very important scientific question of disentangling the possible mechanisms that generate cultural diversity. We do however, address these points about mechanisms in the Discussion section. We want to emphasize that we do check for robustness of the findings using other measures of cultural heterogeneity (other than the CFst) in the Supporting Information Appendix: Figure S2 shows the analysis using variance between countries and Figure S3 shows the analysis using variance within countries. Comparison across these two figures and our main Figure 1 reveals that the results revealed by the CFst measures are indeed driven by high cross-country diversity in religion, as opposed low within-country diversity.\n***\nResponse:\nWe now cite Norenzayan (2016) and added some discussion that relates to this previous work on \"theodiversity,\" as suggested by the reviewer.\n***\nResponse:\nWe thank Reviewer 2 for the detailed evaluation of the manuscript and helpful suggestions."}, {"round": 2, "reviewer_comments": {"reviewer_1": "I appreciate the authors' work improving the paper. The revision has convincingly addressed my previous empirical comments. I continue to believe that this paper is important and yields novel findings.\nMy main suggestions at this stage involve theoretical tightening, mostly between pages 1-2 of the manuscript. I think the focus of the study could still be clearer in the introductory text. I will try to comment on a few specific sections in the introduction that I think are misleading. I think these comments are important to address before the paper is published, because there is still a mismatch between what the paper suggests it will do in the introduction and what it will ultimately do in the results.\nQuote, Page 1: \"However, attempts to quantify the relative importance of religion compared to other correlated cultural traits have been scarce (11). Specifically, it is unclear whether religion per se is the source of global variation in cultural traits, or whether some other factors associated with religion are the main components of global diversity.\"\nComment: This paragraph is misleading. It is setting up the question of whether religion is the *source* of global variation in cultural traits mentioned earlier in the paragraph (education, crime, well-being), but the paper does not answer this question. The paper analyzes religiosity as the target of variation rather than the source. It is also underspecified what is meant by \"the main component of global diversity.\" This term \"component\" conflates the causes of diversity (not addressed in this paper) with the manifestation of diversity (addressed in this paper).\nIn my view, the first half of this paragraph (up until \"Global divergence in religiosity can result...\") suggests that the paper will answer a different question than it ultimately answers.\nQuote, Page 1; \"There are reasons to believe that religious affiliation and religiosity are deep roots of a broad array of cultural traits\"\nComment: Again, this is setting up a hypothesis (that religious affiliation and religiosity are the causes of cultural variation in many traits) that are not the focus of this paper.\nQuote, Page 1: \"First, a key element of globally prevalent religions is a central concern with morality (12). Omniscient Gods and spirits are believed to be particularly interested in the moral behaviors and intentions of human beings. Experimental studies show that such beliefs have measurable effects on prosociality (13.\"\nComment: I don’t view this literature as relevant to the authors’ hypotheses about religion as a source of global variation. If anything, the prosocial religions literature would predict that religions around the world share a common emphasis on parochial morality. This claim is not tested in the paper, and it also does not align with the later hypothesis of low within-group variation and high between-group variation.\nQuote, Pages 1-2: \"Moreover, religion galvanizes beliefs, rituals, and sacred commitments as means of creating a moral community (14–16). This key feature of world religions that have come to define the majority of the world consolidate values, beliefs and preferences within a superordinate identity (4, 11, 17, 18). From this, we hypothesize that within-group variation in religiosity is low and between-group variation in religiosity is high. Second, this community building aspect of religion has been particularly potent in facilitating large-scale cooperation across geographic and linguistic boundaries by solving commitment and cooperation problems in anonymous groups (12). Again, this would reduce within-group variation and potentially differentiate groups along their religious beliefs and practices.\"\nComment: The logic for this hypothesis is more reasonable, but this theory does not align with what is tested in the paper. This past work emphasizes how religion enforces specific moral virtues (e.g., charitable giving) and beliefs (e.g., belief in one god rather than many gods and spirits) at the group level. But the current paper is looking broadly at the importance of religion in different domains. It is not testing for variation in the kinds of values and attitudes studied by this past work.\nQuote, Page 2: \"Third, people affiliated with distinct religious traditions diverge in their attitudes and preferences, further amplifying global diversity (7, 18, 19).\"\nComment: Although this is marked \"third\", it seems like a reformulation of the first and second points of this paper (people from different religious groups have different values, potentially because of adaptive cultural evolutionary pressures).\nQuote, Page 2: \"Fourth, secularization has spread in some parts of the world such as Europe, North America, Australia, and East Asia, altering moral values and other social preferences, such as attitudes towards family, sexual morality, and individual autonomy (20, 21). This suggests that global divergence in religiosity may be high, independently of affiliation with a particular religious tradition.\"\nComment: I agree that secularization is crucial for understanding this paper's results. In fact, it seems like the dominant mechanism for the paper's findings. But the comment about \"moral values and other social preferences, such as attitudes towards family, sexual morality, and individual autonomy\" is misleading because none of these morals and attitudes are the focus of this paper.\nMy general comment is that all of this theorizing seems mismatched with the focus of the current paper. It seems better focused to a paper documenting the role of religiosity for explaining differences in attitudes and values, such as the paper published by White, Muthikrishna, and Norenzayan in 2021.\nI apologize for the redundancy of these comments. But I think the focus of the paper is important to clarify, especially if this paper is placed in a high-impact generalist journal. Even the first paragraph of the paper (not quoted here) is basically positioning religion as the IV and other values/attitudes as the DV, which is misleading due to the focus of the paper.", "reviewer_2": "The paper was already strong; the revision is even stronger. I recommend acceptance."}, "author_response": "Response:\nThank you for taking the extra time to suggest further improvements and for inspiring us to sharpen the text further. We truly appreciate this. We have rewritten the first two pages of the introduction substantially. In the introduction, we now state four main points that were not communicated clearly in the previous draft.\n1. Motivate why studying cultural diversity is important. Paragraph 1 (starting with “Worldwide, there is”).\n2. Motivate the plausibility of our hypothesis: Cultural diversity in religion is potentially large and potentially larger than other cultural dimensions. This has no causal flavor to it. Paragraph 2 (starting with “Of the myriad”).\n3. Motivate why we are placing our analytic focus on religion: It may potentially be implicated in a wide range of important and interesting variables, such as education, prosociality, science engagement, etc. This can be construed as a causal statement, and other work we cite has advanced that line of argument, but the causality question is not embedded in our hypothesis. We hope this is clear now. First part of Paragraph 3 (starting with “Our focus on”).\n4. Explain how our analysis contributes to #3. Second part of Paragraph 3 (starting with “In this study”).\nYour particular quote is part of paragraph 3. We hope that it is now clear that this is not our hypothesis, but simply meant to motivate why studying religion is important. What we are saying is that religion matters for socio-economic outcomes, and thus studying it is relevant for a social scientist. This was unclear before, but we hope we have made it clear now.\n***\nResponse:\nWe agree. We have removed this part.\n***\nResponse:\nWe agree and have removed this part.\n***\nResponse:\nWe have deleted much of this section and instead use parts of it as examples of our point #2 (motivating our hypothesis).\n***\nResponse:\nWe agree and have written the different points into one point: Our point #2 (motivating our hypothesis).\n***\nResponse:\nWe have removed the particular misleading part and relegated secularization into the section describing our point #2 (motivating our hypothesis).\n***\nResponse:\nOnce again, we really appreciate the extra time you took to help us clarify the text. We have gone through the remaining text with the same focus. In particular, we changed:\n• From “Taken together, these steps increase our confidence that it is religion, rather than other variables associated with it, that is the source of global cultural diversity.” to “Taken together, these steps increase our confidence that it is religious diversity that we detect, rather than other variables associated with it.”\n• From “We test the extent to which global divergence is explained by the intensity of religiosity, or by affiliation to different religious denominations.” to “We test the extent to which global religious divergence constitutes divergence in the intensity of religiosity, or affiliation to different religious denominations.”\n• From “These findings suggest that differences in religiosity are a larger source of global cultural diversity than affiliation with different religious denominations.” to “These findings suggest that differences in religiosity take up a larger share of global cultural diversity than affiliation with different religious denominations.”\n• From “It is, therefore, plausible that peoples’ relationship with religion is a significant driver of global diversity in cultural values and preferences.” to “It is, therefore, plausible that peoples’ relationship with religion reflects a significant share of global diversity in cultural values and preferences.”\n• From “We find that different levels of religiosity and affiliation with different religious traditions are a potent source of global variation.” to “We find that different levels of religiosity and affiliation with different religious traditions take up a potent share.”\n***\nResponse:\nWe agree that this translation could introduce new bugs. To check for bugs, we have ensured that three of four co-authors could run the code on their PCs and had one independent researcher unaffiliated with our team reproduce the entire code. No bugs were found. Furthermore, previous versions of this paper were based on methods and Stata codes that were substantially different. Yet, we found the same conclusions. We are therefore confident in the reproducibility of these results."}, {"round": 3, "reviewer_comments": {"reviewer_1": "The authors have addressed my concerns about framing. This is an excellent paper, and I believe it is ready for publication."}, "author_response": ""}]

Decision letter