Research Article

The Church, intensive kinship, and global psychological variation

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Science  08 Nov 2019:
Vol. 366, Issue 6466, eaau5141
DOI: 10.1126/science.aau5141
  • Cross-country relationship between exposure to the medieval churches, kin-based institutions, and psychology.

    As predicted by our theory, countries with a longer exposure to the medieval Western Church have lower rates of cousin marriage (A); countries with lower rates of cousin marriage have a more individualistic and impersonally prosocial psychology (B); and countries with a longer exposure to the medieval Western Church have a more individualistic and impersonally prosocial psychology (C). Blue dots, green diamonds, and gray triangles denote countries primarily exposed to the Western Church, to the Eastern Church, and with no church exposure, respectively. ρ^ denotes Spearman correlation.

  • Fig. 1 Church exposure and kinship intensity around the world.

    (A) Exposure to the medieval Western (blue shading) and Eastern (green shading) Churches at the country level. The inset shows the Western Church exposure for regions within Europe based on the diffusion of bishoprics between 550 and 1500 CE (blue shading). The map delineates the boundaries of the Carolingian Empire (orange line) and the divide between Western and socialist Europe (pink line; after Churchill’s Iron Curtain speech). (B) The kinship intensity index (KII) for ethnolinguistic groups around the world.

  • Fig. 2 Medieval Church exposure, kinship intensity, and psychological variation.

    Cross-country relationship between our Individualistic-Impersonal Psychological Scale and (A) medieval Church exposure and (B) kinship intensity. The inset in (B) shows the relationship for cousin marriage rates, while the main plot shows the relationship with the KII. Countries primarily exposed to the Western Church are identified with a dot (blue solid best-fit lines), and countries primarily exposed to the Eastern Church are identified by a diamond (green short-dashed best-fit lines). Triangles denote minimal church exposure (i.e., an exposure of <0.3 centuries). Color coding refers to the duration of Eastern (green) and Western (blue) Church exposure. The reported correlation coefficients for the Western (Eastern) Church were computed after excluding the Eastern (Western) Church–exposed countries.

  • Fig. 3 Cousin marriage and psychology in European regions.

    Relationships between regional cousin marriage and (A) individualism-independence, (B) conformity-obedience, and (C) impersonal prosociality [generalized fairness and trust (in the inset)]. In each panel, linear best-fit lines are displayed along with Spearman’s ρ and their associated significance levels. The shape and color of each data point indicate the corresponding region’s country.

  • Table 1 Psychological and behavioral measures.

    The 24 measures are grouped into three packages for expositional convenience. The notation “std” indicates that a variable has been standardized, and a percent sign indicates that a variable is expressed as a percent. An asterisk identifies those variables that were used to compute our Individualistic-Impersonal Scale. WVS, World Values Survey (95); ESS, European Social Survey (96); WHO, World Health Organization; UN, United Nations; Lab exp., laboratory experiment; Obs., observation.

    Individualism and independence
    1*Individualism (std)ScaleCountries102Hofstede’s widely used scale integrates questions about goals, achievement-orientation, and family ties (97).
    2*Creativity (std)SurveyCountries78Asks how important it is to “think up new ideas and be creative; to do things one’s own way” (WVS).
    3*EmbeddednessSurveyCountries68Psychological scale capturing an individual’s commitment to stable social relationships and the
    existing social order (98, 99).
    4*Analytical thinking (%)TaskCountries31Online task to assess analytical versus holistic thinking (100). In a series of triads, participants are asked whether
    a target, such as a rabbit, goes with either an analytical option (categories, such as a dog) or a holistic or
    relational option (e.g., a carrot).
    5Individualism-independence (std)SurveyRegions/migrants>13KA two-question index on the importance of individualism and independence (ESS).
    Conformity and obedience
    6*Tightness (std)ScaleCountries32Scale measuring people’s perceptions of how closely norms in their society are monitored and
    enforced through social pressures and reputational judgments (47).
    7*Asch conformity (%)Lab exp.Countries16Line judgment task based on a meta-analysis of 133 studies (see text) (11, 101).
    8*Tradition (std)SurveyCountries78Asks people about the importance of tradition (WVS).
    9*Obedience (%)SurveyCountries109A binary measure on the importance of inculcating obedience in children (WVS).
    10*Proper behavior (std)SurveyCountries78Asks people about the importance of behaving properly and avoiding behavior that others say is wrong (WVS).
    11Conformity-obedience (std)SurveyRegions/migrants>13KIndex based on four questions about the importance of conformity and obedience (ESS).
    Impersonal prosociality: Impartiality
    12*UN diplomatic ticketsObs.Countries149The number of unpaid New York City parking tickets per diplomat, accumulated by UN delegations under immunity (85).
    13*Nepotism (std)SurveyCountries117Based on interviews with top executives at the World Economic Forum regarding the degree
    to which their senior executives were relatives (102).
    14*Particularism (std)Vignette surveyCountries43Based on a vignette called the passenger’s dilemma, this is the percentage of people who endorse lying in
    court to help a friend whose reckless driving killed a pedestrian (103).
    15*Honesty dice game
    (% high claims)
    Lab exp.Countries23Students report die rolls of a six-sided die and are paid according to their reported rolls (6).
    The percent of high-paying claims indicate dishonesty.
    Impersonal prosociality: Impersonal cooperation and trust
    16*Public Goods Game (PGG)
    first-round contributions
    (% endowment)
    Lab exp.Countries15First-round contributions in a 10-round laboratory PGG as a percentage of the endowment (4). Participants
    were placed in groups with three strangers and interacted anonymously. In each round, they were endowed
    with a fixed sum and permitted to contribute any portion to a group project. Contributions were increased
    by 60% and distributed equally among the four members.
    17*PGG with punishment,
    average contributions
    Lab exp.Countries15Mean contributions over 10 rounds in a laboratory PGG with punishment (% of endowment) (4).
    In this PGG, participants faced the same situation as above, except that they could pay to take money
    away from (i.e., punish) other players.
    18*Blood donations
    (per 1000 people)
    Obs.Countries/Italian provinces169/92Frequency of voluntary, unpaid, anonymous blood donations from countries (WHO) and Italian provinces (104).
    19*Out-in-group trust (std)SurveyCountries77A six-question index that contrasts trust in family, friends, and neighbors to foreigners, strangers, and
    religious outsiders (WVS).
    20General trust (std)SurveyRegions/migrants>15KAsks whether “most people can be trusted” or “you can’t be too careful” (ESS).
    21General fairness (std)SurveyRegions/migrants>15KAsks whether most people will treat you fairly (ESS).
    22Use of checksSurveyItalian regions>32KBinary variable indicating whether a household uses checks (104).
    23Loans from family/friendsSurveyItalian regions>32KBinary variable indicating whether a household has loans from friends or families (104).
    24% of wealth in cashSurveyItalian regions>32KPercentage of a household’s financial wealth that is kept in cash versus other assets (104).

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  • Table 3 Baseline cross-country regressions for psychological outcomes.

    Country-level regressions of psychological outcomes with observations from >40 countries on Western and Eastern Church exposure, the KII, and log % cousin marriage. Outcome variables were standardized (z-scores), unless otherwise indicated. All regressions include the set of baseline controls: ruggedness, mean distance to waterways, caloric suitability, and absolute latitude. Robust standard errors are reported in parentheses. Significance levels are based on two-tailed tests.

    Individualism and independence Conformity and
    Impersonal prosociality
    IndividualismCreativityEmbeddedness Obedience
    Tradition UN tickets
    (per 1K)
    W. Church exp.
    (in 100 years)
    E. Church exp.
    (in 100 years)
    N147926868 9268 13710413567
    N151937171 9671 14110813870
    Cousin marriage
    (%, log)
    N69574444 5644 64556244

    P ≤ 0.1, *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001

    • Table 4 Regression of psychological outcomes on exposure to the medieval Western Church.

      Individual-level ordinary least squares (OLS) regressions of ESS-based psychological outcomes on Western Church exposure. Outcome variables were standardized (z-scores). The basic controls are country and survey-wave fixed effects, individual characteristics (gender, age, and age2), and basic geographic controls (agricultural suitability, absolute latitude, mean distance to the sea, and average terrain ruggedness). Robust standard errors clustered for the 440 regions are reported in parentheses. Significance levels are based on two-tailed tests.

      PredictorsIndividualism-independenceConformity-obedienceGeneralized trustGeneralized fairness
      Church exposure
      (in 100 years)
      Basic controlsYesYesYesYesYesYesYesYes
      Religiosity and denominationNoYesNoYesNoYesNoYes

      *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001

      • Table 5 The children of immigrants in Europe: Regression of psychological outcomes on Church exposure, the KII, and cousin marriage.

        Panel 1 reports our OLS regressions of the four psychological outcomes on mother’s origin country’s Western and Eastern Church exposure (in 100 years), KII, and log % cousin marriage. An observation is a respondent with an immigrant mother. All regressions control for standard demographic variables (age, age2, gender), ESS wave and residence-country fixed effects, and origin-country baseline geographic controls (absolute latitude, ruggedness, caloric suitability for agriculture, and mean distance to waterways). Panel 2 mirrors panel 1, except that these regressions were estimated in a non-MFP sample—i.e., the subsample of individuals whose mother’s country of origin experienced <120 years of the MFP. Panel 3 also mirrors panel 1 but reports regressions of the psychological outcomes on the KII of ancestral ethnicity, and with origin-country fixed effects instead of origin-country baseline geographic controls; these regressions also include ethnicity-level controls for settlement complexity, jurisdictional hierarchy, reliance on fishing, animal husbandry, agriculture as means of subsistence, and use of irrigation. Robust standard errors clustered at the resident-country level are reported in parentheses. Significance levels are based on two-tailed tests.

        PredictorsIndividualism-independenceConformity-obedienceGeneralized trustGeneralized fairness
        Panel 1: Kinship intensity and church exposure of the mother’s country of origin (full sample)
        Western Church exposure0.024**
        Eastern Church exposure0.035**
        Cousin marriage (%, log)−0.067***
        Panel 2: Kinship intensity of the mother’s country of origin (non-MFP sample)
        Cousin marriage (%, log)−0.093**
        Panel 3: Kinship intensity of the ancestral ethnicity, with origin-country fixed effects

        P ≤ 0.1, *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001

        Supplementary Materials

        • The Church, intensive kinship, and global psychological variation

          Jonathan F. Schulz, Duman Bahrami-Rad, Jonathan P. Beauchamp, Joseph Henrich

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