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Demographic trends in today's world are dominated by large fertility differentials between nations, with ‘less developed’ nations having higher fertility than the more advanced nations. The present study investigates whether these fertility differences are related primarily to indicators of economic development, the intellectual level of the population, or political modernity in the form of liberal democracy. Results obtained with multiple regression, path models and latent variable models are compared. Both log-transformed GDP and measures of intelligence independently reduce fertility across all methods, whereas the effects of liberal democracy are weak and inconsistent. At present rates of fertility and mortality and in the absence of changes within countries, the average IQ of the young world population would decline by 1.34 points per decade and the average per capita income would decline by 0.79% per year.

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Abma, J. C. & Martinez, G. M. (2006) Childlessness among older women in the United States: trends and profiles. Journal of Marriage and the Family 68, 10451056.
Boonstra, O. (1998) The impact of education on the demographic life course: the family reproduction process of literates and illiterates in the Netherlands at the end of the nineteenth century. History of the Family 3, 303313.
Clark, G. (2007) A Farewell to Alms. A Brief Economic History of the World. Princeton University Press, Princeton, NJ.
Clark, G. & Hamilton, G. (2006) Survival of the richest: the Malthusian mechanism in pre-industrial England. Journal of Economic History 66, 707736.
Colom, R., Flores-Mendoza, C. E. & Abad, F. J. (2006) Generational changes on the Draw-a-Man test: comparison of Brazilian urban and rural children tested in 1930, 2002 and 2004. Journal of Biosocial Science 35, 3339.
Daley, T. C., Whaley, S. E., Sigman, M. D., Espinosa, M. P. & Neumann, C. (2003) IQ on the rise. The Flynn effect in rural Kenyan children. Psychological Science 14, 215219.
Dickens, W. T. & Flynn, J. R. (2001) Heritability estimates versus large environmental effects: the IQ paradox resolved. Psychological Review 108, 346369.
Doepke, M. (2004) Accounting for fertility decline during the transition to growth. Journal of Economic Growth 9, 347383.
Flynn, J. R. (1984) The mean IQ of Americans: massive gains 1932–1978. Psychological Bulletin 95, 2951.
Flynn, J. R. (1987) Massive IQ gains in 14 nations: what IQ tests really measure. Psychological Bulletin 101, 171191.
Frejka, T. & Westoff, C. F. (2008) Religion, religiousness and fertility in the US and in Europe. European Journal of Population 24, 531.
Friedlander, D., Schellekens, J. & Ben-Moshe, E. (1991) The transition from high to low marital fertility: cultural or socioeconomic determinants? Economic Development and Cultural Change 39, 331351.
Hadeishi, H. (2003) Economic well-being and fertility in France: Nuits, 1744–1792. Journal of Economic History 63, 489505.
Haines, M. R. (1992) Occupation and social class during fertility decline: historical perspectives. In Gillis, J. R., Tilly, L. A. & Levine, D. (eds) The European Experience of Declining Fertility 1850–1970. The Quiet Revolution. Blackwell Cambridge.
Heer, D. M. (1968) Economic development and the fertility transition. Daedalus 97, 447462.
Jablonski, N. G. & Chaplin, G. (2000) The evolution of human skin coloration. Journal of Human Evolution 39, 57106.
Jones, G. & Schneider, W. J. (2004) Intelligence, human capital, and economic growth: an extreme-bounds analysis. URL:∼garjone/JonesSchneApr.pdf.
Khaleefa, O., Abdelwahid, S. B., Abdulradi, F. & Lynn, R. (2008) The increase of intelligence in Sudan 1964–2006. Personality and Individual Differences 45, 412413.
Knodel, J., Havanon, N. & Pramualratana, A. (1984) Fertility transition in Thailand: a qualitative analysis. Population and Development Review 10, 297328.
Kost, J. & Forrest, J. D. (1995) Intention status of U.S. births in 1988: differences by mothers’ socioeconomic and demographic characteristics. Family Planning Perspectives 27, 1117.
Kreyenfeld, M. (2003) Crisis or adaptation – reconsidered: a comparison of East and West German fertility patterns in the first six years after the ‘Wende’. European Journal of Population 19, 303329.
Lamson, H. D. (1935) Differential reproduction in China. Quarterly Review of Biology 10, 308321.
Lee, R. D. (1987) Population dynamics of humans and other animals. Demography 24, 443465.
Leet, D. R. (1977) Interrelations of population density, urbanization, literacy, and fertility. Explorations in Economic History 14, 388401.
Lesthaeghe, R. & Neels, K. (2002) From the first to the second demographic transition: an interpretation of the spatial continuity of demographic innovation in France, Belgium and Switzerland. European Journal of Population 18, 325360.
Loehlin, J. C., Lindzey, G. & Spuhler, J. N. (1975) Race Differences in Intelligence. W. H. Freeman & Co., San Francisco.
Lutz, W., Testa, M. R. & Penn, D. J. (2006) Population density is a key factor in declining human fertility. Population and Environment 28, 6981.
Lynn, R. (1996) Dysgenics. Genetic Deterioration in Modern Populations. Praeger, Westport, CT.
Lynn, R. (2006) Race Differences in Intelligence. An Evolutionary Analysis. Washington Summit Books, Athens, GA.
Lynn, R. (2008) The Global Bell Curve. Race, IQ, and Inequality Worldwide. Washington Summit Publishers, Augusta, GA.
Lynn, R. & Harvey, J. (2008) The decline of the world's IQ. Intelligence 36, 112120.
Lynn, R., Meisenberg, G., Mikk, J. & Williams, A. (2007) National IQs predict differences in scholastic achievement in 67 countries. Journal of Biosocial Science 39, 861874.
Lynn, R. & van Court, M. (2004) New evidence of dysgenic fertility for intelligence in the United States. Intelligence 32, 193201.
Lynn, R. & Vanhanen, T. (2001) National IQ and economic development: A study of eighty-one nations. Mankind Quarterly 41, 415435.
Lynn, R. & Vanhanen, T. (2002) IQ and the Wealth of Nations. Praeger Westport, CT.
Lynn, R. & Vanhanen, T. (2006) IQ and Global Inequality. Washington Summit Books, Athens, GA.
Maddison, A. (2007) Historical Statistics. URL: (accessed September 2008).
Matthews, R. C. O., Feinstein, C. H. & Odling-Smee, J. C. (1982) British Economic Growth 1856–1973. Stanford University Press, Stanford, CA.
McPherson, G. R. & Weltzin, J. F. (2008) Implications of peak oil for industrialized societies. Bulletin of Science, Technology and Society 28, 187191.
Meisenberg, G. (2003) IQ population genetics: it's not as simple as you think. Mankind Quarterly 44, 185209.
Meisenberg, G. (2004) Talent, character, and the dimensions of national culture. Mankind Quarterly 45, 123168.
Meisenberg, G. (2007) In God's Image. The Natural History of Intelligence and Ethics. Book Guild, Brighton.
Meisenberg, G. (2008) How universal is the negative correlation between education and fertility? Journal of Social, Political and Economic Studies 33, 205227.
Meisenberg, G., Lawless, E., Lambert, E. & Newton, A. (2005) The Flynn effect in the Caribbean: generational change of cognitive test performance in Dominica. Mankind Quarterly 46, 2969.
Neiss, M., Rowe, D. C. & Rodgers, J. L. (2002) Does education mediate the relationship between IQ and age of first birth? A behavioural genetic analysis. Journal of Biosocial Science 34, 259275.
Parker, M. P. (2004) Chrestomathy: Annual Review of Undergraduate Research at the College of Charleston 3, 167181.
Raven, J. (2000) The Raven's Progressive Matrices: change and stability over culture and time. Cognitive Psychology 41, 148.
Raven, J., Raven, J. C. & Court, J. H. (1998) Raven Manual: Section 1. General Overview. Oxford Psychologists Press, Oxford.
Retherford, R. D. & Sewell, W. H. (1988) Intelligence and family size reconsidered. Social Biology 35, 140.
Retherford, R. D. & Sewell, W. H. (1989) How intelligence affects fertility. Intelligence 13, 169185.
Rindermann, H. (2008a) Relevance of education and intelligence at the national level for the economic welfare of people. Intelligence 36, 127142.
Rindermann, H. (2008b) Relevance of education and intelligence for the political development of nations: democracy, rule of law and political liberty. Intelligence 36, 306322.
Rodgers, J. L. & Wänström, L. (2007) Identification of a Flynn effect in the NLSY: moving from the center to the boundaries. Intelligence 35, 187196.
Sallume, X. & Notestein, F. W. (1932) Trends in the size of families completed prior to 1910 in various social classes. American Journal of Sociology 38, 398408.
Shayer, M., Ginsburg, D. & Coe, R. (2007) Thirty years on – a large anti-Flynn effect? The Piagetian test Volume & Heaviness norms 1975–2003. British Journal of Educational Psychology 77, 2541.
Soares, R. R. (2005) Mortality reductions, educational attainment, and fertility choice. American Economic Review 95, 580601.
Sundet, J. M., Barlaug, D. G. & Torjussen, T. M. (2004) The end of the Flynn effect? A study of secular trends in mean intelligence test scores of Norwegian conscripts during half a century. Intelligence 32, 349362.
Teasdale, T. W. & Owen, D. R. (2008) Secular declines in cognitive test scores: a reversal of the Flynn effect. Intelligence 36, 121126.
Templer, D. I. (2006) Temperature, skin color, per capita income, and IQ: an international perspective. Intelligence 34, 121139.
Tuddenham, R. D. (1948) Soldier intelligence in World Wars I and II. American Psychologist 3, 5456.
Udry, J. R. (1978) Differential fertility by intelligence: the role of birth planning. Social Biology 25, 1014.
United Nations (1987) Fertility Behaviour in the Context of Development. Evidence from the World Fertility Survey. United Nations, NY.
United Nations (2004a) Worldmark Encyclopedia of the Nations, 11th edition, Vol. 1. Gale, Detroit.
United Nations (2004b) Human Development Report. United Nations URL: (accessed 15th October 2008).
United Nations (2005) Human Development Report. URL: United Nations (accessed 10th October 2008).
United Nations (2007) Abortions Legally Induced, Urban and Rural. United Nations Statistics Division, Common Database (accessed 28th November 2007).
van de Walle, F. (1980) Education and the demographic transition in Switzerland. Population and Development Review 6, 463472.
Vining, D. R. (1995) On the possibility of the reemergence of a dysgenic trend with respect to intelligence in American fertility differentials: an update. Personality and Individual Differences 19, 259263.
Vinovskis, M. A. (1976) Socio-economic determinants of interstate fertility differentials in the United States in 1850 and 1860. Journal of Interdisciplinary History 6, 375396.
Weede, E. (2004) Does human capital strongly affect economic growth rates? Yes, but only if assessed properly. Comparative Sociology 3, 115134.
Weede, E. & Kämpf, S. (2002) The impact of intelligence and institutional improvements on economic growth. Kyklos 55, 361379.
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Journal of Biosocial Science
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  • EISSN: 1469-7599
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