Human fertility and fitness optimization

Abstract

Census and other sur\ej data from across the norld releal maJor differences m fertdlt! rates hetueen the more economIcall> debeloped and the less economIcall\ developed socletles The former are slgmficantly more likely than the latter to feature famlhes of tHo children or fewer hlultlple regression analysis shoHs that, among larlous mdlcaters of 'Umodernlzatlon." three (female level of education. female gainful emplo!ment. and proportion of phjslclans m the population) account for 71Cr of the barlatlon m farnil) size. all three larlables hale strong13 srgmficant. direct. and negatlre effects on fertdlt> The paper hvpotheslzes about the possible evolution of a reproductwe pqcholog> toward the two-child farnIl and seehs to explain hIghIS depressed rates of reproduction bl reference to both ultimate and proximate factors In some hIghI\ deleloped countries, zero-child and one-child rates of fertdlt\ represent together up to 40°C of all eter-married women. The findmgs stress the Importance of qstematlc research toward estabhshmg the proximate factors that are most hkelj to facdltate or Impede fitness optlmlzatlon-the Importance. that IS. of surrounding the optlmlzatlon prrnclple with the logic and ancdlarj propositions that will gwe It a greater and more dlrectl\e reach ICE\ MORDS Fertllltv hlodermzatlon ELolutlon of tarnil\ patterns Natural selection Fitness optlmlzatlon FarnIl\ IVomen Addres, reprlnt rcquc\ts IO .lo>eph Lopredro Ph D Department of Soc~olog\ Llnl\erslr\ ot Texas at Au>rln Austin TX 7X712-I08X EthologL and Soc~ob~olog\ 9 269-28Y I 1988, i Else\ler Saense Publl&mg Co Inc 1988 52 Vanderbllr Abe Nea Iork Ncu 'r'orb lOOI

Fertility decline in the modern world and in the original demographic transition: Testing three theories with cross-national data

“…Our results are broadly consistent in one way with those from an ear- lier study by Lopreato and Yu (1988). They carried out a multiple regression analysis on data from 63 contemporary nation-states.…”

“…Child mortality for 1990 thus included infant mortality. We also added the number of physicians in the population because this measure has been used in a study similar to ours by Lopreato and Yu (1988), who found it to be the best predictor of fertility. Female empowerment was measured as a combination of female secondary educational enrollments and percentage of women in the labor force.…”

Social and biological determinants of reproductive success in Swedish males and females born 1915–1929

“…There is some evidence that adverse effects on health and development persist 8,16,17 but some studies have also found that larger natal family size and/or higher birth order is associated with higher fertility [18][19][20][21] . Not all study populations born in the early 20 th century show this relationship 22,23 and several report it to be stronger in women than in men 18,19 . The mechanisms of the association are also unclear, although they may result from a large natal family increasing an individual's own fertility preferences.…”

Temporal-spatial patterns of one-person households in China, 1982-2005

“…As early as the 1960s, Goode (1963) had already pointed out that industrialisation brings structural and cultural changes that are conducive to smaller families across countries, although he did not predict the dramatic increase in one-person households that we see today. Controlling for demographic factors such as marriage and fertility rates, cross-national comparative studies have found that socioeconomic development, as measured by indicators such as GDP per capita, the share of agriculture in GDP, and school enrolment rate, has a strong negative correlation with household size, controlling for demographic factors such as marriage and fertility rates (Fu and Heaton 1995;Lopreato and Yu 1988). Klinenberg (2012) suggests that socioeconomic development and urbanisation provide the fundamental structural and cultural conditions for solo living.…”