The Experts below are selected from a list of 13131 Experts worldwide ranked by ideXlab platform
Michael D Jennions - One of the best experts on this subject based on the ideXlab platform.
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coevolution of Parental Investment and sexually selected traits drives sex role divergence
Nature Communications, 2016Co-Authors: Lutz Fromhage, Michael D JennionsAbstract:Sex-role evolution theory attempts to explain the origin and direction of male-female differences. A fundamental question is why anisogamy, the difference in gamete size that defines the sexes, has repeatedly led to large differences in subsequent Parental care. Here we construct models to confirm predictions that individuals benefit less from caring when they face stronger sexual selection and/or lower certainty of parentage. However, we overturn the widely cited claim that a negative feedback between the operational sex ratio and the opportunity cost of care selects for egalitarian sex roles. We further argue that our model does not predict any effect of the adult sex ratio (ASR) that is independent of the source of ASR variation. Finally, to increase realism and unify earlier models, we allow for coevolution between Parental Investment and Investment in sexually selected traits. Our model confirms that small initial differences in Parental Investment tend to increase due to positive evolutionary feedback, formally supporting long-standing, but unsubstantiated, verbal arguments.
Nigel Barber - One of the best experts on this subject based on the ideXlab platform.
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Parental Investment, Human Capital, and Cross-National Differences in Wealth
Cross-Cultural Research, 2002Co-Authors: Nigel BarberAbstract:Economists have recently turned to family variables in search of explanations for why the economies of some countries grow more rapidly than others. This research tested the hypothesis that crossnational indicators of Parental Investment and human capital would be predictive of GNP per capita of 147 countries. Regression analysis found that close to two thirds of the variance in GNP was explained by Parental Investment factors (including total fertility rates, the adult sex ratio, polygyny, contraception, and school attendance rates). The effects of Parental Investment/human capital on wealth remained after controlling for climate, geography, endemic diseases, religion, and government policies, even though each of these was predictive of GNP. The data support the hypothesis that wealth differences between countries are associated with human capital differences accruing to differential Parental Investment.
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Does Parental Investment Increase Wealth, or Does Wealth Increase Parental Investment?
Cross-Cultural Research, 2002Co-Authors: Nigel BarberAbstract:Possible causal relationships between Parental Investment and economic growth and productivity were investigated cross-nationally. Composite variables were constructed to measure Parental Investment (PI), human capital (HC), national health, government effectiveness, and economic development for 148 countries. Some composites were highly intercorrelated, particularly PI, HC, and health, and all predicted absolute (dollar value) annual growth (1990-1998) as well as GNP (1996). Regression analysis showed that PI strongly predicts wealth, but not growth, when government stability and level of economic development are controlled. Results suggest that PI (and health, HC) is more a product than a cause of national wealth.
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Parental Investment Prospects and Teen Birth Rates of Blacks and Whites in American Metropolitan Areas
Cross-Cultural Research, 2002Co-Authors: Nigel BarberAbstract:Parental Investment theory was used to identify predictors of nonmarital teen birth rates for Blacks and Whites in U.S. metropolitan areas. Regression models predicted Black teen births, White teen births, and both together using indices of Parental Investment (male income, unemployment rates, marital opportunity for women) with various controls. White teen births decreased with increased marital opportunity for women, and the same was true of Blacks, although these effects were comparatively small. In the combined model, Parental Investment measures and the control variables accounted for 70% of the variance in nonmarital teen birth rates. Adding race as a variable did not significantly increase the variance explained, indicating that Black-White differences in nonmarital teen reproduction can be explained by differences in Parental Investment prospects. Early nonmarital reproduction can be seen as an adaptive response to diminished prospects for Parental Investment.
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Marital opportunity, Parental Investment, and teen birth rates of Blacks and Whites in American states
Cross-Cultural Research, 2001Co-Authors: Nigel BarberAbstract:This study used Parental Investment theory to identify predictors of teen pregnancy rates for Blacks and Whites for 41 U.S. states for which data were available for 1995. Regression models were built that predicted Black teen births, White teen births, and both together using indices of Parental Investment (unemployment, prison incarceration rates, poverty, marital opportunity for women as indexed by gender ratios) and controlling for economic development (urbanization, infant mortality rates). White teen births increased with state poverty rates and incarceration rates and decreased with marital opportunity for teens. Black teen births increased with incarceration rates and decreased with marital opportunity. In the joint model, all measures of Parental Investment predicted teen births, and they explained all of the Black and White differences therein. Early reproduction and its variation across states and racial groups can be seen as an adaptive response to diminished prospects for Parental Investment.
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Why Parents Matter: Parental Investment and Child Outcomes
2000Co-Authors: Nigel BarberAbstract:Preface The Big Picture: Societal Differences in Parenting Higher Investment and Its Outcomes Lower Parental Investment and Social Problems Divorce and Parental Investment Sibling Competition as a Tragedy of the Commons Money and Parental Investment Nine to Five: The Influence of Occupational Trends on Parental Investment Teen Mothers and Reduced Parental Investment Group Differences in Child Socialization Can You Increase Parental Investment? Can High Parental Investment Produce a Civil, and Enlightened, Society? Appendix Bibliography Index
Ruth Mace - One of the best experts on this subject based on the ideXlab platform.
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Parental Investment in Tibetan populations does not reflect stated cultural norms
2017Co-Authors: Ruth Mace, L BarrettAbstract:In this paper, we examined both stated norms of sex preference and actual sex-biases in Parental Investment in a Tibetan pastoralist society. We collected detailed demographic data on infant mortality, infant feeding, the length of interbirth intervals, and a decision when giving gifts, to examine sex-biased Parental Investment. Our results indicate a mismatch between self-reported son preference and measures of actual Parental Investment that favor daughters. We interpret this female-biased Parental Investment as a possible response to daughters generating more economic resources. However, the stated sex preferences of both sexes reflect cultural norms that appear to have remained unchanged over a long period, which may reflect the importance of male roles in the past. Our behavioral measures of Parental Investment are those most likely to be in the control of women (such as breastfeeding and interbirth interval), so this mismatch between stated and actual Investment may be especially true of women.
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Parental Investment in child health in sub saharan africa a cross national study of health seeking behaviour
Royal Society Open Science, 2016Co-Authors: Caroline Uggla, Ruth MaceAbstract:Parents face trade-offs between investing in child health and other fitness enhancing activities. In humans, Parental Investment theory has mostly been examined through the analysis of differential child outcomes, with less emphasis on the actions parents take to further a particular offspring’s condition. Here, we make use of household data on health-seeking for children in a high mortality context where such behaviours are crucial for offspring survival. Using Demographic and Health Survey (DHS) data from 17 sub-Saharan African countries, we examine whether maternal factors (age, health, marital status) and child factors (birth order, health, sex, age) independently influence Parental Investment in health-seeking behaviours: two preventative behaviours (malaria net use and immunization) and two curative ones (treating fever and diarrhoea). Results indicate that children with lower birth order, older mothers and mothers with better health status have higher odds of Investment. The effects of a child’s sex and health status and whether the mother is polygynously married vary depending on the type of health-seeking behaviour (preventative versus curative). We discuss how these results square with predictions from Parental Investment theory pertaining to the state of mothers and children, and reflect on some potential mechanisms and directions for future research.
Lutz Fromhage - One of the best experts on this subject based on the ideXlab platform.
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coevolution of Parental Investment and sexually selected traits drives sex role divergence
Nature Communications, 2016Co-Authors: Lutz Fromhage, Michael D JennionsAbstract:Sex-role evolution theory attempts to explain the origin and direction of male-female differences. A fundamental question is why anisogamy, the difference in gamete size that defines the sexes, has repeatedly led to large differences in subsequent Parental care. Here we construct models to confirm predictions that individuals benefit less from caring when they face stronger sexual selection and/or lower certainty of parentage. However, we overturn the widely cited claim that a negative feedback between the operational sex ratio and the opportunity cost of care selects for egalitarian sex roles. We further argue that our model does not predict any effect of the adult sex ratio (ASR) that is independent of the source of ASR variation. Finally, to increase realism and unify earlier models, we allow for coevolution between Parental Investment and Investment in sexually selected traits. Our model confirms that small initial differences in Parental Investment tend to increase due to positive evolutionary feedback, formally supporting long-standing, but unsubstantiated, verbal arguments.
Shuang Chen - One of the best experts on this subject based on the ideXlab platform.
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Parental Investment After the Birth of a Sibling: The Effect of Family Size in Low-Fertility China
Demography, 2020Co-Authors: Shuang ChenAbstract:A large body of research has examined the relationship between family size and child well-being in developing countries, but most of this literature has focused on the consequences of high fertility. The impact of family size in a low-fertility developing country context remains unknown, even though more developing countries are expected to reach below-replacement fertility levels. Set in China between 2010 and 2016, this study examines whether an increase in family size reduces Parental Investment received by the firstborn child. Using data from the China Family Panel Studies (CFPS), this study improves on previous research by using direct measures of Parental Investment, including monetary and nonmonetary Investment, and distinguishing household-level from child-specific resources. It also exploits the longitudinal nature of the CFPS to mediate the bias arising from the joint determination of family size and Parental Investment. Results show that having a younger sibling significantly reduces the average household expenditure per capita. It also directly reduces Parental Investment received by the firstborn child, with two exceptions: (1) for firstborn boys, having a younger sister does not pose any competition; and (2) for firstborn children whose mothers have completed primary education or more, having a younger brother does not reduce Parental educational aspirations for them. Findings from this study provide the first glimpse into how children fare as China transitions to a universal two-child policy regime but have wider implications beyond the Chinese context.
