Hostname: page-component-68c7f8b79f-b57wx Total loading time: 0 Render date: 2026-01-03T00:06:53.200Z Has data issue: false hasContentIssue false
  • English
  • Français

Extrinsic mortality is not the same as diminishing marginal returns on mortality reduction

Published online by Cambridge University Press:  11 November 2025

James Holland Jones Open the ORCID record for James Holland Jones [Opens in a new window]
James Holland Jones*
Affiliation:
Department of Environmental Social Sciences, Stanford Doerr School of Sustainability, Stanford, CA, USA jhj1@stanford.edu
*
*Corresponding author.
Get access Rights & Permissions [Opens in a new window]

Abstract

The force of selection on survival changes with age and models of reproductive effort (RE) reflect this finding that increases in infant and adult mortality have different effects on optimal effort. Using an age-structured demographic model, I show that infant mortality constrains selection on the human life cycle. Effort directed at increasing infant survival is strongly favored over efforts to increase adult survival. Complete accounts of human reproductive decisions require age-specificity of effects.

Information

Type
Open Peer Commentary
Information
Behavioral and Brain Sciences , Volume 48 , 2025 , e110
Check for updates
Copyright
© The Author(s), 2025. Published by Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable

References

Abrams, P. A. (1993). Does increased mortality favor the evolution of more rapid senescence?. Evolution, 47(3), 877–887. https://doi.org/10.1111/j.1558-5646.1993.tb01241.xX CrossRefGoogle ScholarPubMed
André, J.-B., & Rousset, F. (2020). Does extrinsic mortality accelerate the pace of life? a bare-bones approach. Evolution and Human Behavior, 41(6), 486–492. https://doi.org/10.1016/j.evolhumbehav.2020.03.002 CrossRefGoogle Scholar
Boserup, E. (1965). The conditions of agricultural growth: The economics of agrarian change under population pressure. Aldine Transaction.Google Scholar
Caswell, H. (2001). Matrix population models: Construction, analysis and interpretation. (2nd ed.) Sinauer.Google Scholar
Charnov, E. L., & Schaffer, W. M. (1973). Life-history consequences of natural selection: cole’s result revisited. The American Naturalist, 107(958), 791–793. http://www.jstor.org/stable/2459713 10.1086/282877CrossRefGoogle Scholar
Coulson, T., & Tuljapurkar, S. (2008). The dynamics of a quantitative trait in an age-structured population living in a variable environment. American Naturalist, 172(5), 599–612. https://doi.org/10.1086/591693 CrossRefGoogle Scholar
Frankenhuis, W. E., Panchanathan, K., & Smaldino, P. E. (2023). Strategic ambiguity in the social sciences. Social Psychological Bulletin, 18, 1–25. https://doi.org/10.32872/spb.9923 CrossRefGoogle Scholar
Geronimus, A. T. (2003). Damned if you do: culture, identity, privilege, and teenage childbearing in the United States. Social Science & Medicine, 57(5), 881–893. https://doi.org/10.1016/S0277-9536(02)00456-2 CrossRefGoogle Scholar
Goodman, L. A., Keyfitz, N., & Pullum, T. W. (1974). Family formation and the frequency of various kinship relationships. Theoretical Population Biology, 5, 1–27. https://doi.org/10.1016/0040-5809(74)90049-5 CrossRefGoogle ScholarPubMed
Hamilton, W. D. (1966). The moulding of senescence by natural selection. Journal of Theoretical Biology, 12(1), 12–45. https://doi.org/10.1016/0022-5193(66)90184-6 CrossRefGoogle ScholarPubMed
Hayward, A. D., Holopainen, J., Pettay, J. E., & Lummaa, V. (2012). Food and fitness: associations between crop yields and life-history traits in a longitudinally monitored pre-industrial human population. Proceedings of the Royal Society B: Biological Sciences, 279, 4165–4173. https://doi.org/10.1098/rspb.2012.1190 CrossRefGoogle Scholar
Jones, J. H. (2007). demogR: a package for evolutionary demographic analysis in R. Journal of Statistical Software, 22(10), 1–28. https://doi.org/10.18637/jss.v022.i10 CrossRefGoogle Scholar
Jones, J. H. (2009). The force of selection on the human life cycle. Evolution and Human Behavior, 30(5), 305–314. https://doi.org/10.1016/j.evolhumbehav.2009.01.005 CrossRefGoogle ScholarPubMed
Jones, J. H., & Tuljapurkar, S. (2015). Measuring selective constraint on fertility in human life histories. Proceedings of the National Academy of Sciences, 112(29), 8982–8986. https://doi.org/10.1073/pnas.1422037112 CrossRefGoogle ScholarPubMed
Lee, R. D. (1986). Malthus and Boserup: a dynamic synthesis. In Coleman, D. & Schofield, R. (Eds.), The state of population theory (pp. 96–130). Blackwell.Google Scholar
Mejía-Guevara, I., Zuo, W., Bendavid, E., Li, N., & Tuljapurkar, S. (2019). Age distribution, trends, and forecasts of under-5 mortality in 31 sub-Saharan African countries: a modeling study. PLOS Medicine, 16(3), e1002757. https://doi.org/10.1371/journal.pmed.1002757 CrossRefGoogle ScholarPubMed
Moorad, J., Promislow, D., & Silvertown, J. (2019). Evolutionary ecology of senescence and a reassessment of williams’ ‘extrinsic mortality’ hypothesis. Trends in Ecology & Evolution, 34(6), 519–530. https://doi.org/10.1016/j.tree.2019.02.006 CrossRefGoogle Scholar
Netting, R. M. (1993). Smallholders, householders: Farm families and the ecology of intensive, sustainable agriculture. Stanford University Press.10.1515/9781503622067CrossRefGoogle Scholar
Preston, S. H. (2007). The changing relation between mortality and level of economic development. International Journal of Epidemiology, 36(3), 484–490. https://doi.org/10.1093/ije/dym075 CrossRefGoogle ScholarPubMed
Williams, G. C. (1957). Pleiotropy, natural selection, and the evolution of senescence. Evolution, 11(4), 398–411. https://doi.org/10.1111/j.1558-5646.1957.tb02911.x CrossRefGoogle Scholar
Wood, J. W., & Smouse, P. E. (1982). A method of analyzing density-dependent vital rates with an application to the gainj of papua new guinea. American Journal of Physical Anthropology, 58(4), 403–411. https://doi.org/10.1002/ajpa.1330580408 CrossRefGoogle Scholar
Zhang, D. D., Lee, H. F., Wang, C., Li, B., Pei, Q., Zhang, J., & An, Y. (2011). The causality analysis of climate change and large-scale human crisis. Proceedings of the National Academy of Sciences, 108(42), 17296–17301. https://doi.org/10.1073/pnas.1104268108 CrossRefGoogle ScholarPubMed