The Trivers-Willard hypothesis of parental investment

No effect in the contemporary United States

Matthew C. Keller, Randolph Nesse, Sandra Hofferth

Research output: Contribution to journalArticle

71 Citations (Scopus)

Abstract

The Trivers-Willard hypothesis (TWH) predicts that parents will bias their sex ratio toward sons when in good condition and toward daughters when in poor condition. Many human studies have tested the related hypothesis that parents' bias allocation of resources to existing sons and daughters according to the same principle. The present study used time diary and self-report data from the parents of 3200 children in the US to test the hypothesis that as status increases, parents will allocate more resources to sons vs. daughters. It finds no evidence that higher-status parents invest more in sons or that lower status parents invest more in daughters. This finding illustrates the specificity of situations in which the TWH effects should be expected. Only certain types of parental investment - such as protection and a bias in the sex ratio - may have been selected to vary according to parental condition. Optimal allocation of resources after the child is born, however, is achieved not by the simple bias predicted by the TWH, but by allocating resources among offspring in ways that yield the largest marginal inclusive fitness gains.

Original languageEnglish (US)
Pages (from-to)343-360
Number of pages18
JournalEvolution and Human Behavior
Volume22
Issue number5
DOIs
StatePublished - Sep 2001
Externally publishedYes

Fingerprint

parental investment
Nuclear Family
parents
Parents
resource allocation
resource
sex ratio
trend
inclusive fitness
resources
Resource Allocation
Sex Ratio
fitness
effect
Daughters
Resources
Self Report
testing
evidence
allocation

Keywords

  • Evolutionary anthropology
  • Evolutionary psychology
  • Parental investment
  • Sex allocation theory
  • Sex ratio
  • Sociobiology
  • Trivers-Willard hypothesis

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Ecology, Evolution, Behavior and Systematics
  • Development

Cite this

The Trivers-Willard hypothesis of parental investment : No effect in the contemporary United States. / Keller, Matthew C.; Nesse, Randolph; Hofferth, Sandra.

In: Evolution and Human Behavior, Vol. 22, No. 5, 09.2001, p. 343-360.

Research output: Contribution to journalArticle

@article{1671d4bc77d6429e8bf86450948bc252,
title = "The Trivers-Willard hypothesis of parental investment: No effect in the contemporary United States",
abstract = "The Trivers-Willard hypothesis (TWH) predicts that parents will bias their sex ratio toward sons when in good condition and toward daughters when in poor condition. Many human studies have tested the related hypothesis that parents' bias allocation of resources to existing sons and daughters according to the same principle. The present study used time diary and self-report data from the parents of 3200 children in the US to test the hypothesis that as status increases, parents will allocate more resources to sons vs. daughters. It finds no evidence that higher-status parents invest more in sons or that lower status parents invest more in daughters. This finding illustrates the specificity of situations in which the TWH effects should be expected. Only certain types of parental investment - such as protection and a bias in the sex ratio - may have been selected to vary according to parental condition. Optimal allocation of resources after the child is born, however, is achieved not by the simple bias predicted by the TWH, but by allocating resources among offspring in ways that yield the largest marginal inclusive fitness gains.",
keywords = "Evolutionary anthropology, Evolutionary psychology, Parental investment, Sex allocation theory, Sex ratio, Sociobiology, Trivers-Willard hypothesis",
author = "Keller, {Matthew C.} and Randolph Nesse and Sandra Hofferth",
year = "2001",
month = "9",
doi = "10.1016/S1090-5138(01)00075-7",
language = "English (US)",
volume = "22",
pages = "343--360",
journal = "Evolution and Human Behavior",
issn = "1090-5138",
publisher = "Elsevier Inc.",
number = "5",

}

TY - JOUR

T1 - The Trivers-Willard hypothesis of parental investment

T2 - No effect in the contemporary United States

AU - Keller, Matthew C.

AU - Nesse, Randolph

AU - Hofferth, Sandra

PY - 2001/9

Y1 - 2001/9

N2 - The Trivers-Willard hypothesis (TWH) predicts that parents will bias their sex ratio toward sons when in good condition and toward daughters when in poor condition. Many human studies have tested the related hypothesis that parents' bias allocation of resources to existing sons and daughters according to the same principle. The present study used time diary and self-report data from the parents of 3200 children in the US to test the hypothesis that as status increases, parents will allocate more resources to sons vs. daughters. It finds no evidence that higher-status parents invest more in sons or that lower status parents invest more in daughters. This finding illustrates the specificity of situations in which the TWH effects should be expected. Only certain types of parental investment - such as protection and a bias in the sex ratio - may have been selected to vary according to parental condition. Optimal allocation of resources after the child is born, however, is achieved not by the simple bias predicted by the TWH, but by allocating resources among offspring in ways that yield the largest marginal inclusive fitness gains.

AB - The Trivers-Willard hypothesis (TWH) predicts that parents will bias their sex ratio toward sons when in good condition and toward daughters when in poor condition. Many human studies have tested the related hypothesis that parents' bias allocation of resources to existing sons and daughters according to the same principle. The present study used time diary and self-report data from the parents of 3200 children in the US to test the hypothesis that as status increases, parents will allocate more resources to sons vs. daughters. It finds no evidence that higher-status parents invest more in sons or that lower status parents invest more in daughters. This finding illustrates the specificity of situations in which the TWH effects should be expected. Only certain types of parental investment - such as protection and a bias in the sex ratio - may have been selected to vary according to parental condition. Optimal allocation of resources after the child is born, however, is achieved not by the simple bias predicted by the TWH, but by allocating resources among offspring in ways that yield the largest marginal inclusive fitness gains.

KW - Evolutionary anthropology

KW - Evolutionary psychology

KW - Parental investment

KW - Sex allocation theory

KW - Sex ratio

KW - Sociobiology

KW - Trivers-Willard hypothesis

UR - http://www.scopus.com/inward/record.url?scp=0000631693&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0000631693&partnerID=8YFLogxK

U2 - 10.1016/S1090-5138(01)00075-7

DO - 10.1016/S1090-5138(01)00075-7

M3 - Article

VL - 22

SP - 343

EP - 360

JO - Evolution and Human Behavior

JF - Evolution and Human Behavior

SN - 1090-5138

IS - 5

ER -