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 language | English (US) |
|---|---|
| Pages (from-to) | 343-360 |
| Number of pages | 18 |
| Journal | Evolution and Human Behavior |
| Volume | 22 |
| Issue number | 5 |
| DOIs | |
| State | Published - Sep 2001 |
| Externally published | Yes |
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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 journal › Article
}
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
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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 -