Waiting for Trivers and Willard: do the rich really favor sons?
Parental investment theory has been put forward as a major evolutionary argument explaining male or female biased birth sex ratio, the Trivers-Willard (T-W) hypothesis, predicting that parents living in good circumstances will bias their investment to sons, whereas parents in poor circumstances will...
| Main Authors: | , |
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| Format: | Journal article |
| Language: | English |
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Wiley
2001
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| _version_ | 1826262243245817856 |
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| author | Koziel, S Ulijaszek, S |
| author_facet | Koziel, S Ulijaszek, S |
| author_sort | Koziel, S |
| collection | OXFORD |
| description | Parental investment theory has been put forward as a major evolutionary argument explaining male or female biased birth sex ratio, the Trivers-Willard (T-W) hypothesis, predicting that parents living in good circumstances will bias their investment to sons, whereas parents in poor circumstances will bias their investment toward daughters. Tests of the T-W hypothesis on human beings have shown limited evidence for parents appearing to differentiate their investment to sons or daughters according to the reproductive potential of each sex. The present study tests the T-W hypothesis among a large contemporary Polish sample using first birth interval and extent of breastfeeding as measures of parental investment, and economic status and level of parental education as measures of parental condition. The extents to which parental investment and markers of parental condition vary by sex of the child were examined using log-linear analysis. Weak support for the T-W effect is found among families where fathers were best educated, where a greater proportion of first-born boys are breastfed longer than girls, while the opposite trend is observed among families with fathers with lowest levels of education. Although the present study does not fully support the T-W hypothesis, it gives evidence of greater investment in female offspring at the lower extremes of income, and greater investment in males at higher levels of income. |
| first_indexed | 2024-03-06T19:33:19Z |
| format | Journal article |
| id | oxford-uuid:1e334426-169e-45b6-ad13-11510f5f9629 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T19:33:19Z |
| publishDate | 2001 |
| publisher | Wiley |
| record_format | dspace |
| spelling | oxford-uuid:1e334426-169e-45b6-ad13-11510f5f96292022-03-26T11:15:03ZWaiting for Trivers and Willard: do the rich really favor sons?Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:1e334426-169e-45b6-ad13-11510f5f9629EnglishSymplectic Elements at OxfordWiley2001Koziel, SUlijaszek, SParental investment theory has been put forward as a major evolutionary argument explaining male or female biased birth sex ratio, the Trivers-Willard (T-W) hypothesis, predicting that parents living in good circumstances will bias their investment to sons, whereas parents in poor circumstances will bias their investment toward daughters. Tests of the T-W hypothesis on human beings have shown limited evidence for parents appearing to differentiate their investment to sons or daughters according to the reproductive potential of each sex. The present study tests the T-W hypothesis among a large contemporary Polish sample using first birth interval and extent of breastfeeding as measures of parental investment, and economic status and level of parental education as measures of parental condition. The extents to which parental investment and markers of parental condition vary by sex of the child were examined using log-linear analysis. Weak support for the T-W effect is found among families where fathers were best educated, where a greater proportion of first-born boys are breastfed longer than girls, while the opposite trend is observed among families with fathers with lowest levels of education. Although the present study does not fully support the T-W hypothesis, it gives evidence of greater investment in female offspring at the lower extremes of income, and greater investment in males at higher levels of income. |
| spellingShingle | Koziel, S Ulijaszek, S Waiting for Trivers and Willard: do the rich really favor sons? |
| title | Waiting for Trivers and Willard: do the rich really favor sons? |
| title_full | Waiting for Trivers and Willard: do the rich really favor sons? |
| title_fullStr | Waiting for Trivers and Willard: do the rich really favor sons? |
| title_full_unstemmed | Waiting for Trivers and Willard: do the rich really favor sons? |
| title_short | Waiting for Trivers and Willard: do the rich really favor sons? |
| title_sort | waiting for trivers and willard do the rich really favor sons |
| work_keys_str_mv | AT koziels waitingfortriversandwillarddotherichreallyfavorsons AT ulijaszeks waitingfortriversandwillarddotherichreallyfavorsons |