title: Testing evolutionary theories of discriminative grandparental investment.
abstract: This study tests two evolutionary hypotheses on grandparental investments differentiated by the child's sex: the paternity uncertainty hypothesis and the Trivers-Willard hypothesis. Data are from two culturally different countries: the Dutch Longitudinal Aging Study Amsterdam (n=2375) and the Chinese Anhui Survey (n=4026). In the Netherlands, grandparental investments are biased towards daughters' children, which is in accordance with the paternity uncertainty hypothesis. But in China, grandparental investments are biased towards sons' children, which is in conflict with the paternity uncertainty hypothesis. This study found no support for the Trivers-Willard hypothesis. These results raise doubts over the relevance of paternity uncertainty as an explanation of a grandparental investment bias towards daughters' children that is often found in Western populations. The results suggest that discriminative grandparental investments are better understood as the outcome of cultural prescriptions and economic motives.
authors.affiliation: VU University Amsterdam, the Netherlands.
authors.forename: Ralf
authors.initials: R
authors.lastname: Kaptijn
authors.forename: Fleur
authors.initials: F
authors.lastname: Thomese
authors.forename: Aart C
authors.initials: AC
authors.lastname: Liefbroer
authors.forename: Merril
authors.initials: M
authors.lastname: Silverstein
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005075:Biological Evolution; D002681:China; D003431:Cross-Cultural Comparison; D005195:Family Relations; D005260:Female; D006801:Humans; D007449:Investments; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D010287:Parent-Child Relations; D010334:Paternity; D012737:Sex Factors; D055815:Young Adult