Abstract
Kin-recognition systems have been hypothesized to exist in humans, and adaptively to regulate altruism and incest avoidance among close genetic kin. This latter function allows the architecture of the kin recognition system to be mapped by quantitatively matching individual variation in opposition to incest to individual variation in developmental parameters, such as family structure and co-residence patterns. Methodological difficulties that appear when subjects are asked to disclose incestuous inclinations can be circumvented by measuring their opposition to incest in third parties, i.e. morality. This method allows a direct test of Westermarck's original hypothesis that childhood co-residence with an opposite-sex individual predicts the strength of moral sentiments regarding third-party sibling incest. Results support Westermarck's hypothesis and the model of kin recognition that it implies. Co-residence duration objectively predicts genetic relatedness, making it a reliable cue to kinship. Co-residence duration predicts the strength of opposition to incest, even after controlling for relatedness and even when co-residing individuals are genetically unrelated. This undercuts kin-recognition models requiring matching to self (through, for example, major histocompatibility complex or phenotypic markers). Subjects' beliefs about relatedness had no effect after controlling for co-residence, indicating that systems regulating kin-relevant behaviours are non-conscious, and calibrated by co-residence, not belief.
Full Text
The Full Text of this article is available as a PDF (165.7 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Adams M. S., Neel J. V. Children of incest. Pediatrics. 1967 Jul;40(1):55–62. [PubMed] [Google Scholar]
- Bevc I, I, Silverman I., I Early separation and sibling incest. A test of the revised Westermarck theory. Evol Hum Behav. 2000 May 1;21(3):151–161. doi: 10.1016/s1090-5138(99)00041-0. [DOI] [PubMed] [Google Scholar]
- Bittles A. H., Neel J. V. The costs of human inbreeding and their implications for variations at the DNA level. Nat Genet. 1994 Oct;8(2):117–121. doi: 10.1038/ng1094-117. [DOI] [PubMed] [Google Scholar]
- Hamilton W. D. The genetical evolution of social behaviour. II. J Theor Biol. 1964 Jul;7(1):17–52. doi: 10.1016/0022-5193(64)90039-6. [DOI] [PubMed] [Google Scholar]
- Macintyre S., Sooman A. Non-paternity and prenatal genetic screening. Lancet. 1991 Oct 5;338(8771):869–871. doi: 10.1016/0140-6736(91)91513-t. [DOI] [PubMed] [Google Scholar]
- Penn D., Potts W. MHC-disassortative mating preferences reversed by cross-fostering. Proc Biol Sci. 1998 Jul 22;265(1403):1299–1306. doi: 10.1098/rspb.1998.0433. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sykes B., Irven C. Surnames and the Y chromosome. Am J Hum Genet. 2000 Mar 17;66(4):1417–1419. doi: 10.1086/302850. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tooby J. Pathogens, polymorphism, and the evolution of sex. J Theor Biol. 1982 Aug 21;97(4):557–576. doi: 10.1016/0022-5193(82)90358-7. [DOI] [PubMed] [Google Scholar]
- Yamazaki K., Beauchamp G. K., Kupniewski D., Bard J., Thomas L., Boyse E. A. Familial imprinting determines H-2 selective mating preferences. Science. 1988 Jun 3;240(4857):1331–1332. doi: 10.1126/science.3375818. [DOI] [PubMed] [Google Scholar]