Posts mit dem Label Optimal Outbreeding werden angezeigt. Alle Posts anzeigen
Posts mit dem Label Optimal Outbreeding werden angezeigt. Alle Posts anzeigen

Dienstag, 5. August 2014

Mating Preferences & Racism:

Geoffrey Miller:
>Yeah. It’s a time to experiment, so don’t have tunnel vision about, “Oh, I have to date just the college girls and not the secretaries.” Don’t have tunnel vision about age. You’re allowed to date grad students if they’re into you. And don’t have tunnel vision about ethnicity, either. I had the same thing in college. Like, there were all these Jewish girls who I got along with really well. I’m not Jewish, but the Jewish guys at Columbia were all chasing the blonde Midwestern girls who all seemed new and exciting to them, leaving the Jewish girls neglected. The Jewish girls were really into guys who were smart, and I was kind of smart, and that just worked. If I had preconceptions, like, “Well, I’m kind of white Anglo-Saxon Protestant Midwesterner and I should stick to my people,” that would’ve been just stupid. So, broaden your horizons.<


Tucker Max:
>Not only is it pretty racist, which is ridiculous to begin with, but listen. ...<


[If it is racist to have a mating preference for one's own ethny, it's also sexist to have a mating preference for the other gender. That's nonsense. If you look at the literature about optimal outbreeding you will see that both preferences are adaptive.]

[The people from the Near East may have developed something like an "instinct" for the avoidance of excessive outbreeding. (Which could explain why cousin marriages are so wide spread in the Near East.) In historical times their societies were much more diverse than northwestern European societies. So there were stronger selection pressures against outbreeding tendencies. In comparison, Northwestern Europeans only show a weak tendency to avoid excessive outbreeding, because in historical times those societies were relatively homogeneous. Perhaps from a biological point of view extreme/excessive outbreeding makes as much sense as the marriage of siblings. But while the opportunity for the latter was abundant throughout human history, the opportunity for the former was not.]

Montag, 14. Juli 2014

Fitness consequences of spousal relatedness in 46 small-scale societies

Fitness consequences of spousal relatedness in 46 small-scale societies
Drew H. Bailey, Kim R. Hill, and Robert S. Walker (April 2014)
biology letters


Abstract

Social norms that regulate reproductive and marital decisions generate impressive cross-cultural variation in the prevalence of kin marriages. In some societies, marriages among kin are the norm and this inbreeding creates intensive kinship networks concentrated within communities. In others, especially forager societies, most marriages are between more genealogically and geographically distant individuals, which generates a larger number of kin and affines of lesser relatedness in more extensive kinship networks spread out over multiple communities. Here, we investigate the fitness consequence of kin marriages across a sample of 46 small-scale societies (12 439 marriages). Results show that some non-forager societies (including horticulturalists, agriculturalists and pastoralists), but not foragers, have intensive kinship societies where fitness outcomes (measured as the number of surviving children in genealogies) peak at commonly high levels of spousal relatedness. By contrast, the extensive kinship systems of foragers have worse fitness outcomes at high levels of spousal relatedness. Overall, societies with greater levels of inbreeding showed a more positive relationship between fitness and spousal relatedness.

Mittwoch, 1. Januar 2014

An Association Between the Kinship and Fertility of Human Couples

An Association Between the Kinship and Fertility of Human Couples
Agnar Helgason et al.; 2008


Abstract

Previous studies have reported that related human couples tend to produce more children than unrelated couples but have been unable to determine whether this difference is biological or stems from socioeconomic variables. Our results, drawn from all known couples of the Icelandic population born between 1800 and 1965, show a significant positive association between kinship and fertility, with the greatest reproductive success observed for couples related at the level of third and fourth cousins. Owing to the relative socioeconomic homogeneity of Icelanders, and the observation of highly significant differences in the fertility of couples separated by very fine intervals of kinship, we conclude that this association is likely to have a biological basis.


See also: http://www.sciencemag.org/content/322/5908/1634.2.full.pdf 
(Comment on “An Association Between the Kinship and Fertility of Human Couples” - Rodrigo Labouriau and António Amorim; 2008)



[Thanks @ Tomás]