sean suggests that there is a correlation between consanguintiy and polygamy (or, rather, polygamy and consanguinity). i don’t know if anyone’s ever looked for a correlation between the two. if they have, i haven’t seen it. what someone should do is take the populations from consang.net (not the nations but the populations) and see if there is any correlation between consanguinity and polygamy or not. i’ve put that task on my “to do” list, but i can’t promise that i’ll get to it any time soon.

what i have done is check murdock‘s ethnographic atlas to see what sorts of societies (monogamous, occasionally polygamous, or polygamous) are also consanguineous (here consanguineous means first or second cousin marriage — i haven’t included uncle-niece marriages as that info is not available in the murdock atlas).

the cross tabs i used were DOMESTIC ORGANIZATION and NUMBER OF COUSIN MARRIAGES [Allowed]. the results are sorted into the following rows…

- Missing Data
– Indep. Nuclear Family – Monogamous
– Indep. Nuclear Family – Occasional polygyny
– Indep. Polyandrous Families
– Polygynous – Unusual Co-wives Pattern
– Polygynous – Usual Co-wives Pattern
– Minimal (stem) extended families
– Small extended families
– Large extended families

…and columns…

- Missing Data
– All four cousins
– Three of four cousins
– Two of four cousins
– One of four cousins
– No first cousins
– 1st & some 2nd cousins
– No 1st – 2nd unknown
– No 1st or 2nd cousins

i skipped the two “Missing Data” groups (fourteen results). i also skipped the “No 1st – 2nd uknown” group (twenty-seven results) since the presence or absence of second-cousin marriage was unknown. left out the polyandrous groups (all three of them), too. and i also drilled down (manually!) in the extended family categories (minimal/stem, small extended, and large extended) to check for consanguinity and polygamy there ’cause i couldn’t figure out how work that into the table (you’re welcome). i then combined all the monogamous, occasionally polygamous, and polygamous groups together (n=142 in total).

what did i find?:

consanguinity and polygamy 02

well, for one thing, there’s a lot more polygamy and occasional polygamy out there in the world than monogamy, but then we all knew that already, didn’t we? there’s also more consanguineous marriage practices out there than not — or, at least, they’re allowed in more societies than not — but we’re all starting to know that now, too, aren’t we? (^_^) even in monogamous societies, there are twice as many that allow some form of cousin marriage (first or second) than those that don’t allow any.

the rate of consanguineous to non-consanguineous marriage allowed in monogamous societies is about 2:1. in polygamous and occasionally polygamous societies it’s about 2.5:1. so, yeah — there are more consanguineous marriages permitted in polygamous societies than monogamous ones, but is the correlation between the two (consanguinity and polygamy) very strong? i dunno. doesn’t really seem like it, but you tell me.

in Ya̧nomamö, chagnon suggests that groups that practice polygamy marry their cousins with greater frequency partly because the individuals in those societies have more cousins. he gives as example two ya̧nomamö extended families, one that had a founder with more wives than the other. because he founded so many lineages, as it were, the descendants of the guy with more wives were able to more easily find a cousin to marry simply because more persons who were their cousins existed. don’t know if this holds true for other polygamous groups, but it’s an interesting idea.

here are the numbers for you:

consanguinity and polygamy 03

consanguinity and polygamy 04

btw, the monogamous groups which allow(ed) cousin marriage are:

- the inca
– the badjau (pacific region)
– the burmese
– the romans
– the bribri (south america)
– the chinese (in chekiang)
– the tuareg
– the copper eskimo
– the lapps
– the iban (pacific region)
– the japanese (southern okayama)
– in the punjab (west)
– the vedda
– the yapese (pacific region)
– the manchu (aigun district)
– the kaska (north america)
– the toradja (pacific region)

(note: comments do not require an email. some toradja folks.)