all i want for christmas

jayman said: “M.G., I noticed that your map [of consanguinity rates in twentieth century italy] correlates very well with my map of IQs in Italy here, right down to the large difference between Friuli and Sicily.”

yes, they do correlate well. here is jayman’s map of iqs in europe (click on images for LARGER view):

and, for good measure, here is the reluctant apostate’s map of pisa scores in italy (pisa scores being a good proxy for iq scores):

and here is m.g.’s map of the average consanguinity rates (first-cousin marriage rates) for italy from 1930-1964:

so, yeah — in general, higher consanguinity rates in southern italy + lower iq/pisa scores. meanwhile, lower consanguinity rates in northern italy + higher iq/pisa scores. coincidence? maybe. but, you know, inbreeding depression and lower iqs….

jayman also said: “I wonder what would happen if we made a map of historical consanguinity for Europe as a whole.”

yes, please! or how about … the WHOLE WORLD! that’s what i’m asking santa for christmas this year, anyway — historical consanguinity data for all human societies. (just drop it in my stocking, santa. doesn’t need to be wrapped or anything! i’ve been a really good girl this year — i promise! (~_^) )

the data for consanguinity rates in italy came from cavalli-sforza and co. they collected dispensation records from the catholic church in italy, i.e. permissions granted by the church to cousin couples that wished to marry. cavalli-sforza, et. al., published data going back to 1910 — but they collected data as far back as 1780, but that hasn’t been published as far as i know. (d*mn!)

theoretically, there should be such data for all catholic countries in europe (and elsewhere?) going back — i dunno — for as long as they’ve been keeping records. there seems to be some civil records from the medieval period for parts of italy, too. the protestant nations are trickier since in many it has been ok to marry a cousin, so there are no dispensation records. (d*mn!) some protestant nations did have some anti-cousin marriage laws, though, and also kept really good records — like the efficient swedes. the eastern orthodox church? i don’t really know, but my impression is (after reading about mating patterns in greece) that there aren’t much of any records there, but i could be wrong. i really don’t know.

for anyone who’s curious about mating patterns in europe, you might want to skim through my Inbreeding in Europe series of posts (see links in left-hand column down below ↓). i’ve got some data posted here and there for some countries. there’s also my big timeline of european mating patterns, but that’s (*ahem*) very much a “work in progress.”

footnote: note that there are objections to richard lynn’s iq data as well as to using pisa scores as a proxy for iq scores. see the discussions in this comments thread as well as this one, and italianthro’s blog in general.

(note: comments do not require an email. friûl lībar!)

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8 Comments

  1. theoretically, there should be such data for all catholic countries in europe (and elsewhere?)

    True, and this made me think I should poke around the French-language web (I live here and speak it) so I did and lo and behold, 20th-century consanguinity numbers by region for France and Belgium. I’ll see if I can cook those up into some nicer-looking maps.

    Maybe I’ll try the same for Spain (I speak a bit) and also don’t forget that Austria and large parts of Germany, Switzerland, and the Netherlands are Catholic too. I bet the data’s out there somewhere…Someone with better German skills than I could perhaps find some scholarly articles reporting on it.

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  2. @m.g. – “lo and behold, 20th-century consanguinity numbers by region for France and Belgium. I’ll see if I can cook those up into some nicer-looking maps.”

    wheee! awesome! well done, well done! (^_^) i look forward to seeing the maps! (^_^)

    i tried one night to search for consang data for german-speaking countries — i don’t speak german so the project didn’t work out very well. (~_^)

    if anyone does know the correct terminology in german (or other languages, for that matter) for: consanguinity, consanguineous marriages, cousin-marriage — please, let me know. then i can happily sit googling those terms during the long winter evenings here to see if i find anything. (^_^)

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  3. What I also find interesting is that, for Western Europe anyway, the pockets of lower IQ that stick out (Ireland, southern Spain, Portugal, southern Italy) are the same areas that are exempted from the late-marriage pattern west of the Hajnal line:
    (Finland excepted). Apparently, as your postings discuss, these were the pockets of inbreeding in Western Europe.

    But I’ve become interested about east of the line, particularly northeastern (Slavic) Europe, who seem to have IQ’s comparable to the Western European groups. That late marriage patterns of Western Europe contributed the rise of democratic ideals seems to have good merit at this point, but I wonder if there’s a similar connection between the early marriage/high fertility patterns of Eastern Europe (a pattern which apparently continued east into China and Japan) and the governments these peoples embraced:

    The Slavic nations seem do to form a cluster with the East Asian ones.

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  4. @jayman – “That late marriage patterns of Western Europe contributed the rise of democratic ideals seems to have good merit at this point, but I wonder if there’s a similar connection between the early marriage/high fertility patterns of Eastern Europe (a pattern which apparently continued east into China and Japan) and the governments these peoples embraced: The Slavic nations seem do to form a cluster with the East Asian ones.”

    your thoughts here are echoing those of emmanuel todd in “The Explanation of Ideology” (see my post here) and “L’invention de l’Europe” (which i haven’t read ’cause i don’t read french [lame!], but m.g. has read it and posted a bit about it on those who can see).

    todd’s main interest is family types, but he also gets into early and late marriage. (and while he does talk about endogamy and exogamy, he misses out on the biological/evolutionary significance of inbreeding/outbreeding.)

    take a look at his “exogamous community family” type:

    – cohabitation of married sons and their parents
    – equality between brothers defined by rules of inheritance
    – no marriage between the children of two brothers
    – russia, yugoslavia, slovakia, bulgaria, hungary, finland, albania, central italy, china, vietnam, cuba, north india (note that many of these countries, the eastern european ones, also have a tradition of marrying young)
    – communism, socialism

    he’s definitely on to something, but he doesn’t really understand — or think about, i think — the underlying biological mechanisms. that’s ok. what he’s written is very insightful!

    Reply

  5. @jayman – “What I also find interesting is that, for Western Europe anyway, the pockets of lower IQ that stick out (Ireland, southern Spain, Portugal, southern Italy) are the same areas that are exempted from the late-marriage pattern west of the Hajnal line:
    (Finland excepted).”

    i meant to say and i forgot (typical!) that most of these populations — the piigs, minus ireland and not including finland — might also represent the recent neolithic arrivals from the fertile crescent. maybe.

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  6. @anonymous – “follow this link for an interactive Christmas present”

    yes, thanks! the consang.net site is great and i use it a lot. (^_^) but i do have some problems with the consang data, which i explained a little bit about here. (one of these days i’ll have to do a proper post on the matter….)

    Reply

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