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!)