flatlanders vs. mountaineers revisited

if you’ve been following along, you’ll know that last year i posted about a bit of research by an anthropologist(?) by the name of joseph westermeyer the results of which suggested that peoples in lowland areas below 500m above sea level have a tendency to outbreed (i.e. avoid cousin marriage) while uplanders above 500m above sea level (and, perhaps, peoples in other marginal areas) have a tendency to inbreed (i.e. favor cousin marriage). (see also here.) westermeyer only looked at southeast asia, but i, too, seemed to be finding that pattern repeating in many places: balkans peoples – largely inbreeders, especially the ones way up in the hills; populations in the caucasuses – inbreeders; the auvergnats in france – inbreeders; heeland scots – inbreeders until quite late; afghanis – generally inbreeders, but more so in the mountains than in lowland areas; etc.

on friday, i posted about the wrist-knife wearing, ak-47 some sort-of big gun carrying turkana of east africa (kenya) who also appeared to confirm the pattern: they are a bunch of outbreeders (they avoid anything closer than second cousin marriage) and they live in a lowland region. and they’re pastoralists to boot — teh anthropologists keep saying that pastoralism leads to close marriages (like with the arabs). not!

well. last night i came across this book — Reproduction and Social Organization in Sub-Saharan Africa (1989) — which just blows this flatlanders vs. mountaineers theory right out of the water! (yipee! it’s almost like i’m doing real science! almost. ok, not really. but uncle karl would be so proud!)

in the second chapter, “The Components of Sub-Saharan Reproductive Regimes and Their Social and Cultural Determinants: The Empirical Evidence,” there’s a table on pages 74 and 75 indicating the presence or absence of cousin marriage for 47+ sub-saharan populations (data from murdock’s Ethnographic Atlas), and, as far as i can tell, there’s no rhyme or reason for why some groups inbreed and others don’t. at least the pattern (if there is one!) doesn’t appear to be connected to living in upland or lowland areas.

here is the table from the book (i’ve removed the columns that weren’t related to cousin marriage):

cousin marriage - africa

so far i’ve only run through the outbreeders (mostly), but here’s what i’ve got for where these different groups live. i’ve divvied them up by country and indicated approximately where each of the groups lives on the maps (topographic maps from wikipedia — click on maps for LARGER views — not sure who the Kru people from liberia are, so i’ve skipped them for now):

KENYA [source]
0-Kalenjin – uplanders
0-Kikuyu – uplanders
0-Kisii (AbaGusii) – uplanders
0-Luhya – uplanders
0-Luo – uplanders
0-Meru-Embu – uplanders
0-Mijikenda – lowlanders
0-Turkana – lowlanders
1-Arab groups [somalis, etc.] – lowlanders

kenya - ethnic groups + topography

CAMEROON
0-Adamawa groups – uplanders
0-Bafia – uplanders
0-Baya (Gabaya) – uplanders
0-Cameroon Western Highland groups – uplanders
0-Duala – lowlanders
0-Mandara groups – uplanders

cameroon - ethnic groups + topography

SENEGAL
0-Diola (Jola) – lowlanders

(btw – check out the HUGE velingara circular structure to the right of where i typed “diola.” impact crater? [pdf])

senegal - ethnic groups + topography

GHANA
0-Kusasi – lowlanders (below 500m)
0-Tallensi – lowlanders

ghana - ethnic groups + topography

BURKINA FASO
0-Mossi – lowlanders

burkina faso - ethnic groups + topography

see? that’s eleven upland groups right there which are — if the data are correct — outbreeders not inbreeders. either the flatlanders vs. mountaineers theory is wrong, or the sub-saharan africans are some sort of exception to this rule.

again, most of the groups practice polygamy which does complicate the picture wrt genetic relatedness. i’ll work the inbreeders into the maps one day soon. promise!

previously: this one’s for g.w. and the flatlanders vs. the mountain people

(note: comments do not require an email. velingara circular structure.)

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36 Comments

  1. Could there be any correlation with religion? Exposure to Arabs? It’s odd you mention this area, the Mandara uplands.

    Reuters had a dreadful story today about a young Christian woman abducted by Boko Haram terrorists and told she must convert to Islam and marry one of these men. It said she picking corn in that area and they dragged her off. She finally escaped. She was held in the Mandara area. I looked it up on Google images just to get a photo of the Mandara mountains to post with the story. Very odd geology.

    The area you mention is along the Muslim/Christian fault line, lots of problems due to that. I haven’t any idea if there’s a connection, but the Muslim tribes were presumably converted by Arabs, and the Christians by European missionaries.

    Reply

  2. @frau katze – “Could there be any correlation with religion? Exposure to Arabs?”

    absolutely. any of the muslim groups in sub-sahara africa who are marrying their cousins — i’d be suspicious that they picked that up from the arabs (or whomever) when they converted to islam. especially if they do the arab cousin marriage thing and marry their father’s brother’s daughter (fbd) — like the somalis. they definitely got that practice from the arabs.

    i know that there are some groups in west and south africa that do marry their cousins, almost always their maternal cousins (not paternal like the arabs), so they probably developed these traditions on their own.

    whether or not any of the sub-saharan african groups avoid cousin marriage as a result of converting to christianity — maybe in some cases, but i’ll really have to sit down and look at them (all!) on a case-by-case basis to find out. the turkana that i posted about on friday, for instance — they avoid cousin marriage, but they mostly have not converted to christianity (or islam), so it’s unlikely that they picked up that practice from christian missionaries.

    also, the catholic church okayed cousin marriage for africans in 1897 — probably to encourage them to convert — so there may not have ever been much pressure on africans from roman catholic missionaries to avoid cousin marriage.

    @frau katze – “The area you mention is along the Muslim/Christian fault line….”

    gosh. i didn’t realize that the muslim line there in west africa was so far south! i need to brush up on my african geography.

    Reply

  3. Didn’t know that about the Catholic Church, LOL! The line isn’t really clear cut of course, but I know in Nigeria it roughly splits the country in half.

    And of course, you’re right, some groups may be neither. I just know from reading news stories where the troubled areas are. There’s a good map from the Pew Forum here,

    http://www.pewforum.org/2010/04/15/executive-summary-islam-and-christianity-in-sub-saharan-africa/

    But it may be unrelated of course.

    Reply

  4. Great post. I think we need to consider urban vs. rural populations however. The data above claims that Yoruba don’t practice cousin marriage, but this might not be universally true:

    “Even in the few populations common between Bittles and Black and the HGDP-CEPH
    panel, the population results are different. The reason might be the differences in sampling location and time.
    This is well illustrated by the Yoruba of Nigeria for whom Bittles and Black found 51% of consanguineous marriages in a rural sampling location in 1974 when we only report 6% of consanguineous matings in an urban area in the 1990’s”.

    ftp://ftp.cephb.fr/hgdp_hbd/leutenegger-EJHG.pdf

    Reply

  5. Have seen a few extracts from this book (good but expensive). Can’t recall if you have mentioned it before. I think that you did?

    “Consanguinity in Context” – Alan H. Bittles

    He reports that the Bamileke account for 20% of Cameroon’s population but 70% of cases of albinism in the country, and that this is reportedly due to higher rates of consanguineous marriage among them.

    Reply

  6. The Kru, although described as being from the interior of Liberia, have been best known as coastal fishermen, and were often hired (not enslaved) to man boats around West Africa.

    Tribes did migrate somewhat, so I’m not sure how useful a modern highlands/lowlands breakdown is without a little sense how long a tribe has been where it is.
    http://en.wikipedia.org/wiki/Krahn_people

    Reply

  7. @james the lesser – “The Kru, although described as being from the interior of Liberia, have been best known as coastal fishermen, and were often hired (not enslaved) to man boats around West Africa.

    “http://en.wikipedia.org/wiki/Krahn_people”

    thanks, james! i couldn’t figure out yesterday if the kru in this study were these kru people or these kru(men) people. unfortunately, the “kru” don’t seem to be included in the online version of murdock’s atlas. don’t know why.

    and, now you give me a THIRD link to the “krahn” people. (O_O) now i am officially confused. (~_^) well, i’ll have to sort them out one of these days….

    @james the lesser – “Tribes did migrate somewhat, so I’m not sure how useful a modern highlands/lowlands breakdown is without a little sense how long a tribe has been where it is.”

    yes. that is another element that has to be taken into consideration.

    Reply

  8. @chris – “He reports that the Bamileke account for 20% of Cameroon’s population but 70% of cases of albinism in the country, and that this is reportedly due to higher rates of consanguineous marriage among them.”

    yeah, i don’t know where he gets that the bamileke of cameroon practice consanguineous marriage. they are one of the “cameroon west highland groups” (from the post) and so should be avoiding cousin marriage.

    afaics, the only bamileke who went for cousin marriage were some tribal chiefs in the past who wanted to keep the royal bloodlines pure (of witches!). otherwise, the reports are that the bamileke avoid marrying all of their maternal relatives and generally their paternal relatives who are connected back four generations. -?-

    dunno. maybe bittles has some other info. i don’t have access to the source that he referenced (Puri et al., 1997). or else maybe he’s only referring to those chiefs?

    Reply

  9. @chris – “The data above claims that Yoruba don’t practice cousin marriage….”

    oh, gee. i missed the yoruba (nigeria and benin) on my maps, didn’t i? oops! i’ll have to fix that. (did i miss anybody else?)

    Reply

  10. @chris – “I think we need to consider urban vs. rural populations however. The data above claims that Yoruba don’t practice cousin marriage, but this might not be universally true.”

    very good point. thanks!

    the yoruba data in the post come (like i said) from murdock’s ethnographic atlas — and i’ve just found murdock’s book Atlas of World Cultures on google books. there we can see that the yoruba data refer to the oyo subtribe (whoever they are) — and was gathered by one samuel johnson, a christian missionary, in 1890! also from The Yoruba-Speaking Peoples of South-Western Nigeria pub. in 1951, but that’s not available on google book (dr*t!).

    there are a LOT of yoruba. they could be doing different things wrt marriage: different subtribes, urban vs. rural like you say, some are christians and some are muslims. need to check and double-check this data.

    Reply

  11. i said: “i’ve just found murdock’s book Atlas of World Cultures on google books.”

    i also said: “i couldn’t figure out yesterday if the kru in this study were these kru people or these kru(men) people.”

    the “kru” people appear to be the coastal population. from pg. 17 in murdock’s book:

    “…the peoples along and near the Guinea Coast who speak languages of the Twi and Kru branches of the Kwa sub-family….”

    Reply

  12. @chrisdavies. Looks like a good book, I looked on Amazon and it’s only $23.72 (USD) for Kindle version. I can read any Kindle book on my iPad, with the free Kindle app.

    Its expensive for an e-book, but the physical book is over $90. And no delivery charge for e-books.

    Thanks for the tip.

    Reply

  13. Recently John Stossel, the libertarian Fox news anchor, announced on one of his show about ‘myths’ that the idea (myth) that it is harmful to marry your cousin has now been shown to be false. He stared right into the camera and told everyone to go ahead and marry their cousin if they liked – “it’s OK”.

    I wonder where he’s getting his genetic info?

    I did Basic Training at Fort Knox in Kentucky. I could always tell the native hillbillies who were from the nearby Appalachians. They had rotted stumps for teeth. Marrying your cousin shows up in your children’s smile.

    Victoria and Albert were cousins too. They had a number of defective children and grandchildren. These genetic defectives inspired a number of movies – several based on rumors around ‘Jack the Ripper’ and more recently ‘The King’s Speech”. None of them were quite as extreme as Charles of “Don Carlos” fame. He was very close to a monster – a monster of consanguinity.

    Then again I see from 23andme that I have a lot more cousins than I had ever imagined. It looks like over time everyone on the planet will prove to be at least my tenth cousin.

    Reply

  14. For what it’s worth, the highlands of Africa are much lower than those of other continents. That and a warm climate makes for smaller differences than elsewhere.

    Then there is the matter of how long they have been highlanders and how they became it – by choice or being displaced.

    Lots of variables…

    Reply

  15. Sub-Saharan Africa is a pretty flat place overall. Not quite as flat as Australia, but many of the highlanders are more like plateau-dwellers. As an illustration, Eastern Colorado is around 4,000 feet in elevation, but it’s not very hard to get to the next town.

    Cavalli-Sforza measured this mountaineer inbreeding tendency in the Appennines a long time ago. Italian hill-dwellers became more out-breeding when bus service came to their villages. My wife has some kind of ancestor or relative from a village outside of Rome who was considered an extreme romantic because he wooed a girl from a village down in the valley, and had to walk home up 500 meters after every date.

    Reply

  16. @steve – “Sub-Saharan Africa is a pretty flat place overall. Not quite as flat as Australia, but many of the highlanders are more like plateau-dwellers.”

    yeah. so maybe it’s not just elevation but…dunno…how steep your mountains are and how deep your valleys. i’ll have to go have a look at southeast asia where westermeyer did his study. i haven’t a clue how plateau-ish or not that area is.

    certainly the cameroon west highlands are pretty much just a big plateau (for instance).

    @steve – “Italian hill-dwellers became more out-breeding when bus service came to their villages.”

    only thing is, the mountaineers in northern early medieval italy — around florence — had very exogamous marriage practices — more than the urbanites. sometimes weird cultural practices can just push people to do odd things.

    @steve – “My wife has some kind of ancestor or relative from a village outside of Rome who was considered an extreme romantic because he wooed a girl from a village down in the valley, and had to walk home up 500 meters after every date.”

    (^_^)

    Reply

  17. Have you considered the difference between high plateaux and rugged formations? Grade as opposed to altitude itself. On a high plain a substantial-size polity may more easily exist, and monopolize violence, whereas rugged lands, hard to traverse, may have rugged people who need high inbreeding to support vendetta law.

    Reply

  18. You might be interested in Xenophon’s Anabasis (380? BC), because the fleeing Greek mercenary army fights some mountain people (among other people) — and they sound just like mountain people of today. Not that’s its so surprising I guess. There is some other interesting anthro in there — it was a less credulous time than the time of Herodotus.

    Reply

  19. May I suggest a simple criterion, the availability of arable land within walking distance from the village. Arable land nearby will be readily available in the plains or on a plateau, but will be scarce in hilly country where the gradient is steeper. In places where the residents have had to carve out terraces on hillsides by manual labor in order to establish an arable field, they will want to keep it in the family:

    Reply

  20. “I did Basic Training at Fort Knox in Kentucky. I could always tell the native hillbillies who were from the nearby Appalachians. They had rotted stumps for teeth. Marrying your cousin shows up in your children’s smile.”

    Marrying your first cousin is illegal in Kentucky. Unlike in, say, New York. The hillbillies had rotten teeth because they practiced bad oral hygiene. Believe it or not, teeth will rot if you don’t take care of them, no matter what your genes are like. Whiskey’s not good for your teeth either, might want to put it down, Pat

    Reply

  21. James C. Scott argues that the uplanders of SE Asia live in the mountains to escape the coercion of lowland states (http://www.amazon.com/The-Art-Not-Being-Governed/dp/0300169175). The same seems plausible of the other groups you mention in the post- they’ve all lived next to state societies for 2000-4000 years. The common recipe for the resistance of state control over that kind of timeframe seems to be
    1. Geographic barriers.
    2. Strong ingroup loyalty/outgroup suspicion.

    The Sub-Saharan African Exception might be caused by the lack of states to flee from.

    What do breeding patterns look like in the uplands of other historically stateless regions? Do we know if Native Americans in the Appalachians and Rocky Mountains were inbreeders? Or maybe highland New Guinea?

    Reply

  22. Those on the flatlands and those in the mountains….interesting. My father was a general contractor and though I did not go into his field I have always been interested in where people live. Given their druthers, you get well-to-do white people living in the cooler mountains throughout the world and poorer non-whites living in the warmer valleys.

    Reply

  23. @rs – “You might be interested in Xenophon’s Anabasis (380? BC), because the fleeing Greek mercenary army fights some mountain people (among other people) — and they sound just like mountain people of today.”

    cool! thanks! (^_^) yes, that sound like just the long-weekend reading for me. (^_^)

    Reply

  24. @vasilis – “May I suggest a simple criterion, the availability of arable land within walking distance from the village.”

    could be. i was kinda hoping for a Theory of Everything, though — one that would encompass hunter-gatherers and pastoralists, too. maybe that doesn’t exist, however. (but i’ll keep plugging away at it!)

    Reply

  25. @bleach – “Marrying your first cousin is illegal in Kentucky.”

    yeah, but only since 1946. kinda recent. and a lot of peoples in the appalachians come from rather inbred groups (border reivers, scots, irish).

    Reply

  26. @alex – “What do breeding patterns look like in the uplands of other historically stateless regions? Do we know if Native Americans in the Appalachians and Rocky Mountains were inbreeders? Or maybe highland New Guinea?”

    good questions! i have no idea. (*^_^*) Further Research is RequiredTM!

    don’t know at all about the native americans in the appalachians. i know that some of the png highlanders do marry close cousins, but i don’t know if that’s a general pattern or not, or what the lowland/coastal pngers do. i shall endeavor to find out!

    Reply

  27. @staffan – “Then there is the matter of how long they have been highlanders and how they became it – by choice or being displaced.”

    yes! very good point. the bamileke, it turns out, live in a rugged area, but they originated on a highland plateau. could be that they brought their flatlander (plateau) mating patterns with them when they moved to the cameroon west highlands where they are now.

    Reply

  28. @patrick “…the idea (myth) that it is harmful to marry your cousin has now been shown to be false.”

    the thing with cousin marriage is, it’s unlikely to be a problem if your marriage to your cousin is a one-off thing. however, if your family or your population have been regularly inbreeding (marrying cousins, for example) for a long time, then the risks of having kids with some sort of genetic disorder will be much higher.

    it’s common sense, really.

    Reply

  29. @frau katz – “Looks like a good book, I looked on Amazon and it’s only $23.72 (USD) for Kindle version.”

    oh! is that all it is now?! i’ll have to buy it. (^_^) last time i checked, it was $90 hardcover (or some horrible price like that). ouch!

    Reply

  30. Vasilis
    “May I suggest a simple criterion, the availability of arable land within walking distance from the village.”

    hbdchick
    “i was kinda hoping for a Theory of Everything, though — one that would encompass hunter-gatherers and pastoralists, too. maybe that doesn’t exist”

    Imo that is it though – or at least related to it. It’s not highlands per se as population density. Highlands generally correlate because they generally correlate with lower population density. It’s why you’d expect lowland swamps to be inbred also.

    nb Latitude and altitude are both at play here because they both effect micro-climate and therefore population density. Even at the same elevation highlands nearer the equator will be warmer e.g. back when they were at the same level of technology was the population density of Cameroon highland pastoralists higher than Swiss mountain pastoralists? It might even be higher now.

    Reply

  31. hbdchick
    “i was kinda hoping for a Theory of Everything, though — one that would encompass hunter-gatherers and pastoralists, too. maybe that doesn’t exist”

    Theory of Everything

    (not really but hopefully illustrating the point about population density)

    1) Hunter-gatherers, very low population density requiring explicit outbreeding via moeity-type systems to prevent very rapid inbreeding effects.

    http://en.wikipedia.org/wiki/Moiety_(kinship)#Lineages.2C_clans.2C_phratries.2C_moieties.2C_and_matrimonial_sides

    2) Agriculture, much larger population densities combined with land ownership and the consequent need for inheritance systems both *allows* more extended family level inbreeding (because you have a larger pool of people) and also favors more family level inbreeding to keep property in the family (i.e. arranged marriage systems within a network of extended families).

    #variations of agriculture#

    2b) Agriculture in marginal terrain, as (2) but the lower population density resultign from the marginal terrain creates a Catch 22, firstly the marginal nature of the terrain makes it more important to keep land/herds in the family for survival reasons but at the same time the lower population density means the inbreeding will be more pronounced.

    2c) Agriculture in very favorable terrain e.g. fertile valleys, as (2) but particularly high population densities leads to less inbreeding simply through weight of numbers.

    2d) As 2c but with a caste system which artifically reduces the effective population density.

    2e) Agriculture on terrain which is marginal for any *permanent* crop farming but which is *also* marginal for full pastoralism leading to semi-nomadic village-level slash and burn agriculture with village-level inheritance instead of family level inheritance and a village-level, kindred form of inbreeding.

    (I’d say fishing based populations are likely to be similar to this for the same collective resourse reasons with inbreeding on a village level rather than extended family level.)

    #

    So the theory is you have optimal forms of food-getting (based on the terrain and the available technology) and cultural adaptations to reinforce those forms which create different levels of inbreeding which creates the various effects you have outlined. The key point is it is the *interplay* of the physical environment and the cultural reinforcement – particularly marriage – systems.

    #

    Then on top of that general pattern in a messy world you also have cultural adaptations that are in the wrong place or artificial:

    1) Misplaced cultural adaptations e.g. desert adaptations applied outside the desert through conquest.

    2) Transitional adaptations i.e. a group that was recently in one food-getting category and then moved to another (or had another move to it e.g. desertification) and is in the process of changing from one set of cultural adaptions to another.

    3a) Cultural adaptations created for non food-getting reasons e.g. as a result of conquest, e.g. castes.

    3b) Cultural adaptations created for non food-getting reasons e.g. Aquinas.

    Reply

  32. @grey – “Hunter-gatherers, very low population density requiring explicit outbreeding via moeity-type systems to prevent very rapid inbreeding effects.”

    yes! THANK you for explaining the “why” behind moieties. never understood them, and they’re soooo confusing, too. what you say makes sense! (^_^)

    Reply

  33. @grey – It’s not highlands per se as population density. Highlands generally correlate because they generally correlate with lower population density. It’s why you’d expect lowland swamps to be inbred also.”

    yes, that makes sense!

    @grey – “Then on top of that general pattern in a messy world you also have cultural adaptations that are in the wrong place or artificial.”

    yeah. complicating. =/

    the bamileke, for instance, are living now in the cameroon west highlands, an area which is rugged, but they originated on the adamawa plateau. they migrated to the highlands in the 1500-1600s, and they may have brought their outbreeding mating system with them from their days on the plateau. unfortunately, i have no way of telling (right now — need the bamilieke to get their genomes sequenced so we can look at how many roh they’ve got! (~_^) ).

    Reply

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