Archives for posts with tag: mating patterns matter

yesterday was the galton institute’s annual conference in london, which i (and anybody else!) was able to virtually attend thanks to the live-tweeting of attendees andrew sabisky, michael story, and rory. (^_^) the conference was on mate choice and included presentations such as “Mate choice and assortative mating on the internet”, “Findings from the ‘Born in Bradford’ project and their relevance to the understanding of contemporary mate choice”, and “Patterns of consanguineous marriage across the world and their consequences” by professor alan bittles (mr.

andrew has kindly storifyed the tweets covering the conference, so now you can belatedly virtually attend, too. (you’ll have to supply your own tea and bikkies, tho. (~_^) ) enjoy!:

Annual Conference of The Galton Institute – Mate Choice, 2015.

(note: comments do not require an email. galtonia candicans.)

it finally clicked in my head while thinking about polygamy what the importance of family types — nuclear vs. extended, etc. — might be in the selection for altruistic behavioral traits, especially nepotistic altruism or clannishness. i should’ve thought through polygamy sooner instead of putting it off, but hey — procrastination is heritable, too, so in the words of h. solo, it’s not my fault! (~_^)

the logic of the mating patterns/inbreeding-outbreeding theory goes that, given the right set of circumstances (i.e. certain sorts of social environments), selection for nepotistic altruism/clannishness ought to go quicker or be amplified by inbreeding (close cousin marriage or uncle-niece marriage) simply because there will be more copies of any nepotistic altruism genes (alleles) that happen to arise floating around in kin groups. in other words, inbreeding should facilitate the selection for clannishness…if clannish behaviors are being selected for in a population.

the thing is, though: the individuals carrying certain versions (alleles) of nepotistic altruism genes need to direct their nepotistic behaviors towards other individuals carrying those same alleles, otherwise their actions will be for naught. (yeah. kin selection.) if they direct their nepotistic actions towards people who don’t share the same alleles, then the actions will be “wasted” and the behavioral traits won’t be selected for — or at least not very strongly — and they might fizzle out altogether.

let’s take an imaginary society as an example: say everyone in our pretend population always marries their first cousins. their father’s brother’s daughters (fbd) even, so that we get a lot of double-first cousin marriage. h*ck! let’s throw in some uncle-niece marriages on top of it all. the inbreeding coefficients in such a society would be very high, and if clannishness was being selected for in our highly inbred population, the selection ought to move pretty quickly.

but suppose we separated all the kids at birth from their biological families and set them out for adoption by unrelated individuals — people with whom they likely did not share the same nepotistic altruism alleles. think: the janissary system, only on a population-wide scale. if we did that, there should be virtually no selection for clannishness despite all the inbreeding since pretty much no one’s nepotistic behaviors would be directed towards other individuals with the same nepotistic altruism genes. in this case, kin selection would just not be happening.

such a society does not exist, and i don’t think ever has. but there are societies out there with certain family types — namely nuclear families (or even post-nuclear family societies!) — which ought to have a similar dampening effect on any selection for clannishness.

northwestern “core” europe has had very low cousin marriage rates since around the 800s-1000s, but it has also, thanks to manorialism, had nuclear families of one form or another (absolute or stem) since the early medieval period — nuclear families are recorded in some of the earliest manor property records in the first part of the ninth century from northeastern france [see mitterauer, pg. 59]. on the other hand, eastern europeans, like the russians and greeks, while they also seem to have avoided very close cousin marriage for several hundreds of years (which is not as long as northwestern europeans, but is quite a while), have tended to live in extended family groupings. you would think that nepotistic altruism could be selected for, or maintained more readily, in populations where extended family members lived together and interacted with one another on a more regular basis than in societies of nuclear family members where individuals interact more with non-kin. societies comprised of nuclear families are more like my hypothetical janissary society above where the altruism genes that might’ve been selected for via kin selection instead fade away in the wash.

we have to be careful, though, in identifying nuclear family societies. the irish of today, for instance, are typically said to be a nuclear family society, but the extended family does still interact A LOT (i can tell you that from first-hand experience). same holds true for the greeks and, i suspect, the southern italians. i would say that these populations have residential nuclear families, but not fully atomized nuclear families which have infrequent contact with extended family (think: the english). the early anglo-saxons in england were also characterized by residential nuclear families — the extended family (the kindred) was still very important in that society. the individuals in a residential nuclear family society probably do interact with non-family more than individuals in a society structured around extended families or clans, but less so than a true nuclear family society.

the thought for the day then?: family types can also affect the selection for clannishness/nepotistic altruism.

that is all! (^_^)

previously: polygamy, family types, and the selection for clannishness and “l’explication de l’idéologie”

(note: comments do not require an email. irish nuclear family.)

jayman’s got a cool new post up on clannishness and western inventiveness! here are a few thoughts from me…

jayman said re. the abstract thinking type of westerners vs. the holistic thinking type of easterners (a la nisbett) [my emphasis]:

“[A]nother key difference between Western vs. Eastern (i.e., WEIRDO vs. clannish) thought: the former see things (and themselves) as atomized individuals, while the latter view objects in the world as part of an interconnected whole. This is a defining aspect on the clannishness dimension: low-clannishness peoples (WEIRDOs) see themselves as atomized individuals, who form associations voluntarily and not necessarily based on kinship. High-clannishness peoples see themselves as inherently part of the group (e.g., family, clan, tribe, village/town, etc.)….

“How did this penchant for abstraction come about among NW Europeans? I suspect that part of it has to do with the rise of high-trust and social atomization (i.e., individualism) in NW European societies. As clannishness disappeared, and as people were no longer bound to their families or clans (and indeed, we were free to interact with non-relative in cooperative ventures), people became more free to engage in intellectually stimulating thought. Mental space previously devoted understand one’s place in society and keep ahead of schemers now could be used on more abstract pursuits.

while it’s an interesting idea, i don’t think that freed up mental capacity once dedicated to clannish traits was co-opted in the brains of westerners (nw europeans) in their post-clannishness state and then devoted greater abstract thought. maybe. but i suspect the connection is (somehow) much more direct: i think (theorize, speculate, etc.) that in simply becoming more independent individuals — i.e. less genetically like others around them thanks to outbreeding — that the mindset simply shifted. atomized individuals, atomized (and, therefore, abstract) thinking. please don’t get your panties all in a bunch. yes, this is complete and wild speculation on my part. i can’t even guess what the mechanism might have been, so don’t sue me if i’m wrong. (nw europeans, btw, began to think of themselves as individuals in the middle of the eleventh century a.d.)

another much more informed guess: that nw europeans’ exceptional ability for inventiveness especially in science (which cannot be divorced from their high average iqs — as jayman pointed out, africans are pretty inventive, but without enough iq points, no one there’s going to the moon) has a LOT to do with the selection pressures that happened thanks to the manor system which was found in nw europe during the middle ages, specifically bipartite manorialism.

to back up for a sec: inventiveness/creativity/scientific reasoning in east asians, or the relative lack of it. jayman suggests that their tendency for holistic — and, therefore, not abstract — thinking hobbles east asians when it comes to inventiveness, etc. that, i think, makes a lot of sense. i do think, though, that the cochran-harpending idea of conformity in east asia (“nails hammered down”/low levels of adhd) also makes a lot of sense. the two ideas go well together, imho. wrt the “nails hammered down” hypothesis, my bet is that that selection process goes waaaay back. complex chinese civilization (that centered around the yellow river valley) is three or four thousands of years old. i think they’ve been hammering down the contrarians/independent thinkers there for a very long time. greg cochran has mentioned that the high-altitude adaptation of tibetans works better than those of other groups adapted to living in the clouds because the tibetan adaptations have been under selection for longer (even some acquired from the denisovans and/or other archaic humans?). i suspect that this is why conformism/lack of independent thinking is so strong in east asia: it’s been under selection there for a very long time. northwest europe’s civilization is obviously much, much younger.

now, to return to northwest “core” europeans: i strongly suspect their inventiveness/abstract thinking style/scientific thinking (and other behavioral traits, for that matter) were selected for thanks to the the following medieval trifecta:

– outbreeding (i.e. the abandonment of close cousin marriage) which meant that the selection for nepostic altruism was curbed since family members would no longer share so many “genes for altruism” in common (see: renaissances), PLUS individuals became “atomized” (therefore more abstract thinking arose, etc.);
– change in family types from extended to nuclear, which again would limit the selection for nepotistic altruism since individuals would interact more with non-kin than family;
bipartite manorialism, which began in frankish territories in northeastern france/belgium and spread across nw and central europe in areas that are pretty much coterminous (prolly not coincidentally) with the hajnal line.

oh. and the ostsiedlung.

bipartite manorialism, in which tenant farmers would work for (later pay rent to) the head of a manor but also farm for themselves, operated as a sort-of franchise system in which the tenants on their individual farms had to make it or break it independently (i.e. without support from an extended family/clan, the dumber members of which would no longer be a drag on our independent farmers). there was, no doubt, cooperation between the tenant farmers which, once the outbreeding reduced the selection for nepotistic altruism, could’ve resulted in the selection for a more general, reciprocal altruism. but bipartite manorialism, i think, would’ve also selected for other traits like a propensity to be hard working, delayed gratification, and inventiveness: those individuals who came up with new ideas for improving their farming (or related) techniques could’ve bettered their place on the manor and been more successful reproductively.

chonologically, bipartite manorialism came first, arising out of the abandoned latifundia system in what had been roman gaul perhaps as early as the 500s. there also appears to have been pressure from very early on on these manors for nuclear families, so the reduction in family size may very well have come next. finally, the avoidance of cousin marriage came into full swing in the frankish territories in the 800s.

the final stage — at least as far as the medieval period goes — in the selection for “core” europeans was the ostsiedling: this was The Big Self-Sorting to the east of individuals who were already well underway to being outbred/manorialized in western germanic regions — in other words, they were well underway to being westernized as we know it. i don’t think it can be a coincidence that the heart of human accomplishment in western europe (which is also pretty much the heart of human accomplishment) is found in the manorialized regions of europe and very much where the ostsiedlung happened (see also here). my bet is that it was very much hard-working, innovative (especially, at the time, in agricultural/engineering techniques), high-achievers who went forth into the east during the medieval period. and they prospered and multiplied once they were there.

so that’s the picture as i see it so far. i reserve the right to change my mind/be utterly and completely wrong. (~_^)

oh. wrt to thinking like a westerner (abstract/atomized) vs. thinking like an easterner (holistic/group), i still suspect that peripheral europeans (like me!) might think more like easterners (i.e. holistically) than northwest “core” europeans. dunno for sure, and i didn’t have enough data to confirm or refute this little idea, but i’m still hanging on to it for now. really wish an actual scientist would check it out.

jayman also said [his emphases]:

“The reality is that evolution proceeds much quicker than you think. Just as HBD’ers generally understand that human evolution didn’t stop 50,000 years ago, it also did not stop 10,000 years ago, or even 1,000 years ago, or even 500 or 200 years ago. Evolution continues right up to the present day. The reason I bring this up is because I keep hearing about how X group was doing this 2,000 years ago or about how Y group was doing this 1,000 years ago, so how could they be so different now? The reason is that they have changed since that time.

hear, hear! and…duh! human evolution is recent, both global and local, ongoing, and can be pretty rapid. not in one generation, obviously, but twenty or forty is plenty of time. also, gene frequencies in populations move upwards or downwards over time — they do not (have to) remain stagnant. i quoted stephen stearns recently (here):

“Well I think what is very probably going on is that selection is moving a population up and down all the time. It goes off in a certain direction for a while, and then it goes back in the other direction. It’s only if you get a significant change in the environment that it will then continuously go in a new direction.”

and average differences in gene frequencies in populations is all you need for average differences in behavioral traits, etc. for example, i think the ancient greeks might’ve moved from a shame to a part-guilt and back to a shame culture again thanks (at least in part) to changes in mating patterns over the course of several hundreds of years. evolution does not have to be unidirectional.

anatoly karlin said:

“Ancient Greeks did a lot of abstract thinking, and produced the greatest cultural/scientific peak until the Renaissance (according to the same Charles Murray’s figures). During the Middle Ages, in pure scientific terms, the Islamic world was most advanced. The Renaissance began in northern Italy. Only in the 17th century did the bulk of scientific discoveries move to NW Europe.”

as i mentioned above, it looks like the ancient greeks (the athenians) went from inbred to outbred and back to inbred again. mind you, i only have some pretty slim historic/literary evidence for that, so you should take my claim with a large grain of salt, but i’ll keep working on the Greek Question. the romans, who were also pretty sharp, at least when it came to engineering, were very clearly outbred (they bequeathed their outbreeding practices to us). the renaissance did begin in northern italy, and that doesn’t come as a big surprise to me ’cause northern italy was the most heavily manorialized part of italy (i’ll tell you more about this in my long overdue series on manorialism). northern italians were also prboably quite outbred during the medieval period, although further research is required on that front, too. the scientific revolution, however — especially the development of the scientific method — was very much a north european baby, though. from what i understand of science in the medieval islamic world, most of that was down to the persians. can’t tell you anything about medieval persian society, unfortunately, ’cause i don’t know anything about it.

that’s it. outta energy. more soon!

(note: comments do not require an email. De revolutionibus orbium coelestium.)

there appears to be a north-south divide in spain on several crucial metrics. for example, pisa scores (good proxy for iq scores/intelligence — see here and here):

spain - pisa scores and latitude

gdp per person (2012 — from here):

spain - gdp per person


the speculation in hbd circles has long been that these differences have something to do with southern spain’s moorish history vs. northern spain’s visigothic, later catholic, one. but now, from the upcoming american society of human genetics conference, we have this:


so, if this proves to be correct, the major genetic divide in spain is an east-west one, not a north-south one! as razib pointed out:

why, then, the apparent north-south divide in spain (if it’s real)?

not sure. but there is another major difference between northern and southern spain, and that is in the traditional mating patterns/family types — southern spain is (traditionally) outside the hajnal line, while northern spain falls within it:

hajnal line

in other words, northern spain has for a long time been marked by the western european marriage pattern — i.e. late marriage, fewer children — whereas southern spain has not. from what i can tell, this late marriage pattern is found in those areas of europe in which bipartite manorialism was present during the medieval period, but i honestly don’t know if this holds for spain/the iberian peninsula. i shall endeavor to find out! jayman found, btw, that iq scores in europe correspond pretty well to the hajnal line — higher scores within, lower scores outside the line. this also appears to be the case in spain:

jayman's map + hajnal line

high historic rates of cousin marriage also tend to be present outside the hajnal line. historians generally agree that very close endogamous marriage practices were common in moorish spainfbd marriage even — and they continued right up into (at least) the sixteenth century.

perhaps regional differences in mating patterns/family types persisted in spain despite the movement of peoples during the reconquista. it could be that northerners who moved south through the country, replacing (or eventually outnumbering) the moors, adopted closer mating habits as they moved southwards. it wouldn’t be the first time, i don’t think, that a transplanted group adopted the marriage practices of the broader host population.

dunno. all still speculative at this point. watch this space! (^_^)

see also: Mapping The 2009 PISA Results For Spain And Italy from the reluctant apostate and IQ Ceilings? from jayman.

previously: northern vs. southern spanish iq, redux and la endogamia en la españa medieval and inbreeding in spain in the 19th & 20th centuries and big summary post on the hajnal line

(note: comments do not require an email. medieval spain.)

here’s an excerpt from ed west‘s latest kindle single, Asabiyyah: What Ibn Khaldun, the Islamic father of social science, can teach us about the world today (u.k. link) [kindle locations 256-286]:

“As a rule, the English are not a very family-orientated people. Social life lacks the warmth of the Mediterranean world with its joyful and welcoming extended families. In contrast, many English people don’t especially like their relatives or are apathetic towards them. My father never took much interest in his relations, many of whom are fascinating, lovely people, and it was largely left to my Irish mother to maintain a connection. Meanwhile her family have always been close and this extends to first and second cousins in the more traditional west of Ireland. To the English, although family connections do count, they matter less, and associations with a school, club or other institution define them more.

“Yet despite there being no big fat English weddings with lots of relations called Nigel or Rupert, there are great advantages to a society with weak family connections. It is not a total coincidence that it was in England that clubs first took off in the 17th century, playing an important role in the country’s political and economic growth; in specific cases clubs allowed inventors to meet investors, but they also helped expand the general levels of trust. Countries that are not clannish tend to have far more clubs, institutions and other organizations that are collectively called ‘civil society’. In contrast societies with strong families tend towards low civic capital and in consequence higher corruption. This is reflected in the political cultures of different states.

“Asabiyyah, therefore, can work in two ways; the group feeling can lie at the nationwide level, or it can exist within tribes, clans or religious communities, and this has a profound effect on a state’s institutions and how well a democracy can function.

“At the other end of the spectrum to the English are the Bedouin, whose famous phrase ‘me and my brother against my cousin, me and my cousin against the world’ reflects concentric circles of trust, one limited to family members.

“Mark Weiner wrote in The Rule of the Clan about countries governed by ‘clannism’ that: ‘These societies possess the outward trappings of a modern state but are founded on informal patronage networks, especially those of kinship, and traditional ideals of patriarchal family authority. In nations pervaded by clannism, government is co-opted for purely factional purposes.’

“In these societies, especially in the Middle East and Africa, ‘the nuclear family, with its revolutionary, individuating power, has yet to replace the extended lineage group as the principle framework for kinship or household organization’.

“Clannish states have little sense of wider civic asabiyyah and therefore civic responsibility. Indeed, as social anthropologist Stanley Kurtz wrote, tribes were used to preying on others: ‘Once a particularly powerful tribe or tribal coalition actually captured a state, they simply routinized their predation under official guise. (Saddam and his Sunni tribal allies fit the bill.) The state, such as in the Middle East, offers but a thin alternative to ‘the war of all against all’. Too weak to provide public utilities, policing, or impartial justice, most Middle Eastern states are just reincarnations of the predatory, winner-take-all tribal coalitions of old. Why exchange the protection of your family, tribe, or sect for submission to a weak or predatory state?’

“The relationship between this type of state and the tribal peasant, wrote Philip Carl Salzman of McGill University in Canada, ‘is that of the shepherd to his flock: the state fleeces the peasants, making a living off of them, and protects them from other predators, so that they may be fleeced again’. Salzman describes such clan-based states as ‘cliques determined to impose their power for the pleasure of dominance and the profit of extortion’. The inevitable result of clannism is kin-based corruption whereby resources, positions and other rewards are monopolised within family groups. Nepotism is found wherever humans are, but is far more widespread in clannish societies, and this affects both a country’s corruption levels and its ability to sustain democracy.”


see also: The Islamic historian who can explain why some states fail and others succeed from ed west, Ed West’s Kindle Single on ibn Khaldun and Asabiyyah from steve sailer, and Introducing: Asabiyah from t.greer.

previously: asabiyyah

(note: comments do not require an email. ibn khaldun.)

here are a couple of thoughts on ashkenazi jews and the apparently high frequencies of mediterranean mtdna found in that population. i was going to include these in my response to prof. macdonald (prolly still will), but since that isn’t happening anytime soon, i thought i’d throw these out there. remember that these are just ideas, so don’t flip out on me!

if it’s correct that 80% of the mtdna of ashkenazi jews is of european — specifically mostly mediterranean, even more specifically very much italian — orgin, then it could very well have been that some male jews (traders?) from judea or alexandria married some roman women, either in or around rome or maybe even in southern gaul. as costa et al. proposed in their paper:

“Overall, it seems that at least 80% of Ashkenazi maternal ancestry is due to the assimilation of mtDNAs indigenous to Europe, most likely through conversion. The phylogenetic nesting patterns suggest that the most frequent of the Ashkenazi mtDNA lineages were assimilated in Western Europe, ~2 ka or slightly earlier. Some in particular, including N1b2, M1a1b, K1a9 and perhaps even the major K1a1b1, point to a north Mediterranean source. It seems likely that the major founders were the result of the earliest and presumably most profound wave of founder effects, from the Mediterranean northwards into central Europe, and that most of the minor founders were assimilated in west/central Europe within the last 1,500 years. The sharing of rarer lineages with Eastern European populations may indicate further assimilation in some cases, but can often be explained by exchange via intermarriage in the reverse direction….

“It is thought that a substantial Jewish community was present in Rome from at least the mid-second century BCE, maintaining links to Jerusalem and numbering 30,000–50,000 by the first half of the first century CE15. By the end of the first millennium CE, Ashkenazi communities were historically visible along the Rhine valley in Germany. After the wave of expulsions in Western Europe during the fifteenth century, they began to disperse once more, into Eastern Europe.

These analyses suggest that the first major wave of assimilation probably took place in Mediterranean Europe, most likely in the Italian peninsula ~2 ka, with substantial further assimilation of minor founders in west/central Europe. There is less evidence for assimilation in Eastern Europe, and almost none for a source in the North Caucasus/Chuvashia, as would be predicted by the Khazar hypothesis, — rather, the results show strong genetic continuities between west and east European Ashkenazi communities, albeit with gradual clines of frequency of founders between east and west….

The age estimates for the European founders might suggest (very tentatively, given the imprecision with present data) that these ancestral Jewish populations harboring haplogroup K and especially N1b2 may have had an origin in the first millennium BCE, rather than in the wake of the destruction of the Jerusalem Temple in 70 CE. In fact, some scholars have argued from historical evidence that the large-scale expansion of Judaism throughout the Mediterranean in the Hellenistic period was primarily the result of proselytism and mass-conversion, especially amongst women.”

just a reminder: the romans were outbreeders. they avoided cousin marriage. the proscriptions against cousin marriage were stronger earlier in the republican period than later, going from no marriage to third cousins or closer to first cousin marriage being allowed by the 200s b.c. but changes to mating patterns and people’s attitudes toward them take time. cosider how long it took for northern europeans to start following the church’s cousin marriage bans in the middle ages — around 300 years in the frankish kingdoms. also, cousin marriage is legal in germany today, and has been (mostly) since the days of luther, but cousin marriage rates remain very low. so i doubt if the roman cousin marriage rates shot up dramatically after the 200s b.c. (although you never know).

what i’m thinking is that the romans might have been quite okay with the idea of marrying their daughters off to some foreigners, especially since they didn’t have a tradition of marrying their cousins. jewish traders from the levant or wherever might not have had a hard time finding a nice roman girl to wed, either in rome itself or even in southern gaul perhaps. this could account for the “major wave of assimilation” in the north mediterranean that costa et al. think that they picked up in their mtdna analysis.

that only “minor founders” came from western/central europe might’ve had to do with the fact that northern europeans like the franks didn’t really start avoiding cousin marriage until the 800s, so they might not have been ready to marry some foreigners at all at that point. and that there was very little introgression whatsoever from eastern europeans should come as no surprise, given that it appears that eastern europeans continued to marry their cousins and be awfully clannish until quite late. when jews moved into eastern europe, they would’ve encountered a populace that barely intermarried between its own members, let alone with some outsiders.

if it’s correct that some jewish blokes married some roman chicks and then we got ashkenazi jews outta that combo AND if the theory of inbreeding/outbreeding/clannishness is right in any way (that’s two big ‘ifs’ there, in case you weren’t counting), then a funny thing to contemplate is that perhaps the jews who had moved northwards into germania in the very early part of the medieval period were some of the least clannish people up in that region, by virtue of the fact that they might’ve had a pretty heavy (outbred) roman ancestry while the northerners had barely begun to outbreed yet. i have to admit that this idea amuses me. (~_^) (just like the thought that much of the european introgression into african-americans likely came from the quite clannish ancestors of our southerners. heh.)

unfortunately, i don’t know what the mating patterns of jews in the levant (or elsewhere) looked like in second or first centuries b.c. not sure that we can guess by biblical proscriptions like those in leviticus either. those were from an earlier time, so it’s not certain they were being followed by our guys in italy. and there was a lot of behavioral variety among jews during this era, too — everything from hellenized jews to pharisees and sadducees, not to mention the jews who thought that jesus and his (universalistic) ideas were pretty cool, so i suspect that there must’ve been all sorts of mating patterns in the middle east at the time. so who knows how clannish (or not) the jews in rome were. no idea.

finally, icymi, i think the subsequent mating patterns of ashkenazi jews went like this. Further Research is RequiredTM.

in any case, mating patterns — and marriage traditions — matter.

see also: Genes Suggest European Women at Root of Ashkenazi Family Tree and Did Modern Jews Originate in Italy?

previously: what did the romans ever do for us? and historic mating patterns of ashkenazi jews

(note: comments do not require an email. roman jewish dude.)

i’ve been trying to think through polygamy and if there’s any potential there for the selection for clannishness like i think there is with long-term cousin marriage. (i think i might have sprained a parietal lobe while doing so. (*^_^*) ) i very much have subsaharan african societies in mind here, but, of course, polygamy occurs elsewhere, too.

on the surface it seems obvious that long-term polygamy ought to set the stage for the possible selection for clannish behaviors like cousin marriage (imho) does. like repeated cousin marriage, strict polygamy ought to narrow the relatedness within a population — the result of strict polygamy should be a greater number of half-siblings in a population than in a randomly-mating population, and, of course, half-siblings are more closely related to one another than non-siblings, so a society full of half-siblings could potentially lead to an accelerated selection for nepotistic altruism in a way similar to cousin marrying societies.

however, one big difference is that in polygamous societies generally — even in subsaharan african societies (where there’s a lot of polygamy) — people do not marry/mate with their half-siblings. (it does occasionally happen in some subsaharan societies, but only occasionally.) so, unlike in cousin-marriage societies, “genes for nepostistic altruism” (whatever they might be) might *not* become concentrated in family lineages. yes, there are a lot of half-siblings in polygamous societies, but any particular nepostistic altruism (“clannishness”) genes they might have (gotten from their fathers) will get diluted as they move out into the general population and marry non-relatives. if polygamy isn’t a driver of accelerated selection for nepotistic altruism (and i’ve rather persuaded myself that it isn’t), that could explain why subsaharan africans are generally pretty civic-minded, comparatively speaking. (the poor outcomes seen in african nations are perhaps more the result of other factors like low iq, high disease rates, etc., rather than clannishness. dunno. Further Research is RequiredTM.)

i should note here that polygamy in subsaharan africa is extremely variegated — in some societies, it’s typical for the first wife to actually be a cousin, and then the rest not. so there can be a layer of cousin marriage in amongst the polygamy. in other societies, cousin marriage is completely avoided. in yet other societies, the series of wives might be sisters (sororal polygyny), which makes all the offspring not only half-siblings (because they have the same father) but also cousins (because their mothers are sisters). here you would think that any selection for nepotistic altruism should very much be amplified. of course, in many subsaharan african societies — especially the polygamous ones — there’s often a lot of hanky-panky going on, so not all of the siblings will truly be half-siblings, etc. that’ll dilute your genes for nepotistic altruism right there.

another thing i also thought of regarding subsaharan and/or polygamous societies is the fact that all of the half-siblings don’t always grow up together. in patrifocal polygamous societies, yes — there you’ll have one man living with all of his wives (poor fellow!) and all of his kids, so all the half-siblings will be raised in the same place and interact with one another — and, presumably, continue to do so as adults. in matrifocal societies, a mother and her children reside with the mother’s family, not her husband and his family. this occurs in some polygamous societies, too.

it seems to me that, even if polygamy was a driver of accelerated selection for nepotistic altruism, such selection couldn’t possibly happen if the carriers of the clannishness genes don’t interact. if the half-siblings from polygamous unions don’t grow up together, or don’t interact much as adults, but rather with their (ordinary, i.e. not inbred) cousins, how would clannishness be selected for? it wouldn’t, i don’t think. or it wouldn’t be selected for in an amplified, accelerated way (which is what i think happens in the long-term cousin marriage scenario).

and that’s as far as i got with thinking through polygamy (i shall return to this topic, i’m sure). but thinking about the patrifocal vs. matrifocal family types got me to thinking about something else.

thought experiment: let’s say you eliminate cousin marriage from a population, but don’t eliminate the extended family. say you get rid of the inbreeding, but individuals continue to interact mostly with their close (extended) family members — more so than with the other members of society who are unrelated to them. you would think that it would take longer for clannishness to disappear — for “genes for nepostistic altruism” to get diluted in the population — than in a society where both cousin marriage AND the extended family were simultaneously eliminated.

i am, of course, talking about medieval western versus eastern europe here. the extended family was eliminated quite early in the middle ages in western europe via manorialism along with cousin marriage (serious changes to both were well underway in western europe by the 800s). in eastern europe, the cousin marriage bans appeared later simply because christianity had arrived later. and, especially the further east one goes (like into russia), the fewer pressures there were to eliminate the extended family. quite the opposite, really. for example, this was the situation in the baltic regions, including belorussia, in ca. the fifteenth century [pg. 440]:

a “…’kinship holding’, was collectively held by the extended family. Rural settlements often contained more than one kinship holding, and each holding was in turn subdivided among smaller households within the extended family….”

and in russia as late as the late seventeenth and early eighteenth centuries [pg. 444]:

“Russian manorialism was distinctive in several important ways…. In Russia…it was the peasant commune that allocated these taxes and obligations among the households. The village commune in Russia had emerged in the late seventeenth or early eighteenth centuries in response to increasing demands from the state and the landowning elite; peasant communes not only allocated obligations, but also chose their officials, held court, selected recruits for conscription levies, and kept written records of their activities. The communal clerk was sometimes the only member of his commune who could read and write….

“[O]n Russian manors, where hired labour was often not available, the peasant family had to personally perform labour obligations at the same time that it worked its own farm. This required large, often multi-generational, households with enough labour capacity to serve the simultaneous needs of both the manorial economy and the family farm…. As Steven Hoch has shown, however, life in the large household was hardly a rural idyll; household patriarchs formed a communal elite that ruled with despotic brutality, ruthlessly exploiting their families and denying any autonomy to the adults under them. At the same time, however, the large household also protected the peasant family from ruin.”

(hmmm. ever wonder where the russian love for [left-wing] authoritarianism comes from?)

even if eastern europeans/russians began to avoid cousin marriage around, say, 1000 (conversion to christianity), they didn’t quit residing in extended families and mostly interacting with their extended family members until, like, yesterday. (again, this pattern appears to be more pronounced the further east one travels.) so the dilution of nepotistic altruism genes in eastern european populations — via nepotistic behaviors being misapplied to individuals not sharing the same altruism genes (i.e. unrelated individuals) — didn’t happen as quickly as it did in western europe where people began regularly interacting with non-kin much earlier in the middle ages.

family types matter.

that’s all i’ve got for you for now. more soon! (^_^)

previously: start here and cousin marriage in sub-saharan africa and fulani, hausa, igbo, and yoruba mating patterns

(note: comments do not require an email. russian peasants.)

further to the point of when did the arabs start marrying their fathers’ brothers’ daughters (fbd marriage), from kudelin (2005) – “Family-Matrimonal Relations in the 5th-7th Centuries Arabia and Their Reflection in the Early Arabic Poetry” [pgs. 8-9]:

“According to one point of view, in the 5th-7th century Arabia there was a decay of the communal-clan system which was reflected, in particular, in the ‘tendency towards isolation of a consanguine group by regulating family and matrimonial relations’ with the transformation of such group from an exogamic into an endogamous one. At that period the exogamic form of marriage was gradually losing its ‘oneness and ubiquity’ and edogamy was becoming firmly established. Obviously, during some period of time both forms of marriage coexisted simultaneously….

“Consistent introduction of paternal relations and the distribution of endogamy lead to such well-known form of matrimonial relations as [fbd] marriage which prevailed on the Arabic Peninsula from the 6th-7th century. In the conditions of the growing role of endogamy in this period the most suitable spouses in the Arabic society were ‘a son of an uncle on the father’s side’ (*ibn ‘amm*) and ‘a daughter of an uncle on the father’s side (*bint ‘amm*). If a girl did not have a first cousin, the right to marry her passed to the patrilineal cousins of further degrees. Usually the right did not pass further than the girl’s cousins of the third or fourth degrees…. In case of divorce, the right for the woman passed to other patrilineal cousins, beginning from the closest degree of kinship. An agnatic cousin had the right not to marry his relative, while she could not marry anyone else without his consent. An exterior competitor had to ask a patrilineal cousin for his permission and even pay him ‘compensation’….

“The coexistence of the exogamic and the endogamous forms of marriage in the 5th-7th century Arabia was reflected in the early Arabic poetry and determined its uniqueness.”

so it looks as though that, thanks to a quirky twist of history (the fall of the roman empire, perhaps?), the arabs adopted the form of cousin marriage that leads to the most inbreeding (fbd marriage) at just around the same time that europeans (especially northwest europeans) began to abandon cousin marriage altogether. how’s THAT for a clash of civilizations?!

there should be more on this here in robertson smith’s Kinship and Marriage in Early Arabia, which i haven’t looked at yet.

around three or four hundred years after europeans started taking the medieval church’s cousin marriage bans seriously (ca. the 800s judging by the franks — ymmv), european languages shifted to reflect this change in mating patterns. a general term for “cousins” (and aunts and uncles) became the norm, replacing the older terms which specified “mother’s brother’s daughter” or whatever. it was no longer necessary to distinguish the “bint ‘amm” (father’s brother’s daughter in arabic) or “biǎo” cousins (cousins other than those descended from the father’s brother in chinese [mandarin?]) because all cousins were now off limits as far as marriage was concerned. this linguistic shift occurred between the twelfth and fifteenth centuries in german and also happened in english, french, etc. (interestingly, a similar linguistic shift happened in ancient greek, indicating…?)

the funny thing is, though, that the same linguistic shift also happened in italian, even though plenty of (especially southern) italians kept right on marrying their cousins — up until, like, yesterday. well, now i’ve stumbled across some historic regional differences in kinship terminology in italy. from “Land, Kinship, and Consanguineous Marriage in Italy From the Seventeenth To the Nineteenth Centuries” [pgs. 532-533]:

“In a rural town of Calabria in the province of Catanzaro, patrilateral parallel cousins were called *cugini giusti* (right cousins), or *surrea* and *frateu* in the case of the patrilateral parallel female and male cousins, respectively….

“At Prodo, in Umbria, we find virtually the same terminology as in Calabria. The strongest bond was between the males; patrilateral parallel cousins were called ‘brother-cousins,’ while others were simply called cousins….

“In Desulo, first cousins through brothers were known as *karrales*, and even second cousins, the sons of *karrales*, were referred to as *ermanos primargios*.”

so there you go. and there’s only something on the order of a million and one dialects in italy, so who knows how many different terms there might be for cousins in “italian” (and how those terms might differ regionally)?

from anglo-saxon england, from the laws of wulfstan (d.1023), apparently the punishment (or one of the punishments) for violating the incest laws was a fine — a fine reckoned based upon how closely you were related to your partner in crime. sounds like it was a bit like applying some sort of wergeld calculation in order to try to enforce the cousin marriage bans. never heard this before [pg. 227]:

“There is particular concern and precision in the laws associated with Wulfstan: ‘if anyone commits incest, he is to pay compensation according to the degree of relationship, whether by wergeld or by fine or by all his possessions. It is not equal whether a man has intercourse with his sister, or with a more distant relation.’ Laws composed by Wulfstan prohibited marriage ‘within the sixth degree of relationship, that is within the fourth knee [*cneowe*]’, thus prohibiting marriage to fourth cousins, or marriage ‘with the widow of a man as nearly related to him as this’.”


(note: comments do not require an email. wulfstan.)


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