inbreeding and the evolution of altruistic behavior

michael wade (the beetle guy) and felix breden worked up some mathematical models of the possible frequencies of “genes for altruism” in several different types of inbreeding populations.

they took different degrees of inbreeding/outbreeding …

– mating with oneself or a clone (100% related)
– mating with a sibling (50% related)
– mating with a more distant relative (20% related, i.e. not quite half-siblings)
– no inbreeding at all (0% related)

… and via wizardry (i.e. advanced algebra) they worked out how “genes for altruism” would fare in each of these populations over the course of many generations. in other words, would altruism genes become more frequent or not in these various populations?

they factored in different parameters such as whether the gene(s) (alleles) in question were dominant or recessive, and whether the selection pressures on the alleles were weak or strong. weak selection apparently refers to those cases in which one “phenotype is slightly advantageous over another.” presumably strong selection means the opposite.

here’s what wade and breden found:

under weak selection — instances in which the altruism alleles only confer slight advantages to those who have them (top two graphs) — the altruism alleles really only increase in any significant way when the individuals self-mate (or mate with clones) or mate with their full-siblings. there’s some increase in altruism alleles in populations where mating occurs between individuals who are almost half-siblings and the alleles are dominant, but that increase really doesn’t become apparent until after several hundred generations of inbreeding.

under strong selection (lower two graphs), again the altruism alleles increase in frequency the most when the individuals self-mate or mate with full-sibs. however, there is also a marked increase in populations where mating occurs between individuals who are almost half-sibs AND the alleles are dominant. in fact, the slope really takes off after just fifty generations or so (solid line, bottom graph).

the authors conclude that: “Increasing the level of inbreeding can greatly increase the rate of change of gene frequency of the altruistic allele.”

i’m interested in the evolution of altruism in humans, though, and not many humans mate with themselves (yet) or even their full-siblings. what’s more common, as we all know by now, is cousin marriage.

mating with your first-cousin in a population where inbreeding doesn’t normally occur means your relatedness to your cousin is probably around 12.5%, much lower than the lowest inbreeding rate that wade and breden looked at (20%). however, in populations where inbreeding is frequent and regular, the coefficients of relatedness are much higher — for instance, some (many?) pakistani and saudi cousins have a coefficient of relatedness of around 22% (11% coefficient of inbreeding x 2). that’s pretty much the same as the lowest degree of inbreeding that wade and breden looked at.

i think it’s apparent by looking at human behavior that inbreeding affects the frequencies of altruism alleles in different human populations, but since we don’t even know what those alleles are yet, this hasn’t been proven one hundred percent. if wade and breden did their sums right, then my guess is that (at least some) altruism alleles in humans must be dominant and must confer a good deal of advantage to those who have them. in other words, if we could graph the frequencies of altruism alleles in humans who marry their cousins regularly over time, i think they would look something like the bottom graph above, although perhaps with a trajectory that wasn’t quite so sharp (since in no population does cousin marriage happen one hundred percent of the time in every generation).

the arabs, for example, have been marrying their first-cousins (often double-first-cousins) since at least mohammed’s days, or something like 1400 years ago. if we take a very conservative generation length as twenty-five years, that’s roughly 56 generations of inbreeding up to the present. at least. plenty of time, according to wade and breden, for altruism alleles to increase in that population — provided the alleles are dominant and the selection is strong.

a couple of other things to keep in mind: 1) like genes for height or intelligence, there are probably many genes for altruism, so we have to imagine some sort of cumulative effect of many genes on human behavior, i.e. we’d have to draw many charts to map the frequencies of many genes; 2) individuals in a population might share lots of alleles for reasons other than recent inbreeding, such as a population’s ancestors having gone through a bottleneck at some point in the past. you’d think that that could also contribute to the number of shared altruism alleles in a population.

update 04/30: see also more on inbreeding and the evolution of altruistic behavior

update 05/30: see also inbreeding and the evolution of altruistic behavior ii

previously: technical stuff and which altruism genes?

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english individualism ii

i’ve started reading alan macfarlane’s “The Origins of English Individualism” in which macfarlane makes the case that english individualism stretches back to (at least) the 1200s. haven’t finished it yet — but luke reminded me of this article by macfarlane: “The Origins of English Individualism: Some Surprises” [pdf] (thnx, luke!).

in the article (and the book), macfarlane argues that during the medieval period — going as far back as the 1200s — the english were not peasants, unlike most other europeans (and many other populations around the world), but rather individual farmers for whom the nuclear family was the most important kinship group. he describes a peasant society thusly [pgs. 255-56]:

“The basic element of society is not the individual, but the family, which acts as a unit of ownership, production and consumption. Parents and children are also co-owners and co-workers. The separation between the household and the economy … has not occurred. For our purposes, the central feature is that ownership is not individualized. It was not the single individual who exclusively owned the productive resources, but rather the household. The present occupants of the land are managers of an estate; they cannot disinherit their heirs, the father is merely the leader of a production team…. Land is not viewed as a commodity which can be easily bought and sold. There is a strong emotional identification with a particular geographical area. Consequently, there is rather little geographical mobility; any movement to the towns is one-way, with few people returning to the countryside. The villages are thus filled with people linked by real and fictive kin ties and marriages often occur over a short distance…. The society is also divided into many self-contained, though identical, local communities, with their own customs, dialect and beliefs.”

that the english were not peasants has several implications, according to macfarlane, including [pgs. 262-63]:

“[I]f the argument is correct, one of the ‘most thoroughly investigated of all peasantries in history’ turns out to be not a peasantry at all. The classical example of the transition of a ‘feudal,’ peasant-based society into a new, capitalist, system turns out to be a deviant case.”

in other words, if we want to understand how the first society to become an industrialized one did so relatively painlessly (maybe why they did so at all) — and if we want to figure out how other societies might follow suit — it’s a good idea to truly understand what pre-industrial english society was like, i.e. that it was not a peasant society made up of extended-families and strong kinship connections, but had, in fact, been an atomized, individualistic society for quite a long time before industrialization.

macfarlane wrote these works on individualism in england in the late stone age 1970s** and, at the time, there wasn’t all that much evidence to back up his argument. plenty of historical research since then supports his idea. i posted about one example of such research here.

there is also a very good summing up of what fourteenth and fifteenth english society was like in barbara hanawalt’s “The Ties That Bound: Peasant Families in Medieval England” published in 1989. in this book, hanawalt describes anglo-saxon (i.e. early medieval) kinship terminology [pgs. 79-80]:

“Kinship terminology in English is not very diversified. Anthropologists expect to find rather elaborate kinship terminology in societies where kinship plays an important part of an individual’s life, but even Anglo-Saxon had few words to describe any ties but those to the nuclear family. They did not even have a word for cousin until the introduction of French. This paucity of kinship terms is in startling contrast to the continent, which had extensions to fourth cousins. The minimal kinship terms already common in the seventh and eighth centuries in England did not appear on the continent until after the Black Death.

“Anglo-Saxon kin terminology had an easy flexibility, with the same word used for grandson and nephew, granddaughter, and niece. The interchangeability of terms suggests that the modes of behavior toward these family relationships were similar. Nuclear-family terms were virtually the only ones that were important, and compounds based on them formed lineal ascent and descent. The only extended family member meriting a unique appellation was the father’s brother, indicating a special relationship with the spear-side uncle.

“Middle and modern English adopted from the Normans the French root words for kinship terms such as uncle and aunt, but no more complicated term than cousin was used for more distant kin. Although the special term for a relationship to father’s brother was dropped, the kinship terminology perpetuated Anglo-Saxon practices. Thus we continued to form clumsy compounds such as grandmother or fourth cousin once removed. The lack of words for extended kin indicates that they were not a part of daily parlance because they were not needed….”

a linguistic shift in kinship terminology in german did, indeed, happen during the medieval period starting in the twelfth century. in the case of german, all cousins became just “cousin” (or whatever it is in german) because all cousins were off-limits to marry. before that, the germans used to distinguish between cousins on the mother’s side and cousins on the father’s side, likely because it was preferential to marry one over the other — or forbidden to marry one over the other. (arabs today, for instance, have separate terms for all the cousins since they still prefer to marry the father’s brother’s daughter. the chinese, too, distinguish between certain cousins.)

if the anglo-saxon terminology was already simplified as early as the seventh or eighth centuries (and i hadn’t read that until tonight), that is remarkable. that would mean that either: 1) the church’s ban on cousin marriage took hold very strongly amongst the anglo-saxons in the 600s (see below) — this seems unlikely; or 2) that anglo-saxon kinship was already very loose before they adopted christianity.

i’m not sure where hanawalt got her info on anglo-saxon kinship terminology. i think it might be from here. i’m going to double-check this since it’s so unlike the rest of the germanic tribes — but maybe it’s correct! if so, maybe this is related to the distribution of todd’s absolute nuclear families? that the anglo-saxons have, in fact, been outbreeding for a very, very long time? dunno.


christianity was first brought to britain by some of the romans, but it had to be reintroduced to the anglo-saxons (and jutes) once they got there. we’re talking the 600s a.d., so any adoption by the anglo-saxons of the church’s bans on inbreeding would date from after that time.

via a series of letters from augustine of canterbury (late 500s-early 600s) to the pope back in rome, we know that the anglo-saxons at the time of conversion were marrying their cousins [pgs. 34-37], so that seems to contradict hanawalt. my guess still is that, beginning in the 600s (and the start was probably slow), the anglo-saxons, et. al., began loosening their genetic ties until by at least as early as the 1200s (who knows? might’ve been earlier) those ties were loose enough so that the english, as we can call them by then, were behaving like a bunch of individuals and not a bunch of clannish peasants. on the other hand, maybe the anglo-saxons had a head start over other europeans.

undoubtedly there were selection pressures on the medieval english population related to altruistic behaviors other than just their mating patterns which got them from point a — clannish/tribal peasants — to point b — atomized individualistic farmers/craftsmen/traders. but outbreeding was definitely one of them and, i’d argue, the most important one since you can’t even begin down the road towards point b without it (i think).

interestingly, marriage in the late fourteenth and fifteenth centuries in parts of rural northern italy was also, like medieval england, very exogamous.

previously: english individualism i and but what about the english? and exogamous marriage in northern medieval italy

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sh*t people believe

the other day i poked a bit of fun at some folks who believe in a cargo cult, and then i got concerned that ya’ll might think i go around making fun of people who are — let’s admit it — not very bright. i want you to know that nothing could be futher from the truth. i laugh at EVERYbody! all of us. as far as i can tell, humans will believe anything.


by way of example, here is a short list of things that people believe — and this is just the tip of the tip of the iceberg:

– that the world was created in seven days
– that a bird created everything
– that a chicken created the land
– that a wagtail created the land
– that the world was created from birds’ eggs
– that humans are made of corn
– that humans are descended from bears
– that the earth sits upon a big tree
– that the earth sits upon the back of a big turtle
– that the earth is flat
– that the earth is the center of the universe
– that the sun is the center of the universe
– that they are the center of the universe
– that magic is real
– that some people are magical
– that the parts of some dead animals are magical
– that the parts of some dead people are magical
– that some smelly socks are magical
– that some woman gave birth to a child without having sex
– that another guy was conceived in a highly unusual way, too
– that a really old lady gave birth to a child
– that one guy was born an old man
– that you can get pregnant from a bunch of feathers
– that you can get prenant from a swan
– that a piece of bread can turn into the flesh of a man-god
– that there is a man-god
– that there is a god
– that there are many gods
– that there definitely isn’t a god
– that you can persuade people who believe in god to believe that there isn’t one
– that they’re definitely not brains in vats
– that there is life after death
– that dead people will need their things in the next life
– that dead people will need money in the next life (and that you can send it to them)
– that they’ll come back to haunt you if you don’t
– that there are many lives after death (gonna need a lot of cash)
– that little green men are drawing pretty pictures in fields
– that the little green men were invading on october 30, 1938
– that the world is gonna end this year (omg!)
– that the world is gonna end in 2060 (whew!)
– that the world is gonna end in 2240. or 2280. or 3797. (whatever.)
– that some people born in certain years are bad luck
– that certain days are bad luck
– that certain numbers are bad luck
– that certain animals are bad luck (or maybe good luck)
– that certain actions are bad luck
– that you can predict future events from the most mundane things
– that they are rational
– that they aren’t biased
– that they perform better than most
– that they are at all honest with themselves
– that fiat currency has intrinsic value
– that iq isn’t important
– that gender doesn’t make a difference

– that all people everywhere are fundamentally the same in almost every way

(note: comments do not require an email. be more skeptical!)

here’s one i made earlier

i drew this (well, outlined some of the countries on this map!) a couple of weeks ago thinking it might correlate with todd’s family systems or the hajnal line or something, but it doesn’t really seem to. well, maybe. kinda/sorta. or not.

what this is is a map of which european countries have jury trials or not — or something in between.

i based this on this paper here: “A Comparison of Criminial Jury Decision Rules in Democratic Countries” [opens pdf]. the author looked at which countries have jury trials for criminal cases. he defined a jury as: “a group of more than three unelected laypersons who are selected or appointed to sit in judgment on a criminal case at the trial level; such laypersons are not generally ‘professionalized’ jurors and may be involved in deciding questions of fact, law, and/or punishment. Groups of professional lay judges who serve over long periods of time, elected laypersons, and very small numbers of lay assessors sitting with professional judges do not constitute a jury for my purposes here.” iow, he was looking for where you would be judged by a jury of your peers.

the color-code is:

– yellow = countries with (mostly) ‘pure’ juries – a pure jury is one in which jurors “deliberate and issue verdicts apart from professional judges.”

– light green = countries with (substantially) ‘mixed’ juries – a mixed jury is one in which “jurors and judges to deliberate and issue verdicts or sentences together.”

– dark green = countries without criminal juries. *gulp*

here are todd’s family systems again (h/t m.g. @those who can see!):

it could look like places with the authoritarian (“stem”) family system (germany, sweden, czech republic, switzerland partly) prefer authoritarian court systems, i.e. only judge and no juries. but what happened to poland and ireland then? did poland just inherit the german system, and the irish the british one? nations with mixed family systems (france, italy, norway) seem to prefer a mixed court system — maybe. and nations with nuclear families (england, spain) seem to go for jury trials — but not greece (or poland).

maybe there’s something here. dunno. still, it’s awfully interesting to know that you won’t get a jury trial amongst the germanics or (some of) the scandis! wtf?!

(note: comments do not require an email. juries are better, right?)

interracial / interethnic marriage rates up in u.s.

from a new pew survey:

– About 15% of all new marriages in the United States in 2010 were between spouses of a different race or ethnicity from one another, more than double the share in 1980 (6.7%). Among all newlyweds in 2010, 9% of whites, 17% of blacks, 26% of Hispanics and 28% of Asians married out. Looking at all married couples in 2010, regardless of when they married, the share of intermarriages reached an all-time high of 8.4%.

– Gender patterns in intermarriage vary widely. About 24% of all black male newlyweds in 2010 married outside their race, compared with just 9% of black female newlyweds…. Intermarriage rates among white and Hispanic newlyweds do not vary by gender.

– [W]hite/Asian newlyweds of 2008 through 2010 have significantly higher median combined annual earnings ($70,952) than do any other pairing, including both white/white ($60,000) and Asian/Asian ($62,000). When it comes to educational characteristics, more than half of white newlyweds who marry Asians have a college degree, compared with roughly a third of white newlyweds who married whites. Among Hispanics and blacks, newlyweds who married whites tend to have higher educational attainment than do those who married within their own racial or ethnic group.

– Couples formed between an Asian husband and a white wife topped the median earning list among all newlyweds in 2008-2010 ($71,800)…. As for white female newlyweds, those who married a Hispanic or black husband had somewhat lower combined earnings than those who “married in,” while those who married an Asian husband had significantly higher combined earnings.

– Intermarriage in the United States tilts West. About one-in-five (22%) of all newlyweds in Western states married someone of a different race or ethnicity between 2008 and 2010, compared with 14% in the South, 13% in the Northeast and 11% in the Midwest.

– Several studies using government data have found that overall divorce rates are higher for couples who married out than for those who married in….

looks like a big report. lots to read. and data, too (state-by-state even)!

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me and max

weber, that is. (^_^)

here’s a bit from alan macfarlane’s “The Origins of English Individualism” which i started reading last night [pgs. 50-51]:

“Behind Weber’s work there is a general evolutionary model that sees societies originating in a stage at which kinship dominates all life and large ‘clans’ absorb the individual, moving through an intermediate phase in which the larger grouping have been broken down by various pressures, to modern society where the family and kinship no longer dominate economic and social life. In China and India such a movement has never occurred. In China ‘the fetters of the kinship group were never shattered,’ every individual was completely submerged in the clan system, and any nascent move towards individualistic capitalism was crushed by the power of kinship groups, by the intimate link between family and land. In Europe, however, a number of factors worked together to break the original ‘clan’ system, according to Weber. One was Christianity, which encouraged an abstract, non-familistic attitude, stressed the individual believer: ‘every Christian community was basically a confessional association of individual believers, not a ritual association of kinship groups.’ This ‘all-important destruction of the extended family by the Christian communities…’ was the foundation upon which an autonomous bourgeoisie developed in the cities of western Europe. But while Christianity in general was a dissolvent of the earlier state, Protestantism was especially powerful in its attack on the earlier kinship ‘fetters.’ Weber argued that:

“‘[T]he great achievement of ethical religions, above all of the ethical and asceticist sects of Protestantism, was to shatter the fetters of the kinship group. These religions established the superior community of faith and a common ethical way of life in opposition to the community of blood, even to a large extent in opposition to the family.’

“In addition to Christianity and Protestantism, there were other pressures. The growth of towns in the middle ages also put a stress on the individual rather than the wider kinship group. Furthermore, the politcal system of feudalism was incompatible with extended kinship ties; ‘the land is divided by the feudal lord, in independence of clan and kinship…. We may simplify Weber’s ideas into the argument that there had been three stages in the evolution of modern society. First was ‘clan’ society, where kinship was paramount and the basic economic, social and religious unit was a wide group of kin; this had disappeared in north-western Europe by at least the thirteenth century, although traces remained. This was replaced by a second, intermediate, phase in which the basic unit was the household of parents and children…. This configuration was finally destroyed, Weber argues, first in England from the later fifteenth century, and later elsewhere, allowing for the third stage — the separation between family and business and the economic isolation of the individual.”

like i said before, bigger and (much!) better brains than mine have thought long and hard about the individualistic nature of northwest europeans, which stands in stark contrast to just about everybody else on our little planet, and how we got this way. but what most (all?) of them missed is the biology of it.

and that’s O.K.! ’cause they’ve been historians and philosophers and so on, and weren’t really thinking about biology (although it’s high time that they did! and a lot of them now are, which is a good thing.) and max weber was busy, you know, laying the foundations of sociology and other disciplines, so it’s ok that he missed the biology of it.

otherwise, i think he was right on target here. he really identified some of what i think were the major selection pressures on medieval european populations that resulted in their shift from clannish to individualistic societies. macfarlane criticizes weber for getting the timing wrong (i haven’t finished the book yet, but i think this is where he is going) — i.e. that english individualism happened a lot before weber’s suggestion of the fifteenth century — but otherwise i think weber was very much on target.

i think he might’ve been wrong about protestantism, though. weber seems to have been imagining that sentiments and attitudes are mutable in a blank slate kinda way — like these things just float out of the ether or something. obviously this is not the case — people have natures that are innate — and different peoples have different natures (not completely different — we are all human). and, so, to get from clannishness to individualism, you need some change in the nature of the people.

my guess is that this change has to do with, for one thing anyway, genes related to altruistic behaviors — and since altruistic behaviors are related to (heh) relatedness — then the changes in nw european behavior, i think, came from changes in mating patterns (which would’ve changed the relatedness) rather than just some abstract notions like “confessional associations.” in other words, you need to break down — biologically — the clans before you can get to the “confessional associations.”

why do i think weber was wrong about protestantism? many protestant sects — particularly in germany, but interestingly not in scandinavia nor, i think(?), in england (have to check that) — actually reversed the roman catholic church’s edicts on cousin marriage. iow, cousin marriage was once again allowed after luther’s day in large parts of europe (the specifics vary from place to place and time to time), so protestant europe was not the source of the breakdown of genetic ties in europe. it was the catholic church that got that ball rolling. i think that what many of the more ascetic, individualistic protestant sects were (are) were an expression of the newly forged individualistic natures of nw europeans. but, i could be wrong about that.

macfarlane’s quotes from weber come from weber’s “General Economic History,” so i guess that’s another book to add to the list. (^_^)

(note: comments do not require an email. not this max.)

emmanuel todd’s absolute nuclear family

steve sailer posted about the curious distribution of todd’s absolute nuclear family (the yellow bits on the map over here) — this family system, according to todd, is found in the eastern parts of england and scotland, denmark and southern norway, what looks like frisia to me, and brittany. steve points out that all of these were anglo-saxon lands back in the day — except for brittany.

todd (in “The Explanation of Ideology”) describes the absolute nuclear family as having these characteristics:

– no precise inheritance rules, frequent use of wills;
– no cohabitation of married children with their parents;
– no marriage between the children of brothers.

here are a couple excerpts from his chapter on nuclear families:

pg. 100:

“Peter Laslett, with the help of household lists, has thus studied household composition as far back as the sixteenth century, and Alan Macfarlane has extended the analysis back to the thirteenth century by reinterpreting medieval documents about inheritance customs. The result of this research is clear: extended families have never existed in England where, at least since the Middle Ages, the nuclear model has been the dominant form…. What the research conducted in England in the 1960s and 1970s shows is that the individual, in the sociological sense of the word, has always existed in certain regions of Europe.”

well, not always but, rather, since at least the medieval period.

i’ve got alan macfarlane’s “The Origins of English Individualism” sitting on the shelf here. i’m hoping he can shed more light on this anglo individualism/nuclear family thing.

more from todd. pg. 101:

“The dislocation of traditional English and (northern) French societies by a complex process of ubanization, industrialization and the spread of literacy, has been comparatively less painful than in cultures dominated by a family ideal that emphasizes the complementary qualities of parents and children. The rural exodus separates the generations and erodes the core of complex families of the exogamous community and authoritarian models. It has no effect on a system dominated by nuclear households, where the early breakdown of domestic groups is socially acceptable and prepared for by an apprenticeship in individual autonomy from childhood. Urbanization in England started early and was soon complete. By comparison with Germany and Russia which developed later, the process in England seems to have been an easy one. It occurred in a peasant society which was already very flexible.”

previously: “l’explication de l’idéologie” and behind the hajnal line and medieval manoralism and the hajnal line

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