With much confused discussion in the press about lineages and racial inheritances stemming from the publication of Nicholas Wade’s A Troublesome Inheritance, it’s worthwhile to look at an old article on genealogy. From The New Republic, August 6, 2007:
By Steven Pinker
… A fascination with ancestry has long been part of the human condition, from the “begat’s” of the Bible to the Roots miniseries and the restoration of Ellis Island. …
For all its fascination, kinship is a surprisingly neglected topic in the behavioral sciences. A Martian reading a textbook in psychology would get no inkling that human beings treated their relatives any differently from strangers. Many social scientists have gone so far as to claim that kinship is a social construction with no connection to biology. But assuming the creationists are wrong and humans are products of evolution, it would be surprising if our species entirely escaped the powerful forces that shape organisms’ behavior toward their kin. Genetics and evolutionary theory predict that the biology of kinship should have biased our thoughts and emotions about relatives in several ways.
The first is the simple fact that blood relatives are likely to share genes. To the extent that minds are shaped by genomes, relatives are likely to be of like minds. Close relatives, whether raised together or apart, have been found to be correlated in intelligence, personality, tastes, and vices. …
The similarities among blood relatives mean that they are likely to share values, and shared values can lead to easy solidarity because of what ecologists call mutualism and economists call positive externalities. A pair of associates with the same interests can benefit each other just by being selfish–always the most painless route to altruism. If two roommates have similar tastes in music, each will benefit the other every time she brings home a new CD, and each has a reason to value the other’s well-being. To identify a blood relative, then, is to identify a potential soul mate. Adoptees who track down their biological parents and siblings often report an instant solidarity as they quickly discover shared quirks and passions.
There’s both sibling revelry and sibling rivalry (Robert Trivers’ great contribution was to account for familial rivalries using evolutionary theory): people who share a lot also have a lot to fight over, like all the great Brother Wars in pop music history: Everly Brothers, Kinks, Oasis, Creedence, etc. How well have the Van Halens gotten along? (I’ve never met either Van Halen, but the extended families seemed close: Alex’s son was the centerfielder on my son’s baseball team and sometimes Eddie’s son Wolfgang would come to watch his cousin’s ballgames, which seemed like a nice, homey thing among people who must have all sorts of unusual opportunities and pressures.) Similarly, the Koch Brothers have a lot in common, but they often don’t get along with each other. If they were less genetically similar, they’d probably wouldn’t drive each other so crazy.
A more direct tug of shared genes on family emotions comes from the phenomenon that biologists call inclusive fitness, kin selection, and nepotistic altruism. … In traditional societies, genetic relatives are more likely to live together, work together, protect each other, and adopt each other’s orphaned children, and are less likely to attack, feud with, and kill each other. Even in modern societies, which tend to weaken ties of kinship, studies have shown that the more closely two people are genetically related, the more inclined they are to come to each other’s aid, especially in life-or-death situations.
Somebody should do a study of kidney donors and recipients. For example, writer Virginia Postrel donated a kidney to save her friend writer Sally Satel’s life about a decade ago, but mostly I hear of people donating kidneys to close relatives. (There are genetic reasons for greater compatibility among close relatives, but a study could adjust for that.)
Solidarity between pairs of relatives is further amplified by the fact that they have other relatives in common. My brother and I are close not just because each of us has copies of genes in the other, but because we share a mother, a father, a sister, and nieces and nephews, so our genetic interests are yoked together. This triangular altruism also explains why non-blood relatives can feel various degrees of affinity–most dramatically in the case of a husband and wife, whose long-term genetic interests are fused in their children, and to a lesser extent in the case of stepsiblings and in-laws,
I’d add the phenomenon of quasi- or pseudo-cousins, which seems seldom discussed. For example, when I moved to Chicago in 1982, I got an apartment with my cousin R., who isn’t really my cousin: he’s my mother’s best friend’s son. He knew a girl named L who introduced me to her cousin, whom I married. Except my wife isn’t exactly L’s first cousin, they are first cousins once removed, but are the same age so they grew up like cousins.
I suspect that there are a lot of social networks like this based upon affiliations that aren’t technically kin relations or not quite as close genealogically as they seem, but they make use of the behavioral modules evolved for kin relations.
as long as they are not in zero-sum competition for the common relative’s affections or resources.
Children often don’t like their widowed parents remarrying for this reason: a threat to the inheritance. For example, after my mother’s ex-brother-in-law (my mother’s first husband was killed on Iwo Jima in 1945, and we were close to her former in-laws for the rest of the century) was widowed, he got engaged to a middle-aged lady. His kids were furious at this gold-digger. So, my mom finally had her ex-brother-in-law’s fiance over for an inspection. She turned out to be a very nice widow who wasn’t interested in stealing the kids’ inheritance at all.
But now comes a crucial bit of arithmetic. In sexually reproducing species, every organism has two parents, and every organism makes up half the parentage of each of its offspring. The result is that as people are separated by more generations, they are related to an exponentially greater number of people, and their genetic relatedness to any of them plummets, also exponentially. Going upward, you have two parents, with whom you share half your genes apiece; four grandparents, with whom you share one-quarter; eight great-grandparents; sixteen great-great-grandparents; and so on. Going downward, if you and your descendants have two children apiece, then you’ll have four grandchildren, eight great-grandchildren, and so on. And going sideways, you share half your genes with your sibling, one-eighth with each of your first cousins, one-thirty-second with each of your second cousins, and so on.
Exponential functions quickly explode to unimaginable magnitudes or peter out to infinitesimal ones, and the inability of our intuition to keep track of them leads to many paradoxes of kinship. In an old Smothers Brothers routine, Tommy explained why the population explosion is a myth. We have two parents, he noted, and four grandparents, eight great-grandparents, sixteen great-great-grandparents, and so on. The further back you go, the more ancestors you have. So, he concluded, “The population isn’t growing–it’s tapering off!” Like many of their jokes, this one depends on a subtle truth. If you assume twenty-five years per generation, you can calculate that you had around three billion ancestors at the time of the signing of the Magna Carta, one hundred billion during the Norman invasion, two quintillion at the fall of the Roman Empire, and around 1,200,000,000,000,000,000,000,000 at the birth of Jesus. Needless to say, the Earth did not contain a fraction of that many people in those eras.
The paradox is resolved by the realization that our ancestors must have married their cousins of various distances and removes, so that vast numbers of the slots in one’s family tree are filled by the same individuals. …
But the other reason is that our sense of kinship is triggered not by relatedness itself, but by the perception of relatedness. After all, when we encounter a possible relative, we generally do not demand a cheek swab and analyze its DNA. Instead we rely on cues that in the evolutionary past tended to correlate with relatedness. Recent experiments by Debra Lieberman, John Tooby, and Leda Cosmides have shown that two kinds of life experience are crucial in triggering family feelings toward siblings (such as doing them favors and being willing to donate a kidney to them). One consists of observing the sibling being cared for by one’s mother when it was an infant. The other is having grown up in the same household as the sibling. That is why children adopted at birth can be emotionally close to their parents and siblings despite the lack of genetic overlap: the early close association sets off everyone’s kinship detectors, a kind of benign illusion. And because these experiences also trigger repugnance at the thought of having sex with the relative, incest avoidance is not perfectly correlated with biological relatedness. Unrelated children who are brought up together (like nursery-mates in kibbutzim) tend to shun each other as sexual partners in adulthood, as if they were siblings. And children who meet a parent or sibling for the first time in adulthood can find him or her sexually attractive, as the novelist Kathryn Harrison recounted in The Kiss, her memoir of a four-year affair with her father.
I didn’t really need that example.
… In large part, the institutions of modernity depend on a dissolution of family ties. It is hard to run an effective organization if you cannot fire the knucklehead brother-in-law forced on you by your wife’s family, nor can civil society function if the instruments of government are treated as the spoils of the most powerful local clan. Public safety is more effectively guaranteed by a disinterested police and court system than by a threat that your male relatives will avenge your murder, and national defense above all depends on the willingness of citizens to neglect the bonds of kinship. In The Godfather: Part II, Sonny Corleone upbraids Michael for his sympathy with the men who enlisted after Pearl Harbor: “They’re saps because they risk their lives for strangers. Your country ain’t your blood. Remember that.”
In the struggle between society and family, the exponential mathematics of kinship ordinarily works to the advantage of society. As time passes or groups get larger, family trees intertwine, dynasties dissipate, and nepotistic emotions get diluted. But families can defend themselves with a potent tactic: they can graft the twig tips of the family tree together by cousin marriage. …
In January 2003, during the buildup to the war in Iraq, the journalist and blogger Steven Sailer published an article in The American Conservative in which he warned readers about a feature of that country that had been ignored in the ongoing debate. As in many traditional Middle Eastern societies, Iraqis tend to marry their cousins. About half of all marriages are consanguineous (including that of Saddam Hussein, who filled many government positions with his relatives from Tikrit). The connection between Iraqis’ strong family ties and their tribalism, corruption, and lack of commitment to an overarching nation had long been noted by those familiar with the country. In 1931, King Faisal described his subjects as “devoid of any patriotic idea … connected by no common tie, giving ear to evil; prone to anarchy, and perpetually ready to rise against any government whatsoever.” Sailer presciently suggested that Iraqi family structure and its mismatch with the sensibilities of civil society would frustrate any attempt at democratic nation-building.
Read the whole thing there. I then extended Pinker’s logic to racial topics in VDARE here.
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I guess your father was of a lower status than your mother’s first husband, since if the husband is someone with any kind of status he will ask the wife to have nothing to do with the former in-laws.
Also, Pinker is childless like Galton. For some reason childless people tend to be more interested in this kind of topic.
http://www.unz.com/isteve/pinker-on-genealogy/#comment-566630
Sailer and Unz….long lost cousins?