How many were already fathers?

Hanging outside Newgate Prison (Wikicommons)

In England, executions peaked between 1500 and 1750 at 1 to 2% of all men of each generation. Were there genetic consequences? Were propensities for violence being removed from the gene pool? Did the English population become kinder and gentler? Such is the argument I made in a recent paper with Henry Harpending.

In this column, I will address a second criticism made against this argument: Many executed criminals already had children, so execution came too late in their lives to change the makeup of the next generation.

Reproductive success

Hayward (2013) provides a sample of 198 criminals who were executed in the early 1700s. Of this total, only 32 (16%) had children at the time of execution, and 12 of them had one child each. Their reproductive success breaks down as follows:

Family size — # executed criminals (out of 198)

1 child  -    12

2 children - 3

3 children - 3

3-4 children - 1

5 children - 3

9 children - 1

"children" - 9

Although the above figures include illegitimate children, some executed criminals may have had offspring that they were unaware of or didn't wish to acknowledge. So we may be underestimating their reproductive success. But what were the chances of such children surviving to adulthood and reproducing? In pre-1840 England, 30% of all children were dead by the age of 15; in pre-1800 London, only 42% of all boys reached the age of 25 (Clark and Cummins, 2009). Chances of survival were undoubtedly even lower for children raised by single parents.

Here and there, we find references to high infantile mortality among the progeny of executed criminals. The coiner John Johnson regretted "the heavy misfortune he had brought upon himself and family, two of his children dying during the time of his imprisonment, and his wife and third child coming upon the parish." Prospects seemed better for childless widows, as noted in the life story of the thief Robert Perkins: "He said he died with less reluctance because his ruin involved nobody but himself, he leaving no children behind him, and his wife being young enough to get a living honestly" (Hayward, 2013).

Reproductive success was also curbed by marital instability. The footpad Joseph Ward was married for all of two days:

The very next morning after their wedding, Madam prevailed on him to slip on an old coat and take a walk by the house which she had shown him for her uncle's. He was no sooner out of doors, but she gave the sign to some of her accomplices, who in a quarter of an hour's time helped her to strip the lodging not only of all which belonged to Ward, but of some things of value that belonged to the people of the house. (Hayward, 2013)

In these life stories, the word "wife" is often qualified: "lived as wife," "whom he called his wife," "who passed for his wife," "he at that time owned for his wife," etc. Overall, only 40% of the executed criminals had been married: 38% of the men and 80% of the women.

Age structure

The age composition of the executed criminals suggests another reason for their low reproductive success. More than half were put to death before the age of 30. Since the mean age of first marriage for English men at that time was 27 (Wikipedia, 2015b), it's likely that most of these criminals were still trying to amass enough resources to get married and start a family.

Ages  — # executed criminals (out of 198)

10 - 19 years - 18

20 - 29 years - 88

30 - 39 years - 41

40 - 49 years - 20

50 - 59 years - 6

60 - 69 years - 0

70 + years - 1

Many criminals may have planned to steal enough money to give up crime and lead a straight life. Such plans came to nought for the thief John Little:

[...] the money which they amass by such unrighteous dealings never thrives with them; that though they thieve continually, they are, notwithstanding that, always in want, pressed on every side with fears and dangers, and never at liberty from the uneasy apprehensions of having incurred the displeasure of God, as well as run themselves into the punishments inflicted by the law. To these general terrors there was added, to Little, the distracting fears of a discovery from the rash and impetuous tempers of his associates, who were continually defrauding one another in their shares of the booty, and then quarrelling, fighting, threatening, and what not, till Little sometimes at the expense of his own allotment, reconciled and put them in humour. (Hayward, 2013)

Nonetheless, it is possible that others would have saved up a "nest egg," started a family, and moved on to a respectable life. Dick Turpin, for instance, was able to abandon highway robbery and pose as a horse trader. His ruse ultimately failed because he continued to run afoul of the law (Wikipedia, 2015a). The extent of this life strategy is difficult to measure because the existing information almost wholly concerns those criminals who were caught and executed.

Conclusion

Clearly, some of the executed criminals had already reproduced, but the overall reproductive success was very low, and probably lower still if we adjust for infantile mortality. Instead of arguing that executions had little impact on the gene pool because too many of the executed had already reproduced, one could argue the opposite: the genetic impact was inconsequential because so few would have reproduced anyway, even if allowed to live out their lives.

Reproductive success was highly variable in the criminal underclass. Many would have had few children with or without being sent to the gallows. But some would have done much better. At the age of 26, the highwayman William Miller already had two children by two wives, and many other women gravitated around him, even as he prepared for death: "Yet in the midst of these tokens of penitence and contrition several women came still about him." At the age of 25, the murderer Captain Stanley had fathered three or four children by one woman and was looking for a new wife. One might also wonder about some of the executed teenagers. At the age of 19, the footpad Richard Whittingham was already married, though still childless, and the thief William Bourne likewise at the age of 18.

In an earlier England, such young men would have done well reproductively, as leaders of warrior bands. But that England no longer existed, and criminal gangs offered the only outlet for engaging in plunder, violence, and debauchery with other young men.

References

Clark, G. and N. Cummins. (2009). Disease and Development: Historical and Contemporary Perspectives. Urbanization, Mortality, and Fertility in Malthusian England, American Economic Review: Papers & Proceedings, 99,2, 242-247

http://neilcummins.com/Papers/AER_2009.pdf

Frost, P. and H. Harpending. (2015). Western Europe, state formation, and genetic pacification, Evolutionary Psychology, 13, 230-243. http://www.epjournal.net/articles/western-europe-state-formation-and-genetic-pacification/  

Hayward, A.L. (2013[1735]). Lives of the Most Remarkable Criminals - who Have Been Condemned and Executed for Murder, the Highway, Housebreaking, Street Robberies, Coining Or Other Offences, Routledge.

http://www.gutenberg.org/files/13097/13097-h/13097-h.htm

Wikipedia. (2015a). Dick Turpin

http://en.wikipedia.org/wiki/Dick_Turpin

Wikipedia (2015b). Western European Marriage Pattern

http://en.wikipedia.org/wiki/Western_European_marriage_pattern

French lesson

A burning car during the 2005 riots. (Wikicommons: Strologoff)

 

The gruesome attack on Charlie Hebdo has earned condemnation around the world. It has been called "cowardly" and "evil" by Barack Obama, "a barbaric act" by Stephen Harper, and an "infamy" by François Hollande.

Yes, violence is serious. It's a crime when done by an individual and war when done by a country. It's a grave breach of the rules that govern our society. Whatever differences we may have, they are to be settled peacefully, through the courts if need be. Violence is just not to be done.

Except it increasingly is. The attack on Charlie Hebdo is not an isolated incident. It's part of a worsening trend of violence by people described as jeunes [youths] or simply not described at all. That was not the case in the recent attack; the victims were too well known. But it is generally the case, and this conspiracy of silence has become something of a social norm, particularly in the media.

Yet statistics do exist, notably those compiled by the Gendarmerie. According to French criminologist Xavier Raufer:

The criminality we are talking about is the kind that is making life unbearable for the population: burglaries, thefts of all sorts, assaults, violent thefts without firearms, etc. In these specific cases, 7 out of 10 of these crimes are committed by people who in one way or another have an immigrant background, either directly (first generation on French territory, with or without a residence permit) or indirectly (second generation). (Chevrier and Raufer, 2014)

The word "immigrant" is misleading. Many if not most are French-born, and they tend to come much more from some immigrant groups than from others. In general, they are young men of North African or sub-Saharan African background, plus smaller numbers of Roma and Albanians. 

This criminality, when not being denied, is usually put down to social marginalization and lack of integration. Yet the reverse is closer to the truth. The typical French person is an individual in a sea of individuals, whereas immigrant communities enjoy strong social networks and a keen sense of solidarity. This is one of the reasons given why the targets of the crime wave are so often Français de souche [old-stock French]. "Whites don't stick up for each other."

Personal violence in human societies

In France, as in other Western countries, personal violence is criminalized and even pathologized. The young violent male is said to be "sick." Or "deprived." He has not had a chance to get a good job and lead a nice quiet life.

Yet this is not how young violent males perceive themselves or, for that matter, how most human societies have perceived them down through the ages. Indeed, early societies accepted the legitimacy of personal violence. Each adult male had the right to defend himself and his kin with whatever violence he deemed necessary. The term "self-defence" is used loosely here—a man could react violently to a lack of respect or to slurs on his honor or the honor of his ancestors. There were courts to arbitrate this sort of dispute but they typically had no power, enforcement of court rulings being left to the aggrieved party and his male kin. In general, violence was a socially approved way to prove one’s manhood, attract potential mates, and gain respect from other men.

Things changed as human societies developed. The State grew in power and increasingly monopolized the legitimate use of violence, thus knocking down the violent young male from hero to zero. This course of action was zealously pursued in Northwest Europe from the 11th century onward (Carbasse, 2011, pp. 36-56). There were two reasons. First, the end of the Dark Ages brought a strengthening of State power, a resumption of trade and, hence, a growing need and ability by the authorities to pacify social relations. Second, the main obstacle to criminalization of personal violence—kin-based morality and the desire to avenge wrongs committed against kin—seems to have been weaker in Northwest Europe than elsewhere. There was correspondingly a greater susceptibility to more universal and less kin-based forms of morality, such as the Christian ban on murder in almost all circumstances. 

Murder was increasingly punished not only by the ultimate penalty but also by exemplary forms of execution, e.g., burning at the stake, drawing and quartering, and breaking on the wheel (Carbasse, 2011, pp. 52-53). This "war on murder" reached a peak from the 16th to 18th centuries when, out of every two hundred men, one or two would end up being executed (Taccoen, 1982, p. 52). A comparable number of murderers would die either at the scene of the crime or in prison while awaiting trial (Ireland, 1987).

Gene-culture co-evolution?

The cultural norm thus shifted toward nonviolence. There was now strong selection against people who could not or would not lead peaceful lives, their removal from society being abrupt, via the hangman's noose, or more gradual, through ostracism by one's peers and rejection on the marriage market. As a result, the homicide rate fell from between 20 and 40 homicides per 100,000 in the late Middle Ages to between 0.5 and 1 per 100,000 in the mid-20th century (Eisner, 2001, pp. 628-629).

Was this decline due solely to legal and cultural restraints on personal violence? Or were there also changes to the gene pool? Was there a process of gene-culture co-evolution whereby Church and State created a culture of nonviolence, which in turn favored some genotypes over others? We know that aggressive/antisocial behavior is moderately to highly heritable. In the latest twin study, heritability was 40% when the twins had different evaluators and 69% when they had the same one (Barker et al., 2009). The actual neural basis is still unsure. Perhaps a predisposition to violence is due to stronger impulsiveness and weaker internal controls on behavior (Niv et al., 2012). Perhaps the threshold for expression of violence is lower. Perhaps ideation comes easier (van der Dennen, 2006). Or perhaps the sight and smell of blood is more pleasurable (vanden Bergh and Kelly, 1964).

It was probably a mix of cultural and genetic factors that caused the homicide rate to decline in Western societies. Even if culture alone were responsible, we would still be facing the same problem. Different societies view male violence differently:

In Algerian society for example, children are raised according to their sex. A boy usually receives an authoritarian and severe type of upbringing that will prepare him to become aware of the responsibilities that await him in adulthood, notably responsibility for his family and for the elderly. This is why a mother will allow her son to fight in the street and will scarcely be alarmed if the boy has a fall or if she sees a bruise. The boy of an Algerian family is accustomed from an early age to being hit hard without whimpering too much. People orient him more toward combat sports and group games in order to arm him with courage and endurance—virtues deemed to be manly. (Assous, 2005)

In Algeria and similar societies, a shaky equilibrium contains the worst excesses of male violence. Men think twice before acting violently, for fear of retaliation from the victim's brothers and other kinsmen. Of course, this "balance of terror" does not deter violence against those who have few kinsmen to count on.

Problems really begin, however, when a culture that legitimizes male violence coexists with one that delegitimizes it. This is France’s situation. Les jeunes perceive violence as a legitimate way to advance personal interests, and they eagerly pursue this goal with other young men. Conversely, les Français de souche perceive such violence as illegitimate and will not organize collectively for self-defence. The outcome is predictable. The first group will focus their attacks on members of the second group—not out of hate but because the latter are soft targets who cannot fight back or get support from others. 

But what about the obviously Islamist motives of the Charlie Hebdo attackers? Such motives can certainly channel violent tendencies, but those tendencies would exist regardless. Even if we completely eradicated radical Islam, les jeunes would still be present and still engaging in the same kind of behavior that is becoming almost routine. At best, there would be fewer high-profile attacks—the kind that make the police pull out all stops to find and kill the perps. It is this "high end" that attracts the extremists, since they are the least deterred by the risks incurred. The “low end” tends to attract devotees of American hip hop. Keep in mind that less than two-thirds of France's Afro/Arab/Roma population is even nominally Muslim.

Conclusion

Modern France is founded on Western principles of equality, human betterment, and universal morality. Anyone anywhere can become French. That view, the official one, seems more and more disconnected from reality. Many people living in France have no wish to become French in any meaningful sense. By "French" I don't mean having a passport, paying taxes, or agreeing to a set of abstract propositions. I mean behaving in certain concrete ways and sharing a common culture and history.

This reality is sinking in, and with it a loss of faith in the official view of France. Faith can be restored, on the condition that outrageous incidents stop happening. But they will continue to happen. And they will matter a lot more than the much more numerous incidents tout court—the rising tide of thefts, assaults, and home invasions that are spreading deeper and deeper into areas that were safe a few years ago. The attack on Charlie Hebdo matters more because it cannot be hidden from public view and public acknowledgment. How does one explain the disappearance of an entire newspaper and the mass execution of its editorial board? 

The Front national will be the beneficiary, of course. It may already have one third of the electorate, but that's still not enough to take power, especially with all of the other parties from the right to the left combining to keep the FN out. Meanwhile, the Great Replacement proceeds apace, regardless of whether the government is "left-wing" or "right-wing."

References 

Assous, A. (2005). L'impact de l'éducation parentale sur le développement de l'enfant, Hawwa, 3(3), 354-369.

http://booksandjournals.brillonline.com/content/journals/10.1163/156920805774910033 

Barker, E.D., H. Larsson, E. Viding, B. Maughan, F. Rijsdijk, N. Fontaine, and R. Plomin. (2009). Common genetic but specific environmental influences for aggressive and deceitful behaviors in preadolescent males, Journal of Psychopathology and Behavioral Assessment, 31, 299-308.

http://www.researchgate.net/publication/226851959_Common_Genetic_but_Specific_Environmental_Influences_for_Aggressive_and_Deceitful_Behaviors_in_Preadolescent_Males/file/9fcfd506c1944288cb.pdf  

Chevrier, G. and X. Raufer. (2014). Aucun lien entre immigration et délinquance ? Une France peu généreuse avec ses immigrés ? Radiographie de quelques clichés "bien pensants" à la peau dure, Atlantico, November 26

http://www.atlantico.fr/decryptage/aucun-lien-entre-immigration-et-delinquance-france-peu-genereuse-avec-immigres-radiographie-quelques-cliches-bien-pensants-peau-1875772.html  

Eisner, M. (2001). Modernization, self-control and lethal violence. The long-term dynamics of European homicide rates in theoretical perspective, British Journal of Criminology, 41, 618-638.

http://www.researchgate.net/publication/249284795_Modernization_Self-Control_and_Lethal_Violence._The_Long-term_Dynamics_of_European_Homicide_Rates_in_Theoretical_Perspective/file/60b7d52cbfa9aec78c.pdf

Ireland, R.W. (1987). Theory and practice within the medieval English prison, The American Journal of Legal History, 31, 56-67. 

Niv, S., C. Tuvblad, A. Raine, P. Wang, and L.A. Baker. (2012). Heritability and longitudinal stability of impulsivity in adolescence, Behavior Genetics, 42, 378-392.

http://europepmc.org/articles/PMC3351554

Taccoen, L. (1982). L'Occident est nu, Paris: Flammarion. 

Vanden Bergh, R.L., and J.F. Kelly. (1964). Vampirism. A review with new observations. Archives of General Psychiatry, 11, 543-547.

http://archpsyc.jamanetwork.com/article.aspx?articleid=488664  

Van der Dennen, J.M.G. (2006). Review essay: The murderer next door: Why the mind is designed to kill, Homicide Studies, 10, 320-335.

http://hsx.sagepub.com/content/10/4/320.short

Dear Fred

In a recent post, Fred Reed asks:

Why should I not indulge my hobby of torturing to death the severely genetically retarded? This would seem beneficial. We certainly don't want them to reproduce, they use resources better invested in healthy children, and it makes no evolutionary difference whether they die quietly or screaming.

The short answer is that any killing, for whatever reason, increases the likelihood of killing for other reasons. One exception is self-defence, but that's not done for pleasure. Another exception is capital punishment, but that, too, is not done for pleasure. More to the point, no single citizen can carry out an execution. It requires a lengthy judicial process. The same reasoning applies to the final exception of war. No single citizen can declare war.

It's not for nothing that killing is so taboo, especially recreational killing. Several things have contributed to the success of Western societies, but a leading one is the relatively peaceful nature of social relations. When people can go about their business without fearing for their lives, much becomes possible that otherwise would not be. This taboo is so crucial that we even extend it to nonhumans. Cats and dogs have no inherent right to life, yet it is a serious offence to torture them to death.

 

That's society. What about biology?

At this point, Fred may speak up: "But those are social reasons against killing of any sort. What are the biological reasons?"

The immediate biological reason is empathy. If I try to hurt someone, I feel the pain I inflict. Truth be told, the only life forms I enjoy killing are flies and mosquitoes. If a moth flies into our home, I'll go to some length to capture it and set it free outside, and I know others who do similar things. Just think of all the car drivers who come to a screeching halt to avoid running over some poor animal.

It's empathy that makes me and others act that way. And I cannot easily turn it off. It shuts down only when feelings of contempt enter my mind, as with those contemptible flies and mosquitoes.

Empathy is hardwired. It's 68% heritable in the case of affective empathy, i.e., the capacity to respond with the appropriate emotion to another person's mental state (Chakrabarti and Baron-Cohen, 2013). To date, studies have focused on disorders caused by too much empathy or too little. Psychopaths may have intact cognitive empathy, but impaired affective empathy. They keenly understand how others feel without actually experiencing those feelings. The reverse impairment may affect autists. As for depressives, they may suffer from being too sensitive to the distress of others and to guilt over not helping them enough. 

These disorders exist at the tail ends of a normal distribution. By focusing on these extremes, we forget the variability among healthy individuals. We all vary in our capacity for empathy, just as we do for almost any mental capacity.

 

How can evolution explain empathy?

Why do we feel empathy? How could natural selection favor such selflessness? This is of course the point that Fred is trying to make. Empathy keeps us from doing things that supposedly make evolutionary sense. Therefore, it could not have evolved. It must have been given to us by a Great Designer.

But why did this Great Designer give more of it to some people than to others? We're talking about a heritable trait. It's not as if everyone starts off the same way, with some later falling behind through their own wrongdoing.

And how has the Great Designer preserved this selfless behavior? Unless something is done, empathic people will eventually be overwhelmed by a tidal wave of cheaters, free riders, and people shouting "Gimme! Gimme! Gimme!" This is as much a mystery for creationists as it is for evolutionists. It's one thing to explain how altruism came to be. It's another to explain how it manages to survive in this cynical world.

These questions passed through my mind when I was going through my late mother's effects. I discovered she had for years been donating money for various projects in the Third World, at a time when she was a widow with no pension. Meanwhile, as a teenager, I had to take on all kinds of odd jobs to help us make ends meet. Looking over those donor receipts I shook my head and felt some resentment. How do good Christians like her manage to survive?

Yet she did, like others before her. For one thing, she was suspicious of strangers, and this suspicion extended to some ethnic groups more than to others. She was prejudiced and "postjudiced." If someone acted dishonestly with her once too often, she would have no more to do with him or her. Such people were "contemptible."

Today, that sort of behavior might seem un-Christian. But her Christianity was of an older, judgmental sort, being inspired more by the punitive Old Testament than by the forgiving New Testament. She would judge people, and her judgment could be harsh, very harsh.

 

Over space and time

Just as the capacity for empathy varies from one individual to another, it also varies statistically from one human population to another, being strongest in the "guilt cultures" of Northwest Europe. Guilt is the twin sister of empathy. Both flow from a simulation of how another person thinks or feels (an imaginary witness to a wrongdoing, a person in distress) and both ensure correct behavior by inducing the appropriate feelings (anguish, pity).

Why are guilt and empathy so strong in Northwest Europeans? Other societies ensure good behavior by relying on close kin to step in and enforce social rules. This policing mechanism has been less effective west of the Hajnal line (which runs roughly from Trieste to St. Petersburg) because kinship ties have been correspondingly weaker. There has thus been stronger selection for internal means of behavior control, like guilt and empathy.

This zone of relatively weak kinship is associated with unusual demographic tendencies, called the Western European Marriage Pattern:

- relatively late marriage for men and women

- many people who never marry

- neolocality (children leave the family household to form new households)

- high circulation of non-kin among different households (Hajnal, 1964; ICA, 2013)

The Western European Marriage Pattern was thought to have arisen after the Black Death of the 14th century. There is now good evidence for its existence before the Black Death and fragmentary evidence going back to 9th century France and earlier (Hallam, 1985; Seccombe, 1992, p. 94). Historian Alan Macfarlane likewise sees an English tendency toward weaker kinship ties before the 13th century and even during Anglo-Saxon times (Macfarlane, 2012; Macfarlane, 1992, pp. 173-174). I have argued that this tendency probably goes still farther back (Frost, 2013a; Frost, 2013b).

 

Whatever the ultimate cause, Northwest Europeans seem to have been pre-adapted for later shifts away from kinship and toward alternate means of organizing social relations (i.e., ideology, codified law, commerce). This tendency has taken various forms: the intense guilt-driven Christianity of the Anglo-Saxon penitential tradition and, later, Protestantism; the medieval alliance between Church and State to pacify social relations; and the post-medieval rise of the market economy. This cultural evolution has been described by the historical economist Gregory Clark for the English population between the 12th and 19th centuries. As England became a settled society, success went to those who could resolve disputes amiably and profit from thinking ahead—in short, those who had middle-class values of thrift, foresight, self-control, nonviolence, and sobriety. This English middle class, initially tiny, grew in numbers until its lineages accounted for most of its country’s gene pool (Clark, 2007; Clark, 2009a; Clark, 2009b).

 

But what does that have to do with evolution???

 

At this point, Fred may again speak up, with more than a touch of exasperation: "You're ducking my question! You're talking about culture, society, and religion! What does that have to do with evolution???"

Everything, Fred. Everything. Unlike other animals, humans have to adapt not only to their physical environment but also to their cultural environment. In short, we've become participants in our own evolution. We have domesticated ourselves.

Let me return to your initial question. What's to stop you from torturing to death the severely retarded? First, your sense of empathy should. If it doesn't, you're the one with a severe mental defect. I wouldn't want you as a fellow citizen, let alone as a neighbor. The law of the jungle may give you the right to torture defenceless people to death, but it also gives me the right to organize a lynch mob and hang you from the nearest tree.

 

References

Chakrabarti, B. and S. Baron-Cohen. (2013). Understanding the genetics of empathy and the autistic spectrum, in S. Baron-Cohen, H. Tager-Flusberg, M. Lombardo. (eds). Understanding Other Minds: Perspectives from Developmental Social Neuroscience, Oxford: Oxford University Press.

Clark, G. (2007). A Farewell to Alms. A Brief Economic History of the World, Princeton: Princeton University Press.

Clark, G. (2009a). The indicted and the wealthy: Surnames, reproductive success, genetic selection and social class in pre-industrial England.

http://www.econ.ucdavis.edu/faculty/gclark/Farewell%20to%20Alms/Clark%20-Surnames.pdf  

Clark, G. (2009b). The domestication of man: The social implications of Darwin. ArtefaCTos, 2, 64-80.

http://campus.usal.es/~revistas_trabajo/index.php/artefactos/article/viewFile/5427/5465

Frost, P. (2013a). The origins of Northwest European guilt culture, Evo and Proud, December 7

http://evoandproud.blogspot.ca/2013/12/the-origins-of-northwest-european-guilt.html 

Frost, P. (2013b). Origins of Northwest European guilt culture, Part II, Evo and Proud, December 14

http://evoandproud.blogspot.ca/2013/12/origins-of-northwest-european-guilt.html

Hajnal, John (1965). European marriage pattern in historical perspective. In D.V. Glass and D.E.C. Eversley (eds). Population in History. Arnold, London.

Hallam, H.E. (1985). Age at first marriage and age at death in the Lincolnshire Fenland, 1252-1478, Population Studies, 39, 55-69. 

ICA (2013). Research Themes - Marriage Patterns, Institutions for Collective Action

http://www.collective-action.info/_THE_MarriagePatterns_EMP  

Macfarlane, A. (1992). On individualism, Proceedings of the British Academy, 82, 171-199.

http://www.alanmacfarlane.com/TEXTS/On_Individualism.pdf  

Macfarlane, A. (2012). The invention of the modern world. Chapter 8: Family, friendship and population, The Fortnightly Review, Spring-Summer serial

http://fortnightlyreview.co.uk/2012/07/invention-8/

Seccombe, W. (1992). A Millennium of Family Change. Feudalism to Capitalism in Northwestern Europe, London: Verso. 

Japan: A north-south cline in mental and behavioral traits

 

IQ, height, and homicide rate in Japan (red = lowest value, light blue = highest value) (Kura, 2013). The longer and harsher the winter, the greater the need for cognition and male solidarity?

The Japanese are descended from the intermixture 2900 to 1500 years ago of indigenous hunter-gatherers, the Jomon people, with incoming farmers from East Asia, the Yayoi people.  Even today, the Japanese still show an east-west genetic cline, with East Asian haplogroups being most frequent in western regions that face the Korean Peninsula (Kura, 2013).

In addition to this east-west cline, there is also a north-south cline for physical traits like height and skin color. Kura (2013) shows that the Japanese are taller and lighter-skinned the farther north they are. Interestingly, the same study shows a north-south cline in mental and behavioral traits, notably IQ, homicide rate, and divorce rate. In Japan, latitude correlates positively with IQ and negatively with homicide rate and divorce rate.

This north-south cline seems independent of the east-west one. If it likewise has a genetic basis, the reason cannot be varying degrees of Yayoi/Jomon intermixture. The reason must be differences in the way natural selection has acted on the Japanese over the past 1500 years.

Of course, this north-south cline can also be explained on cultural grounds. The climate is milder in southern Japan, and farmers have less need to store food for the lean times of winter and early spring. Consequently, they tend to live more in the present and don’t plan ahead as much. Men are also less necessary as hunters who can bring food when the ground is frozen. Because women are more self-reliant food-wise, they depend less on their male partners. For the same reason, the cost of supporting a second wife is lower for men. There is thus more polygyny, more male-male rivalry for access to females, and less male solidarity. State formation becomes more difficult, and there is no longer a higher authority that can impose a monopoly on violence and thereby pacify social relations.

But this culturalist explanation hardly applies to modern Japan, or even the Japan of the past century or so. To the extent that culture has created this mental/behavioral cline, it has probably done so through gene-culture co-evolution. This is the explanation that Kura (2013) favors. The longer and harsher the winter, the greater the demands on cognition and the sexual bond … and the higher the likelihood of survival and reproduction for those who can meet such demands.

Kura also sees this Japanese north-south cline as evidence that evolution did not stop with the emergence of behaviorally modern humans some 100,000 years ago. Evolution has actually been proceeding at a faster rate: 

This conclusion would be in line with the Hawks, Wang, Cochran, Harpending, and Moyzis (2007) idea of ever-accelerating human evolution. They insist that more and more beneficial mutations swept populations, after the advent of agricultural civilizations with metallurgy, letters and complex hierarchical organizations. The Japanese north–south gradient in height and intelligence can be evidence that modern humans have evolved to higher intelligence within the last two millennia. (Kura, 2013)

References 

Hawks, J., E.T. Wang, G.M. Cochran, H.C. Harpending,  and R.K. Moyzis. (2007). Recent acceleration of human adaptive evolution. Proceedings of the National Academy of Science, 104(52), 20753–20758.

http://www.pnas.org/content/104/52/20753.full 

Kura, K. (2013). Japanese north–south gradient in IQ predicts differences in stature, skin color, income, and homicide rate, Intelligence, 41, 512-516.

http://www.sciencedirect.com/science/article/pii/S0160289613000949