The intergenerational correlation can be interpreted as a measure of social entropy. The lower this correlation, the greater the degree of social entropy, and the quicker a particular structure of advantage and disadvantage in any society is dissolved.
The life chances of the descendants of high- and low-status ancestors can be equalized at low social cost. The Nordic countries, after all, constitute one of the richest regions of the world, attractive in many other ways beyond the material: they enjoy high life expectancy, low crime rates, near gender equality, lack of corruption, and political transparency.
Surnames turn out to be a surprisingly powerful instrument for measuring social mobility.
they reveal that there is a clear, striking, and consistent social physics of intergenerational mobility that is not reflected in most modern studies of the topic.
In particular, once we measure generalized social mobility, there is no sign that inequality is linked to social mobility rates. Instead social mobility seems to be a constant, independent of inequality.
These high estimates of underlying intergenerational correlation imply that 50 to 70 percent of the variation in general social status within any generation is predictable at conception.
Our findings do suggest, however, that we can predict strongly, based on family background, who is likely to have the compulsion to strive and the talent to prosper.
To know whether an intergenerational correlation of 0.75 represents a social problem or the best of all possible worlds requires a theory of the source of this persistence. If it is created mainly by the social environment in which people spend their childhoods, then any society will produce a mismatch between individuals’ talents and their social position. But if persistence is created mainly by an unchangeable familial inheritance of ability, we must conclude that, whatever their institutional structure, societies consistently produce matches of innate talents and social positions.
What is the significance of these results for parents socially ambitious for their children? The practical implication is that if you want to maximize your children’s chances, you need to pay attention not to the social phenotype of your marriage partner but instead to his or her status genotype. That genotype is indicated by the social group your potential partner belongs to, as well as the social phenotype of their siblings, parents, grandparents, cousins, and so on to the nth degree of relatedness. Once you have selected your mate, your work is largely done. You can safely neglect your offspring, confident that the innate talents you secured for them will shine through regardless. If, that is, the theory on the source of status persistence conjectured here is correct.
But we see in the various settings studied in this book, as in figure 1.6 , no correlation between inequality and underlying rates of social mobility. If
It is notable, however, that the emancipation of women in recent generations has had no influence on social mobility rates. Emancipated women mate as assortatively as before and transmit their status to children as faithfully as in the patriarchal societies of the past.
Such mobility would suggest that Swedish institutional arrangements—the support for public education, for example, and the progressive taxation of wealth—play a vital role in determining rates of social mobility.
nearly one-third of men born with patronyms changed their surnames, with most of the changes occurring by age 30.
such patronyms are only selectively retained by the modern population.
One way we can measure the status of different surnames, and also the distribution of status, in modern Sweden is from tax records. This information is publicly available and is even sold commercially under the slogan “Know what your neighbors earn.”
Analysis of the tax data shows that those with noble and latinized surnames have higher incomes not only because there are more of them at the upper end of the income distribution but also because there are fewer of them at the bottom of the distribution.
These results again imply that the distant past has a surprising effect on the present even in Sweden. Surnames that were differentiated socially in the eighteenth century remain so even ten generations later. Noble surnames have retained their ranking in the social hierarchy: the surnames of counts and barons carry still higher status than those of the untitled nobles.
Because of the abandonment of patronyms, which was likely more common among the upwardly mobile, the intergenerational correlation estimated here may overestimate the persistence of status among those with patronym surnames.
The enlargement of the political franchise and the institutions of the extensive welfare state of modern Sweden, including free university education and maintenance subsidies to students, have done nothing to increase rates of social mobility.
based on the numbers of master’s theses submitted annually at Sweden’s most selective universities—Gothenburg, Lund, Stockholm, and Uppsala—we can predict that 8 percent of Swedes born in 1990 will complete a master’s thesis at one of these universities.
Could there be high persistence of status at the upper extreme of the distribution, but greater social mobility for 99 percent or more of families in Sweden?
But, as is evident from the tax data, noble and latinized names are as underrepresented at the bottom of the income and wealth distribution as they are overrepresented at the top.
Nearly one hundred years of Swedish social democracy has created a more economically equal society, but it has been unable to change the underlying rate of social mobility.
The elite groups are the descendants of Ashkenazi and Sephardic Jews, the descendants of the wealthy individuals as of 1923–24 who had rare surnames, the descendants of individuals with rare surnames who graduated from Ivy League universities in or before 1850, and people of Japanese descent.
Attorneys are a less exclusive elite than physicians.
For the black population, the estimated recent rate of convergence toward the mean is even slower. The persistence rate per generation is 0.96. This implies that even in 2240, the black population will be represented among physicians at only half the rate of the general population.
emphasized in his work is the “cultural capital” of those of New French descent. 15 Could this community have inherited a cultural legacy that impedes upward social mobility? There are claims that Franco-Americans were more committed to maintaining their language and religious practices than the assimilationist Irish and Italians.
the vast majority of those in the current stock of physicians and attorneys are from families who have been in the United States for three or more generations.
It is estimated, for example, that the French population of Canada in the late nineteenth century derived from fewer than nine thousand original French settlers. 19
In addition, there is evidence that French Canadian immigrants to the United States between 1860 and 1920 were negatively selected from the Francophone population of Canada. Byron Lew and Bruce Cater show that from 1900 to 1920, illiterate French Canadians were significantly more likely to emigrate to the United States than their literate counterparts. 22
It is possible, then, that the low status of modern Franco-Americans stems from the persistence of an ethnic culture maladapted to economic success. But it seems more plausible that their low status in the United States stems from the fact that they are a twice-selected low-status subgroup of the parent French population.
the Gentleman’s Agreement of 1907
Finally, the figure shows “elite” PCC probates, cases in which the deceased person was referred to by a title indicating high status, such as Gentleman.
This finding means that medieval England had mobility rates similar to, though perhaps modestly higher than, those of the modern United States and Sweden.
what did the Scientific Revolution, the Enlightenment, and the Industrial Revolution achieve? Very little. Social mobility existed long before people even thought of it as a feature of the good society.
English citizens may have lost the right of their American cousins to wield death-spitting weaponry, but they have long held the right to change their surnames to whatever they wish by personal fiat,
This locative naming practice started with the Norman conquerors of England. This new elite took surnames that linked them to their home villages in Normandy, such as Mandeville, Montgomery, Baskerville, Percy, Neville,
mobility was consistent even in the Middle Ages, but very slow.
The -field variant is lower in status on average then the -ville variant: this difference is predictable because the mutation to -field was much more likely to occur among lower-status and illiterate holders of the surname.
This implies that modern England actually has lower rates of social mobility than medieval England did.
Again, however, the rate of regression to the mean is startlingly low. It has been 947 years since the Norman conquest of 1066. The fact that Norman surnames had not become completely average in their social distribution by 1300, by 1600, or even by 1900 implies astonishingly slow rates of social mobility during every epoch of English history.
there is a consistent and stable regression of status toward the mean: in the long run, we are all equal in expectation.
if this parameter is valid for medieval and modern England as a whole, then more than four-fifths of social and economic outcomes are determined at birth.
The surname data we examine show absolutely no sign that any of the intellectual, social, and economic advances between 1300 and 2000 in England produced much increase in social mobility. Neither the Reformation in the sixteenth century, nor the Enlightenment of the early eighteenth century, nor the Industrial Revolution of the late eighteenth century, nor the political reforms of the nineteenth century, nor the rise of the welfare state in the twentieth century, seems to have had much effect on intergenerational mobility.
There is no lack of rare surnames.
Given an average gap of thirty years between generations, wealth was inherited by children on average at age 32, just as they were rearing their own children and buying housing. But now people are, on average, fifty years old when they inherit any wealth from their parents.
If longevity continues to increase, then, despite increases in the average age at which women produce children, wealth will increasingly pass from the ancient to the aged.
The rare wealthy surnames show up at very high rates in the initial generation of university entrants, 1830–59. Someone with one of these surnames was fifty times more likely to enroll at Oxford or Cambridge than someone from the general population. Over the next six generations, the last observed being university entrants from 2010 to 2012, there is a substantial decline in the relative representation of these surnames. By the last generation, a member of this surname group was only six times as likely to enter Oxford or Cambridge as someone in the general population.
Educational status persists for this group even more strongly than wealth. Moreover, as with wealth mobility, there is no sign that educational mobility has increased in the past few generations.
The implied rate of mobility is so low that the rich elite surnames will not approach an average representation at Oxford and Cambridge for another seventeen generations (510 years).
Even a fool learns something once it hits him. Homer, The Iliad
Elite surnames can take ten or fifteen generations (300–450 years) to become average in status.
By looking at groups of people (as long as they are grouped by identifiers that do not correlate with this error term, such as race, religion, national origin, or even common surnames), we can reduce this error term by averaging across the group.
The underlying process of social mobility is Markov: it proceeds at the same rate across all generations. 6 In particular, once we know the underlying status of your parents, no further information about your prospects in life can be derived from your earlier lineage.
Slow mobility rates for blacks and Latinos do not reflect an enduring racism in American society; they just reflect the fact that the rate of regression to the mean for underlying social status is inherently low.
The compression of earnings in Sweden compared to the United States will lead to a lower value of θ for Sweden and thus the appearance of more social mobility in general.
Earnings in the United States are a better indicator of the underlying social status of families, and so income is more persistent across generations than it is in Sweden. This explanation also counters the popular belief that as earnings inequality has increased in the past forty years in the United States, social mobility rates have declined.
Across groups of people, longevity is highly correlated with social status.
In reality, your age at death is not strongly predictable from your parents’ age at death. All those saving more for retirement simply because both their parents are fit, healthy, and in their nineties should stop immediately. Your expected additional longevity relative to the average is only three years.
Cognitive abilities in Sweden, for example, are found to be strongly correlated across generations, with an intergenerational correlation of 0.77. But, at least in Nordic countries, other characteristics, such as income, education, and wealth, have a much lower heritability, with correlations often less than 0.3.
Whatever the status of your parents, high-status grandparents predict a better outcome for you. Low-status grandparents predict a poorer outlook.
But why are mobility rates seemingly constant across very different social regimes? Here I conjecture that this is because status inheritance is indistinguishable in form from the inheritance of genetically controlled attributes.
Another implication of this theory is that, other things being equal, elite families with larger numbers of children should see faster regression to the mean. With a finite stock of family resources, the greater the number of children parents must provide for, the less each child gets. By the same reasoning, lower-status families with fewer children should regress upward to the mean more rapidly.
But the parents at the bottom of the distribution in Denmark have negative wealth—that is, debt. This suggests not chronic, grinding poverty (no one, after all, lends much to the truly poor), but more likely indebtedness to finance a business venture or training.
This chapter also calculates the effect of the reservation system on social mobility rates since 1947. It concludes that its dramatic interventions have had modest effects on overall social mobility rates. This is because although it has modestly increased downward mobility among Hindu and Christian elites, its main effect has been to create a new elite composed of groups that were never significantly disadvantaged. In practice, the system has largely hurt the prospects of the truly disadvantaged.
Intermarriage and even social intercourse between different castes were limited. This system of exclusion was so powerful that different castes and subcastes, even within small geographic areas, can now have distinct genetic profiles.
one possibility is that physicians admitted to Indian medical schools through the reservation system find it harder to meet the onerous requirements to practice medicine in the United States: passing the U.S. Medical Licensing Examination and completing the required residencies. Though the reservation changes the measured social status of these individuals, it does much less to change the underlying social competence of these families.
The expectation is that the rarer these surnames are today, the more likely that the holders are actually samurai or kazoku descendants. Thus the rarer the surnames, the greater their predicted overrepresentation among elites.
First, the rarer the surname, the higher indeed its relative representation. The rarest surnames are 12–16 times overrepresented,
In the years 1940–67, for example, marriages involving highly educated husbands or wives produced one-fifth fewer births than those of couples with lower educational attainment.
The elite of any generation typically come from families only modestly less elite. On average, the fabulously rich and the extravagantly talented are the offspring of the moderately rich and moderately talented. The truly poor and completely talentless are the children of the modestly poor and somewhat untalented.
This symmetry implies that if a group deviates in the current generation from the mean social status, set at zero, then on average it will have deviated by a smaller amount, determined by b, in the previous generation.
A group of families now of high social status will have arrived at this status over many generations by a series of upward steps from the mean.
the equation predicts that the chance of a family going from the mean of the status distribution to the top 0.5 percent in one generation is roughly one in five hundred million. It is quite likely that it has never happened in England.
The chance of going from the bottom 0.5 percent to the top 0.5 percent in one generation is essentially zero. It has never happened in the history of any society.
This implies that if the rate of persistence is indeed 0.75 or higher, families observed at any time in the elite spend twenty or more generations (six hundred years) at above-average status. The same holds for families observed at low status: they typically linger at below-average status for twenty generations or more.
Families who end up at the bottom of the status distribution follow a trajectory that looks very similar in shape to that followed by families who end up at the top.
The modern elite has a long history of overrepresentation at the universities.
But the persistent effects of accidents of chance alarm many people. The idea that the abilities and status of our ancestors twelve generations in the past can predict our chances of entering university, being a doctor, or becoming wealthy somehow violates the sense that a fair society should offer equality of opportunity for all in the current generation.
For characteristics other than height, adopted siblings were always significantly correlated, despite their absence of genetic connection. Their shared family environment had an influence. But family environment appears to have only a very modest influence on the later earnings of children.
Genetic inheritance explains three times as much of children’s income variation as does family environment.
But the earnings outcomes suggest that getting into selective colleges had little effect on the future incomes of adoptees, for which the correlations were much lower.
These adoption studies suggest that even if we could make the familial environment of every child in the United States identical, we would reduce the intergenerational correlation of social outcomes by only modest amounts, perhaps one-quarter of existing values.
This would make genetics more than ten times as important as environment in explaining earnings outcomes.
The empirical evidence that middle- and upper-class parents can significantly boost their children’s human capital and economic outcomes through expenditure on children is weak, as Bryan Caplan recently emphasized in his book Selfish Reasons to Have More Kids.
Is there anything that this book can say to people who want the best possible income, wealth, education, and health outcomes for their children? The one scientific contribution we can make is to point out that with the appropriate choice of mates, a family can avoid downward mobility forever.
This means that the people currently occupying the upper tails of the distribution of education, wealth, and occupational prestige tend to include disproportionately the lucky, the ones who benefited from happy accidents. Systematically, at the top, the phenotype is better than the genotype. Symmetrically, concentrated at the bottom are people who have experienced bad luck and unhappy accidents. There, the social genotype is much better than the observed phenotype.
The curse of the elite is that they are surrounded by imposters, possibly including themselves, and thus the marriage market for the upper classes is full of prospects likely to underperform as carriers of a lineage. In contrast, the bottom of the marriage market is full of potential overperformers. Bad luck dominates, rather than bad social genotypes. So outcomes for the next generation tend to be better.
If the way to produce children of the highest possible social phenotype is to find a partner of the highest possible social genotype, the path is clear for those whose aim in life is to produce the highest-achieving progeny possible. To discover the likely underlying social genotype of your potential partner, you need to observe not just their characteristics but also the characteristics of all their relatives. What is the social phenotype of their siblings and their parents? And what is the observed status of their grandparents and cousins?
since mating is highly assortative, the shared genetics of siblings, parents, grandparents, aunts, uncles, cousins, and so on is correspondingly much greater than suggested here. The entire lineage becomes strongly predictive of the underlying status of a potential marriage partner.
If genetics underlies social status, then mating must be highly assortative, so that second cousins are much more closely connected than might be expected.
All this implies that if the weighted score for the relatives is as high as for your potential mate, who is of high status, his or her underlying social genotype is as high as the observed phenotype. For the purpose of producing high-quality children—and for this purpose alone—this potential partner is a bargain on the marriage market. If the weighted score of the relatives is even higher than that of the potential partner, then he or she is a marital fire sale. Conversely, if the relatives are, on average, of lower status, this marriage is unlikely to produce children with social potential as high as the partner’s, because the partner’s social phenotype is better than the genotype.
The more the individual deviates positively from the average social phenotype of that group, the more likely their current status is to be the product of accident, higher than their underlying social genotype. The more they fall below the average for the group, the more likely it is that this status is the result of chance: the person’s underlying social genotype is likely to be better adapted for success. 15
In Selfish Reasons to Have More Kids, Caplan points out correctly that upper-class parents pointlessly invest too much time in the rearing of their children. In his view, genetics is what matters, so you might as well have more children, invest less in each, and enjoy being a parent more. That all seems sensible and humane.