Notes: Gregory Clark on Social Mobility, Migration, and Assortative Mating

Notes on Gregory Clark in conversation with Tyler Cowen — Conversations with Tyler (https://conversationswithtyler.com/episodes/gregory-clark/), 19 February 2025.

Four questions [Adler frame]

Q1 — What is it about as a whole? Economic historian Gregory Clark defends, under sustained live challenge from Tyler Cowen, the central claim of his research programme: that a person’s relative social position — not their absolute living standard — is determined overwhelmingly by inheritance and randomness, has been essentially constant across five centuries of English history and multiple very different societies (medieval England, modern Denmark, Communist Hungary, colonial India), and is barely moved by migration, policy, or institutional change. The conversation ranges across assortative mating, India’s failure to industrialise under British rule, a redefinition of Malthusianism, the policy implications of hereditarian belief, and migration selection effects, before closing on Clark’s forthcoming book on genetics and English social life.

Q2 — How is it argued? By large, purpose-built genealogical and surname datasets rather than by theory. Clark’s evidentiary base throughout is his and Neil Cummins’ English marriage and lineage records (1.7 million marriages from 1837; multi-generational genealogy back to 1600 for the forthcoming book), supplemented by surname-tracing studies of Hungary’s Communist-era elite and of Anglo-Indian entrepreneurship. Cowen’s method is Socratic counter-example: he repeatedly offers a case (Indian-American household income, Paul McCartney’s Liverpool, North Dakota Scandinavians) that seems to strain Clark’s relativist framework, forcing Clark to qualify or restate his claim.

Q3 — Is it true, in whole or part? Clark’s narrow empirical claims — the marriage-matching data, the surname-tracing studies — are his own documented, published research and are internally consistent. [?] His broader interpretive leaps are more contestable and Clark himself signals varying confidence in them: the genetic (rather than cultural) explanation for pre-industrial English ‘survival of the richest’ is asserted rather than demonstrated in this conversation; the claim that assortative mating in Northern Europe from ~1750 helped cause the Scientific Revolution and Industrial Revolution is explicitly speculative on his own telling; and the India industrialisation puzzle he candidly declares unsolved rather than argues to a conclusion. Sheilagh Ogilvie, in a separate Conversations with Tyler appearance, directly disputes Clark’s persistently-low-mobility thesis, arguing England looks comparatively mobile against her own comparison set of German-speaking central Europe — a live scholarly disagreement, not a settled question.

Q4 — What of it? The conversation’s throughline is a live methodological dispute about what ‘mobility’ even means — relative rank versus absolute welfare — and Clark’s related insistence that only geographic migration, not domestic policy, reliably changes people’s material circumstances, even though it does not change their relative rank. His hereditarianism produces a policy inference that cuts against the usual political mapping: belief in strong genetic and inherited determination of outcomes leads him to favour more redistribution, not less, since a good society compresses inequalities people did not earn rather than moralising about them. The wiki’s first sustained treatment of assortative mating, hereditarian social-mobility research, and the surname-based methodology Clark pioneered in The Son Also Rises.

Glossary

Relative social mobility — the strength of the statistical association between a person’s social status (income, education, occupation rank) and their parents’ status; Clark’s central object of study, distinct from absolute living-standard improvement. [§ Relative versus absolute mobility]

Assortative mating — the tendency of people to select marriage partners similar to themselves in social status (rather than, say, height or looks); Clark finds English spouses matching almost as closely as siblings, a pattern that widens the distribution of ability across generations without changing its average. [§ Assortative mating and its trade-off with inequality]

Hypergamy — the hypothesis that women systematically marry men of higher status than themselves; Clark and Cummins’ PLOS One paper finds no evidence of it in English marriage records since 1837. [§ Assortative mating and its trade-off with inequality]

Clarkian Malthusianism — Clark’s own redefinition of a Malthusian economy as any society where fertility rises with living standards under a fixed resource constraint, deliberately decoupled from the popular association of ‘Malthusian’ with poverty; a materially rich society (pre-industrial England, pre-contact Tahiti) can still be Malthusian in this sense. [§ Clarkian Malthusianism]

Hereditarianism — the view, as Clark uses the term, that social and economic outcomes are substantially determined by inherited (largely genetic) rather than environmental or cultural factors; Clark argues this view supports more redistribution, since undeserved inherited advantage should be compressed rather than rewarded. [§ Hereditarianism, redistribution, and Denmark]

Positive/negative selection (migration) — whether the subset of a population that emigrates is drawn disproportionately from the more able and ambitious (positive) or the less successful (negative) end of the distribution; Clark finds this varies significantly by origin and destination, e.g. English emigrants to the US were the least positively selected English emigrant group. [§ Migration, selection, and assimilation]

Key claims by section

Relative versus absolute mobility [§ Relative versus absolute mobility: the central disagreement]

Clark measures mobility as the correlation between a person’s and their parents’ position in a relative status distribution; he finds this correlation essentially unchanged from medieval England to the present, across societies as different as Britain and Denmark.
Cowen’s standing objection: this ignores a roughly fifteenfold rise in absolute living standards since 1800, which Cowen believes is what people actually care about; Clark concedes the absolute gain but maintains relative position is what people are ‘obsessed with’, citing Britain’s fixation on elite-university and parliamentary background.
Clark reads flat relative mobility since ~1700 as evidence England achieved functional meritocracy early — a state where genetics and randomness, not birth, chiefly determine outcomes.

Migration and relative position [§ Migration as the exception that proves the rule]

Clark agrees with Cowen’s Strauss/Caplan-inflected reading that physical migration, not staying in a fixed hierarchy, is what reliably delivers large material gains (citing Indian-American household income far above Indian domestic income).
But his new manuscript finds that when Britons emigrated to Australia, Canada, or the US, their descendants’ relative social standing in the new society closely tracked their standing in Britain, even as absolute welfare rose sharply.
A Hungary natural experiment (surname-traced pre-Communist elite) shows the same pattern under an extreme institutional shock: that elite lost access to parliament under Communism but retained access to medical school admission throughout, then re-entered politics once markets returned. [?]

Assortative mating [§ Assortative mating and its trade-off with inequality]

1.7 million English marriage records (1837–present) show spouses matching on social status with near sibling-level precision — tighter than random pairing, and tighter than cousin marriage would produce.
The degree of assortativeness is traceable only to about 1750; Clark speculates, explicitly as speculation, that this Northern European pattern may have helped enable the Scientific Revolution, Enlightenment, and Industrial Revolution.
Assortative mating does not change a population’s average ability but widens its distribution over generations — more people at the extreme top, and more inequality; Nordic countries have not narrowed PISA score inequality despite heavy income redistribution, which Clark attributes to strong ongoing assortative mating there.
A companion paper with Neil Cummins in PLOS One finds no hypergamy in English marriage data since 1837 — status, not sex-differentiated preference, dominates matching.

The India puzzle [§ The India puzzle and the limits of institutional explanation]

Clark rejects British neglect as the explanation: Anglo-Indian entrepreneurship was large-scale, British policy admitted migrant entrepreneurs freely (e.g. the Sassoon family, Bombay textiles), and even Karl Marx predicted British investment would industrialise India.
Clark rejects factory-level managerial failure: 19th-century cotton mills required few skilled managers and were largely failure-resistant, run successfully elsewhere (Japan) by low-skilled young labour.
Empirical anchor: by 1940, not one of India’s 450 textile mills matched the average productivity of an English mill — a gap Clark calls one of history’s great unresolved puzzles, proposing a prize for whoever explains it.
Clark is sceptical of ‘culture’ as an explanation here or for South Korea’s later transformation, arguing untestable cultural narratives make no scientific progress — Cowen pushes back that this reflects an overly narrow economist’s standard of explanation.

Clarkian Malthusianism [§ Clarkian Malthusianism]

Clark redefines ‘Malthusian’ as any society with a positive fertility–living-standards link under a fixed resource base, deliberately decoupled from poverty — a materially rich society can still be Malthusian by this test.
Pre-industrial England after the Black Death (population under two million, but daily meat consumption and houses comparable to a modern Arlington home) and pre-contact Tahiti (high material living standards sustained via warfare and infanticide killing a third to half of children born) both serve as illustrations.
Applied to sub-Saharan African aid: aid raises welfare directly but is partly offset by resulting population growth in agriculture-dependent economies, favouring aid paired with industrialisation or fertility reduction over withholding aid.

Hereditarianism and Denmark [§ Hereditarianism, redistribution, and Denmark]

Clark’s stated hereditarianism: since outcomes are substantially inherited and not readily changed by policy, a good society compresses resulting inequality rather than moralising about deservingness — he cites Denmark’s high taxation and redistribution as consistent with this.
Cowen’s counter: if migration (not domestic reshuffling) is what raises welfare, Denmark’s generous welfare state should be read as deterring the highest-quality immigrants, so a growth-focused hereditarian should favour lower taxes and more open immigration instead.
Clark partly concedes the tension (Denmark’s actual immigrants have not responded to its social contract the way native Danes have; Danish politics is contested over immigrant selection) while defending Denmark on non-growth grounds: high unskilled wages, minimal visible poverty relative to California, and strong communitarian culture.

Migration selection and assimilation [§ Migration, selection, and assimilation]

Selection varies sharply by stream: English emigrants to the US were the least positively selected English emigrant group; emigrants to Australia/New Zealand more positively selected; Irish migration to England and 19th-century Scandinavian emigration both show negative selection by Clark’s reading. [?]
Descendants of negatively selected Irish migrants to the North of England remained a lower social class for over 150 years; yet Scandinavian-American communities (e.g. North Dakota) appear to perform well today despite Clark’s negative-selection claim for that stream — a tension left unresolved in the conversation.
Assimilation can be rapid and thorough: Huguenot refugees (1685) assimilated within one to two generations yet retained elite advantage (descendants four times more likely to attend Oxford/Cambridge two centuries later); a Jewish family arriving in 1800 produced a Church of England bishop within three generations. Clark locates the barrier to assimilation in economic/social failure, not in origin.

Neighbourhood, family, and place [§ Neighbourhood, family, and the limits of place]

Using his comprehensive English genealogical database, Clark finds being born in the North of England carries little independent cost once parental social position is controlled for — outcomes are overwhelmingly predicted by parental status, not place.
Regional inequality instead reflects centuries of selective internal migration (skilled workers moving south, less-skilled workers moving north), a pattern dating to the 18th century and continuing through the Industrial Revolution.
The same selective-migration frame explains Glasgow’s poor health outcomes despite decent material conditions, in Clark’s account: heavy historical out-migration of the more able left a residual population with a persisting cultural ‘hangover’ in health behaviour.

Genetics and the next book [§ Genetics: heritability, the next book, and open questions]

Clark flags as a genuine, unresolved puzzle the gap between GWAS heritability estimates (weak, even at ~4 million genotyped individuals) and much higher twin-study heritability estimates; the same data limitation may block genetic study of small populations such as Native Americans.
His forthcoming book, provisionally For Whom the Bell Curve Tolls: Genetics and Social Life in England, 1600 to 2025, uses detailed multi-generational English genealogy to test whether birth order, gender, parental death, family size, and grandparental influence affect outcomes.
Headline finding, in his words: ‘we’re mainly the product of our genetics and randomness’ — which he equates with functioning meritocracy, closing with the deliberately provocative aside that parental time investment does not appear to matter much.

Notes — Gregory Clark on Social Mobility, Migration, and Assortative Mating