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A Unified Theory of Marriage

Updated: May 31, 2023

Marriage rates are falling, in some countries faster than others. What explains this global trajectory and heterogeneity? People wed due to social enforcement, loving devotion or economic security. In their absence, marriages plummet. This decline may be sustained by a multitude of single ladies.

Consider three interacting variables:

  • Religion/ social enforcement

  • Companionship vs. sexual variety

  • Women’s financial security.

This theory draws on my qualitative research in Mexico, Morocco, Turkey, India, Cambodia, the US, the Gambia and Zambia.

Why marry?

Respect, love and money

  1. In conservative communities, marriage secures respect, while bachelors are eyed with suspicion and made to feel like failures. “When are you getting married?” pesters a litany of Indian relatives. Chinese singles are derided as ‘bare branches’ and ‘leftover women’. The Tswana kgotla system of village assemblies only included married men. In Catholic Ireland, unwed mothers were shamed and sentenced to forced labour in Magdalene laundries. In Mexico’s small towns, divorcees are still alienated. Fear of ostracism motivates widespread conformity.

  2. If the society liberalises, men marry due to loving devotion. Soulmates join in matrimony to assure each other of monogamous commitment. Family and friends may join the festivities, but this is ultimately a celebration of love. He voluntarily sacrifices sexual variety because he cherishes a woman’s idiosyncratic personality. Companionate marriages are usually based on heartfelt appreciation, adoration and equality.

  3. Most people also want to build a family, with someone who’ll make a ‘good parent’. In India, Indonesia, Zambia and America, grooms put a premium on women’s youth and education. Financial security matters more to brides, who often seek to secure commitment while still in their prime.

Conceptually, (1) reflects a second-order desire for respect, premised on the norm perception that marriage is widely revered. (2) is a first-order desire for one’s true love (whatever others may say). (3) is likewise first-order. This crude binary is merely intended for analytical clarity. Reality is of course a muddied, overlapping spectrum.

If secularisation outpaces gender equality, marriage rates fall.

If social enforcement breaks down, men may opt out of marriage (especially if they prefer sexual variety). Dostoevsky put it best, if God is dead then everything is permitted. As Latin America becomes less religious and more individualistic, there is less compunction to marry. Since Argentina has secularised more rapidly than Mexico, its marriage rate has fallen more sharply.

A plethora of single ladies may perpetuate a negative feedback loop

When eligible bachelors are scarce, women tend to out-compete each other with beautification, sexual charms and sexual invitations. Promiscuity is likewise highest in countries (like the Baltics) where men are in short-supply. As male incarceration in El Salvador makes it harder to find a boyfriend, women may be raising their offer.

Schmitt 2005

Ensuing disappointment depresses trust and commitment. As the share of single ladies grows ever larger, men enjoy even more opportunities for infidelity. Romance comes to resemble a Prisoner’s Dilemma, in which one or both choose to defect.

There is a second reason why the decline of marriage begets a negative feedback loop. If a man expects his dating pool to remain large, he may rather keep his options open. Why settle, when the grass could always be greener?

By contrast, where mates are scarce, men tend to avow monogamy. For example, a college-educated US male whose peers have all tied the knot might anticipate sudden drought and thus eagerly demonstrate commitment. Men make their own choices, but - to paraphrase Marx - ‘they do not make [these choices] under circumstances chosen by themselves’. Skewed ratios and high shares of singles yield myriad temptations.

Why would women opt out of marriage?

Romantic disappointment and economic independence

Since women bear strong attachments to their children and usually earn less than men, they have a strong financial incentive to marry. Mexican women may tolerate abuse and infidelity. To quote two common sayings:

Darlo todo por los hijos” (Everything for the children); No me importa que mi esposo tenga 10 capillas mientras yo sea la catedral” (It does not matter if he has ten chapels, as long as I am the cathedral).

So when women gain economic security (such as through public pensions or lotteries), they be inclined to divorce. We should thus expect more single mothers in communities with small gender gaps in earnings and/or generous public welfare. If women can manage independently, why endure men’s infidelity?

A unified theory of marriage

People marry for love, money or social approval. Financial considerations are especially salient for women, if they earn less and bear responsibility for the kids. But when women become economically independent, they needn’t tolerate disrespect. Systematically, marriage rates tend to fall with secularisation, individualism and gender parity in earnings. The rise in single women may even reinforce a self-perpetuating cycle. Why settle, if there are plenty of fish in the sea? Moreover, a multitude of sexual invitations may exacerbate promiscuity and distrust.

What’s the solution? Well, some seek to reverse this downturn by normatively championing marriage. But such policing won't make any difference in places like the US that are highly individualistic.

Norms are enforced through social policing and ostracism. People praise X and shame Y, eg skinny vs fat. This creates a particular problem for liberals who want to promote marriage norms. They want to be tolerant and inclusive, so they want to praise X without shaming Y. Unworkable. Like King Cnut, commanding the sea to stop, it’s not clear that we can reverse these structural shifts in demography, economics and culture.

SAM PANTHAKY/AFP via Getty Images

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Melvin Baker
Melvin Baker
Sep 07, 2023

If you want to ask for a raise, for example, tell your boss "I'd like to discuss a salary increase

snake game


Unknown member
Apr 30, 2023

> If secularisation outpaces gender equality, marriage rates fall.

The paragraph below just supports the claim that secularization reduces marriage rates, without any note that gender equality growing faster than secularization can prevent this. Particularly since you note that gender parity in earnings also reduces marriage rates.

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