The Logic of Assortative Matching
— Why Does Similarity Create Stability?

Across the many matching phenomena in human society — from business partnerships to academic collaborations, from career choices to long-term relationships — we observe a recurring pattern: similar individuals tend to pair with each other. Economists call this "assortative matching," while sociologists call it the "homophily principle." This is not coincidental but rather an inevitable result deeply rooted in mathematical structures and economic logic. This article explores the modern scientific foundations behind this seemingly traditional wisdom from the intersecting perspectives of matching theory, information economics, and sociology.

I. The Universality of Assortative Matching: From Empirical Facts to Theoretical Questions

In 1954, sociologists Paul Lazarsfeld and Robert Merton first systematically documented the phenomenon of "homophily": people tend to form connections with those similar to themselves.^[1] Decades of empirical research since then have repeatedly confirmed that similarity is one of the strongest predictors across friendship networks, business partnerships, and long-term romantic relationships.^[2]

The universality of this phenomenon is striking. Cross-cultural research shows that assortative matching is the dominant pattern across different societies in Asia, Europe, the Americas, and Africa.^[3] Economist Gary Becker, in his pioneering research on family economics, pointed out that the degree of assortative matching along dimensions such as education level, income, religious beliefs, and racial background has not declined over the past half-century and has actually increased along certain dimensions.^[4]

This raises a core theoretical question: Is assortative matching a result of "preference" or an inevitability of "equilibrium"? In other words, do people choose assortative matching because they "like" similar people, or because assortative matching is a "stable" arrangement — even if preferences do not dictate it?

This article will argue that even without assuming a "preference for similarity," assortative matching can naturally emerge as an equilibrium outcome. This conclusion has profound policy implications: it means that merely changing "attitudes" or "preferences" may not be sufficient to alter matching patterns — we need to understand and adjust the structural factors that produce this equilibrium.

II. Becker's Matching Theory: When Production Functions Determine Matching Patterns

In 1973, Gary Becker published his profoundly influential paper "A Theory of Marriage," providing the first rigorous economic explanation for assortative matching.^[5] Becker's core insight was that matching can be viewed as a "production" activity, where both parties jointly invest resources to produce some form of "joint output."

2.1 Complementarity vs. Substitutability

Let the "types" of two individuals be x and y (for example, think of these as education level, wealth, or any measurable attribute). The joint value they produce when matched is f(x, y). The key question is: the properties of f determine the equilibrium matching pattern.

Definition: If f possesses supermodularity, that is,

∂²f / ∂x∂y > 0

then x and y are said to be complementary. Intuitively, this means that a high-type individual gains more additional value from pairing with another high-type individual than from pairing with a low-type individual.^[6]

Becker's Theorem: If the joint production function f(x, y) possesses supermodularity, then the equilibrium matching is positively assortative — that is, high types match with high types, and low types match with low types.^[7]

2.2 Proof Intuition

Consider the simplest case: two men and two women, with types x_H (high), x_L (low) and y_H (high), y_L (low). There are two possible matchings:

• Assortative matching: (x_H, y_H) and (x_L, y_L)
• Cross matching: (x_H, y_L) and (x_L, y_H)

The total value of assortative matching is:

V_assortative = f(x_H, y_H) + f(x_L, y_L)

The total value of cross matching is:

V_cross = f(x_H, y_L) + f(x_L, y_H)

The supermodularity condition precisely implies that V_assortative > V_cross. Therefore, assortative matching produces a higher total surplus and will emerge as the equilibrium in a competitive market.

2.3 Sources of Complementarity in Reality

What kinds of "production" exhibit complementarity? Becker and subsequent researchers identified several important sources:^[8]

• Human capital investment: Partners with similar high education levels can more effectively support each other's career development and children's education. Research shows that educationally assortative households enjoy economies of scale in children's educational investment.^[9]
• Risk sharing: Partners with similar income levels can more effectively share risk, because their risk preferences and risk tolerance are more aligned.^[10]
• Consumption complementarity: Individuals with similar tastes derive higher utility from joint consumption (such as housing, travel, and cultural activities).^[11]
• Negotiation efficiency: Individuals with similar backgrounds reach consensus more easily in household decisions, reducing conflict costs.^[12]

III. Search Theory: How Information Costs Shape Matching

Becker's analysis assumed complete information — everyone knows everyone else's "type." But the real world is filled with information asymmetry. Search Theory provides another powerful explanation for assortative matching.

3.1 The Costs and Benefits of Search

In the 1970s, George Stigler pioneered search theory, analyzing how people make decisions in markets with incomplete information.^[13] Dale Mortensen and Christopher Pissarides applied search theory to labor markets, developing the "Search and Matching" framework, which earned them the 2010 Nobel Prize in Economics.^[14]

In matching markets, search costs include:

• Direct costs: Time, money, energy
• Opportunity costs: Other opportunities forgone during the search
• Information costs: The difficulty of evaluating potential matches

Core insight: Information costs are significantly lower between individuals with similar backgrounds.^[15]

3.2 Why Is "In-Group" Search Cheaper?

Consider someone from academia evaluating another scholar's "type": they can easily interpret the other person's publication record, academic reputation, and the quality of their research directions. But if they need to evaluate someone from an entirely different field — say, an entrepreneur — they would need to learn a whole new evaluative framework.^[16]

This "asymmetry in evaluation difficulty" exists across many dimensions:

• Educational background: People in the same discipline can more easily assess each other's professional competence
• Social class: People from similar backgrounds share implicit standards for evaluating "taste" and "character"
• Cultural background: People from the same culture can more easily interpret each other's behavioral signals
• Social networks: Mutual friends provide low-cost "reference information"

3.3 Reservation Value and Matching Thresholds

In search theory, every individual has a "reservation value" — potential matches below this threshold are rejected, and the search continues.^[17]

The key is that high-type individuals also have higher reservation values. This creates a "two-way screening" process:

• High-type individuals reject low-type individuals (because they fall below the reservation value)
• Even if low-type individuals are willing, they find it difficult to access high-type individuals (because their social circles do not overlap)

Even without any assumption of "preference for similarity," purely search-cost considerations lead assortative matching to become the equilibrium outcome.^[18]

3.4 Mathematical Model: Search Equilibrium

Let an individual's type be θ, and the search cost be c. In each period, the individual can choose to accept the current match (of type θ′) or continue searching. The value of a match is v(θ, θ′).

In the steady-state equilibrium, the individual's reservation type θ̄(θ) satisfies:

v(θ, θ̄) = c / δ + ∫_θ̄^∞ [v(θ, θ′) − v(θ, θ̄)] dF(θ′)

where δ is the discount rate and F is the type distribution. This equation shows that the higher the reservation type, the lower the expected return from search (because the probability of encountering an even higher type is smaller), while the search cost remains constant. The equilibrium reservation type equates the marginal search cost with the marginal search benefit.^[19]

Under many reasonable assumptions, this model produces "monotone matching" — θ̄(θ) is an increasing function of θ, meaning that high-type individuals have higher reservation thresholds, thereby leading to assortative matching.^[20]

IV. Signaling Theory and Screening: Observable Proxy Variables

Michael Spence's "Signaling Theory," proposed in 1973, provides yet another important perspective for understanding assortative matching.^[21] In a world of information asymmetry, people need to rely on "signals" to infer the other party's "true type."

4.1 Education as a Signal

Spence's classic example is education. Suppose high-ability individuals face lower costs of obtaining education (because learning comes more easily to them), while employers cannot directly observe ability. In equilibrium, high-ability individuals choose to obtain more education — not because education enhances their ability, but because education "proves" the high ability they already possessed.^[22]

The same logic applies to matching markets. When we cannot directly observe a person's "true type" (such as integrity, ability, or future potential), we rely on observable "proxy variables":

• Family background: As a signal of "upbringing quality" and "genetic potential"
• Education level: As a signal of "cognitive ability" and "self-discipline"
• Occupational status: As a signal of "competence" and "social recognition"
• Social circle: As a signal of "character" and "credibility" ("your friends define you")

4.2 Signal Credibility and Interpretation Costs

The key question is: why can individuals with similar backgrounds more effectively interpret each other's signals?^[23]

The answer lies in the fact that "signal interpretation" requires background knowledge. Someone from academia can easily distinguish between "published in Nature" and "published in an obscure journal." But for an outsider, these two signals might appear roughly equivalent.

This creates a "homophily preference in signal interpretation":

• Insiders can interpret signals at low cost and with high accuracy
• Outsiders face high cost and low accuracy in signal interpretation
• Therefore, within-group matching carries lower "information rents" and smaller risks of matching errors

4.3 The Cost of "Not Understanding"

What happens when two people from very different backgrounds attempt to evaluate each other?^[24]

First, they may misjudge each other's type. Someone from a wealthy family might interpret "simplicity" as "poverty," when the other person simply prefers minimalism. Someone from academia might interpret "not reading books" as "uncultured," when the other person simply prefers experiential learning.

Second, they may be unable to assess each other's "market value." If you do not understand the other person's world, you cannot judge their standing within it. This leads to a variant of the "Lemons Problem": high-type individuals may be undervalued, causing them to exit the cross-group matching market.^[25]

V. Transaction Costs and Implicit Contracts

Nobel laureate Oliver Williamson's Transaction Cost Economics provides yet another explanatory framework for assortative matching.^[26]

5.1 Long-Term Relationships as Incomplete Contracts

Any long-term relationship — whether a business partnership or a life partnership — is essentially an "incomplete contract."^[27] We cannot specify in advance all possible scenarios and corresponding actions. Therefore, the success of a long-term relationship depends on:

• Ex ante: Selecting the "right" partner
• Ex post: Effectively handling unforeseen situations

Williamson identified the following transaction costs:^[28]

• Search costs: Finding a suitable partner
• Negotiation costs: Reaching an agreement
• Monitoring costs: Ensuring the agreement is honored
• Enforcement costs: Dealing with breaches
• Adaptation costs: Adjusting the agreement in response to changing circumstances

5.2 Why Does Similar Background Reduce Transaction Costs?

In long-term relationships, many important "agreements" are implicit.^[29] For example:

• How to divide household chores?
• How to make major decisions?
• How to manage relationships with each other's families of origin?
• How to raise children?
• How to allocate income?

These questions are rarely discussed explicitly, yet they are major sources of conflict in long-term relationships. The advantage of similar backgrounds is that partners are more likely to share similar "default answers" to these questions.^[30]

When two people agree on the definition of "normal," many potential conflicts are resolved before they even arise. They do not need to negotiate explicitly, because each other's behavior already falls within the other's expectations. This dramatically reduces the "operating costs" of the relationship.

5.3 The Economics of "Getting Along"

The everyday expression "getting along" actually has profound economic meaning.^[31]

Communication requires "common knowledge" as a foundation. When two people share similar educational backgrounds, cultural experiences, and values, they have more "common knowledge" and communicate more efficiently. They can convey more information with fewer words, because much background knowledge can be "omitted."

Conversely, two people from very different backgrounds must spend more effort on "explaining" and "confirming" in every conversation. This is not just a time cost but also a cognitive burden. Over the long term, this burden erodes the quality of the relationship.^[32]

VI. Cultural Capital: Bourdieu's Sociological Perspective

French sociologist Pierre Bourdieu's concept of "Cultural Capital" provides a deeper sociological explanation for assortative matching.^[33]

6.1 Three Forms of Capital

Bourdieu distinguished three forms of capital:^[34]

• Economic capital: Money and material resources
• Social capital: Social networks and relationships
• Cultural capital: Education, taste, manners, and linguistic ability

Cultural capital can be further subdivided into:

• Embodied: Internalized manners, accent, and taste
• Objectified: Books, artworks, and diplomas
• Institutionalized: Academic degrees and professional certifications

6.2 "Fields" and Matching

Another core concept from Bourdieu is the "field" — a social space with its own rules and standards for capital valuation.^[35] Academia is one field, the business world is another, and the art world yet another.

Within each field, specific types of capital are more valued. Academia values publications and citations; the business world values revenue and market capitalization; the art world values creativity and style.

Key insight: When two people come from the same "field," their capital is "commensurable" — it can be directly compared and evaluated. But when they come from different fields, the "exchange rate" of capital becomes ambiguous.^[36]

Who is "more valuable" — a university professor or a successful entrepreneur? This question has no objective answer, because their value is defined within different fields. This "incommensurability" makes cross-field matching evaluation difficult.

6.3 "Habitus" and Compatibility

Bourdieu's most important concept is "habitus" — an internalized system of dispositions that determines how we perceive, think, and act.^[37]

Habitus is acquired through socialization and reflects our class position and life experiences. It includes:

• Judgments of taste regarding "good" and "bad"
• Intuitive reactions to what is "normal" and "strange"
• Physical sensations of "comfort" and "discomfort"
• Attention allocation toward what is "interesting" and "boring"

Habitus compatibility is key to the success of long-term relationships. When two people share similar habitus, they naturally enjoy the same activities, appreciate the same things, and react to the same situations in the same ways. This sense of "natural" harmony is very difficult to replicate between two people with very different habitus.^[38]

VII. The Mathematics of Matching Stability: Extensions of Gale-Shapley

Let us return to the mathematical framework. The 2012 Nobel Prize in Economics was awarded to Lloyd Shapley and Alvin Roth for their contributions to stable matching theory.^[39] This theory helps us understand why assortative matching tends to be "stable."

7.1 Definition of Stable Matching

Recall the definition of stable matching: a matching is stable if and only if there is no "blocking pair" — that is, no two individuals who would both prefer to be matched with each other rather than their current partners.^[40]

Theorem (Gale-Shapley): For any two-sided matching problem, a stable matching always exists. The deferred acceptance algorithm can find such a matching.

7.2 Assortative Preferences and Stability

Now consider a special case: everyone's preferences over potential partners are "unanimous" — that is, everyone agrees on who is "best," who is "second best," and so on. This is realistic along certain dimensions: most people would agree that health is preferable to illness, wealth to poverty, and intelligence to ignorance.^[41]

Under these "unanimous preferences":

Proposition: If all individuals' preferences over potential partners are unanimous (ordered along a single dimension), then the unique stable matching is perfectly assortative — first-ranked pairs with first-ranked, second-ranked with second-ranked, and so on.

Proof: Suppose the matching is not perfectly assortative, meaning there exists some individual ranked i matched with someone ranked j (i ≠ j). Without loss of generality, assume i < j. Then the i-th ranked person and the other i-th ranked person would form a blocking pair — they would both prefer each other (the i-th ranked person prefers the other i-th ranked person over the j-th ranked person; the other i-th ranked person also prefers this i-th ranked person over their current partner). This contradicts stability.

7.3 The Complexity of Multidimensional Preferences

Of course, real-world preferences are multidimensional. Some people prioritize wealth, others appearance, and still others a sense of humor. This increases the complexity of the problem, but the core insight still holds:^[42]

When two people are "well-matched" across multiple dimensions, their pairing is more likely to be stable. This is because they are unlikely to find an alternative who is better across all dimensions. Conversely, a "cross match" — for instance, someone who scores high on dimension A but low on dimension B paired with someone who scores high on B but low on A — is more easily disrupted. The moment someone who is moderate on both dimensions appears, they may form part of a blocking pair.

VIII. The Costs of Cross Matching: Empirical Evidence

Theoretical analysis suggests that assortative matching should be more stable. Does empirical research support this prediction?^[43]

8.1 Educational Homogamy and Relationship Stability

A large body of research shows that partners with similar education levels have more stable relationships. Schwartz and Mare (2005) analyzed long-term data from the United States and found that relationship dissolution rates for educationally assortative matches were significantly lower than for cross matches.^[44]

Similar findings appear across other dimensions:^[45]

• Religiously assortative matches are more stable
• Partners close in age have more durable relationships
• Partners from similar social classes experience less conflict

8.2 The Long-Term Costs of Cultural Differences

Research on cross-cultural matching provides interesting insights. Although many cross-cultural matches initially report high satisfaction (possibly due to "novelty"), they face more challenges over the long term:^[46]

• Communication barriers (even when speaking the same language, styles of expression may differ)
• Conflicting family expectations
• Differences in parenting philosophies
• Incompatible social networks

This does not mean that cross-cultural matching is doomed to fail — many cross-cultural relationships are very successful. But they require more "investment" to overcome the additional costs created by cultural differences.^[47]

8.3 The Asymmetric Risks of "Marrying Up" and "Marrying Down"

When a match is "asymmetric" — one party is "superior" to the other along certain dimensions — specific risk patterns emerge:^[48]

• Risk for the "advantaged" party: May chronically feel they are "settling," or face external pressure (questioning from family and friends)
• Risk for the "disadvantaged" party: May chronically feel "insecure," worried about the other leaving
• Power imbalance: The party with more resources holds more decision-making power, which may lead to long-term dissatisfaction

These risks are not insurmountable, but they need to be recognized and managed. Many "mismatched" relationships fail not because both parties did not try hard enough, but because they underestimated these structural risks.

IX. "New Homogamy" in Modern Society

Some might ask: in modern society, where traditional "family pedigree" matters less, is assortative matching declining?^[49]

Empirical research gives a surprising answer: assortative matching has not declined — only the dimensions have changed.

9.1 The Rise of Educational Homogamy

Over the past fifty years, the degree of educational assortative matching has risen significantly. This is largely because of rising female education levels — as the number of highly educated women has increased, matching between highly educated men and women has naturally increased.^[50]

Research by Greenwood et al. (2014) showed that the rise of educational assortative matching is one of the important causes of growing income inequality in the United States. When highly educated (high-income) individuals only match with other highly educated individuals, the gap in household income is amplified.^[51]

9.2 Value Homogamy

In modern society, "values" have become a new dimension of homogamy. Attitudes toward the following issues:^[52]

• Political orientation (liberal vs. conservative)
• Lifestyle (veganism, environmentalism)
• Religious attitudes (devout vs. secular)
• Family planning (whether to have children, when to have children)

These "soft" dimensions of homogamy play an increasingly important role in modern matching markets. Dating app algorithms explicitly use these dimensions to recommend matches.^[53]

9.3 Homogenization of Social Networks

The rise of social media has intensified the homogenization of social networks. Algorithms tend to recommend people and content that are "similar to us," creating an "echo chamber" effect.^[54]

This has profound implications for matching markets:

• The people we "encounter" increasingly resemble ourselves
• Opportunities for "cross-group" encounters diminish
• Assortative matching is therefore reinforced

X. Policy Implications and Personal Choice

What policy implications does the economic analysis of assortative matching carry? What insights does it offer for personal choices?

10.1 The Challenge of Social Mobility

Assortative matching is one of the key mechanisms behind the solidification of social classes. When individuals of high socioeconomic status only match with other high-status individuals, their resources (economic, social, and cultural capital) circulate within this group rather than trickling down.^[55]

This negatively affects social mobility. If we wish to increase social mobility, we may need to consider how to break the self-reinforcing cycle of assortative matching — for example, through equalizing educational opportunities, designing public spaces, and promoting mixed-income communities.

10.2 Reevaluating "Traditional Wisdom"

The analysis in this article shows that much of what is considered "traditional" or even "conservative" wisdom about matching actually has solid economic and sociological foundations.^[56]

This does not mean we should blindly follow these "traditions." But it reminds us:

• Certain "traditions" may contain forgotten wisdom
• Challenging "tradition" requires understanding its logic rather than simply dismissing it
• Successful "cross matching" may require special conditions or additional investment

10.3 The Complexity of Personal Choice

Finally, what insights does this analysis offer individuals facing matching decisions?^[57]

First, understand the risks. Cross matching is not impossible to succeed, but it faces additional structural challenges. When entering such a relationship, it is best to go in with open eyes and understand the potential difficulties.

Second, invest in "bridging." If one chooses cross matching, both parties need to invest additionally in "bridging" their differences — learning each other's "language," understanding each other's "field," and building shared "habitus."^[58]

Third, distinguish between "changeable" and "unchangeable" differences. Some differences (such as political leanings and lifestyle preferences) may evolve and converge over time. Others (such as family background and cultural roots) are more deeply entrenched. Prioritizing matches that are similar along "unchangeable" dimensions may be a more robust strategy.

XI. Conclusion: The Wisdom of Equilibrium

This article has analyzed the logical foundations of assortative matching from multiple disciplinary perspectives — matching theory in economics, signaling theory in information economics, transaction cost theory in organizational economics, and cultural capital theory in sociology.^[59]

The core conclusion is that assortative matching is not merely a result of "preference" but an inevitability of "equilibrium." Even without assuming that people "prefer similarity," purely structural factors — search costs, signal interpretation, transaction costs, and cultural compatibility — lead assortative matching to become the dominant pattern.

This conclusion has several important implications:

1. The rational basis of traditional wisdom: Traditional notions of "being well-matched" found in many cultures may contain forgotten wisdom. They are not necessarily "prejudice" or "conservatism" but may reflect an intuitive understanding of matching market structures.
2. The additional costs of cross matching: Successful cross matching is possible, but it requires overcoming additional structural barriers. When entering such a relationship, one should fully recognize these costs and be prepared to invest in overcoming them.
3. The possibility of social design: If we wish to reduce social homogamy (for example, to increase social mobility or reduce polarization), we need to change the structural factors that produce assortative matching, rather than merely calling on people to change their "prejudices."

Ultimately, everyone faces their own matching choices. The analysis in this article is not meant to tell you what you "should" choose but to help you understand the structural environment surrounding your choices. With this understanding, you can make wiser and more deliberate decisions — whether following the logic of equilibrium or consciously challenging it.^[60]

"To understand necessity is the beginning of freedom." — Spinoza

References

1. Lazarsfeld, P. F., & Merton, R. K. (1954). Friendship as a social process: A substantive and methodological analysis. In M. Berger (Ed.), Freedom and Control in Modern Society (pp. 18-66). Van Nostrand.
2. McPherson, M., Smith-Lovin, L., & Cook, J. M. (2001). Birds of a feather: Homophily in social networks. Annual Review of Sociology, 27(1), 415-444. DOI
3. Kalmijn, M. (1998). Intermarriage and homogamy: Causes, patterns, trends. Annual Review of Sociology, 24(1), 395-421. DOI
4. Becker, G. S. (1991). A Treatise on the Family (Enlarged ed.). Harvard University Press.
5. Becker, G. S. (1973). A theory of marriage: Part I. Journal of Political Economy, 81(4), 813-846. DOI
6. Topkis, D. M. (1998). Supermodularity and Complementarity. Princeton University Press.
7. Becker, G. S. (1974). A theory of marriage: Part II. Journal of Political Economy, 82(2), S11-S26. DOI
8. Browning, M., Chiappori, P.-A., & Weiss, Y. (2014). Economics of the Family. Cambridge University Press.
9. Mare, R. D. (1991). Five decades of educational assortative mating. American Sociological Review, 56(1), 15-32. DOI
10. Chiappori, P.-A., & Reny, P. J. (2016). Matching to share risk. Theoretical Economics, 11(1), 227-251. DOI
11. Lam, D. (1988). Marriage markets and assortative mating with household public goods. Journal of Human Resources, 23(4), 462-487. DOI
12. Lundberg, S., & Pollak, R. A. (1996). Bargaining and distribution in marriage. Journal of Economic Perspectives, 10(4), 139-158. DOI
13. Stigler, G. J. (1961). The economics of information. Journal of Political Economy, 69(3), 213-225. DOI
14. Mortensen, D. T., & Pissarides, C. A. (1994). Job creation and job destruction in the theory of unemployment. Review of Economic Studies, 61(3), 397-415. DOI
15. Adachi, H. (2003). A search model of two-sided matching under nontransferable utility. Journal of Economic Theory, 113(2), 182-198. DOI
16. Shimer, R., & Smith, L. (2000). Assortative matching and search. Econometrica, 68(2), 343-369. DOI
17. McCall, J. J. (1970). Economics of information and job search. Quarterly Journal of Economics, 84(1), 113-126. DOI
18. Smith, L. (2006). The marriage model with search frictions. Journal of Political Economy, 114(6), 1124-1144. DOI
19. Burdett, K., & Coles, M. G. (1997). Marriage and class. Quarterly Journal of Economics, 112(1), 141-168. DOI
20. Eeckhout, J. (1999). Bilateral search and vertical heterogeneity. International Economic Review, 40(4), 869-900. DOI
21. Spence, M. (1973). Job market signaling. Quarterly Journal of Economics, 87(3), 355-374. DOI
22. Spence, M. (2002). Signaling in retrospect and the informational structure of markets. American Economic Review, 92(3), 434-459. DOI
23. Hoppe, H. C., Moldovanu, B., & Sela, A. (2009). The theory of assortative matching based on costly signals. Review of Economic Studies, 76(1), 253-281. DOI
24. Mailath, G. J., Postlewaite, A., & Samuelson, L. (2013). Pricing and investments in matching markets. Theoretical Economics, 8(2), 535-590. DOI
25. Akerlof, G. A. (1970). The market for "lemons": Quality uncertainty and the market mechanism. Quarterly Journal of Economics, 84(3), 488-500. DOI
26. Williamson, O. E. (1975). Markets and Hierarchies: Analysis and Antitrust Implications. Free Press.
27. Hart, O. (1995). Firms, Contracts, and Financial Structure. Oxford University Press.
28. Williamson, O. E. (1985). The Economic Institutions of Capitalism. Free Press.
29. MacNeil, I. R. (1980). The New Social Contract: An Inquiry into Modern Contractual Relations. Yale University Press.
30. Dew, J., Britt, S., & Huston, S. (2012). Examining the relationship between financial issues and divorce. Family Relations, 61(4), 615-628. DOI
31. Clark, H. H. (1996). Using Language. Cambridge University Press.
32. Gottman, J. M., & Silver, N. (1999). The Seven Principles for Making Marriage Work. Three Rivers Press.
33. Bourdieu, P. (1984). Distinction: A Social Critique of the Judgement of Taste (R. Nice, Trans.). Harvard University Press. (Original work published 1979)
34. Bourdieu, P. (1986). The forms of capital. In J. Richardson (Ed.), Handbook of Theory and Research for the Sociology of Education (pp. 241-258). Greenwood Press.
35. Bourdieu, P., & Wacquant, L. J. D. (1992). An Invitation to Reflexive Sociology. University of Chicago Press.
36. DiMaggio, P. (1997). Culture and cognition. Annual Review of Sociology, 23(1), 263-287. DOI
37. Bourdieu, P. (1990). The Logic of Practice (R. Nice, Trans.). Stanford University Press. (Original work published 1980)
38. Bourdieu, P. (1996). On the family as a realized category. Theory, Culture & Society, 13(3), 19-26. DOI
39. The Nobel Prize. (2012). Press release: The Prize in Economic Sciences 2012. nobelprize.org
40. Gale, D., & Shapley, L. S. (1962). College admissions and the stability of marriage. American Mathematical Monthly, 69(1), 9-15. DOI
41. Roth, A. E., & Sotomayor, M. A. O. (1990). Two-Sided Matching: A Study in Game-Theoretic Modeling and Analysis. Cambridge University Press.
42. Chiappori, P.-A., Salanié, B., & Weiss, Y. (2017). Partner choice, investment in children, and the marital college premium. American Economic Review, 107(8), 2109-2167. DOI
43. Schwartz, C. R. (2013). Trends and variation in assortative mating: Causes and consequences. Annual Review of Sociology, 39, 451-470. DOI
44. Schwartz, C. R., & Mare, R. D. (2005). Trends in educational assortative marriage from 1940 to 2003. Demography, 42(4), 621-646. DOI
45. Kalmijn, M., & van Tubergen, F. (2010). A comparative study of religious assortative mating in Europe. Social Science Research, 39(3), 516-527. DOI
46. Fu, X., & Heaton, T. B. (2008). Racial and educational homogamy: 1980 to 2000. Sociological Perspectives, 51(4), 735-758. DOI
47. Zhang, Y., & Van Hook, J. (2009). Marital dissolution among interracial couples. Journal of Marriage and Family, 71(1), 95-107. DOI
48. Bertrand, M., Kamenica, E., & Pan, J. (2015). Gender identity and relative income within households. Quarterly Journal of Economics, 130(2), 571-614. DOI
49. Blossfeld, H.-P. (2009). Educational assortative marriage in comparative perspective. Annual Review of Sociology, 35, 513-530. DOI
50. Schwartz, C. R., & Mare, R. D. (2012). The proximate determinants of educational homogamy: The effects of first marriage, marital dissolution, remarriage, and educational upgrading. Demography, 49(2), 629-650. DOI
51. Greenwood, J., Guner, N., Kocharkov, G., & Santos, C. (2014). Marry your like: Assortative mating and income inequality. American Economic Review, 104(5), 348-353. DOI
52. Huber, G. A., & Malhotra, N. (2017). Political homophily in social relationships: Evidence from online dating behavior. Journal of Politics, 79(1), 269-283. DOI
53. Hitsch, G. J., Hortaçsu, A., & Ariely, D. (2010). Matching and sorting in online dating. American Economic Review, 100(1), 130-163. DOI
54. Sunstein, C. R. (2017). #Republic: Divided Democracy in the Age of Social Media. Princeton University Press.
55. Chetty, R., Hendren, N., Kline, P., & Saez, E. (2014). Where is the land of opportunity? The geography of intergenerational mobility in the United States. Quarterly Journal of Economics, 129(4), 1553-1623. DOI
56. Haidt, J. (2012). The Righteous Mind: Why Good People Are Divided by Politics and Religion. Vintage Books.
57. Finkel, E. J., Eastwick, P. W., Karney, B. R., Reis, H. T., & Sprecher, S. (2012). Online dating: A critical analysis from the perspective of psychological science. Psychological Science in the Public Interest, 13(1), 3-66. DOI
58. Putnam, R. D. (2000). Bowling Alone: The Collapse and Revival of American Community. Simon & Schuster.
59. Chiappori, P.-A., & Salanié, B. (2016). The econometrics of matching models. Journal of Economic Literature, 54(3), 832-861. DOI
60. Elster, J. (2007). Explaining Social Behavior: More Nuts and Bolts for the Social Sciences. Cambridge University Press.