limit personal choice for the betrothed, they still exploit network connections. Such marriages are often arranged for legal or economic reasons rather than from a desire to find a suitable partner (in the Western sense), and they are common in the Middle East and Asia. In some cultural settings, customs prescribe that the prospective partners be introduced to each other, and the parents take an active role in vetting the family and the potential spouse. In other settings, however, the marriage is a settled matter from the first meeting, and no courtship is allowed. Across cultures, there is considerable variation in who the matchmakers are (parents, professionals, elders, clergy), what pressures the matchmakers can exert, what qualifications the spouses must have (reputation, wealth, caste, religion), and what sanctions can be imposed if the couple refuses (disinheritance, death).
These practices are not immutable, however, even in societies where arranged marriage was formerly the norm. For example, the percentage of women living in Chengdu in Sichuan, China, who had arranged marriages shrank from 68 percent of those married between 1933 and 1948 to 2 percent of those wed between 1977 and 1987.9 Nevertheless, social-network ties still remain crucial; 74 percent of respondents in Chengdu report that the primary network that connects young people to potential mates is friends and relatives in the same age group.
Regardless of what kind of network people use, whether real or virtual, the process of searching for a mate is usually driven by homogamy, or the tendency of like to marry like (just as homophily is the tendency of like to befriend like). People search for—or, in any case, find—partners they resemble (in terms of their attributes) and partners who are of comparable “quality.” The Chicago Sex Survey, for example, shows that the great majority of marriages exhibit homogamy on virtually all measured traits, ranging from age to education to ethnicity. Other studies show that spouses usually have the same health behaviors (like eating and smoking), the same level of attractiveness, and the same basic political ideology and partisan affiliation (with rare, notable exceptions like Clinton adviser James Carville and Republican strategist Mary Matalin). We would expect more homophily in long-term relationships and less in short-term relationships (one is less finicky when it comes to sexual partners than potential spouses), and to some extent this is indeed the case: 72 percent of marriages exhibit homophily (based on a summary measure involving several traits), compared to 53 to 60 percent for other types of sexual relationships.10 In addition, as we shall see, spouses also become more similar over time because they influence each other (for example, in political affiliation, smoking behavior, or happiness).
On the one hand, homogamy makes intuitive sense. People like being around others who are similar to them. Most people find it comforting to imagine that partners resemble each other because it gives them hope that they, too, will someday be happy in a warm and loving relationship with a kindred spirit. On the other hand, think about the odds of finding someone just like you. Personal ads are full of complex laundry lists that must be very difficult, if not impossible, to satisfy: Wanted: frisky, down-to-earth, nonsmoking, leftist Democrat salsa dancer who likes guns, Bollywood films, NASCAR races, Ouija boards, beach sunsets, Cosmopolitans, country drives, and triathlons.
Indeed, the uniqueness of each human being has implications for how many people out there are a perfect fit in this sense. The age-old debate about whether you have one soul mate or a million rests in part on how picky you are. But even if there are a million compatible people for you, that is just one of every six thousand people in the whole world. If you are choosing at random, you had better go on a lot of dates. The dispiritingly unromantic conclusion is that you will never, ever find Mr. or Ms. Right. Not without some help.
But the surprising power of social networks is that they bring likes together and serve up soul mates in the same room. Bigger and broader social networks yield more options for partners, facilitate the flow of information about suitable partners via friends and friends of friends, and provide for easier (more efficient, more accurate) searching. Hence, they yield “better” partners or spouses in the end. The odds of finding that soul mate just improved substantially.
Given the structure of social networks, our tendency to be introduced to our partners, and our innate comfort with people we resemble, it is not surprising that we generally wind up meeting, having sex with, and marrying people like ourselves. The choice of a partner is constrained by the same social forces that create network ties in the first place. Who we befriend, where we go to school, where we work—all these choices largely depend on our position in a given social network. No matter where people search, their network generally acts to bring similar people together. The fact that spouses are so often similar manifestly disproves the idea that people meet and choose their partners by chance.
Big Fish, Little Pond
American satirist H. L. Mencken famously observed that wealth is “any income that is at least one hundred dollars more per year than the income of one’s wife’s sister’s husband.” With this statement, he captured an idea that is well known to most people but strangely unpopular in the formal study of economics: namely, that people often care more about their relative standing in the world than their absolute standing. People are envious. They want what others have, and they want what others want. As economist John Kenneth Galbraith argued in 1958, many consumer demands arise not from innate needs but from social pressures.11 People assess how well they are doing not so much by how much money they make or how much stuff they consume but, rather, by how much they make and consume compared to other people they know.
An essential truth in Mencken’s quip is that the two men are comparing themselves to those from whom they are three degrees removed. They do not compare themselves to strangers. Instead, they seem intent on impressing people they know. In a classic experiment investigating this phenomenon, most people reported that they would rather work at a company where their salary was $33,000 but everyone else earned $30,000 than at another, otherwise identical company where their salary was $35,000 but everyone else earned $38,000.12 Even though their absolute income is less at the first job, they think they would be happier working there than at the second. We would rather be big fish in a small pond than bigger fish in an ocean filled with whales.
Perhaps not surprisingly, this is also true of our desire to be attractive. In one creative experiment, respondents were asked which of the following two states they would rather be in:
A: Your physical attractiveness is 6; others average 4.
B: Your physical attractiveness is 8; others average 10.
Overall, 75 percent of people preferred being in situation A than in situation B. For most people, their relative attractiveness was more important than their absolute attractiveness.13 We have repeated this experiment with Harvard undergraduates, and their responses were even more skewed: 93 percent preferred situation A, and 7 percent situation B. And, of course, any bridesmaid forced to wear an unflattering dress understands this point.
These results show that our preference for relative attractiveness is more extreme than our preference for relative income. People realize how crucial it is to have sex appeal if they are to have sex. And they realize how important it is to be more attractive than their prospective mate’s other choices. In other words, relative standing is important if it has what is known as an instrumental payoff: a more appealing physique than others is a means to an end.
This preference for relative standing brings to mind another classic anecdote: Two friends are hiking in the woods and come to a river. They take off their shoes and clothes and go for a swim. As they come out of the water, they spot a hungry bear that immediately starts to run toward them. One of the men starts fleeing immediately, but
