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 the other pauses to put on his shoes. The first man screams at the second, “Why are you putting on your shoes? They won’t help you outrun the bear!” To which the second man calmly responds: “I don’t need to outrun the bear; I just need to outrun you.”
It is this same reasoning that drives ever-larger numbers of people to have plastic surgery and with greater frequency. Liposuction might yield a physical advantage for early adopters, but when everybody gets it done, the advantage goes away. As a result, people then demand other kinds of plastic surgery in a kind of silicone arms race. The breadth of services demanded explodes to parallel the spread of services through the network.
Competition for mates can actually be quite stressful. One investigation we conducted suggests that the higher the male-to-female ratio at a time when a man reaches his early twenties, the shorter his life. A man who is surrounded by other men has to work harder to find a partner, and this environment of elevated competition has long-term consequences for his health. In this regard, we are no different from a number of animal species. In one analysis, we examined the effect of the gender ratio in a sample of high-school seniors in Wisconsin in 1957—a total of 4,183 young men and 5,063 young women in 411 high schools. We found that men in high-school graduating classes with lopsided gender ratios (of more men) wound up with shorter life spans fifty years later. In another analysis of more than 7.6 million men from throughout the United States, we found that the availability of marriageable women again had a durable impact on men’s health, affecting their survival well into their later years.14
These results suggest that the people who surround us are not only a source of partners or of information about partners; they also are our chief competitors. As a result, the social network in which we find ourselves defines our prospects. It does so by defining whom we meet, by influencing our taste in what is deemed desirable in a partner, and, finally, by specifying how we are perceived by others and what competitive advantages and disadvantages we have. You don’t need to be the most beautiful or most wealthy person to get the most desirable partner; you just need to be more attractive than all the other women or men in your network. In short, the networks in which we are embedded function as reference groups, which is a social scientist’s way of saying “pond.”
In the 1950s, Robert K. Merton, a very influential social scientist, codified the basic ways that reference groups affect us: they can have comparative effects (how we or others evaluate ourselves), influence effects (the way others dictate our behaviors and attitudes), or both.15 Having unattractive social contacts may make us feel superior (comparison) but may also make us take worse care of ourselves (influence). These two effects may work at cross-purposes in our quest to find a partner.
For decades, reference groups have been seen as abstract categories: people often compare themselves to other “middle-class Americans” or other “members of their grade at school” or other “amateur soccer players.” But exciting advances in network science are now enabling us to map out exactly who these references group are for each person. Many people may be more attractive than we are, but our only real competitors are the people in our intended’s social network.
Everyone Else Is Doing It
People we know influence how we think and act when it comes to sex. To begin with, both friends and strangers affect our perceptions of a prospective partner’s attractiveness, consciously and unconsciously. These effects go beyond basic tendencies that men and women have to make judgments about appearance; for example, it has repeatedly been shown that men find women with low waist-to-hip ratios more attractive, and women value certain facial features in men. Until recently, most research on partner choice and assessments of attractiveness has focused on an individual’s independent preferences. Yet there are good biological and social reasons to suppose that perceptions of attractiveness can spread from person to person.
An experiment suggests how. First, investigators took pictures of men who were rated equally attractive by a group of women.16 Then, they presented pairs of pictures of two equally attractive men to another group of women, but between each pair of pictures, they inserted a picture of a woman who was “looking” at one of the men. This woman was smiling or had a neutral facial expression. The female subjects were much more likely to judge a man to be more attractive than his competitor if the woman interposed between the photos was smiling at him than if she was not.
In another study, a group of women again rated photographs of men for attractiveness. The photos were accompanied by short descriptions, and when the men were described as “married,” women’s ratings of them went up.17 In still another study, men in photographs with attractive female “girlfriends” were judged to be more attractive when the “girlfriend” was in the photo than when she was not. Having a plain “girlfriend,” however, did not enhance a man’s appeal as much.18 And, astoundingly, women’s preferences for men who are already attached may vary according to where the women are in their menstrual cycles. When they are in the fertile phase of the cycle, they have a relative