Games Primates Play: An Undercover Investigation of the Evolution and Economics of Human Relationships

by Dario Maestripieri

  Can the Commitment Problem Be Solved?

  Regardless of whether or not the Handicap Principle is the best explanation for the bizarre behaviors discussed in this chapter, Zahavi’s approach is important because it raises the question of why bonding rituals—and more generally expressions of affiliation and affection—are the way they are. One could argue that engaging in any joint activity, whether fondling each other’s testicles or standing side by side and watching the sun set, can represent a bonding experience for two individuals. Moreover, monitoring your partner’s behavior while engaging in a joint activity can provide some information about the way he or she feels about the relationship. In reality, however, the bonding rituals observed in animals are not arbitrary activities, and the same can be said for some human rituals as well. It is not an evolutionary accident that so many bonding rituals in animals consist of risky interactions involving vulnerable body parts or acts that are otherwise physically intrusive and stressful. And although, in theory, any aspects of a partner’s behavior in a joint activity could provide hints about his or her commitment, in practice the amount and level of imposition a partner is willing to tolerate provides more reliable information than anything else.

  The HP applies this approach not only to bonding rituals but more generally to all aspects of animal and human communication. Human language is a peculiar form of communication in which arbitrary sounds or gestures are paired with objects or concepts. Arbitrary words and gestures that have a culturally agreed-upon meaning are referred to as symbols. In human nonlinguistic communication and in animal communication, however, the signals are not arbitrary. Rather, they are specifically designed to elicit particular responses in their receivers. For example, the alarm calls given by animals after spotting a predator have acoustic characteristics that are designed to elicit attention and arousal in the listener, while the pain cries of animal and human babies have acoustic characteristics, such as high frequency and high pitch, that are designed to elicit anxiety in the caregivers. Consistent with modern evolutionary approaches to communication, the HP raises the question of why expressions of love and affection in humans are “designed” the way they are (why do lovers kiss the way they do?) and suggests that some of these signals have stress-inducing properties. Although the validity of this and other suggestions remains to be tested, the approach is sound, and the questions being raised are valid. Thus, in addition to bringing economic cost-benefit analyses to the forefront of animal behavior research, the HP has also contributed to the incorporation of modern evolutionary approaches into the study of communication and enhanced our understanding of the design and function of signals.

  But going back to the issue of cooperative relationships raised in the previous chapter, does bond-testing with handicaps really solve the commitment problem? Are relationships in which the commitment is frequently tested with impositions more stable and happier than those without such bond-testing?

  Leo Tolstoy’s Anna Karenina famously opens: “Happy families are all alike but every unhappy family is unhappy in its own way.” Romantic and marital relationships can come to an end for many different reasons, including, among others, changes in costs and benefits to one or both partners, changes in feelings, accomplishment of goals, chance encounters with other potential partners, and so on. The same is true for business partnerships and other kinds of cooperative relationships in humans or in animals, especially when these involve individuals that are not genetically related to each other. What the baboons seem to tell us is that when you are in a cooperative relationship, you must keep an eye on it at all times so that you won’t be caught by surprise when things change. However, I doubt that testing the bond in and of itself can make a relationship stronger or more stable, unless it is accompanied by other efforts. Anyone who has seen soap operas or Oprah knows what these efforts are: keep your romantic feelings alive; make sure that the cost-benefit ratio is always favorable for both of you; make sure you always have clear and important shared goals; and don’t look around for other options lest you fall prey to temptation.

  Chapter 8

  Shopping for Partners in the Biological Market

  Finding the Right Partner

  Cooperative relationships—whether it’s an agonistic alliance between primate males, a business partnership between restaurant co-owners, or a marriage between lovers—all have one common risk: things can go wrong because one partner cooperates one moment and cheats in another, or one partner promises eternal commitment one day and ends the relationship the next. So before we enter into a cooperative relationship we should do some research about how our partner has behaved in the past, and then monitor his or her every move; play tit-for-tat; provide incentives and rewards for cooperation as well as discouragement and punishment for cheating; use feelings, morality, religion, and the legal system to make our partner behave; and finally, check the strength of his or her commitment with bizarre, risky, annoying, or sexually daring behaviors on a daily basis.

  Despite all of these precautions, a relationship between two individuals can still go wrong. One simple reason for this failure may be that we picked the wrong partner to begin with—someone who is not a good cooperator in general, or not a good match for us. The success of our cooperative relationships may depend in large part, not on how we or our partners behave, but on who we choose as our partner and whether or not he or she is the right person for us.

  Economists and evolutionary biologists have developed two different types of theoretical models of cooperation—those that focus on partner control and those that focus on partner choice. Models of partner control, such as the Prisoner’s Dilemma, take the formation of a cooperative partnership as a given and concentrate on the strategies that each partner uses to avoid being cheated by the other. Successful strategies in the Prisoner’s Dilemma are those based on the partner’s behavior in the past and the probability of cheating in the future. In this and other models involving one pair of players, it is assumed either that the pairs are formed by some external entity—say, the police officers who arrest and interrogate two suspects of a crime—or that individuals are paired off randomly. For each player, the only alternative to an interaction with the partner is no interaction at all. In the real world, however, people often choose a partner out of many individuals. And in nature, situations in which individuals choose their partners are generally more common than those in which partners arise arbitrarily or are randomly assigned. When animals do business with someone else, first they choose their partner very carefully—after sampling many potential candidates for the job, either at the same time or one after another—and then they monitor and control their partner’s behavior to ensure continuing profit from their venture.

  As I discussed in Chapter 6, the process by which employer and employee or landlord and tenant select each other shares many features with the process through which people search for a romantic partner. In both kinds of cases, individuals operate in a market regulated by the laws of supply and demand. Evolutionary biologists have taken this a step further: they have shown that the process of partner choice in the human employment and marriage markets is remarkably similar to the process through which all organisms—including viruses, bacteria, plants, and animals—find partners for all kinds of cooperative social relationships.1 Some of these enterprises include mutually beneficial interactions between different organisms, such as plants and insects, parasites and their hosts, or different animal species such as the cleaner fish and their clients (discussed in Chapter 5). The same models developed by economists and evolutionary biologists can explain partner choice in all of these seemingly disparate aspects of life. We’ll begin with something everyone is familiar with: the human mating market.

  Human Mating Markets

  Walking on the streets of Bangkok a few years ago, I couldn’t help but notice the high number of heterosexual “mixed” couples made up of a white Caucasian man and a Thai woman. In virtually all cases, the man was older a
nd rather unattractive (bald, with a potbelly and thick glasses), while the woman was young and good-looking. We see well-matched couples all the time: the young and the beautiful typically go with their own kind (like Brad and Angelina), and average-looking middle-aged people are typically married to other average-looking middle-aged people. Occasionally, we run into a very attractive young woman accompanied by an older man, but the man is typically well groomed, in good physical shape, and wearing an expensive Armani suit. In other words, he is wealthy and successful. In the United States or in Europe, you don’t typically see unattractive and socially awkward middle-class men in the company of beautiful young women.

  So what’s going on in Bangkok? Why do we see all these pairings that seem mismatched for age and looks, and all in the same direction? Why don’t we see young and handsome Caucasian men dating older and average-looking Thai women? The Thai women I saw were not escorts—men and their female escorts usually don’t walk around in the middle of the day holding hands. It’s much more likely that these couples were dating or even engaged. These men travel to Bangkok from the United States or Europe, meet these beautiful women, marry them, and bring them back to their country. After returning from Bangkok, I started noticing similar mixed couples in the United States—with the same differences in age and looks—but generally older. These were the couples who probably met in Bangkok ten or twenty years ago and have been living together in the States ever since.

  I am sure that anthropologists and sociologists have many good explanations for this phenomenon, but so do economists and evolutionary biologists. The latter believe that there is a mating or marriage market in which individuals have characteristics that make them more or less attractive to members of the other sex and in which partner selection is regulated by the laws of supply and demand. Individuals who have low value and little bargaining power in one market can move into another, where their characteristics are more in demand. Let me explain the way a mating market works in a little more detail.

  Everyone in the mating market has certain endowments that others may find attractive, such as youth, physical attractiveness, wealth, and social status. Age and physical traits, in particular, are what people often consider first in a potential partner. It’s like looking for ripe cantaloupes at the fruit stand—there are hundreds on display, but you won’t even touch any that are too small or still green. You pick up the ones that meet your criteria for size and color and start palpating them, looking for other indicators of ripeness. Likewise, when a partner has met your initial criteria of age and attractiveness, you consider other traits such as status, wealth, intelligence, honesty, or generosity. That physical characteristics are evaluated first has been shown by many studies conducted by psychologists, including some involving speed-dating, which I discuss later.

  Males and females differ, on average, in how they value the endowments of opposite-sex individuals. Men value youth and physical attractiveness very highly, while women value wealth and status (though they don’t mind physical attractiveness too). Clearly there are not enough young, beautiful women for every man, so a few men get them and most don’t. On the flip side, since young beautiful women are in short supply and high demand, they can select any partner they want. Angelina Jolie found a partner who has all the characteristics that arguably every woman wants: Brad Pitt is (relatively) young, handsome, wealthy, healthy, famous, and powerful, and he also seems like a nice guy and a good father. Well-endowed men with good looks, lots of money, and high social or celebrity status are also rare and in high demand, so they too usually get what they want. But men with low endowments, such as low income or average looks—and there are many of them out there—have limited options. If they are nice and have good social skills, they can settle with a partner with similarly low endowments, but if they happen to be socially awkward or unpleasant to be around, they may not find anyone at all.

  However, in the era of globalization, when it’s easy to travel around the world and meet people through the Internet, the low-endowment men have another option: move into a different mating market, one in which their endowments are deemed more valuable. In Bangkok, where local people are quite poor, a middle-class American man is considered a billionaire. Most of all, marrying an American man offers a Thai woman the opportunity to climb out of poverty, leave her country, become a U.S. citizen, and maybe spend the rest of her life in a suburban house in Florida or California. Thus, in the Bangkok mating market, middle-class, middle-aged American men, despite their baldness, potbellies, and thick glasses, are considered by many Thai women to be more valuable as potential husbands than most Thai men. In this market, American men can pick and choose, and of course they all want young, beautiful women.

  Of course, this is an oversimplification of how human mating markets work. What’s considered valuable in a partner varies depending on whether one is looking for a short-term, mostly sexual relationship or a stable long-term relationship involving marriage and children. Women’s preferences for men’s traits vary depending on what stage of their menstrual cycle they are in: they value good looks and masculinity more around midcycle than at other times.2 Finally, there are cultural differences in partner valuation. People living in Manhattan may have a different idea of what is attractive in a potential partner than people living in rural villages in New Guinea.

  The general point is that when people “shop” for a partner in a mating market, they can’t always get what they want. What they can get depends on their own value and on the laws of supply and demand in the particular market in which they find themselves. The fact that most women and most men seem to value the same qualities in a partner does not contradict the observation that people often end up in relationships with individuals who were not at the top of their wish list. We would all like to live in big mansions, but in practice people live in houses they can afford. Similarly, although people generally agree on who are the most desirable mates, they end up with someone whose value is comparable with their own. Knowing whether one is a 2, a 6, or a 9 on the 1–10 scale of mate value is important, and that’s not something one can figure out by looking in the mirror. It takes time as well as feedback from our fellow human beings.

  When adolescent boys and girls first enter the mating market, experimentation with dating allows them to assess their own mate value: some adolescents discover that they possess traits that are in high demand and make them popular and successful, so they become very choosy; others experience indifference or rejection and realize that they need to be content with the low value of their endowments or work hard at increasing it. According to evolutionary psychologist David Buss, author of The Evolution of Desire: Strategies of Human Mating, it is important that anyone reentering the mating market later in life—for example, after a long marriage that ended in divorce—reassess his or her value on the current mating market:

  The existence of children from the previous marriage generally lowers the desirability of divorced people. The elevated status that comes with being more advanced in their career, on the other hand, may raise their desirability. Precisely how all these changed circumstances affect a particular person is often best evaluated by brief affairs, which allow a person to gauge more precisely how desirable he or she currently is, and hence to decide how to direct his or her mating efforts.3

  The notion that there are mating or marriage markets, of course, is nothing new. Economist Gary Becker at the University of Chicago conducted this type of analysis almost fifty years ago.4 Similar studies have been carried out more recently, such as the work by economist Shoshana Grossbard-Shechtman that resulted in the 1993 book On the Economics of Marriage.5 Evolutionary psychologists have made their contributions to our understanding of human mating markets by studying people’s personal ads or their preferences in speed-dating encounters.

  Personal ads published in newspapers or posted on dating sites such as Match.com serve to advertise both the poster’s own characteristics as well as his or her needs: in o
ther words, their offers and their demands. Ads can be viewed as bids that reflect both people’s self-assessment of value and their knowledge of the market. Various studies of ads have shown that advertisers adjust their bids in light of their perceived market value. In highly competitive markets, individuals with a weak bargaining hand adjust their demands down, while those with a strong bargaining hand adjust them up. In 1999, evolutionary psychologists Boguslav Pawlowski and Robin Dunbar conducted a study of ads in which they objectively assessed the market value for particular age and sex classes of individuals.6 They did this by dividing the proportion of male and female advertisers seeking individuals of a given age (the demand) by the proportion of male and female advertisers of that age (the supply). As expected, they discovered that for women, market value peaks in their late twenties, while for men it peaks in their late thirties. Accordingly, ads posted by women and men in these age categories were those that received the most replies. They also found that women and men with high market value were more demanding and choosy, looking for many specific traits in a potential partner.

  Other interesting findings come from studies of speed-dating. HurryDate is a speed-dating and online dating company for adult singles living in major metropolitan areas in the United States. The people who run this organization set up meeting sessions in which twenty-five men and twenty-five women who have never met before interact with each other for three minutes and subsequently indicate which of the people they met they would like to see again in the future; if there is a match, the organizers give email addresses to the individuals so that they can get in touch directly and arrange a more traditional date.