Human Mating Strategies Human Mating Strategies As descendants of a long line of successful maters, modern humans have inherited the mating strategies that led to their forebear’s success. These include long-term mating, short-term mating, and mixed mating strategies. This article presents empirical evi- dence supporting evolution-based hypotheses about the complexities of these mating strategies, which differ substantially for men and women. array of adaptations specifically dedicated to the David M. Buss, Professor, task of mating. Department of Psychology, Nowhere do people have an equal desire to mate University of Texas, Austin with all people. Everywhere, some people are pre- ferred as mates, others shunned. Desires are central to all facets of mating. They determine who we are attracted to, and who is attracted to us. They influ- ence which attraction tactics will be successful (those that fulfill desires) and which attraction tac- tics will fail (those that violate desires). Successful mate retention tactics involve continuing to provide resources that fulfill the desires of a mate. Failure to Perhaps no adaptive domain is more central to re- fulfill these desires causes breakup and divorce. At production than mating. Those in our evolutionary every step of the mating process, from mate selec- past who failed to mate failed to become ancestors. tion to mate expulsion, desires determine the Modern humans are all descendants of a long and ground rules. unbroken line of ancestors who succeeded in the complex and sometimes circuitous tasks involved in Sexual Selection and Parental Investment mating. As their descendants, modern humans have Although Charles Darwin (1859) recognized that inherited the adaptations that led to the success of survival was central to the evolutionary process, their ancestors. many natural phenomena he observed seemed to Successful mating requires solutions of a num- baffling on the theory of »survival selection.« He ber of formidable adaptive problems. These includ- noticed phenomena such as the brilliant plumage of ing selecting a fertile mate, out-competing intrasex- peacocks, the flamboyant feathers of cardinals, and ual rivals in attracting a mate, fending off attempts the enormous antlers of deer. How could these to poach one’s mate, preventing the mate from de- metabolically costly structures possibly have evol- fecting, and engaging in all of the necessarily sexu- ved? Many seemed like open lures to predators, and al and social behaviors required for successful con- hence detrimental to survival. Darwin also noticed ception to take place. As a consequence of the num- that males and females of many species appeared to ber and complexity of mating problems humans be different in size and shape. Male elephant seals, have recurrently faced over the long expanse of hu- for example, weight roughly 4,000 pounds; female man evolutionary history, it is reasonable to antici- elephant seals weigh only 1,000 pounds. Among pate that humans have evolved a large and complex baboons, males are twice the size of females. SAMFUNDSØKONOMEN NR. 4 – 2002 47 Human Mating Strategies Among humans, males are 12 percent taller than fe- headedness in the population. The key point is that males, on average. Since both sexes have faced the desires of one sex for certain qualities in a mate roughly the same survival problems, why would can create evolutionary change – either an increase they differ in size and morphology? And what could in the frequency of desired qualities or a decrease in account for variation on the degree of sexual dimor- the frequency of undesired qualities. phism across species? Darwin’s theory of sexual selection was initially Darwin’s answer to these empirical puzzles was designed to explain the various empirical puzzles he the theory of sexual selection (Darwin, 1858, 1871). had observed – things like the brilliant plumage of The theory of sexual selection dealt with the evolu- peacocks (preferred by peahens) and the larger size tion of characteristics due to reproductive, rather of males in some species (explained by the advan- than survival, advantage. Darwin described two tage that size gives males in intrasexual competi- component processes through which sexual selec- tion). But many puzzles remained. Darwin observed tion could take place. In the first, called intrasexual that females were often the choosy sex (indeed, he competition, members of one sex (often, but not al- sometimes called the process of intersexual selec- ways, the males) engaged in competitive battles tion »female choice«), but he did not know why. He with each other. Two stags locking horns in combat also observed that males were often the competitive is a prototypical example of intrasexual competi- sex, but he did not know why. Roughly a century tion. The victors in these battles gain preferential would pass before evolutionary biologists devised a sexual access to females. The losers fail to mate. powerful theory to explain what determines which Whatever qualities lead to success in same-sex con- sex will compete and which sex will exercise tests, therefore, are passed down in greater numbers choice, that is, what drives the operation of the two (assuming that these qualities are heritable). What- component processes of sexual selection. ever qualities are linked with losing either fail to get Trivers’s (1972) answer to these questions was passed down or get passed down in fewer numbers. the theory of parental investment. According to this Evolution, that is change over time, occurs as a re- theory, the sex that invests more in offspring would sult of the differential reproduction of the winners be more choosy about mates. In species with inter- and losers in same-sex contests. nal female fertilization, the greater parental invest- It is important to note that intrasexual competi- ment by females makes them a valuable reproduc- tion need not always direct physical combat. Males tive resource. Gestating, bearing, and breast feeding in some species compete for position in the status a child, for example, are costly endeavors. Elemen- or dominance hierarchy through non-physical tary economics tells us that those who hold valuable means, and position in the hierarchy can be linked resources do not give them away indiscriminately. with preferential access to mates (e.g., Betzig, Evolution favored women who were highly selec- 1986). Males in other species scramble for access to tive about their mates. Women who were not choo- territory, and access to territory can be linked to sy would have suffered lower reproductive success. preferential access to mates. The key point is that Those who engaged in careful mate selection, pre- whatever qualities lead to success in intrasexual ferring for example a man who would stay around, competition are passed on in greater numbers, invest in her, and protect her children, enjoyed re- whether the competition is physical combat, ma- productive benefits. The more an organism channels neuvering for position in the hierarchy, or scramble effort into parental investment, according to Trivers, for access to certain resources. The result is evolu- the greater the benefits of exercising careful mate tion through sexual selection. choice. The sex that invests less in offspring, ac- The second process through which sexual selec- cording to this theory, should be more competitive tion occurs is intersexual selection. This process in- with each other for access to the high-investing sex. volves the preferences of members of one sex for In summary, the relative investment of the two sex- members of the opposite sex who possess certain es drives the operative components of sexual selec- qualities. Hypothetically, if all women preferred to tion, with the high investing sex being selected to mate with men who had red hair, those with red hair be the most discriminating and the lower investing would have a mating advantage. Over time, we sex being selected to be the most competitive with would witness an increase in the frequency of red- members of their own sex. SAMFUNDSØKONOMEN NR. 4 – 2002 48 Human Mating Strategies The Menu of Human Mating Strategies is not uncommon, for example, for a person to en- One of the intriguing features of human mating is gage in one long-term committed mateship with that it cannot be characterized by a singular strate- heavy investment in children, while simultaneously gy. One item on the menu is long-term committed pursuing an extramarital affair, or series of affairs, mating, often, but not always, characterized by a on the side. formal public commitment such as marriage. In Humans, in short, are neither solely monoga- long-term mating, both sexes typically invest heavi- mous, nor solely promiscuous; neither polygynous ly in any resultant offspring. As a consequence, and nor polyandrous. Which items on the menu of in accordance with the theory of parental invest- strategies a particular person chooses is heavily de- ment, sexual selection has likely fashioned in both pendent on contexts. These include the sex ratio in sexes high levels of choosiness or selectivity. Poor the mating pool, a person’s mate value, and even long-term mate choices would have been costly for prevailing cultural norms. These issues are briefly either sex, because they would have risked wasting discussed later, but first, we must outline the central their heavy investments. desires of men and women in their pursuit of long- Not all mating, however, lasts a lifetime. Human term and short-term mates. matings can last a few years, a few months, a few weeks, a few days, or even a few minutes. One end Qualities Desired in a Marriage Partner of this temporal continuum may be called short- Given that women have a large obligatory parental term mating. This temporal dimension turns out to investment to produce children, and hence are pre- be critical to many components of mating, perhaps dicted to be discriminating in their mate choice, the none more central than the qualities desired.