Sexual Strategies Theory: Historical Origins and Current Status

David M. Buss

The Journal of Sex Research, Vol. 35, No. 1, The Use of Theory in Research and Scholarship on Sexuality. (1998), pp. 19-31.

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http://www.jstor.org Mon Dec 31 13:22:00 2007 The Journal of Sex Research Vol. 35, No. 1, 1998 pp. 19-31 Sexual Strategies Theory: Historical Origins and Current Status

David M. Buss University of Texas, Austin

In sexually reproducing organisms, no domain is more closely linked with the engine of the evolutionary process than sexuality. Men and women over human evolutionary history have confronted different adaptive problems in the sexual domain. Sexual Strategies Theory offers an account of these adaptive problems and presents a view of human sexual psychology as a rich repertoire of mechanisms that have evolved as adaptive solutions. A host of specific predictions about human sexuality follows from this analysis, including an account of sex differences in the desire for sexual vari- ety, the qualities preferred in short-term and long-term mates, context-dependent shifts in mate preferences, the nature of sexual jealousy, the tactics that are effective for attracting and retaining a mate, and the causes of sexual conflict be- tween men and women. After reviewing the theory's historical origins, I summarize a portion of the extensive empirical research designed to test its tenets. An evaluation of the theory notes its strengths as well as its weaknesses, with a spe- cial focus on the issues of prediction and falsification. It ends with a challenge for other theories of human sexuality to reach an equivalent level of specific predictions, a comparable empirical foundation, an equally parsimonious account of sex differences, a compelling ultimate account of causal origins, and a comparable level of multi-leuel conceptual in- tegration.

harles Darwin's great discovery Many people who lack evolutionary tion," and indeed it was difficult to Cwas that recurrent differential expertise, however, equate imagine how these cumbersome fea- reproduction caused by differences by natural selection with survival tures could possibly aid reproduction. in design attributes-natural selec- selection. This is a mistake. Differen- Next he noticed that the two sexes tion-is the key to evolutionary tial linked with were sometimes quite different in change over time (Darwin, 1859). Be- differences in heritable design fea- structure. Often the males were larg- cause reproduction is central to the tures, not differential survival success, er than the females, sometimes ex- evolutionary process, domains closely is the core of the process of natural ceeding their weight by two or four linked with reproduction should be selection. Survival only becomes im- times. Furthermore, even when the focal targets of selection pressures portant to the extent that it is tribu- sexes were roughly the same size, it and, hence, loci for evolved mecha- tary to reproduction. was not uncommon that the females nisms or adaptations. No domain is Darwin had a wonderful habit were drab and the males displayed closer to reproduction than sexuality. that serves as an exemplar to modern gaudy features-luminescent plum- If the process of selection has not scientists. He kept a special note- age, unwieldy antlers, and other affected the evolution of human sex- book to write down observations that strange features that appeared to uality, then it is unlikely to have af- seemed to falsify his theory. Darwin have nothing at all to do with sur- fected domains less directly linked did this because he realized that he vival. Because the sexes faced similar with reproduction. had a tendency to forget these anom- survival problems, how could these Darwin adopted Spencer's phrase alous observations, more than a cen- sex differences evolve? Why did the "survival of the fittest" to summarize tury ago presaging psychological males tend to possess the strange the process of natural selection, but research on cognitive biases such as and gaudy features, whereas the fe- this choice was unfortunate. Survival the tendency of people to search selec- males were often drab by comparison? is certainly critical. Many adaptations tively for evidence that confirms held In response to apparent anomalies of organisms exist because they suc- hypotheses (Johnson-Laird, 1983). of this sort, Darwin (1871) fashioned cessfully overcame the forces that im- In this notebook, Darwin wrote what he believed to be a second evo- peded survival, the "hostile forces of several observations that seemed puz- lutionary process, which he called nature," such as parasites, diseases, zling based on his theory of natural . According to sexual food shortages, predators, and ex- selection. He noticed the brilliant selection theory, characteristics that tremes of climate and weather. Our plumage of certain bird species and give organisms an advantage in the fears of snakes, spiders, heights, wondered how it could possibly have darkness, and strangers, for exam- evolved. Such plumage is energeti- Correspondence should be addressed to ple, are likely the psychological rem- cally costly and renders the birds David M, Buss, Department of Psychology, nants of our psychology of survival, more vulnerable to predation. This Universitv of Texas, Austin. TX 78712. E- sculpted in an environment long gone. seemed to contradict "survival selec- mail: [email protected]. Sexual Strate@es Theory competition for mates, as contrasted noted. It explained the brilliant plum- mating success. As the genes for the with enhanced survival, can evolve. age and other strange structures, female preference for long-tailed Sexual selection can operate through which evolved because of the mating males become increasingly common, two processes. The first is intrasexual advantage they gave organisms. The the males with long tails will increas- or same-sex competition. If members theory explained many sex differ- ingly experience greater mating suc- of one sex compete with one another, ences, because such differences com- cess. Thus, females with a preference and the victors of these competitions monly were linked with design for long-tailed males will bear "sexy gain preferential sexual access to features that gave organisms an ad- sons" who are highly attractive to mates, then whatever qualities lead vantage in competing with members females. This feedback loop produces to success in same-sex competitions of their sex. But the theory of sexual a "runaway process," such that the will be selected and can evolve over selection remained controversial with- female preference for long tails and time. The large antlers of stags rep- in biology and, in fact, was largely the length of males'tails will co-evolve resent a prototypical image of this ignored for many decades after Dar- at an accelerating pace until halted sort of intrasexual selection, but the win published his major treatise on by the process of natural selection. logic extends to all qualities that it in 1871. In short, Fisher provided one key might give an advantage in same-sex missing ingredient in Darwin's theory competition. These might include ath- Historical Emergence of of sexual selection-a theory about letic ability, piloerection (hair stand- Sexual Selection how mate preferences might evolve. ing on end to scare away a competitor), Darwin's theory of sexual selec- Unfortunately, Fisher's (1930) social skills to enlist allies, or even a tion contained an important gap-it treatise was largely ignored in the biting sense of humor that deters a failed to explain the origins of mate field of evolutionary biology for rea- rival. The key point is that whatever choice (Andersson, 1994).Darwin had sons that are not entirely clear. Per- qualities lead to success in same-sex merely pointed to the existence of haps the notion of female choice was competitions can evolve because of mate preferences but had no expla- seen as granting too much power to the reproductive advantage that ac- nation for how they might arise. The females, who were often assumed to crues to the victor through increas- next major development in sexual be passive in the mating process. ing sexual access. selection theory came in 1930, with Perhaps Fisher's treatise was too The second component of sexual the publication of R. A. Fisher's book, mathematical and may have been selection involves . If mem- The Genetical Theory of Natural Se- difficult for many to understand. Re- bers of one sex display a consensus lection. gardless of the reasons, it was not about the qualities that are desired Fisher's theory of "runaway selec- until several decades later that the in mates, then those who possess the tion." Fisher (193011958)filled the gap theory of sexual selection again desired qualities have a preferential left by Darwin by proposing a two- resurfaced, this time with tremen- mating advantage. Those lacking the step process. First, suppose that there dous force. desired qualities get shunned and is genetic variation in a trait such as The controversy surrounding sex- selectively excluded. Because the de- tail length, and males with slightly ual selection culminated in a reso- scendants of this process are more longer tails survive more than those lution that changed the shape of likely to carry both the preferences with slightly shorter tails (e.g., be- evolutionary biology. Over the past and the characteristics preferred, the cause of the greater agility or gliding three decades, sexual selection theory two may co-evolve over time (Dar- power afforded by the longer tail). has emerged as not only a viable ac- win, 1871; see also Fisher, 193011958). Now, suppose that there is genetic count of the anomalies Darwin noted Sexual selection through mate choice variation among females in their ten- but recognized as a common and per- ultimately reduces to mate competi- dency to choose males of differing tail vasive process affecting many aspects tion, because those possessing desired lengths. Given these conditions, fe- of sexually reproducing organisms features have a competitive mating males who prefer to mate with the (see Cronin, 1991). Indeed, sexual advantage over those of the same sex longer-tailed males will bear sons selection provides the leading theo- who lack the desired features. with longer tails who will survive retical account of the origins of the In sum, intrasexual competition better than short-tailed males. If this large 1,400-cubic centimeter brain and intersexual selection are the two process recurs over generations, genes that humans have, representing a processes by which characteristics can for long tails will spread, as will genes near tripling in size over the past two evolve. They evolve not because of for the female preference for long- million years (see, e.g., Humphrey, any survival advantage, but rather tailed males. 1976). because of reproductive advantage Over evolutionary time, a new ef- Triuers's theory of parental inuest- acquired through successful mate fect will then emerge. The males with meat. Darwin's theory of sexual se- competition. This theory resolved the longer tails will not only survive lection described the processes by problem of the anomalies Darwin longer, they will also enjoy greater which adaptive specializations for mate selection and intrasexual com- members of their own sex for sexual human sexuality proper. The follow- petition could emerge. Fisher's theory access to the higher investing sex. The ing points constituted conceptual con- provided a plausible explanation for higher investing sex becomes a valu- tributions of Symons's 1979 treatise, how a mate preference might emerge. able reproductive resource over which elaborated in subsequent discussions But sexual selection theory lacked two the lower investing sex competes. The (Symons, 1987, 1992). related ingredients-a specification intrasexual competition component of Adaptations and byproducts. All of what drove the two processes (e.g., sexual selection, in short, should be products of the evolutionary process why the males of many species, but engaged most intensely by the lower can be partitioned into three cate- not the females, engage in intrasex- investing sex. gories-adaptations, byproducts of ual combat) and what the content of The two components of sexual se- adaptations, and noise. Symons mate choice might be. The task was lection become connected, or the dis- (1979), drawing heavily on Williams left to , then a graduate tinction blurred, because the mate (1966), argued that adaptation is an student at Harvard University, to preferences of one sex can determine "onerous concept" and should only be begin to fill these two critical gaps. the content of the competition in the invoked when rigorous evidentiary Trivers (1972) reasoned that the other. If females desire males with standards have been met. We do not relative of the territory, for example, then that exerts posit that flying fish have a special sexes in their offspring determined selection pressure on males to compete adaptation to return to water after which of the two components of sexual with one another to acquire what leaping in the air, because a simpler selection was operative for each sex. females desire. Those that succeed in and more parsimonious explana- Parental investment can be defined besting their intrasexual competitors tion-gravity-does the job. The cri- as any time, energy, or effort expended in fulfilling these desires enjoy pref- terion for adaptation is special design; to aid the survival and reproduction erential sexual access. Those that fail attributes such as economy, efficiency, of one offspring at the expense of other suffer sexual exclusion. complexity, precision, reliability of forms of investment, such as effort This situation becomes especially development, and functionality in devoted to intrasexual competition. complex (and interesting) in biparen- solving a specific problem are ways Thus, parental investment is defined tal species such as ours, in which both of detecting special design (see Tooby by decrements in a parent's residual sexes invest. In such species, both & Cosmides, 1992, for an extended reproductive value, including any sexes exert considerable selectivity discussion of adaptation). Adaptations reduction in the parent's survival, in their choice of mates, and both are the primary products of selec- fecundity, mating success, or ability sexes compete intensely with mem- tion. to invest in other relatives (Clutton- bers of their sex for access to desirable Some characteristics of organic be- Brock, 1991). A mammal mother's members of the opposite sex. ings are not adaptations, but instead internal fertilization, gestation, and So the groundwork was established are merely byproducts of adaptations. placentation, for example, are all in 1972, more than a century after In the realm of artificial functional forms of parental investment. Darwin first advanced the revolution- inventions, for example, the light Trivers reasoned that the sex that ary theory of sexual selection, for produced by a light bulb is its proper invests more in offspring should be understanding many remarkable function, but the heat it produces is more selective in choice of mates. The features of animal sexuality. Thus, not. Heat is an incidental byproduct, high-investing sex engages the inter- sexual selection theory guided re- not part of the raison d'etre for which sexual component of sexual selection. search in animal biology, part of a the bulb was designed. The hypothe- By exercising choice, the higher in- broader scientific revolution that sis that something is an incidental vesting sex can select mates on a swept the field. But the means to byproduct should be treated as a sci- variety of grounds, depending on the apply this theory to understanding entific hypothesis, one that requires particular species, to increase sur- human sexuality remained obscure specifying the design of the adapta- vival and reproduction or the survival until the end of that decade, when tion responsible for producing the by- and reproduction of her offspring. the first major treatise on the evolu- product (Tooby & Cosmides, 1992). This can range from selecting mates tionary psychology of human sexual- The third product of the evolution- with "good genes" on one end to se- ity appeared. ary process is noise-random varia- lecting mates who show a willingness tions that tend to be incidental to the Evolutionary Sexual Psychology to invest in her offspring on the functional design of a mechanism. other. The particular content of the This treatise was The Evolution of Minor deviations from smoothness on selectivity depends on the species, Human Sexuality, published in 1979 the surface of the glass encasement its habitat, and the social context in by . The book con- for a light bulb, for example, repre- which it lives. tained a large introductory discussion sent noise introduced randomly in the The low-investing sex, on the other of the logic of , process of light bulb construction. hand, should be more competitive with prior to discussing various aspects of Similarly, in human development, 22 Sexual Strategies Theory random perturbations create imper- behavioral output clarifies many mides & Tooby, 1994). Because suc- fections in the formation of evolved sources of confusion. In this instance, cessful adaptive solutions represent mechanisms that are usually inciden- it suggests that hypotheses about sex tiny pockets amid the vast design tal to their basic functioning. Devia- differences in sexuality are more space of possibilities, organisms need tions from perfect bilateral facial fruitfully sought at the level of psy- specific mechanisms to prevent pro- symmetry, for example, usually repre- chological mechanisms than at the ducing millions of non-adaptive out- sent random perturbations because level of manifest behavior. Because comes. Domain-general mechanisms, of the inability of the organism to sexual desires are constrained by so because they fail to channel behavior maintain perfect homeostasis in the many factors-notably the willing- toward the narrow adaptive pockets, course of development. To the degree ness of desired partners to comply collapse under this constraint. For that one sees organized complexity with the desire-manifest behavior these and other reasons, evolutionary in an organic trait or mechanism, can be misleading. psychologists assume that evolved random variation or noise is unlikely The nature of sexual psychological psychological mechanisms are likely to as an explanation. mechanisms. Another contribution of be many, specific, and functional. In sum, all complex human charac- the Symons (1979) treatise was to Sex differences in sexuality. Sym- teristics, including our sexual charac- clarify the nature of evolved psycho- ons7snext contribution entailed out- teristics, represent either adaptations logical mechanisms. The dominant lining several major arenas in which or byproducts of adaptations. Because assumption in mainstream psychology men and women have faced different a hypothesis about a byproduct re- was that psycholo~calmechanisms adaptive problems in the domain of quires the specification of the adap- are few and highly domain general. sexuality, outlining a series of hy- tation of which it is a byproduct, Skinner's laws of operant condition- potheses about sex differences in sex- characterizing adaptation is an essen- ing were prototypes of these domain- uality, and summarizing the limited tial, not an optional, part of under- general mechanisms, which were empirical evidence from the then- standing human sexual psychology, presumed to operate in essentially available anthropological and psy- Psychology versus behavior. Sym- the same manner across different chological record. ons (1979) clarified an important arenas such as food selection and Because women are clearly the source of conceptual confusion in the mate selection. Symons, in contrast, higher investing sex in our species, sexuality literature. Perhaps because argued that our psychological mecha- for example, ancestral men more than of the reign of behaviorism in the so- nisms are likely to be particular, each women could have benefited in repro- cial sciences in this century, mani- linked to a specific adaptive problem, ductive currencies by securing sexual fest behavior was viewed as the only and numerous, corresponding to the access to a variety of partners. This or primary locus of scientific scruti- many different sorts of adaptive selection pressure, Symons argued, ny. Syrnons argued that behavior, problems humans have faced. could have selected for a different considered alone, can be misleading. The arguments for domain speci- sexual psychology of desire, specifi- Consider short-term heterosexual ficity and numerosity are several, cally for men having a greater desire sexual encounters. Mathematically, but a few key ones involve problem for sexual variety. Symons further the number of short-term sexual en- specificity and combinatorial explo- argued that men and women should counters is constrained to be identi- sion. Problem specificity suggests that have different mate-selection prefer- cal, on average, for men and women. successful solutions to one adaptive ences, with men focusing more on as- Each time a woman has sex with a problem do little to solve other adap- pects of women that signal high man with whom she has never had tive problems. Selecting a reproduc- fertility or reproductive value and sex, a man is simultaneously doing tively valuable mate, for example, women focusing more on the aspects the same. But this identity in behav- requires a different set of solution of men that signal the external pro- ior may conceal a difference in de- criteria than selecting a nutritively visioning of the woman and her chil- sire-men more than women, as is valuable food object for consumption. dren. widely documented, desire a large Because consumption and consum- But Symons did not argue that all number of short-term sexual part- mation require different solutions, it aspects of human sexuality represent- ners (Buss & Schmitt, 1993; Symons, is extremely unlikely that one general ed adaptations. In undoubtedly the 1979). Thus, an important difference mechanism can provide adaptive so- most controversial aspect of his trea- in the sexual psychology of men and lutions to both. tise, he argued that there was no evi- women is obscured by restricting ex- Combinatorial explosion-the out- dence that women's capacity for sexual amination to actual sexual behavior. come of producing millions of possible orgasm was an adaptation; rather, it Manifest behavior is one primary behavioral sequences as a result of the was likely to be an incidental byprod- output of our evolved psychological geometric increase in unconstrained uct. Just as men have nipples that are mechanisms, and making the distinc- systems-is a problem confronted by functionless, an incidental byproduct tion between mechanisms and their all domain-general mechanisms (Cos- of the design shared by the sexes that produces functional nipples in women, Figure 1. Windows on Desire female orgasm, he argued, could be an incidental product of common design that selected for male orgasm. Al- Harmony though Symons may or may not be Between correct in this specific hypothesis, one Sexes I central value of his treatise was iden- tifylng several domains in which the sexes might differ in their sexual psy- chology, highlighting the fact that not all aspects of sexuality are adaptations proper, and formulating testable pre- dictions about human sexual psychol- Derogation om. Conjugal The Focus-Desire as the Competitors Dissolution Foundation of Sexual Psychology Evolutionary psychology is prop- erly considered to be an overarching conceptual framework, and as such, Competition E$!!.;n there can be many different (and com- t'm-sexua'I, 1 ,[ I peting) theories about the evolution of human sexuality (Buss, 1995).With Conflict respect to female orgasm, for example, Between the there are theories (or hypotheses) Sexes that it evolved for a specific function, such as facilitating sperm transport, assuaging men's doubts about pater- nity, or identifying "Mr. Right," as sires constitute key causes of conjugal by selection. Evolution by selection is well as the hypothesis that it is an in- dissolution. The Mfillment of desires the only causal process powerful cidental byproduct. Thus, there are within a relationship, in contrast, con- enough to produce complex organic competing evolutionary theories, stitutes effective mate-retention tac- mechanisms, including sexual mech- each of which is compatible with the tics and produces harmony between anisms. If another causal process ex- larger conceptual perspective. Scien- the sexes. ists, it has not been made generally tific competition among the theories The focus of Sexual Strategies known to the scientific community is adjudicated by criteria such as em- Theory, in short, is on desire and all (Daly & Wilson, 1988). pirical evidence, parsimony, and abil- of its interpersonal ramifications- Psychological mechanisms consti- ity to generate novel predictions. In attraction tactics, derogation of com- tute a key locus of sexual adaptation. the remainder of this article I focus petitor tactics, conflict between the All psychological mechanisms, of on one evolutionary theory of human sexes, mate-expulsion tactics, causes course, have an underlying physical sexuality-Sexual Strategies Theory of conjugal dissolution, mate-reten- (physiological, neurological) sub- (Buss, 1994; Buss & Schmitt, 1993). tion tactics, and harmony between strate. But the psychological level of According to this theory, desire lies the sexes. description, in information-process- at the foundation of sexuality and ing terms, is central to the under- Basic Assumptions of human mating (see Figure 1). The standing of evolved mechanisms. A Evolutionary Psychology focus of the theory, therefore, centers word processing program can be run on identifying desires and all manifold The basic assumptions of Sexual on different physical systems, such as consequences of desires. The desires of Strategies Theory can be divided an IBM or a Mac computer. But re- one sex, for example, determine whch into general assumptions anchored gardless of the physical instantiation, tactics of attraction are effective when in evolutionary psychology and spe- it can be described in information- used by the opposite sex. The pursuit cific assumptions about the evolution processing functional terms. Simi- of a desire by one sex that interferes of human sexuality. In this section I larly, regardless of the underlying with the desires of the opposite sex, to consider the basic assumptions of physical instantiation of psychologi- take another example, is the major evolutionary psychology. cal mechanisms, they are usefully source of conflict between the sexes. All sexual psychological mecha- described in psychological or infor- Within relationships, violations of de- nisms owe their existence to evolution mation-processing terms. Sexual Strategies Theory

Evolved mechanisms are sensitive primate relatives, have primarily a cestral woman having sex with 100 to context and are functional. Mecha- short-term sexual strategy. Mating men in 1year could still not produce nisms evolve in response to specific takes place primarily when the more than a single child. Thus, men environmental contingencies. They females enter estrus, and the males are predicted to devote a larger share are not blind or robotic, nor do they do practically nothing to help raise of their mating effort, compared with express themselves in invariant ways, the offspring. Humans, in contrast, women, to sexual access to a variety insensitive to context. The flexibility have evolved a more complex reper- of partners. of human behavior is caused by the toire of strategies, including long-term A task analysis of men's short-term large collection of evolved mecha- mating characterized by attachment sexual strategy suggests four relative- nisms, activated selectively and between parents and biparental care. ly distinct adaptive problems that sequentially, depending upon context. Short-term mating, however, can must be solved: (a) partner number, They are functional, which means occur before settling on a long-term (b) identification of sexually accessi- that they exist in the form that they mate, in between bouts of long-term ble women, ic/ identification of fertile do because they solved in ancestral mating, or during the course of long- women, and (d) minimal commit- environments specific problems of term mating in the form of brief ment and investment. Men who lack survival or reproduction-problems affairs. mechanisms such as a desire for a that were ultimately tributary to fit- Different adaptive problems must variety of partners, assessment of the ness. be solved when pursuing a short-term degree of sexual accessibility, assess- Men and women have faced differ- as opposed to a long-term sexual ment of physical cues linked with ent adaptive problems over human strategy. The successful pursuit of a fertility, and strategies for keeping evolutionary history. The evolution- strategy requires the solution of spe- time and investments to a minimum ary framework provides a specific set cific adaptive problems. A short-term would have been out-reproduced by of predictions about the locus of sex strategy, for example, requires sexual men who successfully solved these differences and sexual similarities. motivation to mate with a variety of problems entailed by the pursuit of a Sex differences in sexuality are only partners and the ability to identify short-term mating strategy. predicted in the specific domains in partners who are immediately sexu- Although women cannot benefit as which the sexes have faced different ally accessible. A long-term strategy, much or as directly in reproduction adaptive problems. In domains where in contrast, involves assessment of from short-term mating, women can the sexes have confronted similar future trajectories of potential part- potentially reap a host of adaptive adaptive problems, the sexes are pre- ners on dimensions central to repro- benefits: (a) immediate resources for dicted to be similar in their sexual ductively relevant resources. themselves and children; ib) mate in- psychology. Because men and women differ in surance should her regular mate be- minimum obligatory parental invest- come injured, die, or defect from the Basic Premises of ment, men devote a Larger proportion relationship; and fc) genetic benefits Sexual Strategies Theory of their total mating effort than do through mating with superior men. This section outlines the basic women to short-term mating. To pro- Because it is clear that women en- premises of a specific theory of human duce a single child, women must un- gage in short-term mating, and likely sexual strategies (Buss & Schmitt, dergo the burdens of a nine-month have done so throughout human evo- 1993). Other evolutionary theories of gestation, which is costly in time, en- lutionary history, it is unlikely that human mating offer competing hy- ergy, opportunity costs, increased they would have done so in the ab- potheses. Some theorists, for exam- vulnerability, and risk during child- sence of benefits. The hypothesized ple, have argued that humans have birth. This is the minimum invest- benefits constitute some main advan- evolved primarily for long-term ment, and it is obligatory. Men's tages to women of a short-term mat- monogamous mating (e.g., Lovejoy, minimum obligatory investment is a ing strategy. 1981). Others have argued that hu- single act of sexual intercourse. Men Task analysis of long-term mating mans are inherently sexually promis- typically invest much more, of course, suggests a different set of problems cuous (e.g., Small, 1992). Sexual but the key point is that these differ- that must be solved: (a) identifying strategies theorists, in contrast, argue ences in minimum obligatory invest- reproductively valuable women, (b) that humans have a complex reper- ment produce a different benefit ensuring increased probability of pa- toire of mating strategies, both short structure, in the currency of reproduc- ternity, and ic) identifying women term and long term, each activated tive success, to short-term sexual with good parenting skills. Men who differently depending on context. strategies. Specifically, men in our failed to solve these problems, for Men and women have evolved a evolutionary past could increase their example, by being cuckolded and in- strategic repertoire consisting of both reproduction by mating with a vari- vesting unwittingly in the offspring short-term and long-term sexual ety of women directly resulting in an of other men, would have been re- strategies. Chimpanzees, our closest increased number of children. An an- placed over evolutionary time by men who successfully solved these adap- Desire for sexual variety. When Sex differences in the desire for tive problems. asked how many sex partners one sexual variety show up in studies of Women pursuing a long-term sexu- desires within the next month, year, sexual fantasy conducted in Japan, al strategy would benefit from solving decade, or lifetime, men and women Great Britain, and the United States. the following problems: (a) identify- differ in ways precisely as predicted In their sleep men are more likely ing men who have the ability to by the theory (Buss & Schmitt, than women to dream about sexual acquire resources, (b) identifying men 1993). Over the next two years, for events. Men's sexual fantasies more who display a willingness to invest example, men state that they desire often include strangers, multiple part- those resources in them and their eight sex partners, whereas women ners, and anonymous partners (Ellis children, fc) identifying men willing report that they desire approximately & Symons, 1990). Most men report to commit to a long-term relationship, one. Over the course of a lifetime, changing sexual partners during a (dl identifying men willing to protect men report desiring 18 sex partners; single sexual fantasy, whereas women them and their children from aggres- women, 4 or 5. At each time interval, rarely report changing partners. sive members of the same species, and the sex differences are large, with Thirty-two percent of men, but only (e) identifying men with good parent- magnitude of effects ranging from 8% of women, report having imagined ing skills. Women, in this analysis, .49 to .87 in standard deviation units. sexual encounters with more than are predicted to place a greater pre- If you meet someone of the oppo- 1,000 different partners so far during mium than men on a potential site sex who you find attractive, what their lifetime (Ellis & Symons, 1990). mate's external resources, as well as is the likelihood that you would con- Another psychological clue to men's the cues to such resources such as sent to sexual intercourse after dif- strategy of casual sex comes from re- status, older age, ambition, and in- ferent lengths of time? At the searchers who examined shifts in dustriousness. Furthermore, women five-year mark, both sexes agree judgments of attractiveness over the are predicted to shun men who emit that sex is likely. For each shorter course of an evening at a singles bar. cues that signal that they are pursu- time interval, however, men are sig- In one study, 137 men and 80 women ing a short-term, rather than long- nificantly more inclined to consent to were approached at 9:00, 10:30, and term, mating strategy. sex. At one week, for example, men midnight and asked to rate the at- Different contexts trigger which are still positive about sex, but tractiveness of members of the oppo- strategy, or combination of strategies, women are extremely negative, giv- site sex in the bar using a 10-point is pursued. Although exploration of ing it close to a -3 on a scale of +3 scale (Gladue & Delaney, 1990). As these contexts has just begun, a few (definitely yes) to -3 (definitely no). closing time approached, men viewed promising lines have already been Averaged across all time intervals, women as increasingly attractive. identified. Men who are physically the sexes differ in the positivity to- Their judgments of attractiveness at attractive to women, for example, ward sex by d = 1,or a full standard 9:00 were 5.5, but by midnight they should be more successful at pursu- deviation of difference (Buss & had increased to over 6.5. These ing a short-term mating strategy. Schmitt, 1993). shifts in perceptions of attractive- Women whose husbands fail at These sex differences emerge in ness near closing time occur even resource provisioning, or are more behavioral data as well. In one study, after statistically controlling for the likely to die or defect, are predicted men and women were approached by amount of alcohol the men had con- to pursue extra-pair matings. Often, attractive confederates of the oppo- sumed. Women's judgments of men's both sexes pursue a mixed mating site sex and asked whether they attractiveness also increased over strategy, with one long-term rela- would go out on a date that night, go time. But women's ratings overall of tionship and short-term liaisons in back to the confederate's apartment the male bar patrons were lower contexts where the costs are low (e.g., that night, or have sex with the con- than men's ratings of women. in discovery or reputational damage) federate that night (Clark & Hatfield, Women at the bar rated the men as and the benefits high. 1989). Of the women approached by just below 5 at 9:00, increasing at the male confederate, 50% agreed to midnight to only 5.5. Empirical Support for a date, 6% agreed to go back to his In a recent meta-analysis of the Sexual Strategies Theory apartment, and 0% agreed to have sexuality literature, Oliver and Hyde Empirical support for Sexual Strat- sex. Of the men approached by (1993) found that attitudes toward egies Theory comes from a variety of female confederates, 50% agreed to casual sex showed the second largest sources-expressed preferences, ob- the date, 69% agreed to go back to her sex difference among all sexual vari- servational data, physiological stud- apartment, and 75% agreed to have ables examined. Indeed, the magni- ies, demographic statistics, and sex with her. These findings have tude of this sex difference was only laboratory tests. Furthermore, ex- been replicated several times, using exceeded by masturbation frequency. tensive cross-cultural evidence has somewhat different experimental This brief review does not do jus- been gathered to test the theory. designs (Thiessen, 1994). tice to the hundreds of studies that Sexual Strategies Theory support the hypothesis that men even slightly desire a partner who is tainty (Daly, Wilson, & Weghorst, have a greater desire for a variety of promiscuous (possibly a cue to sexual 1982; Symons, 1979). Because a sex- sex partners. Studies of sexual fan- accessibility). Also in the short term, ual infidelity by a man's partner tasy, the relaxation of standards, the men elevate the importance they at- would have been the sole threat to inclination to seek intercourse after tach to sex appeal and sexual experi- his paternity, men's jealousy has little time has elapsed, shifts in judg- ence, compared with the long-term been predicted to focus intensely on ments of attractiveness near closing context. cues to sexual infidelity. Men whose time, and patronage of prostitutes Women also shift their prefer- long-term partners were sexually all point to the same conclusion. ences across temporal context. In the unfaithful would have risked, from a Long-term mate preferences. In long term, women value cues to long- reproductive perspective, all of their the most massive study of its kind, term provisioning, such as a man's mating effort, including the costs of long-term mate preferences were promising career, likelihood of pro- attraction and courtship; all of their examined in 37 cultures located on 6 fessional success, and financial investment in the relationship; all of continents and 5 islands, with a total prospects. Women also dislike men in their partner's parental effort, which sample of 10,047 participants (Buss, this context who lack ambition, are could get redirected toward another 1989a). Across all cultures, men financially poor, and are uneducated. man's gametes; and all of their own placed a greater premium than wo- In the short term, however, women parental effort, which also would men on only two characteristics- place a greater value on immediate have been redirected toward the off- and youth, resources rather than future pros- spring of another man. both known cues to a woman's fertil- pects. Women desire men who spend From an ancestral woman's per- ity and reproductive value (see Gang- a lot of money on them immediately, spective, a sexual infidelity on the estad & Thornhill, 1994; Singh, 1993; give them gifts early, and have an part of her mate would not, in itself, Symons, 1995). extravagant lifestyle. They strongly jeopardize her certainty that she was Women were nearly universal in dislike men who are stingy early in a the mother. Maternity certainty is their expression of a stronger desire relationship. Finally, women seeking 100%.But such an infidelity could be for men with good financial prospects, short-term mates elevate the impor- extremely costly for the woman, be- as well as the cues that lead to tance they attach to a man's physical cause she would risk the loss of her resources, such as ambition, indus- attractiveness, providing circum- mate's time, energy, commitments, triousness, and social status. Fur- stantial support for the "good genes" resources, and parental investments, thermore, women universally desired hypothesis articulated by Gangestad all of which could get channeled to a long-term mates who were older and Thornhill (1994). rival woman and her children. For than they were, another established Taken together, these studies sup- these reasons, evolutionary psychol- cue to the acquisition of resources. port the aspect of the Sexual Strate- ogists had predicted that men's jeal- For most mate characteristics, the gies Theory that suggests that both ousy should be strong, obligate (in sexes showed no differences in de- sexes have both short-term and long- long-term investing relationships), sire. Both equally desired mates who term strategies in their mating reper- and triggered heavily by cues to sex- were kind, intelligent, dependable, toire. Preferences shift according to ual infidelity. In contrast, women's and healthy. The sexes differed only in temporal context in ways that appear jealousy is predicted to be more vari- the narrow pockets where they have to facilitate solutions to the prob- able with culture and context and faced different adaptive problems lems that need to be solved for the more heavily focused on cues to the over human evolutionary history- successful pursuit of each strategy. long-term diversion of commitments, pockets predicted in advance by Sex- Sexual jealousy. A review of the such as a man's emotional involve- ual Strategies Theory. large empirical literature on jeal- ment with another woman. Temporal shifts in mate prefer- ousy reveals few sex differences. On Sexual and emotional infidelity, of ences. Mate preferences shift across global measures of jealousy, such as course, are correlated events in every- temporal contexts in several ways how frequently one gets jealous or day life, and therefore one provides a predicted by Sexual Strategies Theory how intensely jealousy is felt, men cue to the other. Both sexes are pre- (Buss & Schmitt, 1993). Whereas in and women score essentially the dicted to get upset by both forms of the long-term mating context men same. Evolutionary psychologists, infidelity, and research suggests that place a premium on sexual fidelity however, long predicted that men and they do (Buss, Larsen, Westen, & and abhor promiscuity in a woman women might differ in the weighting Semmelroth, 1992). Nonetheless, (solutions to the problem of uncer- given to the triggers of jealousy. when given a choice, men are pre- tainty about paternity), the reverse Specifically, men over human evolu- dicted to be more upset by a sexual is true in a short-term mating con- tionary history have faced an adap- infidelity than women, and women text, in which men are indifferent to tive problem not confronted by women more upset by an emotional infidelity the sexual fidelity of a partner and -the problem of paternity uncer- than men. This predicted sex difference has A second methodological strategy upset men and women experience accrued a large body of supporting entailed asking participants to imag- support these predictions (Buss, empirical evidence. When given a ine that both forms of infidelity have 1989b). Both sexes judge that women forced choice about what would upset occurred and to indicate which aspect will get significantly more upset by or distress them more, a sexual infi- was more upsetting. The results were acts of sexual , such as delity or an emotional infidelity, the conclusive: The sex differences re- trying to force sex acts, demanding overwhelming majority of women in- mained just as robust using these sexual relations, and touching the dicate that an emotional infidelity methodological controls. body without permission. Both sexes would be more upsetting (Buss et al., At this point, the hypothesized sex also judged that men would be more 1992). Men are more evenly split, but differences in jealousy have survived upset by a partner's acts of sexual compared with women, show a far many methodological and conceptual withholding, such as refusing to have greater tendency to endorse the sex- hurdles. They have been replicated sex, saying "no" about having sex, ual infidelity as more upsetting. extensively, show up physiologically, being a tease sexually, and being led These sex differences have been emerge cross-culturally, and emerge on and then turned off. replicated using physiological tech- even when stringent controls are ap- In another study, newlywed men niques (Buss et al., 1992). In response plied to eliminate different condi- complained more than newlywed to imagining a partner having sexual tional probabilities. women about their spouses being intercourse with someone else, men Sexual conflict. A major compo- sexually withholding (Buss, 198913). get more physiologically distressed nent of Sexual Strategies Theory in- Newlywed women complained more than women-their heartbeat in- volves predictions about the domains than newlywed men about sexually creases nearly five beats per minute, in which men and women will expe- aggressive acts such as touching bod- similar to the effect of drinking three rience conflict. Specifically, it predicts ies without their permission. Com- cups of strong coffee at one time; they that conflict results from strategic plaints about these forms of stratesc start sweating; and the corrugator interference-when one person's sex- interference showed sex-linked cor- muscle on the forehead contracts in- ual strategy interferes with the suc- relations with ratings of sexual dis- tensely, signally a frown or negative cessful pursuit of another person's satisfaction. Specifically, the single affect. sexual strategy (Buss, 198913). Al- strongest correlate of sexual dissat- The sex differences have also been though there are many domains in isfaction for men was a partner being replicated by different investigators which strategic interference will occur, sexually withholding (r = .37, p < (e.g., Wiederman & Allgeier, 1993). two will be highlighted here-sexual .001), and the largest correlate of They have been replicated in different aggression and sexual withholding. sexual dissatisfaction of women was cultures, such as Germany, the Nether- Two specific predictions about a partner being sexually aggressive (r lands, and Korea (Buunk, Angleitner, strategic interference can be derived = .36,p < .001). In contrast, a part- Oubaid, & Buss, in press). from the fundamental differences in ner's sexual aggressiveness was Some investigators have raised the mating strategies pursued by the unrelated to men's sexual dissatis- possibility that the sex difference is sexes: (a) Women will be more upset faction, and a partner's sexual with- merely an artifact of the differing and angered by features of men's holding was unrelated to women's imagned conditional probabilities of strategy that interfere with their own, sexual dissatisfaction. the two events, with men believing such as the male tendency toward In short, sexual aggression is more that sexual infidelity implies emo- greater sexual assertiveness or ag- upsetting to women than to men, is tional infidelity more than vice versa, gressiveness-initiating sexual ad- more often experienced by women and women believing that emotional vances sooner, more frequently, more than by men, and when experienced, infidelity implies sexual infidelity persistently, more aggressively, or is more often linked with sexual dis- more than vice versa (e.g., DeSteno with more partners than women; (b) satisfaction in women than in men. & Salovey, in press). Nonetheless, a men, in contrast, will be upset and Sexual withholding is more upsetting series of empirical studies has failed angered by features of women's mat- to men than to women, is more often to confirm this alternative explana- ing strateges that conflict with their experienced by men than by women, tion (Buss, Kirkpatrick, Shackelford, own, such as those involving selec- and when experienced, is more often & Bennett, 1996). Two methods were tively withholding or delaying con- linked with sexual dissatisfaction in used to control for the correlated summation opportunities-declining men than in women. Each sex appears nature of the infidelity types. First, to have sex, desiring it less frequently, to be especially attuned to events the infidelity types were rendered or requiring more stringent external that interfere with a preferred sexual mutually exclusive (e.g., imagine your conditions to be met prior to consum- strategy. partner having sexual intercourse mation. This brief summary does not do with someone else, but there is no Empirical evidence on judgments full justice to the array of research chance of any emotional involvement). about the magnitude of anger and on other aspects of Sexual Strategies Sexual Strategies Theory

Theory. Research has supported pre- evolutionary hypotheses are untest- has survived several rounds of em- dictions about sex differences in the able are simply not warranted. pirical hurdles, and is highly genera- tactics used to attract mates (Buss, Although the theory has survived tive of further testable hypotheses. 1988a; Schmitt & Buss, 19961, tac- many empirical tests, from another Parsimony and internal consis- tics used to derogate competitors perspective there remain many em- tency. Parsimony is often held as a (Buss & Dedden, 1990; Schmitt & pirical tests ahead. Here is a sampling useful criterion for evaluating theo- Buss, in press), tactics used to retain of additional testable hypotheses, all ries, and so it is under certain con- mates (Buss, 1988b1, and causes of derived from Sexual Strategies The- texts. It is often equated with malng conjugal dissolution (Betzig, 1989). ory, that thus far have not been sub- few assumptions or having a few basic Taken together, the corpus of research ject to empirical tests: theoretical principles account for a using data sources widely varying (a) Women whose partners lose large number of phenomena. On this from expressed preferences to physi- their jobs, or whose partners suffer a criterion. Sexual Strategies Theory ological recordings to actual marriage decrement in resources provided to is quite parsimonious. Desire is postu- patterns suggests considerable sup- the mate, will be more likely to seek lated to lie at the foundation of the port for many key premises of Sexual extramarital affairs and divorce be- mating system, and from desire flows Strategies Theory. cause these events violate their de- a plethora of predictions about other sires in a long-term mate. aspects of mating-tactics of attrac- Evaluation and Critique of (b)Men will experience more sex- tion, the content of derogation of com- Sexual Strategies Theory ual jealousy when the rival possesses petitors, the success of particular This final section provides an eval- better job prospects or financial suc- mate-retention tactics, the causes of uation of Sexual Strategies Theory cess. conjugal dissolution, and many oth- on several dimensions, such as testa- (c) Women will experience more ers. There are no internal inconsis- bility and parsimony, areas of weak- sexual jealousy when the rival is tencies within the theory. ness, and the future research agenda more facially attractive, is signifi- Sometimes parsimony is applied for the theory. cantly younger, or has a more attrac- in a different sense of the term to refer Testability and predictive utility. tive body (e.g., a lower waist-to-hip to the number of mechanisms postu- A common misperception of evolu- ratio; Singh, 1993). lated, in this case psychological mech- tionary hypotheses is that they are (d) Men will more easily forgive a anisms. Because sexual strategies untestable speculations, more fit for partner who is emotionally unfaithful theorists postulate many evolved psy- cocktail conversation than for the than one who is sexually unfaithful; chologIca1 mechanisms, wouldn't it be rigors of scientific scrutiny. As docu- women will more easily forgive a more parsimonious to postulate a mented in this article and the empir- partner who is sexually unfaithful smaller number of more domain-gen- ical publications cited, it is obvious than one who is emotionally unfaith- era1 mechanisms? This certainly has that the theory is testable and in fact ful. been the stance of most mainstream has survived numerous empirical (e) Intra-individual variations in psycholog~stsin this century, but I hurdles using methodologies as di- self-esteem will be sex linked, such argue that it is wrong. Atheory needs verse as self-report and physiological that elevations or declines in the em- to explain as many entities as exist recording devices. The predicted sex bodiment of qualities desired by the within the domain of the theory. A differences in jealousy, for example, opposite sex will cause sex-linked ele- human anatomist or physiologist have been found using self-report, vations and declines in self-esteem. would not be criticized for postulat- physiological methods, and public (0When divorce occurs because of ing so many different bodily mecha- documents recording the reasons for a widening mate-value discrepancy, nisms-heart, lungs, liver, larynx, divorce, and they have been replicated the higher mate-value person will kidney, tongue, teeth, toes, and so on. in diverse cultures such as Korea, replace the mate with a partner who If there are many mechanisms in the Japan, Germany, and the Nether- fulfills sex-linked desires in a mate, body, each specialized and serving a lands. The predicted sex differences such as a younger or more physically different function, then there is noth- in mate preferences, to take another attractive partner in the case of a ing unparsimonious about having example, have been found using ex- man with higher mate value and a many mechanisms in one's model of pressed preferences in 37 cultures more financially secure partner in the the body. If selection has fashioned and records of personal ads in several case of a woman with higher mate an analogously large number of psy- cultures and are implied by the sex value. chological mechanisms, then there is differences in the success of tactics of Dozens more predictions have been nothing unparsimonious about hav- mate attraction and mate retention. made, all stemming from the basic ing many mechanisms in one's model Few hypotheses in the social sci- premises of Sexual Strategies Theory of the mind. ences have withstood this number of (Buss, 1994; Buss & Schmitt, 1993). Parsimony most properly applies diverse empirical tests, so claims that The theory is eminently testable, to the number of theoretical processes needed to explain a particular set of across cultures (Buss, 1994; Symons, confront the possibility that we will phenomena, not to the number of phe- 1979).Although less extensively doc- never know precisely the selective nomena that require explanation. In umented than these, sex differences events that sent our species careen- this sense, the evolutionary perspec- in jealousy and causes of conjugal ing in the directions it did. tive generally, and Sexual Strategies dissolution are acquiring a strong Second, there is currently uncer- Theory specifically, are parsimonious cross-cultural foundation (Betzig, tainty about how best to characterize and internally consistent. 1989; Buunk et al., in press). evolved psychological mechanisms Level of emnpirical suppo7-t. Evolu- Much empirical work remains to and a lack of deep knowledge about tionary psychological hypotheses be done, however. In particular, we any particular psychological mecha- typically postulate evolved species- need more detailed and refined task nism. Some evolutionary theorists typical or sex-typical psychological analyses of precisely what it takes to describe psychological mechanisms mechanisms. Manifest behavior is solve each adaptive problem. Further- as information-processing devices predicted to be highly variable with- more, the output of the evolved mech- designed to take in certain classes of in the same individual across differ- anisms has been relatively neglected. input, operate on that input with ent situations, different individuals, Sexual jealousy, for example, can re- decision rules, and produce output in and even cultures. Much variability sult in behavior ran9ng from vig- the form of manifest behavior, phys- is predicted to stem from environ- lance to violence (Buss, 198813). We iologcal activity, or information to mental variability. The same individ- need to know the different behav- other psychological mechanisms ual, for example, confronts different ioral output of each evolved psycho- (Buss, 1995; Tooby & Cosmides, adaptive problems over time and logical mechanism and the causal 1992). At the current time, however, context, and so some mechanisms are conditions under which different be- no evolved mechanism has been activated and others lie dormant in haviors are produced. Does jealousy fully described in these terms. Com- each, giving rise to variable behav- result in increasingly violent behav- pared to our knowledge about evolved ior. The same principle applies to dif- ioral output as the discrepancy in physiological mechanisms such as the ferent individuals, who confront mate value between the partners in- liver, our knowledge of evolved psy- different adaptive problems, and even creases? Does acting upon a desire chological mechanisms is paltry. entire cultures, which recurrently for sexual variety depend on the mag- A third limitation is a predictive confront some adaptive problems nitude of residual reproductive value? one. Detailed analysis of the tasks more than other cultures do. A criti- These and dozens of other questions that are solved to reach an adaptive cal empirical test of evolutionary hy- await empirical research. In this problem enable one to identify what potheses, therefore, is not whether sense, although the empirical foun- is necessary for a successful solution, manifest behavior is universal (it is dation for Sexual Strategies Theory but there is no way to identify in ad- not predicted to be), but rather is solid, the bulk of empirical work vance which solution among the pos- whether the underlying psychologcal lies ahead. sible set of solutions has evolved, or mechanisms are universal, species Current ~eakness.Several key even if a successful solution has typical, or sex typical. Actually, nearly weaknesses of evolutionary psychol- evolved at all! Knowing that warm- all psychologxal theories are based ogy generally, and Sexual Strate~es blooded animals must have evolved on the assumption, usually implicit, Theory specifically, can be highlighted. mechanisms to solve the problem of of the existence of universal mecha- First, we lack a videotape of the thermal homeostatic regulation, for nisms; evolutionary psychology stands selective pressures that have affected example, does not allow us to predict out in being explicit about this as- human sexual psychology over evolu- whether an organism will have sumption. tionary time. Did concealed ovulation evolved sweat glands, adjustable Without empirical evidence for precede the emergence of long-term feathers to control body temperature, universal sex differences in sexual mating and high male parental in- or evaporative mechanisms on a pro- psychology, many tenets of Sexual vestment, or did these three features truding tongue. Similarly, knowing Strategies Theory would collapse. of humans co-evolve simultaneously? that men have faced the adaptive Fortunately, the empirical base is Some selection pressures can be in- problem of uncertainty in paternity secure in some fundamental domains. ferred from the paleontological evi- does not tell us which among the The predicted sex differences in mate dence, comparative analysis, and many possible solutions will have preferences, for example, have been analysis of the current design of our evolved. Indeed, different species documented in 37 different cultures mechanisms. Indeed, the design of have evolved many qualitatively dif- (Buss, 1989a) and have been repli- our current mechanisms constitutes ferent solutions to this problem, in- cated in many others (see Buss, 1994, a record of past selection. Nonethe- cluding sperm plugs, building a for summaries). The sex difference less, reconstructing the evolutionary "fence" around the female, threaten- in desire for sexual variety also ap- history of prior selection remains a ing intrasexual rivals, emitting "anti- pears to be soundly documented daunting task. We may eventually aphrodisiac" scents, sequestering the Sexual Strategies Theory female, and many others (Buss, nisms. The human mind and the theory designed to explain the sexual 1994). In short, knowledge about an 1,400-cubic centimeter brain in which psychology of men and women world- adaptive problem does necessarily it is housed represent one of evolu- wide. Human sexual psychology, in yield precise predictions about which tion's most formidable creations. this account, represents a rich reper- among the possible set of solutions Theories of sexual psychology that toire of short-term and long-term will have evolved. are inconsistent with what is known mating strategies, each activated by A fourth limitation is that Sexual about evolutionary biology stand lit- specific social and sexual contexts. Strategies Theory has been far more tle chance of being correct. Desire, in this account, lies at the successful at predicting and explain- Evolution by selection strongly foundation of the human mating sys- ing sex differences in human sexual- suggests, for example, that when tem. Human desires define to whom ity than it has been in explaining the males and females face recurrently we are attracted, as well as which features of sexuality men and women different adaptive problems over the tactics of attraction are effective. Vio- have in common. Furthermore, it has deep expanse of evolutionary time, lations of desires define conflict be- been even less successful in explain- they will evolve different adaptive tween the sexes, when a strategy ing individual differences in human solutions. Given what is known about pursued by one interferes with a strat- sexuality, although there have been the nature of these different adap- egy pursued by the other. In extreme several successful inroads to this tive problems in the domain of human cases, violations of desires lead to limitation (e.g., Gangestad & Thorn- sexuality-such as the problem of conjugal dissolution. The flip side of hill, 1994). Hopefully, future devel- uncertainty of parenthood confronted the coin, however, is represented by opments of Sexual Strategies Theory by men, but not by women-the odds the fulfillment of desire, which deter- will afford greater insights about our that men and women would be iden- mines successful mate-retention tac- shared sexual psychology as well as tical in their sexual psychology is es- tics and harmony between the sexes. into the ways in which we differ with- sentially zero (Symons, 1992). Thus, The empirical foundation for Sex- in sex. theorists who assume implicitly or ual Strategies Theory is solid and Multi-level conceptual integration. explicitly an identical sexual psy- must be explained by any compre- Scientific progress is often usefully chology for men and women, as some hensive theory of human sexuality gauged by the degree to which a dis- do, are unlikely to be correct. Sexual and mating. Men and women differ cipline achieves conceptual integra- Strategies Theory is thus compatible universally in their desire for sexual tion-the notion that conceptual with this principle of evolutionary variety. Men and women differ in the schemes in one discipline are made biology-sex differences are only pre- qualities they prefer in long-term mutually consistent with what is dicted in those adaptive domains in mates. Men and women differ in the known in other disciplines (Cos- which the sexes have faced recur- weighting given to cues that trigger mides, Tooby, & Barkow, 1992). This rently different problems over human sexual jealousy. Both sexes show is not reductionism, but conceptual evolutionary history. temporal shifts in their desires as integration. The laws of chemistry, for Narrow training, disciplinary iso- they move from long-term to short- example, cannot contradict the laws lationism, disciplinary territoriality, term mating contexts. Theories prem- of physics-the two sets of laws must and xenophobia often prevent the re- ised on the notion that men and be mutually compatible, even though alization of insights in one discipline women are identical in their under- one cannot be reduced to the other. that can be gleaned from understand- lying sexual psychology do not square Similar forms of conceptual integra- ing the basic principles in disciplines with this empirical foundation of sex tion should apply with equal force to operating at different conceptual differences. psychology and evolutionary biology. planes. Sexual Strategies Theory Much conceptual and empirical Models of psychology must be consis- represents a step toward multi-level work remains to be done, and in this tent with what is known about the conceptual integration of evolution- sense, a foundation does not a house principles of evolutionary biology, ary biology and the psychology of make. Conceptually, models are even though one cannot be reduced to human sexuality. needed to explain sex differences in the other. In short, multi-level con- adaptive problems as yet unidentified. ceptual integration remains a wor- Conclusions Task analyses and computational thy goal of all scientific enterprises. The scientific revolution started models are needed for the adaptive Evolutionary psychology generally, by Darwin more than a century ago problems shared by men and women, and Sexual Strategies Theory specif- is finally being realized in the scien- as well as for those on which they ically, represent steps toward this tific study of human sexuality. The differ. The range of behavioral output goal. As far as we know, evolution by tenets of sexual selection theory of the array of evolved psychological selection remains the only known combined with insights from evolu- mechanisms is largely unexamined. causal process capable of creative tionary psychology form the founda- Urgent work is needed on individual complex functional organic mecha- tion of Sexual Strategies Theory-a differences within sex, as well as on the personal and social contexts that ary analysis of human mating. Psychologi- Lovejoy, C. 0. (1981). The origin of man. Sci- ence, 211, 341-350. trigger specific elements from the com- cal Reuieu, 100, 204-232. Buunk, B. P., Angleitner, A,, Oubaid, V., & Oliver,M. B.,& Hyde, J.S. (1993). Gender dif- plex strategc repertoire. Buss, D. M. (in press). Sex differences in ferences in sexuality: A meta-analysis. Even with these limitations, howev- jealousy in evolutionary and cultural per- Psychological Bulletin, 114, 29-51. er, Sexual Strategies Theory provides spective: Tests from the Netherlands, Ger- Schmitt, D. P., & Buss, D. M. (1996). Mate at- the outlines of many fundamental many, and the United States. Psychological traction and competitor derogation: Con- Science. text effects on perceived effectiveness. adaptive problems men and women Clark, R. D.,& Hatfield, E. (1989). Gender dif- Journal of Personality and Social Psy- have faced in the sexual domain. It ferences in receptivity to sexual offers. cholog, 70, 1185-1204. provides a compelling account of men's Journal of Psychology and Human Sexual- Singh, D. (1993). Adaptive significance of fe- and women's sexual psychology as ity, 2, 39-55. male physical attractiveness: Role of solutions to those problems. It has Clutton-Brock, T. H. (1991). The evolution of waist-to-hip ratio. Journal of Personality parental care. Princeton, NJ: Princeton and Social Psychology, 65, 293-307. survived numerous empirical tests University Press. Small, M. (1992). The evolution of female sex- that have put it at risk of falsifica- Cosmides, L., & Tooby, J.(1994). Beyond intu- uality and mate selection in humans. tion. More than any other theory of ition and instinct blindness: Toward an Human Nature, 3, 133-156. human sexuality, it explains why men evolutionary rigorous cognitive science. Symons, D. (1979). The evolution of human sexuality. New York: Oxford University and women have evolved the complex Cognition, 50, 41-77. Cosmides,L., Tooby, J.,& Barkow, J. (1992). In- Press. repertoire of context-contingent short- troduction: Evolutionary psychology and Symons, D. (1987). If we're all Darwinians, term and long-term sexual strateges conceptual integration. In J.Barkow, L. Cos- what's the fuss about. In C. Crawford, that characterize our species today. mides, & J. Tooby (Eds.), D. Krebs, & M. Smith (Eds.), (pp. 19-136). New York: Oxford University and psychology (pp. 121-145). Hillsdale, Press. NJ: Erlbaum. Cronin, H. (1991). The ant and the peacock. Symons, D. (1992). On the use and misuse of Andersson, M. (1994). Sexual selection. Cambridge, England: Cambridge Univer- Darwinism in the study of human behav- Princeton, NJ: Princeton University Press. sity Press. ior. In J. Barkow, L. Cosmides, & J. Tooby Betzig, L. (1989). Causes of conjugal dissolu- Daly, M., &Wilson, M. (1988).Homicide. New (Eds.), The adapted mind (pp. 137-1621, tion: A cross-cultural study. Current An- York: Aldine de Gruyter. New York: Oxford. thropology, 30, 654-676. Daly, M., Wilson, M., & Weghorst, S. J. (1982). Symons, D. (1995). Beauty is in the adaptations Buss, D. M. (1988a). The evolution of human Male sexual jealousy. Ethology and Socio- of the beholder. In P. Abramson & S. D. intrasexual competition: Tactics of attrac- biology, 3, 11-27. Pinkerton (Eds.), Sexual nature, sexual cul- tion. Journal of Personality and Social Darwin, C. (1859). On the origin of the species ture (pp. 80-118). Chicago: University of Psychology, 54, 616-628. by means of natural selection, or preserua- Chicago Press. Buss, D. M. (1988b). From viglance to vio- tion of favoured races in the struggle for Thiessen, D. (1994). Environmental tracking lence: Tactics of mate retention. Efhology life. London: Murray. by females. Human Nature, 5, 167-202. and Sociobiology, 9, 291-317. Darwin, C. (1871). The descent of man and se- Tooby, J., & Cosmides, L. (1992). Psychological Buss, D. M. (1989a). Sex differences in human lection in relation to sex. London: Murray. foundations of culture. In J.Barkow, L. Cos- mate preferences: Evolutionary hypothe- DeSteno, D. A,, & Salovey, P. (in press). Evo- mides, & J. Tooby (Eds.),The adapted mind ses tested in 37 cultures. Behavioral and lutionary origins of sex-differences in jeal- (pp. 19-136).New York: Oxford. Brain Sciences, 12, 1-49. ousy? Questioning the "fitness" of the Trivers, R. (1972). Parental investment and Buss, D. M. (198913). Conflict between the model. Psychological Science. sexual selection. In B. Campbell (Ed.),Sex- sexes: Strategic interference and the evo- Ellis, B. J., & Symons, D. (1990). Sex differ- ual selection and the descent of man, 1871- cation of anger and upset. Journal of Per- ences in sexual fantasy: An evolutionary 1971 (pp. 136-1791, Chicago: Aldine. sonality and Social Psychology, 56, 735-747. psychological approach. The Journal of Wiederman, M. W., & Allgeier, E. R. (1993). Buss, D. M. (1994). The evolution of desire: Sex Research, 27, 527-556. Gender differences in sexual jealousy: Strategies of human mating. New York: Fisher, R. A. (193011958).The genetical theory Adaptationist or social learning explana- Basic Books. of natural selection. New York: Dover. tion? Ethology and Sociobiology, 14, 115- Buss, D. M. (1995).Evolutionary psychology: Gangestad, S. W., & Thornhill, R. (1994). Fa- 140. A new paradigm for psychologcal science. cial attractiveness, developmental stabili- Williams, G. C. (1966).Adaptation and natur- Psychological Inquiry, 6, 1-49. ty, and fluctuating asymmetry. Ethology al selection. Princeton, NJ: Princeton Uni- Buss, D. M., & Dedden, L. A. (1990). Deroga- and Sociobiology. versity Press. tion of competitors. Journal of Personal Gladue, B. A,?& Deleney, J. J. (1990). Gender and Social Relationships, 7, 395-422. differences in perception of attractiveness Manuscript accepted February 26, 1997 Buss, D. M., IGrkpatrick, L., Shackelford, T., of men and women in bars. Personality & Bennett, K. (1996).On the nature of sex and Social Psychology Bulletin, 16, 378- differences in jealousy: Testing alternative 391. hypotheses about origins. Unpublished Humphrey, N. K. (1976).The social function of manuscript, Department of Psychology, intellect. In P. P. G. Bateson & R. A. Hinde University of Texas, Austin. (Eds.), Growing points in ethology. Cam- Buss, D. M., Larsen, R. J.,Westen, D., & Sem- bridge, England: Cambridge University melroth, J. (1992). Sex differences in jeal- Press. ousy: Evolution, physiology, and psychology. Johnson-Laird, P. N. (1983). Mental models. Psychological Science, 3, 251-255. Cambridge, MA: Harvard University Buss, D. M., & Schmitt, D. P. (1993). Sexual Press. Strategies Theory: A contextual evolution- http://www.jstor.org

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You have printed the following article: Sexual Strategies Theory: Historical Origins and Current Status David M. Buss The Journal of Sex Research, Vol. 35, No. 1, The Use of Theory in Research and Scholarship on Sexuality. (1998), pp. 19-31. Stable URL: http://links.jstor.org/sici?sici=0022-4499%281998%2935%3A1%3C19%3ASSTHOA%3E2.0.CO%3B2-B

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References

Causes of Conjugal Dissolution: A Cross-cultural Study Laura Betzig Current Anthropology, Vol. 30, No. 5. (Dec., 1989), pp. 654-676. Stable URL: http://links.jstor.org/sici?sici=0011-3204%28198912%2930%3A5%3C654%3ACOCDAC%3E2.0.CO%3B2-G

Evolutionary Psychology: A New Paradigm for Psychological Science David M. Buss Psychological Inquiry, Vol. 6, No. 1. (1995), pp. 1-30. Stable URL: http://links.jstor.org/sici?sici=1047-840X%281995%296%3A1%3C1%3AEPANPF%3E2.0.CO%3B2-7

Sex Differences in Sexual Fantasy: An Evolutionary Psychological Approach Bruce J. Ellis; Donald Symons The Journal of Sex Research, Vol. 27, No. 4. (Nov., 1990), pp. 527-555. Stable URL: http://links.jstor.org/sici?sici=0022-4499%28199011%2927%3A4%3C527%3ASDISFA%3E2.0.CO%3B2-C

The Origin of Man C. Owen Lovejoy Science, New Series, Vol. 211, No. 4480. (Jan. 23, 1981), pp. 341-350. Stable URL: http://links.jstor.org/sici?sici=0036-8075%2819810123%293%3A211%3A4480%3C341%3ATOOM%3E2.0.CO%3B2-8