Arch Sex Behav (2007) 36:477–507 DOI 10.1007/s10508-007-9175-2 ORIGINAL PAPER Why Humans Have Sex Cindy M. Meston Æ David M. Buss Received: 20 December 2005 / Revised: 18 July 2006 / Accepted: 24 September 2006 / Published online: 3 July 2007 Ó Springer Science+Business Media, LLC 2007 Abstract Historically, the reasons people have sex have Keywords Sexual motivation Á Sexual intercourse Á been assumed to be few in number and simple in nature–to Gender differences reproduce, to experience pleasure, or to relieve sexual tension. Several theoretical perspectives suggest that mo- tives for engaging in sexual intercourse may be larger in Introduction number and psychologically complex in nature. Study 1 used a nomination procedure that identified 237 expressed Why people have sex is an extremely important, but reasons for having sex, ranging from the mundane (e.g., ‘‘I surprisingly little studied topic. One reason for its relative wanted to experience physical pleasure’’) to the spiritual neglect is that scientists might simply assume that the (e.g., ‘‘I wanted to get closer to God’’), from altruistic (e.g., answers are obvious: to experience sexual pleasure, to ‘‘I wanted the person to feel good about himself/herself’’) relieve sexual tension, or to reproduce. Previous research to vengeful (e.g., ‘‘I wanted to get back at my partner for already tells us that the answers cannot be as few or having cheated on me’’). Study 2 asked participants psychologically simple. Leigh (1989), for example, docu- (N = 1,549) to evaluate the degree to which each of the 237 mented seven reasons for sex: pure pleasure, to express reasons had led them to have sexual intercourse. Factor emotional closeness, to reproduce, because a partner wants analyses yielded four large factors and 13 subfactors, it, to please a partner, to make a conquest, and to relieve producing a hierarchical taxonomy. The Physical reasons sexual tension. The most comprehensive existing taxonomy, subfactors included Stress Reduction, Pleasure, Physical framed from a theoretical perspective of dispositional sexual Desirability, and Experience Seeking. The Goal Attainment motives, documented eight reasons: to feel valued by a subfactors included Resources, Social Status, Revenge, and partner, expressing value for a partner, obtaining relief from Utilitarian. The Emotional subfactors included Love and stress, nurturing one’s partner, enhancing feelings of per- Commitment and Expression. The three Insecurity subfac- sonal power, experiencing a partner’s power, experiencing tors included Self-Esteem Boost, Duty/Pressure, and Mate pleasure, and procreating (Hill & Preston, 1996). Guarding. Significant gender differences supported several Several theoretical perspectives suggest that reasons for previously advanced theories. Individual differences in engaging in sexual intercourse might be even more expressed reasons for having sex were coherently linked numerous and complex than even this previous research with personality traits and with individual differences in suggests. With the exception of ‘‘to make a conquest,’’ most sexual strategies. Discussion focused on the complexity of of the documented reasons for having sex above implicitly sexual motivation and directions for future research. assume the context of an ongoing romantic relationship or long-term mateship. Sexual strategies theory (Buss & Schmitt, 1993) and strategic pluralism theory (Gangestad & Simpson, 2000), however, propose that humans have a & C. M. Meston ( ) Á D. M. Buss menu of mating strategies, including long-term, short-term, Department of Psychology, University of Texas at Austin, 108 E. Dean Keeton, Austin, TX 78712, USA and extra-pair mating. Thus, there might be reasons for e-mail: [email protected] having sex with a casual sex partner or extra-pair partner, 123 478 Arch Sex Behav (2007) 36:477–507 such as the desire to experience sexual variety (Symons, implications for prestige, status, and reputation (Buss, 1979) or seeking to improve one’s sexual skills (Greiling & 2003). Having sex with a high status individual, for Buss, 2000) that differ from those that motivate sex in the example, might raise a person’s status within the group. context of an ongoing romantic relationship. Within some groups, having sex with numerous partners Even within the context of an ongoing mateship, there might enhance a person’s reputation, providing the moti- could be numerous reasons for having sex beyond those vational impetus for initiating sex. Sex, of course, can already documented. For example, sex might be used to sometimes damage a person’s status and reputation, pro- reward a partner or as a favor in exchange for something the viding reasons for avoiding it or concealing it from others partner has done. Or sex might be used to punish a partner, in the group. In sum, because sex has consequences for such as when someone engages in a retaliatory affair in status and reputation that can act as incentives (or deter- order to exact revenge on a partner for having committed rents), a person might be motivated to have sex for social some violation within the relationship (Greiling & Buss, reasons that have nothing to do with the personal rela- 2000). Also, within an ongoing relationship, sex might be tionship within which it occurs. All of these diverse theo- used to intensify the relationship, escalate the level of retical perspectives, when taken together, point to a commitment within the relationship, or turn a short-term singular conclusion: The reasons people have sex are likely relationship into a long-term relationship (Buss, 2003). In to be far more numerous and psychologically complex than the clinical literature, Basson (2000) described how women previous taxonomists have envisioned. may engage in sexual intercourse for the ‘‘spin-offs’’ they The current research had several primary goals: (1) to receive, such as emotional closeness, bonding, commit- identify a broader array of potential reasons that motivate ment, love, affection, acceptance, tolerance, and closeness. people to engage in sexual intercourse using a nomina- From yet another perspective, people might use sex as a tion procedure designed to survey the wider domain of form of ‘‘mate guarding’’ (Buss & Shackelford, 1997). This reasons; (2) to develop an organized taxonomy of reasons could function in one of several possible ways. First, satis- for sex using a large sample of women and men; (3) to fying a partner sexually might function to deter the partner provide a more comprehensive research tool that can be from seeking sexual gratification elsewhere. Second, this used by sex researchers; (4) to identify whether women strategic use of sexuality might send signals to potential and men differ in their expressed reasons for engaging in mate poachers, perhaps by rendering the partner less ‘‘open’’ sexual intercourse; and (5) to examine whether individual to extra-pair liaisons, causing potential mate poachers to differences in sexual strategies, as measured by the choose other potential targets (Schmitt, 2004; Schmitt & Sociosexuality Inventory (Simpson & Gangestad, 1991), Buss, 2001). are linked to individual differences in reasons for having Another perspective comes from the literature on sperm sex. competition (Baker & Bellis, 1995; Shackelford, Pound, Regarding gender differences, previous researchers have Goetz, & LaMunyon, 2005). From this perspective, a man explored this issue in a delimited way. Some have found whose partner might have been sexually unfaithful might that men are more motivated by purely physical reasons, seek sex, which functions to displace the sperm of the rival such as physical release or simply because they are ‘‘hor- male. Or a woman might deplete the sperm of her partner, ny,’’ whereas women are more motivated by emotional leaving few available for insemination of rival women. reasons, such as to become psychologically closer to a None of these hypothesized functions, of course, need partner (e.g., Carroll, Volk, & Hyde, 1985; Denney, Field, operate through conscious psychological mechanisms. & Quadagno, 1984; Leigh, 1989). Others have found that More generally, sex can be viewed as a fungible re- men, more than women, have sex in order to provide relief source–something that one person has the potential to give from stress and to enhance their feelings of personal power and something that another person may want. As a sought- (Hill & Preston, 1996). Several evolution-based theories after resource, sex can be exchanged for other resources. suggest that men will be more motivated by the desire for Exchanging sex for money, as in the case of prostitution, is sexual variety (Symons, 1979), the chance for an oppor- one obvious example (Burley & Symanski, 1981). Sex tunistic copulation (Buss, 2003), the physical appearance could also be exchanged for meat, as occurs among many of a potential partner (Buss & Schmitt, 1993), and that traditional hunter-gatherer groups such as the Ache of emotional factors, such as expressing love or intensifying Paraguay (Hill & Hurtado, 1996). Sex could be exchanged psychological commitment, would figure more promi- for favors, special privileges, a preferred job, or indeed for nently in women’s reasons for having sex (Buss, 2003). any resource. The current research was capable of testing these theories, Finally, the psychology of sex does not occur merely as well as providing a more comprehensive atheoretical between the individual partners directly involved. Sex description of a potential