While evolutionary research originally focused on people s g

While evolutionary research originally focused on people\'s general preferences in mate selection and was concerned with the differences between men and women (Buss, 1995; Gangestad & Simpson, 2000), later studies began to examine other issues, such as the length of a relationship. Researchers also began to compare the reasons why individuals preferred short-term relationships (dating, one-night stands) to long-term ones (cohabitation, marriage) (Buss & Schmitt, 1993). Evolutionary psychologists now consider that women may establish short- or long-term relationships for a variety of reasons which depend on environmental circumstances (Durante et al., 2011). Women in developed Z-YVAD-FMK prefer long-term partners who transmit a sense of professional, material and social success, as evidenced in studies that positively correlate suitor\'s preferences and income level, and their degree of job security (Landolt, Lalumière, & Quinsey, 1995). Other studies also corroborate women\'s preference for ambitious suitors focused on their career and ability to earn a high income (Eagly & Wood, 1999). However, women also positively evaluate other signs that men will make good partners and have long-term cooperative attitudes, such as their willingness to invest time in children (Scheib, 2001). Although physical attractiveness is considered to be an important asset, in stable relationships women assign less importance to this than men do (Buss, 1995; Regan, 1998). One of evolutionary psychology\'s main subjects is partner preference in attractive couples, and physical attractiveness and sex appeal are considered to be “honest signals” to opposite-sex members of a mate\'s phenotypic quality (Kirkpatrick, 1996). However, while the desire for a physically attractive partner may be an instinctive preference, Jensen-Campbell, Graziano, and West (1995) observe that for women a suitor\'s physical attractiveness must be complemented by pro-social behaviour: in short, a good candidate for a long-term relationship must have favourable financial prospects (Gustavsson, Johnsson, & Uller, 2008) and solid social status (Buss & Schmitt, 1993); the candidate must also be a little older (Buss et al., 1990), ambitious and hardworking (Lund, Tamnes, Moestue, Buss, & Vollrath, 2007); and, finally he must also be strong and attractive (Gangestad & Thornhill, 1997). On the other hand, the literature observes five basic reasons why women pursue short-term relationships: to obtain material and protective resources; to gain some kind of genetic benefit; to begin the process by which a current partner is eventually replaced; to begin a relationship that may become long-term; and to manipulate a current partner (as a strategy for revenge or deterrence) (Buss, 2014). These reasons also apply in the animal world, where trading sex for resources occurs among primates (Symons, 1980) and in humans in pre-industrial hunter-gatherer societies (Benshoof & Thornhill, 1979). (Note that female primates and women in pre-industrial societies use short-term relationships to attain immediate resources and reduce the time required to forage for their own survival and their offsprings.) In line with the findings of Scheib (2001), however, in the developed world and modern society, women establish short-term or even extramarital relationships mainly to obtain genetic benefits. Women show similar preferences about their suitors’ personal attributes in short- and long-term relationships (Buss, 1994) but consider physical attractiveness to be more important in the short term (Regan, 1998), where casual partners do not usually offer long-term investments and where the woman\'s main concern is genetic quality. Note that an important physical marker of a suitor\'s health is his degree of face and body symmetry (Gangestad & Thornhill, 1997; Greiling & Buss, 2000; Rikowski & Grammer, 1999) and that another sign of health and genetic quality is facial appearance, where suitors with larger and more pronounced lower jaws, stronger brow ridges and more pronounced cheekbones transmit a greater sense of masculinity (Waynforth, Delwadia, & Camm, 2005).