As human females are smaller than and not as strong as males, they and their offspring are prone to being the victims of predators, and violence. Surveys consistently show that females prefer males who are socially dominant and have the respect of their peers. Forming a relationship with a socially dominant male would confer greater direct access to resources and also raise the social status of the female that would indirectly confer resource acquisition. Women pay close attention to how men interact with, and are treated by other men, Sadella et al., (1987)
Grammer & Thornhill (1994) argued that males would prefer symmetrical female faces because such symmetry could only be produced in healthy individuals able to resist genetic and environmental disturbances. They created composite male and female faces and asked males and females to judge them for attractiveness, sexiness, health and dominance. The female composite faces were judged as being more attractive and sexy than the individual photos and this was due to their reduced asymmetry.
Women find men with symmetrical features more attractive than men with asymmetrical features. ‘Fluctuating asymmetry (FA) is a measure of the symmetry of a bilateral character i.e. ear length or hand breadth that fluctuates’ (Laland and Brown 2002, p.191). Zahavi 1975 suggested that females have a preference for males with traits that indicate he is strong and, with the hope that their offspring will inherit these ‘good genes’. This is called good gene sexual selection (GGSS). Women also prefer that men have masculine features, such as strong jaw, facial hair, broader shoulders, narrower hips, and a muscular build, because these indicate sufficient testosterone for fertility. Moller 1990 suggests that low FA (symmetry) represents such traits. Low FA males report more sexual partners, an earlier age of first sexual intercourse and have more offspring than high FA men (Grammer and Thornhill 1994).
To be reproductively successful ancestral males needed to mate with females who had the capacity to produce children. Human female reproductive value cannot be assessed directly as ovulation is concealed (unlike most other mammals). However, there are several clues to a woman's reproductive value (the number of children a person of a given age is likely to have in the future) and ancestral males would have been able to detect and respond accordingly to these signals. Such signals would be reflection of developmental and hormonal health.
In all studies of mate preferences a typical and strong finding is that males prefer females who are at their peak of reproductive potential. Buss found that men typically placed more value than women on the physical attractiveness of their partner. Universally men prefer large eyes, good teeth, lustrous hair, full lips, smooth skin and a low hip to waist ratio. These physical traits are generally associated with youthfulness. ‘To be reproductively successful, ancestral men had to marry women with the capacity to bear children’ (Buss, 1999, p.133.). As males age, they prefer mates who are increasingly younger (Kenrick & Keefe, 1992). Women are only fertile from their mid teens to their late forty’s which is why youthfulness is associated with fertility and therefore can explain men’s preference for such characteristics.
Of course, the preference for younger partners is not always to be predicted, if teenage males preferred younger partners then these females may not be old enough to bear children, it would therefore be predicted that teenage males would prefer slightly older females. Kenrick et al., (1996) asked teenage males and females (aged between 12-19) the ideal age of a dating partner, and the age limits that would be acceptable. Teenage males (unlike older males) preferred mates who were slightly older than themselves.
This relationship is not the same in reverse since men have a lengthy period of fertility. There would not have been the same pressure on ancestral women to seek out youthfulness. Since women have a clear preference for good financial resources and high social status in men then it may be preferably for women to seek older partners which meet such criteria. In his cross-cultural survey Buss (1989) found that the age difference was typically around 4 years older. In studies of real-life choices shown in marriage statistics, Kenrick & Keefe (1992) found that females consistently married males who were around 5 years older than themselves.
Pawlowski, Dunbar and Lipowicz (2000) demonstrated that taller men are reproductively more successful than shorter men, suggesting that there is a preference for stature in male partners. Height is associated with power and status and studies have shown that height confers economic and social advantages as taller men are more likely to be hired, receive higher salaries, and gain promotion than smaller men. Taller men are perceived as being more dominant and we would predict that females should choose taller over shorter males.
In Buss's study, both sexes reported love as an essential requirement for a long term relationship. For long term relationships to work signals of commitment are required. Love, fidelity and dependability may provide this commitment. People in love expect their partners to channel time and effort in to the relationship. The ultimate goal of falling in love is to produce offspring. Being in love will guarantee that successful reproduction for both partners as ancestral females would have demanded commitment before consenting to sex, therefore males who failed to show commitment would lose out in the mating game. From a man's point of view, time invested in paternal care cannot be spent pursuing additional mates, and may be wasted if he is not the father of the child he is investing in.
A key problem for males is that they lack paternity certainty, those males that were able to reduce the risk of cuckoldry (unfaithfulness) would have had greater reproductive fitness than those who could not. It would therefore be predicted that males should have developed adaptations to seek partners (particularly for long-term relationships) who would remain faithful. Males in all cultures view promiscuity and unfaithfulness as being particularly undesirable in a potential long-term partner.
After love and dependability, people want a partner who is emotionally stable and of a pleasing nature as this indicates that the male will be willing to provide resources and continue his investment. It is no use finding a mate who has plentiful resources but who would be unwilling to invest them. Selection should also have favoured mechanisms in the female designed to detect and prefer males who were willing to convert status and resources into paternal assistance, La Cerra (1994). Kindness would be regarded as conducive to mutual investment in off spring. Therefore forming a long-term relationship with an untrustworthy, unreliable person of appalling disposition would not have boded well for ancestral people. The children of a stable relationship would be much more likely to survive.
However some have criticized the evolutionary explanation for human mate selection criteria and offer a cultural explanation. Mead (1968) as cited by Workman and Reader (2004) suggested that because humans vary so much between cultures, in their mating strategies, reproductive behaviour is culturally determine and unrelated to an evolutionary past. Importance of certain preferences varies between cultures. Specific cultural variables need to be looked at more closely to understand why they differ so much.
Developmental flexibility allows humans to adjust to social and economic circumstances within society. suggest that women's decision to seek short or long term mates may depend on environmental circumstances at the time they mate. If the child is going to be born into a world dominated by death and disease it would make sense to mate with a man rich in good genes. On the other hand, if a woman is in an environment where she has difficulty obtaining resources she should favour mating with men of high status and power who exhibit good parenting skills.
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