The origins of mate preference is the result of evolved psychological mechanisms that solved the problem of who to chose in the EEA. Our ancestors probably lived in small tribes where sexual and social relations were fluid, with a lot of infidelity. These preferences are now complex neural circuits that bias mating in favour of individuals with those preferred characteristics. It pays to be choosy as the genetic quality of a mate is an important determinant of the genetic quality of the offspring.
There are two forms of sexual seletion: the selection for indicators and the selection for sperm competition.
Indicators are the behavioural and physical indicators that reveal traits that could be passed on to the offspring (selection for good genes) and information about the mate being able to survive to protect the offspring (selection for good parents.) These indicators are condition dependant in that healthier individuals grow bigger and better indicators or “revealing” in that healthier individuals take better care of their indicators (better groomed.) Humans are pre-programmedto display these important indicators which increases their willingness to mate with the individual who possesses them.
Sperm competition is in many species were the female has multiple partners. As a result the males evolve larger testicles, ejaculate more and have faster swimming sperm. An example of this is chimpanzees. But gorrillas are monogamus, as they have only one partner. There is reduced competition and have small testicles in relation to their body size. Male humans have medium sized testicles suggesting there was some competition so females must have had multiple partners.
Sexual selection is often related to physical charateristics. Sexual dimorphism (physical differences between the sexes) can help bring about a female’s choice. The size differences between males and females suggests our species evolved under a polygynous competition (one male and many females), with more intense male competition, Martin. In relation to facial characteristics, the more neotenous (child-like) a females face is universally the more attractive they are perceived. Males faces with such features as string jaws and larger noses comes across more attractive. Facial symmetry is important as it is associated with the absence of harmful mutations.
Sexual selection has also been linked to mental evolution. In many species neophilia (love of novelty) is linked to sexual selection. In our EEA out ancestors would have to had entertained themselves which would have demanded ever-more creative displays from potential males. Hardly surprising that our history is littered with stories of sexual conquests by intelligent, gifted men.
Support for the universal nature of gender specific criteria comes froms Buss’ study of 37 cultures. He found men value partners in terms of their fecundity (ability to produce and care for offspring) which is expressed as youth and physical attractiveness. He also found females value men with cahracteristics related to resource potential i.e. ambition. Support from this comes from a study of women seeking sperm donors and their choise fitted the same qualities predicted by evolutionary theory. Cultural and historical changes can also cange sexual selection. Bereczkeifound females advertised for men who were family orientated as well as financially sound. This may be a consequence of increasing financial independance for women, meaning they are less concerned with resources and more about a partner who will help care for offspring. But relationships with no reproductive potential (homosexual relationships) cannot be explained by this view of sexual attraction. Dunbar,looked at gay personal ads, found heterosexual women were three times more likely to seek resources than lesbians. Whereas gay men offered resources about half as often as heterosexual men. This further conforms the reproductive success hypothesis.
The view that human behaviour can be explained in terms of selective pressures is by no means universally accepted. We know very little about the EEA. It is likely human nature has continued to evolve in the intervening 10 000 years, given huge changes is our social and physical environment.
Indicators are a good genetic quality, but can be faked easily. Red lipstick and collagen to make lips look fuller and therefore female to look younger can be seen to deceive males. In the animal world, the best indicators are those that are “handicaps” because only a characteristic that is costly can be reliable. If it is not costly it can be easily faked, and offspring of such matings will not increase fitness. In humans faial symmetry is a good indicator as it is diffecult to fake.
Support that humans are more promiscuous than monogamus from Baker and Bellis suggested a worldwide median rate that 9% of fathers are not actually genetically related. It was also indicated that 29% of people admitted to cheating. But we should not overlook the majority of people did know who their father was and majority of people have not cheated challenges the idea.
