Mate choice Flashcards
How and why do mating strategies differ between human males and females and compare this to the mating strategies of other species
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Intro
Certain physical and behavioural differences between males and females can be explained by differential potential reproduction rates. This is the fact that in most species females produce a limited amount of eggs and can only give birth to a small number of young at a time, while males produce millions of sperm and have the potential to fertilise the eggs of many females. These differential potential reproduction rates are thought to underlie many of the differences in mating strategies in both humans and other species. This essay attempts to outline the many factors contributing to the differences in mating strategies and why they occur.
Sexual selection- Darwin, Dimorphism
Complementary to natural selection, which is based upon “survival of the fittest”, Darwin proposed sexual selection which refers to traits that promote mating and therefore the reproductive success and long term genetic survival of an individual, despite these traits being a cost to personal survival. Darwin suggested sexual selection could explain certain types of sexual dimorphism, the fact that the males and females of many species differ from one another in terms of certain physical or behavioural traits over and above the obvious reproductive organs.
Two components of sexual selection
Two components of sexual selection were male to male competition and female choice. Evidence for male to male competition and female choice comes from Sage Grouse Leks (birds). Males, fan tails, puff chest, fight central spot. Stay despite increased risk of predation and in sub-zero temperatures. Females inspect males from the bushes and only enter the Lek to copulate with a certain male. This illustrates male to male competition and female choice, which occurs because females alone produce eggs and have control over which male’s sperm fertilizes them. Females mate with those strong males in the centre of the Lek as it shows they can win out male to male competition and have those dimorphic traits most attractive to females.
Hamilton & Zuk (1982)
Hamilton & Zuk (1982) suggested extravagant features indicate parasite resistance, thereby indicating to the females they are healthy and have good genes, which are a preference for females. Fisher (1930) argued that once a preference gets established in females, it becomes self-reinforcing. He proposed the sexy son hypothesis; if females want to produce sons that are seen as attractive by other females, they must continue to choose mates that exhibit preferred trait. Otherwise, they may lower their long term genetic reproductive success by producing unattractive sons. This sexy son hypothesis can be seen in humans too.
Some examples of sexual dimorphism
Some examples of sexual dimorphism in human males and females include; men; greater height and mass, higher juvenile mortality and greater upper body strength. Clutton, Brock and Harvey (1977) show data that the difference in body size, height, mass etc. allows males to win out on male to male competition. Although this is more true for polygamous societies where winning against other males gains the male exclusivity to a harem of females, evidence from fossils show our ancestors body size dimorphism was much greater than today, suggesting that we have only recently evolved to be mildly polygamous serial monogamists (Hinde, 1982). Another sexually dimorphic trait that differs not only between human males and females but between species, are human female breasts. Most female primates only have enlarged breasts during pregnancy and lactation whereas female humans have constantly enlarged breasts. As the size of female breasts have no correlation with their ability to lactate, it has been suggested they may be a product of runaway selection as males find them attractive.
Physical attractiveness
Physical attractiveness is a trait with higher priority for males when seeking a potential mating partner. Singh (1993) found a preference in males for females waist to hip ratio which lies between 0.67 and 0.8 as it was seen to indicate reproductive value. For females age is a criteria prioritised as it indicated advertisement for fitness and health (due to the ability to have survived the higher risk of mortality in males) and is an indicator of success.
Buss (1989) collected data from 27 cross-cultured countries
Buss (1989) collected data from 27 cross-cultured countries and found on average females married males 2.49 years older than themselves. Buss (2003) argues modern females use subtle context-specific cues for status, such as graduate status. These differences in trait priorities underlie differences in mating strategies between male and female humans. Symons & Ellis (1989) argued because men have higher reproductive potential they are more likely to seek extra mating than females. This may be due to differences in the parental investment theory put forward by Trivers (1972).
Clutton-Brock and Vincent (1992) criticised the parental investment
Trivers argued a difference in mating strategies between males and females may be due to the fact that females are choosier in selecting a mate than males because they have more to lose if they copulate with a poor quality mate. Once their eggs are fertilized, females must gestate them for a period of time and then sometimes raise the offspring without the help of the male. Clutton-Brock and Vincent (1992) criticised the parental investment hypothesis because they argue it is difficult to operationalise. They use the example of male deer, who fight for and guard a harem of females. However, mating criteria in human males and females does overlap in certain aspects since both sexes have evolved to invest heavily in child care.
Buss & Barnes (1986) asked people to list criteria they most valued in a long term mate
Buss & Barnes (1986) asked people to list criteria they most valued in a long term mate and found considerable overlap in attractiveness, college graduate status and good earning capacity. Although there is an overlap, males and females place emphasis on traits differently. Buss (1989) tested 37 different cultures and found men preferred women younger than them 100% of the countries and they placed more emphasis on chastity in 62% of the countries. One hypothesis for this is paternity uncertainty. This is the concept that a female always knows that her offspring are hers whereas the male cannot be so certain. Therefore, males that help raising offspring do not benefit from lots of extra mating.
To conclude
To conclude, human mating strategies between males and females differ in many aspects due to their differential potential reproduction rates and their differences above and beyond their reproductive organs, sexual dimorphism. Female choice is a significant factor influencing the differences in human mating strategies because their eggs are of limited resource and therefore become valuable to males; this gives them greater control over reproduction. Despite these differences, as humans have evolved so that both males and females invest greatly in child upbringing, there is substantial overlap in the criteria for mate choice/selection, although there is some difference in where the emphasis is placed on certain factors. Overall, sexual selection seems to be the greatest influence on how mating strategies differ between the sexes, and this is primarily determined by females.
