Relationships Flashcards
Define sexual selection
It suggests that characteristics that confer a reproductive advantage (i.e. are attractive to the opposite sex or provide an advantage over competitors for reproductive rights) are passed on to produce offspring with the best genes. This is effectively ‘survival of the sexiest.’ In sexual selection, an individual’s survival is not at stake, but rather their ability to leave more descendants.
Define intra-sexual selection
Where traits allow an individual to compete with members of the same sex for access to mating opportunities. Men compete to be able to mate with the fertile women (they compare to be chosen)
Define inter-sexual selection
Where traits increase ‘attractiveness’ and/or induce members of the opposite sex to mate with them. Women evolve preferences for desirable qualities in potential mates to have the highest quality offspring
Define anisogamy
The difference between male and female sex cells.
Define human reproductive behaviour
Any behaviours (actions) that relate to opportunities to reproduce and therefore increase the survival chances of our genes.
Explain the difference between male and female sex cells
Sperm are extremely small, highly mobile, created continuously in vast numbers from puberty to old age and do not require a great expenditure of energy to produce. On the other hand, ova are relatively large, static, produced at intervals for a limited number of fertile years and require a huge investment of energy.
What is the optimum mating strategy for males?
I.e what types of relationships are they looking for and who with
Men prefer short-term relationships to have many offspring. Men are less choosy about who they reproduce with - females who show signs of youth and fertility so that they can pass down their genes (e.g. waist: hip ratio, clear skin etc)
What is the optimum mating stategy for females?
Women’s strategy will be to prefer long-term relationships to have high quality offspring. Women are therefore choosy in who they choose to reproduce with - genetically fit males who are willing to provide resources (older, wealthy men)
As a result, which type of sexual selection is the preferred strategy of each sex?
Males - Intra-sexual selection:
This is the preferred strategy of males. It refers to the competition between (intra) males to be able to mate with a female. The winner of the competition reproduces and passes on the characteristics that contributed to his victory to his offspring.
Anisogamy dictates that the male’s optimum reproductive strategy is to mate with as many fertile females as possible. This is because of the minimal energy required to produce sperm and the relative lack of post-coital responsibility. This results in an increased probability that they will reproduce and pass on their genes. A consequence of this competition for female mates is for males to show a distinct preference (particularly in long-term relationships) for youth and sensitivity to the indicators of youth (e.g. certain facial features) and fertility (e.g. certain body shapes like an hourglass figure) as these are signs of reproductive value. It is also believed that men show less attraction after sexual intercourse as this is an innate mechanism to prevent them from spending too much time with one partner.
Females - inter-sexual selection:
This is the preferred strategy of females. Both sexes are choosy, because both stand to lose if they invest resources in substandard partners. But anisogamy dictates that the consequences of choosing a substandard partner is much more serious for females than males because females make greater investment in terms of time, commitment and other resources before, during and after the birth of her offspring. Combined with there being no shortage of fertile males, it pays for females to be especially choosy in short-term relationships so that any offspring are of a higher quality (i.e. have the best genes) and so their genes are much more likely to be passed on. The female’s optimum strategy for both short and long-term relationships is to prefer and select a genetically fit partner (e.g. tall, strong and so are able to physically protect her and her children) who is able and willing to provide resources (e.g. shelter for her and her offspring, food etc.). This results in a preference for wealthy, older males. Such adaptive mechanisms can be seen in society today as they have been passed down via sexual selection.
What do men look for in women?
Signs of fertility and youth (wide hips)
What do women look for in men?
Signs of strength and ability to provide for offspring (taller, wealthier)
How do men outcompete each other for ‘access’ to women?
Men who have these qualities are better able to compete (e.g. taller, more aggressive to show they can protect women)
How does all of this get passed down?
Men and women who have these characteristics have a reproductive advantage. These characteristics are then passed down to future generations and so evolve via sexual selection.
Using the key terms in question 1 and your answers to questions 2-7, explain the relationship between sexual selection and human reproductive behaviour. Make sure to include what each sex looks for in a partner and how they can outcompete other members of the same sex as well as how the characteristics get passed down.
Sexual selection is an evolutionary explanation of partner preferences. It suggests that attributes or behaviours that increase reproductive success are passed on to offspring. It argues that human reproductive behaviour is controlled by the innate differences between male sperm and female ova (anisogamy). Sperm can be produced very quickly and in large volumes, allowing a man to potentially impregnate hundreds of women in a short space of time, whereas ova and the process of pregnancy require a larger investment of time and energy to produce the ova and carry one foetus. This means that men will typically seek out shorter-term relationships to produce the most offspring possible, whereas women will prefer longer-term relationships to produce the highest quality offspring. This then leads to women displaying inter-sexual selection, where they are more choosy with who they mate with and will select the man who appears to be the most genetically fit whilst having characteristics that make them attractive to the opposite sex to induce them to want to reproduce with them, and men competing amongst themselves to display the most desirable traits to the women in the hopes of mating with her (intra-sexual selection). Since women look to produce high quality offspring, they have evolved to prefer men who show signs of strength and ability to provide for offspring (so will prefer taller, wealthier men). Men on the other hand have evolved to prefer women who display signs of fertility and youth (wide hips for example), in order to maximise the potential for offspring production with each partner. Men and women who have these characteristics have a reproductive advantage. These characteristics are then passed down to future generations and so evolve via sexual selection.
Describe three studies that have supported the relationship between sexual selection and human reproductive behaviour. For each one, explain exactly which predictions of the theory they support using as many of the ideas from questions 1-7 as possible.
Clarke and Hatfield (1989:
Clarke and Hatfield (1989) - Male and female psychology students were sent out across a university campus. They approached other students individually with this question: ‘I have been noticing you around campus. I find you very attractive. Would you go to bed with me tonight?’ Not a single female student agreed to the request, whereas 75% of men did, immediately.
Top tip for A*: you could argue that there is a gender bias to attribute short-term mating strategies only to men, as even though men are more likely to want casual sex and a variety of sexual partners, these mechanisms couldn’t have evolved without the presence of willing females. Perhaps there may have been benefits for women to undergo short-term relationships e.g. allowing them to leave unrewarding relationships if their partner discovered their infidelity or to increase the genetic diversity of their offspring. This type of gender bias is known as alpha bias as it overestimates the differences between the sexes.
This reflects sex differences predicted by anisogamy and supports the predictions derived from sexual selection theory about short-term mating strategies. Males evolved innate mechanisms favouring short-term relationships to maximise their chances of reproductive success, whilst women are choosier to increase the likelihood of high quality offspring. Therefore, this supports the validity of the theory as an explanation of reproductive behaviour.
Buss (1989):
Buss (1989) carried out a survey of over 10, 000 adults in 33 countries. He asked questions relating to age and a variety of attributes that evolutionary theory predicts should be important in partner preference. He found that females placed greater value on resource-related characteristics, such as good financial prospects, ambition and industriousness than males did. Males valued reproductive capacity in terms of good looks and chastity, and preferred younger mates more than females did.
Top tip for A*: However, this lacks external validity as it only looks at partner preferences and not the reality of partner choices (people may need to compromise in reality rather than having the ideal partner) and so may not as strongly support the link between sexual selection and human reproductive behaviour as previously thought. Although, Buss then studied 29 cultures and found that men chose younger women and if they divorced they tended to remarry younger women.
This reflects universal sex differences predicted by anisogamy and supports the predictions about partner preferences derived from sexual selection theory. Men prefer signs of fertility to increase the likelihood of reproductive success, whilst women prefer wealth as a sign of protection and provision for her and her offspring. As the findings apply across different cultures, this reflects that the preferences are not primarily dependent on cultural influences and so support that such preferences may be innate as proposed by the theory, supporting its validity.
Waynforth and Dunbar (1995):
Waynforth and Dunbar (1995) studied lonely hearts adverts in American newspapers. These were opportunities for men and women to describe the qualities that they desired in a partner whilst also sharing what they had to offer. The researchers found that women more than men tended to offer physical attractiveness and indicators of youth (e.g. flirty, exciting, curvy, sexy). Men on the other hand, offered resources more than women did (e.g. successful, fit, mature, ambitious) and sought relative youth and physical attractiveness.
This supports sex differences predicted by anisogamy and supports predictions for long-term mating strategies for women (preferring resources to ensure provision for her and her offspring and therefore the offspring surviving), and short and long-term strategies for men (preferring signs of fertility to increase their likelihood of reproducing). This therefore reflects an innate adaptive mechanism for identifying and preferring signs of fertility and resources, supporting the theory.
Why it is unlikely that partner preferences have entirely evolved? Why is this a problem for the theory?
Partner preferences over the last century have undoubtedly been influenced by rapidly changing social norms of sexual behaviour. These develop much faster than evolutionary timescales imply and have instead come about due to cultural factors, such as the availability of contraception. Women’s greater role in the workplace means that they are no longer dependent on men to provide for them. Researchers argue that this social change has consequences for women’s mate preferences, which may no longer be resource-oriented. Research compared partner preferences in China over 25 years and found that some had changed and some had remained the same, corresponding with the huge social changes in that time.
Mate preferences are therefore the outcome of a combination of evolutionary and cultural influences. Any theory that fails to consider both is therefore a limited explanation of human reproductive behaviour and so we can’t argue that the theory is completely valid.
Name the three factors affecting attraction in romantic relationships.
i.e the theories
Physical attractiveness theory, filter theory and self-disclosure theory
What do we mean by physical attractiveness according to physical attractiveness theory?
How appealing we find a person’s face
What are the two features that make a face attractive?
Facial symmetry and neotenous features
Why is this the case?
Facial symmetry is seen as an honest signal of genetic fitness as you can’t fake it
People are also attracted to faces with neotenous (baby-face) features such as widely separated and large eyes, a delicate chin and a small nose. This is because they trigger a protective or caring instinct (a valuable resource for females wanting to reproduce).
Physical attractiveness leads to the physical attractiveness stereotype. What is this?
This suggests that attractive people are kind, strong, sociable and successful compared to unattractive people. This belief makes them even more attractive to us, so we behave positively towards them.
How does then increase attraction even further?
This in turn makes them more likely to act kindly etc. (a self-fulfilling prophecy), which makes them even more attractive to us.
What is the halo effect?
This becomes a halo effect – one distinguishing feature of a person (their physical attractiveness in this case) disproportionately influences our judgements of their other attributes (their personality).
What is the matching hypothesis? Make sure to include what the compromise is between and who we are attracted to.
Common-sense tells us that we can’t all form relationships with the most attractive people. The matching hypothesis (Walster et al., 1966) suggests that people are attracted to people who approximately ‘match’ us in physical attractiveness.
To do this, we must make a realistic judgement about our ‘value’ to a potential partner.
Therefore, our choice of partner is a compromise between desiring the most physically attractive partner possible and avoiding being rejected by someone who is unlikely to consider us physically attractive.