explanation for partner preference

• Evolutionary approaches explain human behaviour in terms of adaptiveness and reproductive success.
• In 1992, male students showed greater distress (measured by galvanic skin response) when asked to imagine partner’s sexual infidelity, while women were more distressed by thoughts of emotional infidelity.
• These approaches argue that if a behavioural feature (for example, aggression) has been genetically inherited by one generation from another, then it must have a specific value for the human species; it might either help humans adapt better to the environment and survive (natural selection) or might help to attract a mate and have healthy offspring (sexual selection).
• Anisogamy is a concept in evolutionary explanations of partner preferences, explaining differences in partner preferences between males and females.
• Males’ sex cells (sperm) are produced in large quantities, quickly replenished and created continuously from puberty to old age.
• Females’ sex cells (eggs or ova) take a lot of energy to produce, are created in limited numbers during specific time intervals and their production only lasts for a certain number of fertile years.
• These differences mean that males and females need to use different strategies to achieve reproductive success.
• Before the invention of DNA testing, males could never be sure that a particular child is theirs, so the reproductively successful strategy for a male would involve having sex with, and impregnating, as many women as possible.
• For women, however, the energetically expensive process of producing an egg and then carrying a child in the womb for nine months would mean that she needs a partner who will be committed to the relationship in the long run and provide resources for her and the child, ensuring the child’s survival.
• These differences in mating strategies were demonstrated by David Buss (1989), who surveyed over 10,000 adults in 33 countries.
• Buss found that females universally put more importance on resource-related characteristics in a partner, such as ambition, high intelligence and good financial prospects.
• Males, however, preferred younger mates and put more value on signs of a female’s ability to reproduce, such as attractiveness and modesty.
• The principles of sexual selection described above mean that males and females use different strategies to select a suitable mate.
• Since human females do not advertise their fertility openly, males have evolved to pay attention to other signs in a human female’s appearance that show her ability to produce healthy offspring.
• Buss (1989) has discovered that males universally put importance on attractive and healthy looks and youth, which are signs of fertility.
• Further evidence comes from research carried out by Devindra Singh (1993, 2002) who studied preferred waist-to-hip ratio as a sign of female fertility.
• Studying the measurements of waist-to-hip ratio of the winners of the Miss America contest for a decade, Singh found that men generally found any waist and hip sizes attractive, as long as a ratio between them is about 0.7.
• Intra-sexual selection, on the other hand, is a preferred male strategy that refers to the evolutionarily developed features that allow a male to compete with other males for a female mate.
• Anisogamy can also explain the existence of two types of sexual selection: inter-sexual selection and intra-sexual selection.
• Intra-sexual selection can explain the differences in the body size and physical appearance between males and females, known as physical dimorphism.
• Females are more jealous of their partner’s emotional infidelity, as this may result in withdrawing of resources from the female and the child and puts the child’s survival at risk.
• Waynforth and Dunbar (1995) researched ‘lonely hearts’ columns in American newspapers, and discovered that women tended to describe themselves in terms of physical attractiveness and youth (‘exciting, flirty, curvy’)
• Men, on the other hand, advertised their resources and intelligence more than women did.
• Inter-sexual selection, also referred to as ‘female choice', is based on the idea that due to the greater investment of time, energy and resources required from a female to raise a child, females need to be more careful when choosing a partner.
• Sexual selection favours physically strong and aggressive males, as males need to compete with other males for an access to a fertile mate.
• Female choosiness was illustrated by the study conducted by Clark and Hatfield (1989) where 75% of male students agreed to go to bed with a female student, while not a single female student agreed.
• According to Buss (1995), males have much less certainty than females that the child they are raising is theirs, which can explain the difference in jealousy between males and females.
• Women, on the other hand, have adapted to look for the signs of male’s ability to provide resources and protect themselves and a child.
• A female having larger hips and a slim waist achieves this ratio, and men unconsciously interpret this as a sign that the woman is fertile but not currently pregnant.
• The winner of this competition reproduces and passes on to his offspring the genes that contributed to his success.
• Males tend to be more jealous of their partner’s sexual infidelity, as this could result in raising someone else's child.
• Females don’t need to physically compete for a mate, meaning that physical strength and aggression will hold no evolutionary advantage for them.