Evolutionary explanation

• Sexual selection is the idea that human behaviour is driven by the desire to produce healthy offspring that will survive to adulthood
• Anisogamy is the different biological roles males and females play in having children due to differences in male and female sex cells or Gametes
• EG of anisogamy sperm is highly mobile and created continuously from puberty to old age and does not require much energy to be produced however eggs are only produced roughly every 28 days and stop being produced after menopause
• Intersexual selection is partner choice
• Trivers (1972) theorises that women are more intersexually selective as they have a higher investment cost in children as they give up more time and resources to have the child meaning they have more to lose from selecting a bad partner
• Fisher's (1930) "sexy son's hypothesis" states that due to intersexual selection, females choose a male mate based on desirable traits that will make their children more desirable to future generations and therefore more likely to reproduce and have children of their own
• Intrasexual selection is mate competition
• Males are more intrasexually selective as they have lower parental certainty than females meaning they aim to have a high number of mates to increase the chances of having offspring that is actually theirs increasing competition from other males
• Intrasexual selection increases over time as secondary sexual characteristics being chosen by both sexes cause them to become more common in the wider population causing more candidates with desirable traits increasing competition
• Sexual dimorphism is how males and females end up looking very different based on intrasexual selection EG males are more likely to overcome competition with physical advantages such as size
• Desirable traits to males include signs of youth and fertility such as large breasts and big eyes
• Desirable traits to women include evidence that the male can provide for offspring such as physical strength
• Strength; cross cultural research by Singh (1993 2002) shows the theory is not culturally relative as he showed men from different cultures different body shapes and found a consensus that a hip waist ratio of 0.7 is deemed most attractive HOWEVER this used an artificial task of showing images of body types which reduces mundane realism
• Strength; research support shows that women are more intersexually selective as Clark and Hatfield (1989) had 36 male and 36 female psychology students ask other students on campus to "go to bed" with them and found 0% of women said yes but 75% of men said yes HOWEVER this study was a natural experiment which lacked control over extraneous variables such as whether those asked were in a relationship
• Strength; research support for desirable traits for men and women as Buss (1989) conducted a survey of 10,000 people across 33 countries and found females valued resources and males valued signs of fertility HOWEVER the use of a questionnaire can lack depth such as why these traits are found to be attractive
• Weakness; this theory could be contextual as Buss and Schmitt (2016) argue that in long term relationships, men and women look for similar traits in partners and are equally selective due to both having a high investment cost; not only does this show that the theory only applies to short term relationships but also displays alpha bias in the theory as differences between males and females may not be as big as it suggests
• Weakness; historically relative as it does not consider modern social factors of choosing a partner for example women may now not require a mate with resources due to having a bigger role in the workplace meaning they are less financially reliant on men
• Weakness; deterministic as it argues we are biologically determined to pick a certain type of mate and does not consider how free will and preference may determine our partner choice