Psychology; Relationships: Evolutionary explanations for partner preferences
Assessing the relationship between sexual selection and human reproductive behaviour.
Sexual Selection- Darwin (1871): The selection of characteristics is concerned with
successful reproduction moreover survival. E.g. physical features such as a male peacocks
tail, is a sign of genetic fitness. Females who select these characteristics will produce strong
offspring, and preference for these characteristics are passed through generations.
Adaptive characteristics- such as aggression, provide an advantage for male competitors for
reproductive rights of a female. This characteristic, if genetically determined, is passed on to
offspring and the characteristic remains in the population.
Anisogamy: This is the basis of human reproductive behaviour, referring to the differences
in Male and Female sex cells. (Gametes).
Sperm cells: small, highly mobile, created continuously in vast
numbers from puberty to old age and do not need much energy to
be produced
Eggs: In contrast, large, produced at intervals for a limited number of
fertile years and requires a significant investment of energy.
There is no shortage of fertile males, but a fertile woman is a much
rarer ‘resource’, anisogamy introduced two types of partner preference….
1. Inter-sexual selection
Refers to between the sexes; strategy for males to select females or vice-versa.
Preferred by females (Quality over Quantity).
(Trivers, 1972) states how both sexes can be picky, because
both stand to lose if they invest into a partner that proves to be
below expectations, However consequence of wrong choice is
worse for female due to higher investment in regards to giving
birth and child bearing. So, females seek to select the most
genetically fit males who can provide all needs and desires.
Therefore, it’s the female preference that determines the characteristics of offspring
e.g. Female is attracted to height so offspring are tall, their offspring are tall etc.
‘Sexy sons hypothesis’ genes today have reproductive success, as females
prefer characteristics given to offspring, their sons inherit the ‘sexy’ trait
that will cause them to be selected by generations of females…cycle.
2. Intra-sexual selection
Refers to within sexes; strategies between males to be the one that is selected,
preferred by Males (Quantity over Quality).
Winner of the competition of selection reproduces with female and passes on
characteristics too offspring.
Dimorphism- meaning ‘two forms’. Males and females look very different because
of this. E.g. during physical competition, size matters! Females don’t compete for
reproductive rights, so there is no preference for larger females in that sense.
However, youthfulness is preferred by males as more fertile. (Narrow waist)
Behavioural consequences- preferred behaviour is types allowing males to
outcompete e.g. aggression, intelligence. Males can protect their female from
competing males using this behaviour (mate retention).
