Relationships
Relationships
The evolutionary explanations for partner
preferences
The relationship between selection and human
reproductive behaviour
Evolution
‣ The process whereby humans have adapted to the environment over millions of years
‣ Evolutionary explanations are based on the premise that some human behaviour are at
least partly innate and can be a ected by natural selection
‣ A behaviour is said to be adaptive if it leads to increase survival meaning the genes
which cause this behaviour will be passed to the next generation
Sexual selection
‣ Two forms: inter-sexual selection and intra-sexual selection
‣ An evolutionary explanation of partner preference
‣ Attributes or behaviours that increase reproductive success are passed on and may
become exaggerated over generations of o spring
‣ Attraction is seen as an adaptive behaviour which leads to increase survival and
reproduction
Sex di erences in parental investment
‣ Evolutionary psychology argues that there is an imbalance or asymmetry between what
Mum and Dad put into or ‘invest’ in their kids
‣ Stereotypically, the mum has has less sleep, contributes more to contraception and
resources to foetus during pregnancy and breastfeeding as well as taking risks during
childbirth and devoting more time to the child in the rst year of life
‣ The dad, however, is only thought to contribute the money to provide for the child
‣ woman can only have up to about 30 children in her lifetime whilst a man can have
A
in nite amounts and a woman can no longer be a mother after about 45 years old
whereas a man could be a father up until he dies
Anisogamy
‣ Biology has programmed men and women to adopt di erent reproductive behaviours
‣ This dictates that the male’s optimum reproductive strategy is to mate with as many
fertile females as possible as minimal energy is required
‣ Anisogamy leads to intra- and inter-sexual selection
‣ Intra-sexual selection is the strategies which the sexes use between them to select
the other sex and inter-sexual selection are the strategies that the sexes use within
their gender to be the one that is selected
Male Female
Gamete ‣ sperm (millions per ejaculate) ‣ ovum (egg)
Reproductive ‣ from puberty until death ‣ eggs (ova) produced from puberty until
life ‣ long reproductive life menopause
‣ short reproductive life
Page 1 of 20 A Level Psychology Paper 3
fi ff ff ff fi ff
, Relationships
Male Female
Characteristics ‣ young females ‣ faithful
sought through ‣ an hourglass shape ‣ committed
intersexual ‣ large eyes ‣ strong
selection ‣ rosy cheeks ‣ able too gain recourses at ease
Reproductive ‣ promiscuity is best as it maximises ‣ choosy
behaviour the opportunity for mating success ‣ select the best available mate as their baby
needs the best genes
Inter-sexual selection (mate selection)
‣ The preferred strategy of the female - quality over quantity
‣ Ova are rarer than sperm and require greater energy to produce, therefore, women
need to be choosy and pick the most t partner who is able to provide resources
‣ Female preference determines which features are passed on to their o spring
‣ If height is considered an attractive trait, then over successive generations of
females, it would increase in the male population because females would mate
with tall males and over time produce sons who are taller
‣ Fischer (1930) argues the ‘sexy son hypothesis’
‣ A female mates with a male who has a desirable characteristic, and this ‘sexy’ trait
is then inherited by her son
‣ This increases the likelihood that successive generations of females will mate with
her o spring
Intra-sexual selection (mate competition)
‣ The preferred strategy of the male - quantity over quality
‣ The competition between males to be able to mate with a female and the winner of the
competition gets to reproduce and pass on to his o spring his characteristics that won
him the victory
‣ This strategy leads dimorphism, the obvious di erences between male and females
‣ In a competition between males, size matters so larger males have an advantage;
females do not compete for reproductive rights so there is no evolutionary drive
‣ Males optimum reproductive strategy is to mate with as many fertile female as possible
and protect them from competing males
‣ Intra-sexual selection has psychological and behavioural consequences and some of
them are controversial
‣ For males to acquire fertile females and protect them from competing males, they
may bene t from behaving aggressively
Key di erences in reproductive behaviours
Buss and Schmitt (1993)
‣ Found men tend to be much more likely to have short-term relationships or one-night
stands than women
‣ Shows how men prefer quantity over quality and their optimum reproductive strategy is
to mate with as many fertile females as possible
Buss (1993)
‣ Asked male and female students to imagine their partner having sex with someone else
or being in love with someone else
‣ Men were more distressed at the thought of their partner being sexually unfaithful but
women were distressed at the idea of their partner being in love with someone else
Page 2 of 20 A Level Psychology Paper 3
ff ff fi fi ff ff ff
, Relationships
‣ Shows that females search for committed and faithful characteristics in men whereas
males become jealous when they are not able to pass on their genes
Ellis and Symons (1990)
‣ Found men are more likely to have sexual dreams than women, especially those
involving multiple or anonymous partners and strangers
Evaluation of the Theory
Strengths Weaknesses
Males have been found to be more likely Ignores relationships that are not sexual and
to engage in risky behaviours, which relationships that aren’t aimed at
could be a strategy to indicate two reproducing
females they are physically strong
Zahavi (1975) argued that females seek Non-falsi able - they can never be fully
males with signs of a handicap that tested scienti cally as evolution takes place
indicate strength over adversity over millions of years and it is unrealistic for
research to take place over this time frame
Davis (1990) found that in personal
adverts, males tended to seek out health
and attractiveness and females looked
for high status and resources
The theory of sexual selection and
human reproductive behaviour has a
sound scienti c bias as it is founded on
evolutionary theory
KEY STUDY: Clark and Hat eld (1989)
Aim
To investigate the di erences in reproductive behaviour between men and women.
Procedure
‣ Attractive male and female experimenters approached total strangers on a university
campus and said ‘Hi, I’ve been noticing you around campus and I nd you very
attractive…
1. Would you go on a date with me?
2. Would you go back to my apartment?
3. Would you have sex with me?
‣ There were 45 men and 45 women included in the experiment
Findings
Males Females
Would you go on a date with 50% 56%
me?’
Would you go back to my 69% 6%
apartment?’
Would you have sex with me?’ 75% 0%
Page 3 of 20 A Level Psychology Paper 3
fi fifi ff fi fi
Relationships
The evolutionary explanations for partner
preferences
The relationship between selection and human
reproductive behaviour
Evolution
‣ The process whereby humans have adapted to the environment over millions of years
‣ Evolutionary explanations are based on the premise that some human behaviour are at
least partly innate and can be a ected by natural selection
‣ A behaviour is said to be adaptive if it leads to increase survival meaning the genes
which cause this behaviour will be passed to the next generation
Sexual selection
‣ Two forms: inter-sexual selection and intra-sexual selection
‣ An evolutionary explanation of partner preference
‣ Attributes or behaviours that increase reproductive success are passed on and may
become exaggerated over generations of o spring
‣ Attraction is seen as an adaptive behaviour which leads to increase survival and
reproduction
Sex di erences in parental investment
‣ Evolutionary psychology argues that there is an imbalance or asymmetry between what
Mum and Dad put into or ‘invest’ in their kids
‣ Stereotypically, the mum has has less sleep, contributes more to contraception and
resources to foetus during pregnancy and breastfeeding as well as taking risks during
childbirth and devoting more time to the child in the rst year of life
‣ The dad, however, is only thought to contribute the money to provide for the child
‣ woman can only have up to about 30 children in her lifetime whilst a man can have
A
in nite amounts and a woman can no longer be a mother after about 45 years old
whereas a man could be a father up until he dies
Anisogamy
‣ Biology has programmed men and women to adopt di erent reproductive behaviours
‣ This dictates that the male’s optimum reproductive strategy is to mate with as many
fertile females as possible as minimal energy is required
‣ Anisogamy leads to intra- and inter-sexual selection
‣ Intra-sexual selection is the strategies which the sexes use between them to select
the other sex and inter-sexual selection are the strategies that the sexes use within
their gender to be the one that is selected
Male Female
Gamete ‣ sperm (millions per ejaculate) ‣ ovum (egg)
Reproductive ‣ from puberty until death ‣ eggs (ova) produced from puberty until
life ‣ long reproductive life menopause
‣ short reproductive life
Page 1 of 20 A Level Psychology Paper 3
fi ff ff ff fi ff
, Relationships
Male Female
Characteristics ‣ young females ‣ faithful
sought through ‣ an hourglass shape ‣ committed
intersexual ‣ large eyes ‣ strong
selection ‣ rosy cheeks ‣ able too gain recourses at ease
Reproductive ‣ promiscuity is best as it maximises ‣ choosy
behaviour the opportunity for mating success ‣ select the best available mate as their baby
needs the best genes
Inter-sexual selection (mate selection)
‣ The preferred strategy of the female - quality over quantity
‣ Ova are rarer than sperm and require greater energy to produce, therefore, women
need to be choosy and pick the most t partner who is able to provide resources
‣ Female preference determines which features are passed on to their o spring
‣ If height is considered an attractive trait, then over successive generations of
females, it would increase in the male population because females would mate
with tall males and over time produce sons who are taller
‣ Fischer (1930) argues the ‘sexy son hypothesis’
‣ A female mates with a male who has a desirable characteristic, and this ‘sexy’ trait
is then inherited by her son
‣ This increases the likelihood that successive generations of females will mate with
her o spring
Intra-sexual selection (mate competition)
‣ The preferred strategy of the male - quantity over quality
‣ The competition between males to be able to mate with a female and the winner of the
competition gets to reproduce and pass on to his o spring his characteristics that won
him the victory
‣ This strategy leads dimorphism, the obvious di erences between male and females
‣ In a competition between males, size matters so larger males have an advantage;
females do not compete for reproductive rights so there is no evolutionary drive
‣ Males optimum reproductive strategy is to mate with as many fertile female as possible
and protect them from competing males
‣ Intra-sexual selection has psychological and behavioural consequences and some of
them are controversial
‣ For males to acquire fertile females and protect them from competing males, they
may bene t from behaving aggressively
Key di erences in reproductive behaviours
Buss and Schmitt (1993)
‣ Found men tend to be much more likely to have short-term relationships or one-night
stands than women
‣ Shows how men prefer quantity over quality and their optimum reproductive strategy is
to mate with as many fertile females as possible
Buss (1993)
‣ Asked male and female students to imagine their partner having sex with someone else
or being in love with someone else
‣ Men were more distressed at the thought of their partner being sexually unfaithful but
women were distressed at the idea of their partner being in love with someone else
Page 2 of 20 A Level Psychology Paper 3
ff ff fi fi ff ff ff
, Relationships
‣ Shows that females search for committed and faithful characteristics in men whereas
males become jealous when they are not able to pass on their genes
Ellis and Symons (1990)
‣ Found men are more likely to have sexual dreams than women, especially those
involving multiple or anonymous partners and strangers
Evaluation of the Theory
Strengths Weaknesses
Males have been found to be more likely Ignores relationships that are not sexual and
to engage in risky behaviours, which relationships that aren’t aimed at
could be a strategy to indicate two reproducing
females they are physically strong
Zahavi (1975) argued that females seek Non-falsi able - they can never be fully
males with signs of a handicap that tested scienti cally as evolution takes place
indicate strength over adversity over millions of years and it is unrealistic for
research to take place over this time frame
Davis (1990) found that in personal
adverts, males tended to seek out health
and attractiveness and females looked
for high status and resources
The theory of sexual selection and
human reproductive behaviour has a
sound scienti c bias as it is founded on
evolutionary theory
KEY STUDY: Clark and Hat eld (1989)
Aim
To investigate the di erences in reproductive behaviour between men and women.
Procedure
‣ Attractive male and female experimenters approached total strangers on a university
campus and said ‘Hi, I’ve been noticing you around campus and I nd you very
attractive…
1. Would you go on a date with me?
2. Would you go back to my apartment?
3. Would you have sex with me?
‣ There were 45 men and 45 women included in the experiment
Findings
Males Females
Would you go on a date with 50% 56%
me?’
Would you go back to my 69% 6%
apartment?’
Would you have sex with me?’ 75% 0%
Page 3 of 20 A Level Psychology Paper 3
fi fifi ff fi fi
