Sexual selection- evolutionary explanation of partner preference. Attributes/behaviours that
increase reproductive success are passed on=become exaggerated over succeeding generations of
offspring
Selection of characteristics that aid reproduction
Physical characteristics- peacock tail is sign of genetic fitness=females select these males=produce
robust offspring=preference is perpetuated in future generations
Aggressiveness- adaptive as it provides advantage for male over competitor=passed to offspring if
they are genetically determined
HUMAN REPRODUCTIVE BEHAVIOUR- behaviours that relate to opportunity to reproduce=increase
survival chances of our genes. Includes evolutionary mechanisms underlying partner preferences
(mate choice/competition)
ANISOGAMY- basis of human reproductive behaviour- small differences between male/female sex
cells- male gametes/sperm are small, mobile, created continuously in vast numbers, don’t need
much energy to produce
Female gametes/eggs are large, static, produced at intervals for limited no, require energy
CONSEQUENCE- no shortage of fertile males
But fertile female is rarer.
IT GIVES RISE TO 2 TYPES OF SEXUAL SELECTION
INTER SEXUAL SELECTION- between sexes
Strategies males use to select females vice versa. This is preferred strategy of female (quality over
quantity)
TRIVERS- female makes greater investment of time, commitment, resources before, during, after
birth of offspring.
Both sexes are choosy as both stand to lose if they invest resources in substandard partners
Female is especially selective as consequences of wrong partner choice are more serious for her.
The optimum mating strategy is to select genetically fit partner able to provide resources
FEMALE PREFERENCE- this determines which features passed on to offspring. EG if they consider
height attractive in males=increases in the male population over generations as in each females
select tallest males=characteristic becomes exaggerated=runaway process
FISHER SEXY sons hypothesis- genes we see today are those that enhanced reproductive success.
Female who mates w male who has certain characteristic=has sons that inherit the sexy trait=sons
are more likely to be selected in successive generations by females=sexy trait is perpetuated.
INTRA SEXUAL SELECTION- within each sex- preferred strategy of male (quantity of quality due to
plentiful supply of sperm)
, Competition between males to be selected to mate w female=winner reproduces= characteristics
are passed to offspring=dimorphism (males and females end up looking different due to intra sexual
selection) EG- size matters in a physical comp between males=larger males have adv=more
reproductively successful. COTRASTINGLY- females don’t compete for reproductive rights so no
evolutionary drive to favouring larger females.
BUT IN FEMALES YOUTHFULNESS IS SELECTED AS MALES HAVE preference to mate w younger more
fertile women.
INTRA SEXUAL HAS BEHAVIOURAL CONSEQUENCES- favoured characteristics are passed to those
that allow a male to outcompete his rivals (deceitfulness, intelligence, aggression)=males benefit
from behaving aggressively to acquire fertile females and protect them from competing males=leads
to selection of aggressiveness in males.
STRENGTH- evidence supports specific role of female choosiness in heterosexual partner preference-
study- sent male and female psych students to a uni campus=they approached other students w
questions- I have been noticing you around campus. I find you to be v attractive. Would you go to
bed w me tonight?- not a single female agreed but 75% males did immediately. FEMALES ARE
CHOOSIER THAN MALES IN SELECTION AND males evolved different strategy to ensure reproductive
success.
HOWEVER- one strategy is adaptive for all males another is adaptive for all females is simplistic.
Strategies differ according to length of relationship. Sexual strategies theory- both males and
females adopt similar mating strategies when seeking LT relationships= both are v choosy look for
loving, loyal, kind partners. MORE COMPLEX VIEW OF how evolutionary pressures influence partner
preference
STRENGTH- evidence support for predictors of sexual selection theory- survey over 10000 adults in
33 countries- asked q relating to different attributes that evolutionary theory predicts are important
in partner preference=females place greater value on resource related characteristics than males
(good financial prospects, ambition) males valued physical attractiveness/youth- signs of good
reproductive capacity more than females.
Limitation- overlook influences of social/cultural factors on partner preference. Partner preferences
over last century are influenced by rapid changing social norms of behaviour=they develop faster
than evolutionary timescales imply=they come about due to cultural factors. Women’s greater role
in workplace=no longer dependent on men to provide=no longer resource orientated. Preferences
are outcome of evolutionary and cultural influences.
FACTORS AFFECTING ATTRACTION
SELF DISCLOSURE- revealing personal info about yourself- romantic partners reveal more about true
selves as relationship develops=strengthens romantic bond when used appropriately. Share likes,
dislikes, hopes, fears, interests, attitudes=more we like them
increase reproductive success are passed on=become exaggerated over succeeding generations of
offspring
Selection of characteristics that aid reproduction
Physical characteristics- peacock tail is sign of genetic fitness=females select these males=produce
robust offspring=preference is perpetuated in future generations
Aggressiveness- adaptive as it provides advantage for male over competitor=passed to offspring if
they are genetically determined
HUMAN REPRODUCTIVE BEHAVIOUR- behaviours that relate to opportunity to reproduce=increase
survival chances of our genes. Includes evolutionary mechanisms underlying partner preferences
(mate choice/competition)
ANISOGAMY- basis of human reproductive behaviour- small differences between male/female sex
cells- male gametes/sperm are small, mobile, created continuously in vast numbers, don’t need
much energy to produce
Female gametes/eggs are large, static, produced at intervals for limited no, require energy
CONSEQUENCE- no shortage of fertile males
But fertile female is rarer.
IT GIVES RISE TO 2 TYPES OF SEXUAL SELECTION
INTER SEXUAL SELECTION- between sexes
Strategies males use to select females vice versa. This is preferred strategy of female (quality over
quantity)
TRIVERS- female makes greater investment of time, commitment, resources before, during, after
birth of offspring.
Both sexes are choosy as both stand to lose if they invest resources in substandard partners
Female is especially selective as consequences of wrong partner choice are more serious for her.
The optimum mating strategy is to select genetically fit partner able to provide resources
FEMALE PREFERENCE- this determines which features passed on to offspring. EG if they consider
height attractive in males=increases in the male population over generations as in each females
select tallest males=characteristic becomes exaggerated=runaway process
FISHER SEXY sons hypothesis- genes we see today are those that enhanced reproductive success.
Female who mates w male who has certain characteristic=has sons that inherit the sexy trait=sons
are more likely to be selected in successive generations by females=sexy trait is perpetuated.
INTRA SEXUAL SELECTION- within each sex- preferred strategy of male (quantity of quality due to
plentiful supply of sperm)
, Competition between males to be selected to mate w female=winner reproduces= characteristics
are passed to offspring=dimorphism (males and females end up looking different due to intra sexual
selection) EG- size matters in a physical comp between males=larger males have adv=more
reproductively successful. COTRASTINGLY- females don’t compete for reproductive rights so no
evolutionary drive to favouring larger females.
BUT IN FEMALES YOUTHFULNESS IS SELECTED AS MALES HAVE preference to mate w younger more
fertile women.
INTRA SEXUAL HAS BEHAVIOURAL CONSEQUENCES- favoured characteristics are passed to those
that allow a male to outcompete his rivals (deceitfulness, intelligence, aggression)=males benefit
from behaving aggressively to acquire fertile females and protect them from competing males=leads
to selection of aggressiveness in males.
STRENGTH- evidence supports specific role of female choosiness in heterosexual partner preference-
study- sent male and female psych students to a uni campus=they approached other students w
questions- I have been noticing you around campus. I find you to be v attractive. Would you go to
bed w me tonight?- not a single female agreed but 75% males did immediately. FEMALES ARE
CHOOSIER THAN MALES IN SELECTION AND males evolved different strategy to ensure reproductive
success.
HOWEVER- one strategy is adaptive for all males another is adaptive for all females is simplistic.
Strategies differ according to length of relationship. Sexual strategies theory- both males and
females adopt similar mating strategies when seeking LT relationships= both are v choosy look for
loving, loyal, kind partners. MORE COMPLEX VIEW OF how evolutionary pressures influence partner
preference
STRENGTH- evidence support for predictors of sexual selection theory- survey over 10000 adults in
33 countries- asked q relating to different attributes that evolutionary theory predicts are important
in partner preference=females place greater value on resource related characteristics than males
(good financial prospects, ambition) males valued physical attractiveness/youth- signs of good
reproductive capacity more than females.
Limitation- overlook influences of social/cultural factors on partner preference. Partner preferences
over last century are influenced by rapid changing social norms of behaviour=they develop faster
than evolutionary timescales imply=they come about due to cultural factors. Women’s greater role
in workplace=no longer dependent on men to provide=no longer resource orientated. Preferences
are outcome of evolutionary and cultural influences.
FACTORS AFFECTING ATTRACTION
SELF DISCLOSURE- revealing personal info about yourself- romantic partners reveal more about true
selves as relationship develops=strengthens romantic bond when used appropriately. Share likes,
dislikes, hopes, fears, interests, attitudes=more we like them
