Evolutionary explanation of attraction and mate selection

Evolutionary explanation of mate selection and human reproductive behaviour

What is the evolutionary explanation?

• states that we behave in certain ways that increase our chances of survival/reproduction (passing on our genes)

• The genes that are passed on influence our physiology (brain, NTs) that in turn promote adaptive behaviour

Evolutionary explanation of mate selection and human reproductive behaviour

Natural selection (survival of the fittest)

Members of a species who have characteristics adaptive to their environment = more likely to survive to reproduce = pass on adaptive traits

Evolutionary explanation of mate selection and human reproductive behaviour

Sexual selection (survival of the sexiest)

the ‘best mate’ is chosen to produce and protect the most healthy offspring

2 types - inter/intra

Evolutionary explanation of mate selection and human reproductive behaviour

Inter-sexual selection

• B/w sexes

• typically female selects

• traits that are more attractive to the opposite sex survives

Evolutionary explanation of mate selection and human reproductive behaviour

Intra-sexual selection

• competition within the same sex for access to a member of the opposite sex to mate w/

• Mate competition - usually done between men

Evolutionary explanation of mate selection and human reproductive behaviour

What is sexual dimorphism?

Why is it attractive?

What is it?

• Physical differences between sexes of the same species

• Males need characteristics to help them compete w/ each other + attract a mate

• More masculine/feminine = more sexually dimorphic

Why is it attractive?

• Signifies better genes → they report lower levels of sickness

• SO attractive bcs offspring = more likely to survive reproductive age → gene line survives

Evolutionary explanation of mate selection and human reproductive behaviour

What traits do people generally find attractive?

• Healthy looking

• Symmetrical features

• Sexual dimorphism

Evolutionary explanation of mate selection and human reproductive behaviour

Parental investment theory

Trivers (1972)

• Sexual selection is driven by levels of investment by (fe)males in their offspring

• The sex with higher investment is more selective

• associated w/ greater reproductive benefits

Evolutionary explanation of mate selection and human reproductive behaviour

Differences in female/male parental investment:

• female = more investment - physically, time, energy

• males = less investment (see above), but can offer other forms (eg: providing food, finding/defending territory, protection, social status)

Evolutionary explanation of mate selection and human reproductive behaviour

Cross-cultural study on mate selection:

Buss (1989)

• questionnaire where preferences were ranked for 27 cultures

• Found:

  • Males: 37/37 = younger female (2.6 years), more concerned w/ chastity, more concerned w/ good looks

  • Females: older male (3.4 years), 34/37 ambition/industrious more important, 36/37 preferred financial prospects over men

Evolutionary explanation of mate selection and human reproductive behaviour

Why do males prefer younger females?

• More fertile (decreases with age) so easier to conceive

• Therefore, more likely to reproduce successfully

• Reproductive value - mid-teens = start of fertility, and have more time to have babies

• Peak fertility - mid 20s -> producing the best quality eggs

Evolutionary explanation of mate selection and human reproductive behaviour

Why do females prefer males who are older?

• value financial prospects, ambition, and industriousness more than males

• Bcs of female investment to children, may require the man to provide resources, stability, shelter

• older men are more likely to have this

• Also more likely to have a higher status

• Male's fertility DOESN'T decrease with old age

Evolutionary explanation of mate selection and human reproductive behaviour

Why are more more concerned with chastity than females?

• unlike females, Males don't 100% know child is theirs, so don't want to invest time/effort/resources into raising someone else's offspring (cuckoldry)

• Chastity provides assurance they are the father

Evolutionary explanation of mate selection and human reproductive behaviour

Why are males more concerned w/ good looks than females?

• Suggests strong genes → seen as attractive

• Females may find other traits attractive (eg: financial prospects) bcs rely on a partner more during child rearing

• Men can acquire resources bcs don't put the same effort into child rearing → primarily concerned w/ good genes + healthy offspring

Evolutionary explanation of mate selection and human reproductive behaviour

Evaluation: supporting research

Clarke and Hatfield (1989) found when approached by a stranger on uni campus and asked to sleep with them 75% of males said yes, 0% of women said yes, supports because females more ‘picky’ (bcs parental investment theory), and males usually have to engage in intra-sexual selection (so take opportunity)

Evolutionary explanation of mate selection and human reproductive behaviour

Evaluation: Cross-cultural research

Buss (1989) found 36/37 females preferred financial prospects to males, 37/37 males preferred a younger female, so because of cross-cultural consistency means more likely biological sex differences than cultural factors that result in parental investment → mate preferences

Evolutionary explanation of mate selection and human reproductive behaviour

Evaluation: not comprehensive enough

Concordance rates in twin studies suggest genetics influence same sex attraction, BUT evolutionary explanation suggests mate selection = bcs of reproduction, so isn't comprehensive enough bcs same-sex attraction cannot result in offspring

Evolutionary explanation of mate selection and human reproductive behaviour

Evaluation: social sensitivity

Ideas proposed (eg: inter-sexual selection) are used by certain groups (eg: incels) to justify hatred/violence towards women/men who are more 'sexually dimorphic', so it socially sensitive

Evolutionary explanation of mate selection and human reproductive behaviour

Evaluation: Unfalsifiable

All evidence is correlational, and theories are unfalsifiable because you can't go back in time and track evolution so not v scientific

Evolutionary explanation of mate selection and human reproductive behaviour

Evaluation: biologically reductionist

Only considers impact of biological/hereditary factors, not socialisation or lived experience influence attraction/mate selection, so is biologically reductionist.

Evolutionary explanation of mate selection and human reproductive behaviour

Evaluation: socialisation

Women are more likely to be victims of sexual/physical violence from males than males from females, so women may have been socialised to be more careful w/ who they sleep for safety than men.

Evolutionary explanation of mate selection and human reproductive behaviour

Evaluation: alt explanation: Social Structural theory (SST)

Eagly and Wood (1999) SST suggests that mate preference are a result of societally constructed gender roles (want a mate who will fulfil society definition of good wife/husband) and this drives attraction not evolution → found correlation from UN suggesting when gender equality increased, stereotypical mate preferences decreased