Evolutionary explanations for human behaviour
What is an evolutionary explanation for behaviour?
- Evolutionary psychology is part of the biological approach to explaining behaviour (based on Darwin’s theory) which explains how and why behaviours e.g. aggression, memory, language, partner preference are the products of natural selection
- Natural selection is the process whereby behaviours and traits which are useful for survival and reproduction are retained – and those which are not eventually die out
- Adaptive behaviours are those which increase the chances of survival and reproductive success which is why they are passed down through the generations i.e. how we behave now is the product of ultimate causes
What is an evolutionary explanation for partner preference?
- Evolutionary psychology proposes that males look for female partners who are young and who look healthy (e.g. clear skin, glossy hair) and fertile (e.g. wide hips)
- Evolutionary psychology proposes that females look for male partners who have resources (e.g. a good job, money, stability) and who will be able to provide a secure home for the children that the couple produce
- The theory of anisogamy states that females are more choosy than males when it comes to selecting sexual partners
- Female choosiness is based on the idea that ‘sperm is cheap; eggs are expensive’ i.e. men produce billions of spermatozoa on a daily basis but a woman produces only one egg per month
- A man may have sex (and impregnate) many women without much consequence but if a woman has sex there is always the chance that she will become pregnant, ergo she must be choosy as to who she has sex with as a male without resources is not good material as the potential father of her children
- A proximate cause of behaviour might be seen in a person showing jealousy and wishing to keep their partner close but an evolutionary ultimate cause of behaviour would say that this jealousy is based on a primeval fear of losing either the opportunity to continue one’s genetic line (males) or the protection afforded by a partner (females)
A sexist stereotype? Evolutionary psychology says no…
What are the flaws in an evolutionary explanation of partner preference?
- While it is true that there are plenty of examples of rich old man/pretty young woman couples, this is a reductionist way of explaining partner preference – and it encourages stereotyping and sexism too
- Some women prefer younger men, some men prefer older women; plenty of women are able to provide resources for themselves and their family; some women are not remotely interested in money; some men do not wish to have children
- This theory makes no accommodation for homosexuality, as it is purely focused on heterosexual partnerships
- There is no way of gathering empirical evidence to support this theory as it based on inferences drawn from observing proximal behaviours based on ultimate causes
Which studies investigate evolutionary explanations of partner preference?
- Buss (1989) – a cross-cultural large-scale survey of attitudes towards partner preferences
- Clarke & Hatfield (1989) – a field experiment which investigated female choosiness in terms of partner selection
The studies by Buss (1989) and Clarke & Hatfield (1989) can be found in ‘Two Key Studies of Evolutionary Explanations for Behaviour’ on this site: just navigate the Genetics & Behaviour topic to find it
Exam Tip
Evolutionary explanations for partner preference seem, frankly, outdated and ridiculously sexist to a modern, 21st-century person. If you find yourself feeling outraged, angry, furious etc. about the theory make sure that this doesn’t come through on your exam response!
Have a good discussion in class about the theory but restrict your personal feelings to that discussion – your exam response should be considered, impartial and evidence-based. It is fine to poke huge holes in the theory but try to do so in a way which will increase your marks, not obliterate them!
Worked example
ERQ (Extended Response Question) - 22 marks
‘Discuss evolutionary explanations for behaviour’. [22]
The following paragraph shows you how to critique the theory without becoming overly emotional or judgemental:
Evolutionary psychology seems to suggest that we are mere products of evolution who are at the mercy of our genetically inherited drives that govern responses such as mating preferences. An evolutionary approach to explaining behaviour is reductionist as it excludes and ignores the sophisticated, complex ways in which human beings interact with the world and the ways in which cognition mediates biological imperatives. An evolutionary psychologist would explain male-female relationships as stemming from a desire for youth and fertility (men) or for a partner with resources (women). Such a binary approach to relationships does not explain why some men prefer older women or why some women do not want children or marriage. It also ignores the issue of homosexuality altogether which makes the theory untenable to modern thinking about relationships.