Examine one evolutionary explanation of behaviour
You will no doubt remember how the theory of evolution works from Biology classes (or at least you should!), so you have a good foundation already for beginning to apply this idea to Psychology. The video below can be used to remind you of the details if you need it.
BUT.... BE CAREFUL. Psychology is about the study of BEHAVIOUR, not just physical traits like coloured wings or long necks. Evolutionary psychology looks at the evolution of behaviour, but this is a much more complicated task than just looking at the evolution of physical characteristics.
First, listen to this Psych Files podcast on evolutionary explanations, featuring David Buss, whose study we will be looking at later. This gives you a great introduction to the main ideas of evolutionary psychology.
Mate selection as an evolved behaviour
The specific behaviour that we will look at is mate selection. Mate selection is the process by which animals (including humans) select who they mate with. this selection depends on a number of traits, such as the person's attractiveness, health, wealth and so on.
It should be clear that mate selection is very likely to be a behaviour that is affected by evolution. All species must select a mate, and many species display bizarre and costly traits to attract a partner (see this, or this for example). Also, these behaviours are crucial for the passing on of characteristics through the animals genes (the whole point of the process), so it is clearly an area where evolutionary pressures could be expected to apply. |
Assumptions of mate selection theoriesOne important feature is mate selection theories is that males and females have different requirements and strategies when it comes to finding a partner. Given that in almost all species it is the female which undergoes a pregnancy and gives birth, the female's reproductive success is limited by the number of possible successful pregnancies that she can have in her lifetime. Without this limitation, a male has very different possibilities. The only limit on a males reproductive success is the number of females that he is able to mate with. This is known in Biology as 'Bateman's Principle'.
Bearing these two facts in mind, it becomes clear that males and females will have very different requirements when selecting a mate. The female will want a partner who gives her the best chance of having a successful pregnancy (and beyond). They will therefore value a mate who is able to provide protection and resources for the child. A male, on the other hand, will care only about fathering as many healthy offspring as they are able to, and will therefore value little other than the physical signs that a mother is likely to produce healthy offspring - namely youth and attractiveness. Searching for differences such as these in the mate preferences of humans has become a key area of study for human evolutionary psychology, and it is one such study into this which we will turn to now. |
Buss et al. (1990) – International preferences in selecting mates. A study of 37 Cultures
The story of David Buss' famous study is almost as interesting as the results it produced. Buss was inspired by reading Donald Symons famous book 'The Evolution of Human Sexuality, and decided to carry out a comprehensive cross-cultural study to test the claims made by the book. He termed this the 'International Mate Selection Project', and aimed to see if there were certain universal traits which influenced mate selection worldwide (if a trait is evolved, then we would expect it to be universal - to be present to some degree in all human populations. Culture may have some effect, but the basic trait should still be present regardless).
Nothing if not persuasive, Buss managed to persuade his collaborators across the world to travel to some of the most remote and politically unstable parts of the globe, carrying with them translated versions of his questionnaires on mate selection. Lions, hostile tribes and communist governments were just some of the perils that were faced (the questionnaires had to be smuggled out of China in code so as not to alert the authorities). In the end, 37 cultures, from 33 countries contributed to a total sample size of nearly 10000 people, an extremely large number for a study of this kind.
Nothing if not persuasive, Buss managed to persuade his collaborators across the world to travel to some of the most remote and politically unstable parts of the globe, carrying with them translated versions of his questionnaires on mate selection. Lions, hostile tribes and communist governments were just some of the perils that were faced (the questionnaires had to be smuggled out of China in code so as not to alert the authorities). In the end, 37 cultures, from 33 countries contributed to a total sample size of nearly 10000 people, an extremely large number for a study of this kind.
Procedure:
Participants were 9,474 individuals from 37 cross-cultural samples (33 countries and five islands on six continents; mean age 23.15). The data was collected through two questionnaires developed in the USA and translated. Results:
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Assignment 1 - Drawing conclusions from research findingsLook at the 'results' section to the left. What conclusions could you draw from these findings? Do they support the basic ideas of evolutionary psychology and mate selection? Why or why not?
Write a 1/2 page summery of your conclusions. Try to look at both sides of the argument. These results are not totally in support of any one position. Make sure you analyse these complexities. Assignment 2 - Do your conclusions match Buss et al's?Now have a go at reading Buss et al's report of their study. Although long, it is pretty accessible and very interesting. Do their conclusions about what the data shows match the ones which you drew from the summary? Why or why not?
Write half a page showing where your ideas were similar or different to the authors' interpretations.
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Evaluation of Buss et al's findings
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Some general evaluative points regarding evolutionary psychology
N.B Make sure you relate these to Buss' study and to mate selection behaviours specifically!
There are LOADS of things that could be said here. The debate about the value of evolutionary psychology is a very fierce on in the subject at the moment, and some serious questions have been raised about a lot of the research and conclusions ade by the discipline. A good summary, if you want to go into this in more depth, can be read here.
There are LOADS of things that could be said here. The debate about the value of evolutionary psychology is a very fierce on in the subject at the moment, and some serious questions have been raised about a lot of the research and conclusions ade by the discipline. A good summary, if you want to go into this in more depth, can be read here.
- Evolutionary psychology explains but does not predict. Because evolution of complex behaviour takes millions of years, we can't do an experiment where we watch it in action. All scientists can do is to observe what we do now and try to find evolutionary ways of explaining it. This seems a very unscientific method. Evolutionary psychologists would counter that they do make predictions (e.g. Buss predicted that males and females would display different mating strategies, and his results supported this). This is true, but it is still not the same as finding experimental proof of a hypothesis in controlled conditions, so there will always be a degree of uncertainty in all evolutionary psychology findings.
- Not all behaviour needs to have evolved. The next book I choose to read is not an evolved behaviour, for example. But it is not clear which behaviours evolution does effect and which it does not. This has lead some evolutionary ideas to be over-extrapolated and used too widely, to explain behaviours that are almost certainly not directly affected by evolution. Linked to this, we need to understand that...
- Traits evolve, behaviours don't. We have too many different behaviours for each one to have been specifically shaped by evolution (we can't have a 'gene for basketball' or a 'gene for TV watching' or even a 'slut gene'). A good evolutionary psychologist would reply that they agree, instead we have evolved 'traits', underlying tendencies to behave in certain ways. These traits will then have an effect on lots of different behaviours which we then produce (though we still have some control of exactly how we behave, and our environment/culture will also have an effect). However, it is all too common to find people suggesting that specific genes have been linked to specific behaviours, both in the press and in research papers. This is incorrect.
- Is evolutionary psychology unethical or sexist? Many of the conclusions that could be drawn from evolutionary psychology seem to support some very controversial and seemingly old-fashioned ideas about, for example, the role of women. The idea that women might be innately (and universally) more caring and more concerned with rearing children than men is highly controversial. Good evolutionary psychologists would reply that discovering behavioural differences between the sexes is no more controversial than saying that there are physical differences between them. Importantly, they would argue that these differences are not deterministic. Possessing traits does not mean that you are forced to exhibit specific behaviours (see the point above). This means that we cannot use findings such as Buss (1990) to support unethical and incorrect ideas about women being better suited to having children than having a career, for example.
Triangulating evidenceAny evidence which deals with genes and their effect on our behaviour, will inevitably implicate evolution, as this is the mechanism through which these genes spread or disappear. Therefore we can use studies such as Capsi et al (2003) and Bouchard et al (1990) to help to reinforce some of the conclusions of this section. for example:
Assignment 3 - summarising research
Answer these questions in as much detail as you can. |
A further study... Confer, Perriloux and Buss (2010)This is the abstract to this research paper:
Studies of physical attractiveness have long emphasized the constituent features that make faces and bodies attractive, such as symmetry, skin texture, and waist-to-hip ratio. Few studies, however, have examined the reproductively relevant cues conveyed by faces and bodies as whole units. Based on the premise that fertility cues are more readily assessed from a woman's body than her face, the present study tested the hypothesis that men evaluating a potential short-term mate would give higher priority to information gleaned from her body, relative to her face, than men evaluating a potential long-term mate. Male and female participants (N=375) were instructed to consider dating an opposite sex individual, whose face was occluded by a “face box” and whose body was occluded by a “body box,” as a short-term or long- term mate. With the instruction that only one box could be removed to make their decision about their willingness to engage in the designated relationship with the occluded individual, significantly more men assigned to the short-term, compared to the long-term, mating condition removed the body box. Women's face versus body information choice, in contrast, was unaffected by the temporal dimension of the mating condition. These results suggest that men, but not women, have a condition-dependent adaptive proclivity to prioritize facial cues in long- term mating contexts, but shift their priorities toward bodily cues in short-term mating contexts. |
22 mark Section B essay question
All sections with a Level 3 command term can be assessed in a 22 mark essay (remember that a learning objective with a 22 mark command term could also come up as an 8 mark question, but not vice versa).
Although any Level 3 command term could be asked, we'll concentrate on the one given in the learning objective, so the question is Examine one evolutionary explanation of behaviour (22) You will need to plan an essay which will be about 2-3 sides of A4 long, including a detailed focus on the command term. The marking criteria are below. ALWAYS refer to these before you begin to plan your essay. It is crucial that you know what the examiners are looking for so that you can write exactly what is needed for top marks! |
Planning a great 22 mark questionKNOW THE COMMAND TERM! This is absolutely crucial! A different command term requires a different style of essay, so you need to tailor what you write to the question. You will still be able to use the same pieces of information, but how you use them may vary.
PLAN PLAN PLAN! Every year the examiners' comments mention that essays which are clearly planned score the best marks. FOLLOW THEIR ADVICE! Don't be afraid to spend up to 10 minutes in an exam planning your essay (and longer earlier in the year when are learning and practising). USE EVIDENCE! You have 2 detailed studies here to use, but you should also look to find triangulating evidence using other experimental methods or from other areas of the syllabus EVALUATE! You must evaluate the studies you present. Evaluating means talking about the strengths and weaknesses of the study as well as the strengths and weaknesses of the level of analysis as a whole with reference to the question (e.g. reductionist explanation of genetics in some behaviour) |
Revision |
ExtensionFor a superb (but detailed) introduction to the evolution of behaviour, try these lectures by Robert Sapolsky (who we met in the 'Hormones' section).
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