David Buss 1989

AIMS: In 1872 Charles Darwin established the principles of Sexual Selection. In terms of  human reproductive behaviour, the Evolutionary Psychology, which developed from Darwin’s work, has tended to allocate quite different reproductive strategies to men and women, based on the respective size of their gametes (mature sex cells). As men make sperm in their millions, the best reproductive strategy to pass on your genes is to impregnate as many women as possible. For women, with a much, much smaller number of eggs,the opportunity to pass on their genes is much more limited. Therefore, the emphasis has to be on nurturing the fertilised egg and the child that comes from it. This reflects Robert Trivers’ (1972) concept of Parental Investment - it costing the woman far more (9 months’ pregnancy and, usually, the bulk of the child-rearing in at least the first 5 years) while it might cost the man no more than a few minutes of casual sex to pass on his genes.

From an Evolutionary perspective, therefore, it makes sense for a woman to partner a man who has resources to support her and the young child.

From an Evolutionary perspective, if a man is to limit his reproductive opportunities by partnering just one woman, then he has to be sure of both her fertility (the probability of reproduction now - George Williams, 1975)) and her reproductive value (the probability of reproduction in the future - Donald Symons, 1979). Since a woman’s fertility peaks in her late teens or early twenties, Evolutionary theory predicts men will favour younger women.

Another factor to take into consideration is the fact that a women knows that, unless there has been a child swap, any offspring is hers. Prior to DNA tests, the man could only hope the child was his. According to Mildred Dickemann (1981) and Martin Daly, Margo Wilson & Suzanne Weghorst (1982), this explains why men place such a value on the chastity of their partners and often guard them jealously,

Like a great many Evolutionary psychologists, David Bus took the view that, the more an attitude or behaviour held across different cultures, the more likely it was to be the results of evolutionary pressures.

Bus wanted to test several predictions across multiple cultures...namely that:-

PROCEDURE (METHOD): 37 samples were acquired from 33 countries covering 6 continents. Countries with culturally-distinctive sub-populations - eg: Israel, Canada and South Africa - had separate samples taken from each group. Eg: separate samples were used of English- and French-speaking Canadians. In total 10,047 people participated - 4,601 males and 5,446 females. The mean sample size was 272 and their mean age was 23.05 years old.

Sampling methods varied from country to country - though were generally opportunity or self-selecting. The Estonian participants were people applying for marriage licences in certain districts. In Venezuela the sample consisted of every 5th household in a series of neighbourhoods that varied in socioeconomic class. The Zulu sample from  South Africa were from a rural population, some of whom had to have the questions read aloud to them. (Some of the Zulu women were reluctant to take part initially because they were concerned that Zulu men would use the knowledge of what the women looked for to manipulate them to their advantage!) The Germans were those who responded to newspaper adverts. Several countries used university students. The New Zealand participants were children from 3 secondary schools!

2 questionnaires were administered to all participants in their native language.

The first...

• collected biographical data (including age, sex, religion, marital status and number of brothers and/or sisters)
• asked about preferred age to marry, the optimum age difference between partners and the number of  children desired
• measured the importance of 18 factors affecting mate choice. Some were irrelevant to the study - eg: sociability; others were the target variables of age, good looks, good financial prospects, chastity, industriousness and no previous sexual experience. Each factor was rated on a scale of 0-3, 0 being irrelevant and 3 being indispensable

The second questionnaire asked participants to rank 13 factors affecting mate choice in order of importance, including the target variables of ‘good earning capacity’ and ‘physical attractiveness.

Where English was not the first language of the participant communities, 3 translators were used - one to translate the questionnaire into the native language, one to translate the answers into English and one to resolve any discrepancies. Care was taken to avoid using words that were emotive or were not sex neutral - eg: ‘physically attractive’ rather than ‘handsome’ (male) or ‘beautiful’ (female). Some amendments were also made to the wording to take into account cultural factors. Eg: in Sweden many couples do not marry but simply live together. In Nigeria polygny is practised so the questionnaire had to allow for the possibility of multiple wives.

The level of statistical significance set was p<0.05.

FINDINGS (RESULTS): Overall the results supported Evolutionary theory - but support was not absolute in every instance.

Only in Spain did was the importance placed by women on finance fractionally more important than that given by men. In the other 36 cultures (97%) the importance placed by women on finance was significantly more important than that given by men.

In 34 of the 37 cultures (92%) women placed more emphasis on ambition and industriousness than men; but the

partners.

In all 37 cultures the average age of men’s ideal woman (24.83) was significantly younger than themselves. Similarly, in all 37 cultures women wanted older men (average 28.81) - ie: around 4 years. The preferred age difference varied from 1 or 2 years in Scandinavia to 6 or 7 in Nigeria and Zambia - men in polygynous systems tending to acquire wives later in life than in monogamous systems.

In all 37 cultures men rated good looks more important than women - in 34 cultures this difference was great enough to be statistically significant.

Averaged out across cultures, the top 7 most desirable personality traits in a partner were:-

1. Kind and understanding
2. Intelligent
3. Exciting
4. Healthy
5. Emotionally stable and mature
6. Dependable character
7. Pleasing disposition

Chastity and lack of previous sexual experience was the factor that varied most across cultures. Out of the Western European countries, only Ireland placed much emphasis on chastity. In only 23 of the 37 cultures (62%) - eg: China, India, Taiwan, Iran - was there a gender difference in the importance placed on chastity - but in all 23 it was men who placed more importance on it than women.

CONCLUSIONS: Buss concluded that there was support for all the predictions from Evolutionary theory tested in the study.

There was a strong trend for men to choose mates on the basis of aged and attractiveness - and, to some extent, on chastity.

Women, however, placed more emphasis on ambition, industriousness and earning capacity.

These findings do suggest that parental investment, reproductive value and paternal probability do play a role in mate selection in humans - though the average desirable age of men’s ideal woman (24.83) would seem to indicate fertility was seen as more important than reproductivity..

CRITICISMS (EVALUATION): Buss’ study was seminal - the first of its kind.

It was also impressively large-scale, with over 1,000 participants from 33 countries representing every inhabited continent and a wide range of cultures.

The use of 2 questionnaires about factors affecting mate preference is also considered a strength of the study, as it enables the researcher to look for consistency on 2 different instruments. Some sociologists and social psychologists regard questionnaires like these as better measures than (‘real life’) marriage records which may measure mate selection, rather than mate preference or, in cultures where arranged marriages are the norm, the preferences of the marital partners’ families.

However, people can and do lie on questionnaires - perhaps as a result of social desirability bias. Carl Bergstrom & Leslie Real (2000) take the view that how people actually behave in ‘real life’ situations is more important than what they say when questioned in an abstracted manner.

Buss’ study is particularly vulnerable to criticisms over the sampling methods used and the fact there were such uneven numbers from different cultures. While the findings do appear to support the Evolutionary hypotheses across multiple cultures, it can be argued that, had the sample numbers been more representative, there is no guarantee the hypotheses would have been so well supported.

A perhaps inevitable omission in Buss’ study - given the year it was conducted in - was the idea of female promiscuity as a way of acquiring better genes than the committed resource provider could contribute. Just 4 years later Matt Ridley (1993) exploded Darwin’s idea of the promiscuous male and the coy, chaste female with evidence that suggested a sizeable number of Britain’s children were actually not their ‘father’s’ but the offspring of an illicit liaison between their mother and another man. Geoffrey Miller (2000 - who had, in fact, been researching into female promiscuity since 1970) and Tim Birkhead (2000) followed with headline-grabbing work to further develop the notion.

However, David Schmitt, Cheung-Leung Luk & the International Sexual Descriptor Project (2003), in just one part of an ongoing project that dwarfs Buss’ 1989 study, had 100 psychologists simultaneously administer an anonymous self-report survey to 17,837 individuals representing 52 different nations, 6 continents and 13 islands. (The exercise used 30 languages!) Their hypothesis was that men, because of their low parental investment, would seek sex with a variety of women; while women, in need of resources, would be choosier. In every culture surveyed, with the results statistically significant, the researchers found that men desired a larger number of mates.

difference was of statistical significance in only 29 of the cultures (78%). In 3 samples - Spain, Columbia and Zulu South Africa - the position was actually reversed - ie: men rated ambition and industriousness in women more important than women did in men. (The Zulu research collaborator thought might be because physical tasks (such as building the house) were considered women’s work.)

Both sexes in the Nigerian, Zulu, Chinese, Taiwanese, Estonian, Israeli Palestinian, Colombian and Venezuelan samples rated this mate characteristic highly.

Interestingly, when very high-earning American women were asked how much they would want their ideal partner to earn, they placed much more emphasis on a good income than women who earned a more modest living. In addition, the well-off women wanted their men to be well-educated and professionally qualified, to have high social status, to be tall, independent and self-confident. In contrast, wealthy American men placed little emphasis on the wealth and social power of their female