Evolution of human sex roles more complex than described by universal theory

Apr 24, 2009

A new study challenges long-standing expectations that men are promiscuous and women tend to be more particular when it comes to choosing a mate. The research, published by Cell Press in the April issue of the journal Trends in Ecology and Evolution, suggests that human mating strategies are not likely to conform to a single universal pattern and provides important insights that may impact future investigations of human mating behaviors.

A new study by St Andrews academics challenges the long-standing expectations that men are promiscuous and women more particular when it comes to choosing a mate.

The research suggests that human mating strategies are not likely to conform to a single universal pattern and provides important insights that may impact future investigations of human mating behaviour.

Dr Gillian Brown, from the School of Psychology, and Professor Kevin Laland, from the School of Biology, examined the evolution of human sex roles, assessing the universal applicability of the now famous research in 1948 by Angus J Bateman on fruit flies.

Bateman showed that male fruit flies have greater variance in mating success (the number of sexual partners) and in reproductive success (the number of offspring) compared to female fruit flies. In addition, Bateman demonstrated that there is a stronger relationship between mating success and reproductive success in males than females.

Dr Brown explained, "The conventional view of promiscuous, undiscriminating males and coy, choosy females has also been applied to our own species.

"We sought to make a comprehensive review of sexual selection theory and examine data on mating behaviour and reproductive success in current and historic human populations in order to further our understanding of human sex roles."

Bateman concluded that, because a single egg is more costly to produce than a single sperm, the number of offspring produced by female animals is limited by the number of eggs that she can produce, while the number of offspring produced by male animals is limited by the number of mating partners. This study supported the conventional assumption that male animals are competitive and promiscuous while female animals are non-competitive and choosy.

In collaboration with Professor Monique Borgerhoff Mulder from the Department of Anthropology at the University of California, Davis, Dr Brown and Professor Laland examined the general universal applicability of Bateman's principles. To test one of Bateman's assumptions, they collated data on the variance in male and female reproductive success in 18 human populations, mostly from Europe, Africa and South America.

Dr Brown said, "While male reproductive success varied more than female reproductive success overall, huge variability was found between populations; for instance, in monogamous societies, variances in male and female reproductive success were very similar."

The researchers argue that evolutionary theory can help us to understand this variability between populations.

"Recent advances in evolutionary theory suggest that factors such as sex-biased mortality, sex-ratio, population density and variation in mate quality, are likely to impact mating behaviour in humans," said Dr Brown.

Dr Brown and colleagues concluded that the diversity in human mating strategies suggests that a single universal principle is unlikely to fully describe human behaviour.

She commented, "We should not expect human mating strategies to be explained by the simple rules derived from Bateman's experiments.

"Taking a new perspective on what evolutionary theory predicts about mating strategies will have important implications for how we think about male and female sex roles. We're entering an exciting new era in which evolutionary theory can help us to understand the diversity of human mating strategies."

More information: Brown et al.: "Bateman's principles and human sex roles." Researchers include Gillian R. Brown, University of St Andrews, U.K.; Kevin N. Laland, University of St Andrews, U.K.; and Monique Borgerhoff Mulder, University of California at Davis, CA.

Source: Cell Press (news : web), University of St Andrews

Explore further: A clear, molecular view of how human color vision evolved

add to favorites email to friend print save as pdf

Related Stories

Sex in the morning or the evening?

Jun 26, 2007

Most research on sexual conflict ignores the fact that the fitness pay-offs of mating may change drastically over a short timescale, for example over a single day.

Mating that causes injuries

Feb 20, 2009

Researchers at Uppsala University can now show that what is good for one sex is not always good for the other sex. In fact, evolutionary conflicts between the two sexes cause characteristics and behaviors that are downright ...

Recommended for you

Contrasting views of kin selection assessed

Dec 17, 2014

In an article to be published in the January issue of BioScience, two philosophers tackle one of the most divisive arguments in modern biology: the value of the theory of "kin selection."

Microbiome may have shaped early human populations

Dec 16, 2014

We humans have an exceptional age structure compared to other animals: Our children remain dependent on their parents for an unusually long period and our elderly live an extremely long time after they have ...

DNA sheds light on why largest lemurs disappeared

Dec 16, 2014

Ancient DNA extracted from the bones and teeth of giant lemurs that lived thousands of years ago in Madagascar may help explain why the giant lemurs went extinct. It also explains what factors make some surviving ...

User comments : 6

Adjust slider to filter visible comments by rank

Display comments: newest first

LuckyBrandon
3 / 5 (2) Apr 24, 2009
all in all, men and women are both the same...the same desires, the same strength of desires, etc....its just that females tend to control themselves better with it.
And btw, there is no such thing as a monogomous society, if there were, spouses (male or female) wouldnt cheat...
food for thought...
Quantum_Conundrum
3 / 5 (2) Apr 27, 2009
A new study by St Andrews academics challenges the long-standing expectations that men are promiscuous and women more particular when it comes to choosing a mate

====

This paragraph is absurd. It takes two to tango, so its not physically possible for men in general to be "promiscuous" while women are not. After all, the man is with a woman, if we are truly discussing "mating".

====

LuckyBrandon:

Its is true a lot of people, probably most, "cheat", but not everyone.

Lots of people marry and never cheat.
LuckyBrandon
1 / 5 (1) Apr 27, 2009
quantum-you do have a good point, but you do have to admit, that percentage is likely much lower than those who do cheat. I myself am having my 8th wedding anniversary today, and I can say that I have not cheated...however about 6 months back, my wife did come close, but got caught I THINK before she was able to do anything real by bragging to her friends about it, and it has caused hell ever since....especially within my mind where I am still trying to decide what to do.
Justavian
5 / 5 (1) Apr 30, 2009
It may take two to Tango, but that doesn't necessarily indicate that men and women must be at the same level of promiscuity. If you have just a few women who are unusually promiscuous, they could be with dozens of men. So, most women could be virtuous (whatever that really means) and most men could be promiscuous - given that there are a couple of women who are nymphos.

Clearly, not an important point, but i thought it should be mentioned nonetheless.
ormondotvos
not rated yet May 26, 2009
Sorry, but the bias in the writing of the article is once again politically correct, i.e., men and women are essentially the same. It's going to take a lot more than this to convince me.
LuckyBrandon
1 / 5 (1) May 27, 2009
justavian-no its a good point

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.