Women's Choice of Men Goes in Cycles
Women are attracted to more masculine-looking men at the most fertile time of their menstrual cycle, psychologists have shown.
During the less fertile times, they choose men with more feminine-looking faces. These are seen as kinder and more co-operative, but less strong and healthy genetically.
More masculine faces have squarer shapes, heavier, straighter eyebrows and thinner lips.
The study was carried out by researchers in Scotland and Japan. They asked women to select the one face from a range that they were most attracted to as a partner for a short-term sexual relationship.
They found that in the most fertile week of their menstrual cycle, women preferred more masculine faces.
However, the choice of face did not vary for women using an oral contraceptive (i.e. not fertile) or those asked to choose the most attractive face for a long-term relationship.
Smell of success
The results are supported by previous research which showed that a male hormone smells unpleasant to women, except in the week of fertility. Also, the smells of more symmetrical, and therefore more attractive, men are preferred by women but again only in that week.
Men who look more masculine have higher levels of male hormones and also show a better ability to fight off disease. This makes them attractive as potential mates because their children will inherit this useful characteristic.
A controversial implication of the new research is that, in evolutionary terms, it is "natural" for a woman to be unfaithful in order to secure both the best genes and the best carer for her children.
However, the head of the laboratory at St Andrews University where the research was done, Professor David Perrett, told BBC News Online: "This suggestion is a possibility, but we don't know how behaviour is affected by the preferences we see. We're assuming that preferences for different faces are affecting the choices women make. But whatever is best in an evolutionary sense is not necessarily the moral thing to do socially. We are not advocating any particular strategy," he said.
Professor Perrett believes that preferences for certain types of faces will have an effect on the partners people choose: "We keep finding very strong links between the appearance of males and their perceived personality. People reckon they can judge personality from the way others look."
"And as long as those links are there, I think preferences will be a profound influence on choice," he said.
He also points out that there are real links between face form and behaviour. For example, a study has shown that more masculine-looking US servicemen are more likely to get divorced and be violent towards their partners.
Not real life
However, Dr Paula Nicolson, a psychologist at the University of Sheffield, thinks this kind should not be seen as applicable to everyday relationships. She will deliver a lecture next month to the British Psychological Society's conference called "Evolutionary psychology is not the answer to everything."
"The research uses experimental methodology which accounts for extraneous variables and for social context. So they find the essence of human nature, which in this case is to do with mating behaviour," she told BBC News Online.
"But this methodology is also a weakness because this is not actually how people live – decisions about choice of partner are made on a whole range of issues. I think the effect of facial preferences is probably lost in today's social context. It is important to look at human biology in a basic sense but even most biologists would admit that biology is not that clear-cut."
The study is published in the journal Nature. The initial research was carried out through BBC Tomorrow's World Magazine, co-ordinated by Damian Carrington.
[24 June, 1999, http://news.bbc.co.uk/1/hi/sci/tech/376321.stm]
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Study: Women's Beauty Peaks Monthly
A woman's facial appearance changes each month to make her appear more beautiful when she is at her highest stage of fertility, according to a recent study.
While researchers say more work is needed to identify the exact physical changes, they speculate that the appearance shifts could include variation in lip color and size, eye pupil dilation, and changes in skin color and tone. An earlier study suggested a woman's ears, fingers, breasts, and other soft tissue areas become more symmetrical.
For the latest research, groups of between 124-127 males and females in Newcastle, England, and Prague, Czech Republic, rated photographs of women who were snapped both during the peak stages of fertility (8-14 days into their menstrual cycle) and after these levels dropped (days 17-25 of the cycle).
In both Newcastle and Prague, men and women judges rated the fertile women to be more beautiful approximately 51-59 percent of the time, a percentage rate that is greater than random chance.
The findings are published in the current Royal Society Biology Letters.
S. Craig Roberts, lead author of the study and a research associate in the Evolution and Behavior Group Research Group at the University of Newcastle, told Discovery News that he was unavailable for comment.
However, in his paper, Roberts and his colleagues explained their results.
"Our results indicate that the perceived attractiveness of womens' faces varies across the menstrual cycle and is higher in the periovulatory (pre ovulation stage when eggs begin to form) than in the luteal phase (when the lining of the uterus prepares itself for fertilized egg attachment)," Roberts and his team wrote.
They added, "This increase in facial attractiveness is clearly subtle and the mean effect size is small. Even such subtle effects, however, can have substantial reproductive benefits if they raise value in the mating market."
In addition to increased beauty, women in their fertility prime become more flirtatious and give off odors that men find alluring, according to previous studies.
Hair fullness and symmetry might also be a factor. Roberts and his team took photos of women with their hair and ears covered. While this did not seem to affect the judgment of male raters much, it did seem to throw off women judges, which suggests that females may be more sensitive to the appearance changes.
Maryanne Fisher, a psychologist at York University in Toronto, Canada, recently made a somewhat similar determination. She found that women during their most fertile stages became more critical of other women.
"Since men have what appears to be an evolved preference for attractive women, it seems that women should compete in terms of attractiveness," Fisher told Discovery News.
While men's faces do not appear to change on a monthly basis, women's taste in men does.
Researchers Anthony Little and David Perrett of the School of Psychology's Perception Lab at the University of St. Andrews, Scotland, found that fertile women tend to go for more masculine-looking men, but then seem to prefer more feminine-faced males for long-term relationships.
Little and Perrett said, "Work on the timing of affairs has shown that flings or affairs tend to coincide with a w
oman's peak fertility."
Such flings are not as common in humans as they are in apes because humans have a predisposition for monogamy to ensure better parental care for children.
Sexual cues in apes and chimps are less subtle; female genitals often will swell in size and turn bright pink.
[6April2004, Jennifer Viegas, Discovery News, http://dsc.discovery.com/news/briefs/20040405/beauty_print.html]