TORONTO - Many men might say they're most attracted to women who are svelte, icons of that so-called feminine ideal portrayed in magazines and other media.
But never fear, you ladies of more Rubenesque proportions: it seems a man's body size preference can be somewhat fluid — and one of the factors that appears to affect it is stress.
British researchers have found that men faced with a stressful situation tend to change their assessment of what constitutes an attractive female, moving away from slender to a range of plumper women.
For Olympics devotees, think heftier weight lifters or hammer throwers rather than lean and lithe gymnasts or sprinters.
"Evolutionary psychology tells us that what you find attractive about someone tells you about their health and their fertility," said neuroscientist Martin Tovee of Newcastle University, co-author of a study published online Wednesday in the journal PLoS One.
"But what's healthy and fertile — body-size shape — is going to vary depending on your environment," Tovee said Wednesday from Newcastle-Upon-Tyne.
In the U.K., Canada and other western countries with abundantly available food, having a higher body mass suggests a person is not only less healthy, but also may belong to a lower socioeconomic group, because cheaper food tends to have a higher fat content, he said.
Contrast that with parts of rural South Africa, for instance, where food is generally less plentiful and there are periods of severe food shortages. In that kind of environment — which Tovee described as stressful — a heftier body type is a sign of physical well-being.
"Also it means that you're higher status because you can afford to be heavier. So you choose somebody heavier because that's best in that environment.
"But in this environment," he said of the U.K. and other developed nations, "the reverse is true."
To test the effects of stress on men's notions of the most attractive form of female body, Tovee and co-author Viren Swami of the University of Westminster in London recruited 81 heterosexual men for their study. The men were all Caucasian, aged 18 to 42, with a body mass index ranging between about 17 and 31.
Forty-one of the subjects were subjected to a number of back-to-back stress-inducing tasks, including a mock job interview in front of a four-person panel that was being recorded and videotaped. The other 40 participants — the control group — were taken to a room where they sat quietly.
Both groups were then shown photographs of a variety of female body types, ranging from emaciated through obese, with the faces removed.
The stressed group gave significantly higher attractiveness ratings to normal weight and overweight figures than did the non-stressed group, said Tovee. Men in the stressed group also indicated attraction to a broader range of sizes among the figures, compared with those in the non-stressed group.
"Although you read a lot in evolutionary psychology that our preferences for attractiveness are hard-wired and we can't do anything about it, that's probably not true," he said.
"If you follow somebody (moving) from rural South Africa to the U.K., over the course of about 18 months their preference will shift towards that of somebody who was born in the U.K. They prefer a thinner body."
Tovee said the preference of many men in western society for slender women is somewhat out of sync with reality, as the average BMI is drifting upwards.
"And if you think of this pressure on people to try and fit this ideal, it's not terribly healthy. It does cause quite a lot of body image dissatisfaction."
Turning to the distaff side, he said women's ideas of what makes a man attractive are somewhat more complex and harder to study. Where males focus on overall body mass, attractiveness for females includes such factors as personality and physique.
"When you look at what women look for in men's physical appearance, body mass is quite important, but the big thing is body shape — they're looking for the V-shape, with wide shoulders and the narrower waist.
"So it's less straightforward to do a shift in body mass with women."
The Science Of Attraction
The Colour Of Love
Like a red rag to a bull it would seem the colour red also fires up the passion in women. A study at the University of Rochester asked 288 female and 25 male undergraduates to look at photos of a man in which his shirt was digitally coloured either red or another colour. Women in a variety of countries agree that the red shirt made the man appear "more powerful, attractive and sexually desirable."
The Scent Of A Man
Women can subconsciously sense if a man is attracted to her by the smell of his sweat, according to a study at Rice University in Texas. A group of 19 women in their twenties were exposed to two types of male sweat - one labelled 'normal' and the other 'sexual'. The normal sweat was obtained from the men while they were watching educational videos while the 'sexual' sweat was gathered while they were watching an erotic video. The women's brains were monitored while they were exposed to the sweat. The brain activity showed that they recognised and responded to the sexual sweat.
The Perfect Ratio
Anthropologists in New Zealand carried out studies to find the precise waist to hip ratio that drives men wild. Volunteers were asked to rate the attractiveness of images of women that had their bust, hip and waist sizes digitally altered. The eye movements of the participants were tracked using infra-red cameras. Most men were drawn to the breasts but hips and waists were also important. The most attractive ratio was the waist measuring 70% of the hips. Not surprisingly, Marilyn Monroe, Kate Moss and Jessica Alba all share this ratio.
Masculine Men And Feminine Faces
Men with high levels of testosterone are attracted to women with highly feminine faces, a study at Aberdeen University found. A group of 70 women and 30 men underwent a series of tests to examine the role of testosterone in attraction between the sexes. It was found that attitudes towards the opposite sex changed depending on their fluctuating testosterone levels throughout the day. Researcher Dr Ben Jones, said "When men's testosterone levels were high, they were more attracted to feminine women. When women's testosterone levels were high they were more attracted to masculine men."
The Time For Love
According to a study by Florida State University men are unconsciously attracted to a woman's scent when she is ovulating. Four female volunteers - two who were ovulating and two who were not - were asked to wear a plain white T-shirt for three consecutive nights. Male volunteers were asked to smell the T-shirts. Those who smelled the T-shirts of the ovulating women had testosterone levels 37% higher than those who smelled the T-shirts of the women who were not ovulating.
It's a long-held belief that we are naturally attracted to people that resemble ourselves. In an experiment conducted by the University of Illinois, volunteers were shown pictures of of two faces morphed together. One group was shown images of faces of strangers morphed together while the other group was shown faces that were a composite of a stranger's face and up to 45% their own face. The subjects shown images containing their own face found the picture more sexually attractive.
Contrary to the theory that we choose partners similar to ourselves and backing up the old adage 'opposites attract', scientists have found an evolutionary reason why we may be attracted to those who are genetically most different to us. A Brazilian study found tthat people are more likely to choose someone with differences in the DNA region that governs the immune system as parents with dissimilar genetic regions could provide their offspring with a better chance to ward infections off because their immune system genes are more diverse.