What makes a person desirable? Is it her ample cleavage? Or his manly jaw?
In their new book, psychologists Viren Swami and Adrian Furnham claim to have unlocked the secrets of attraction.
Here, ESTHER WALKER explains what they discovered - and what it can teach us. Scroll down for more...
Body perfection? Hollywood legend Marilyn Monroe's waist/hip ratio helped her attractiveness, say experts
Does body size matter?
Pick up any fashion magazine today and you could be forgiven for thinking that the ideal female body shape is that of an adolescent boy.
But although the most fashionable silhouette in recent years has been an extremely slender one, its not one we necessarily find attractive.
Studies have shown that people favour those who are of normal weight, and that people caught up in an accident are far more likely to be rescued if they are of a normal weight than their underweight - or overweight - peers.
Slenderness (as exemplified by Audrey Hepburn) is regarded as a cultural preference. Scroll down for more...
Slender stars such as Breakfast At Tiffany's Audrey Hepburn are only found alluring by certain cultures. In poorer nations, portliness - a sign of wealth - is preferred
In poorer cultures, being portly can be a sign of wealth, and therefore desirability.
People value thinness more "as you move up the social and economic scale", Adrian Furnham says.
"As you get richer, you get thinner. Where food is scarce, tubbier women are thought of as more attractive."
That aside, Furnham and his co-author Viren Swami found that body size matters very little in the grand scheme of things.
Being a fairly superficial lot, what we really care about are people's faces and how attractive they are.
Are bigger breasts better? Cartoon character Jessica Rabbit from Who framed Roger Rabbit?
Are bigger breasts better?
When it comes to bosoms, it is often taken for granted that more is more - how else can you explain the popularity of models like Jordan or the sultry appeal of the cartoon figure Jessica Rabbit?
In fact, most studies contradict this. There is little evolutionary evidence to suggest that breast size has anything to do with fertility or health.
Studies into the ideal breast size are inconclusive, and the results vary according to personal taste and culture.
In terms of how it contributes to overall attractiveness, studies have repeatedly shown that breast size comes below both body weight and shape.
So, you have been told.
Is there such a thing as the perfect human body?
Marilyn Monroe, the Venus de Milo, Sophia Loren, Scarlett Johansson - at different times, these women have all been considered among the most desirable on Earth.
Quite apart from their beautiful faces, they all boast, or boasted, a low waist/hip ratio (WHR).
Used by our hunter-gatherer forefathers to judge the health and fecundity of women, the WHR explains why men find more curvy (but not necessarily overweight) figures such as Scarlett Johansson attractive.
To work out WHR, divide the waist measurement by the hip measurement.
Most women's WHR falls between 0.7 and 1.0. WHRs of 0.7 or 0.8 are most attractive, with attraction decreasing as the WHR increases.
Unlike breasts, where bigger doesn't mean better, attraction increases as WHR decreases, even if the waist is artificially cinched in with a belt or corset.
But a woman's WHR isn't necessarily lower the thinner she is; it's about how small her waist is compared with the hips.
"Young women can be chubby, but still have a low WHR," say the authors of The Psychology Of Physical Attraction.
"As women get older, their waists thicken and their fertility goes down in proportion to their age - that explains why a slim waist, a signal of fertility, is attractive."
A low WHR doesn't have universal appeal, though. A Tanzanian tribe, the Hadza, who subsist by foraging for wild foods, are unaffected by the female WHR. Another isolated tribe, the Matsigenka of southern Peru, simply prefer the larger lady.
New heights: Sacha Baron Cohen and Isla Fisher
It's all because of what we perceive as healthy. When resources were scarce, being overweight - and thus well fed - was good.
Today, being overweight is associated with health problems.
Can a man be too tall?
Women are always looking for someone tall, dark and handsome, right? No one specifies "short, mousy and ugly" in a personal ad.
But how much does a man's height matter? Taller men have more children than their averagely tall counterparts, and receive more replies to personal ads.
At 6ft 3in, Sacha Baron Cohen is a full foot taller than his fiancee Isla Fisher.
But don't worry, Mr Five Foot Nine (the average height of the UK male): many studies show that men of average height are more attractive and likeable than very tall men.
Above-average height may even indicate poor health.
Why are gay men always at the gym?
While lesbians reject body fascism, gay men embrace it with zeal.
Gay men are more likely to be unhappy with their bodies than straight men and are more likely to have an eating disorder. They also idealise slightly underweight bodies.
Gay men also tend to idealise upperbody strength - particularly well-defined biceps and abdominal muscles - over and above other physical aspects.
One theory is that having an overdeveloped musculature is a way for gay men (otherwise thought of as effeminate) to assert their masculinity and to distance themselves from being thought of as girly.
Hairless: LA Galaxy star David Beckham
Should you wax?
Hairlessness on women is perceived as good because it indicates youth and fertility.
However, total hairlessness on women and men (eyebrows aside) is not as attractive, as it is a sign of pre-pubescence and, therefore, the inability to have children.
Male waxing makes little evolutionary sense, as chest hair shows masculinity, but such depilation is common in Western societies; a 2005 study found that 60 per cent of men regularly removed body hair.
Of course, if like David Beckham you are naturally hairless, it's not an issue.
Whether a man waxes is down to personal choice and is largely affected by culture.
The current obsession with female bikini waxes can be blamed on fashion - there's no reason we should find it attractive, and some would say they don't.
Are 'beer-goggles' a myth?
You know how it is; that man who, at midnight, looked like the dreamiest hunk in the world turns out the next day to look more like actor Steve Buscemi's ugly cousin.
Most people blame too much alcohol but, while being drunk doesn't help, it's not just hops that make you hop into bed with a monster.
A study of singles bars in 1979 found that as the evening wore on, people rated members of the opposite sex as more attractive.
The author of the study argued that as time went by and the risk of going home alone increased, the singles downgraded their criteria for attractiveness.
Pale: Actress Nicole Kidman
How interesting is pale?
In most pre-industrial societies, a tan indicated that the person in question worked outdoors, probably as a manual labourer, and had a low social status and income.
Historically, pale skin like Nicole Kidman's (above) - an indication that you were rich enough to sit indoors all day - has been revered as beautiful.
In the 20th century, having a tan (especially when the weather in your country is cold) became a sign that you were rich enough to fly off to Jamaica in the winter, and became desirable.
This has been complicated recently by the rise of budget airlines and tanning booths; an all-year tan no longer equals wealth.
When a skin tone (light or dark) becomes associated with low economic or social status, it ceases to be attractive.
Is beauty colour-blind?
Physical attraction is, pleasingly, not racist. Not taking into account personal prejudices and cultural pressures, all races can appeal to all other races - because what's more important than skin colour is the symmetry of a person's facial features and body.
Beauty and the beast? Formula One supremo Bernie Ecclestone with wife Slavica
Evolutionary psychologists argue that only the healthiest people are able to develop symmetry in their faces and bodies, which is why people find Will Smith or Brad Pitt attractive.
How do ugly boys get gorgeous girlfriends?
In lonely hearts adverts, men usually emphasise what they are looking for in a woman physically, whereas women look for wealth and status.
The difference in priorities might explain why the Formula One supremo Bernie Ecclestone is married to a stunningly tall wife, Slavica.
Women often find feminine features attractive on a man. Brad Pitt has plump lips and large eyes.
This is because women look for a trade-off between good mates and good fathers, and feminine features hint at better parenting skills.
Facial hair: Actor Johnny Depp
Male facial hair - hot or not?
Studies in the 1970s and 1980s often came to opposite conclusions.
Bearded men are usually regarded as looking older and more masculine, dominant, courageous and confident, but that doesn't mean that women want to go to bed with them.
Some find beards a turn-off and associate them with being dirty. Beards have no basis in evolutionary history, so whether you like them depends on fashion and individual taste. Here's a handy guide: Johnny Depp, hot; Alan Sugar, not.
In their new book, psychologists Viren Swami and Adrian Furnham claim to have unlocked the secrets of attraction.
Here, ESTHER WALKER explains what they discovered - and what it can teach us. Scroll down for more...
Does body size matter?
Pick up any fashion magazine today and you could be forgiven for thinking that the ideal female body shape is that of an adolescent boy.
But although the most fashionable silhouette in recent years has been an extremely slender one, its not one we necessarily find attractive.
Studies have shown that people favour those who are of normal weight, and that people caught up in an accident are far more likely to be rescued if they are of a normal weight than their underweight - or overweight - peers.
Slenderness (as exemplified by Audrey Hepburn) is regarded as a cultural preference. Scroll down for more...
In poorer cultures, being portly can be a sign of wealth, and therefore desirability.
People value thinness more "as you move up the social and economic scale", Adrian Furnham says.
"As you get richer, you get thinner. Where food is scarce, tubbier women are thought of as more attractive."
That aside, Furnham and his co-author Viren Swami found that body size matters very little in the grand scheme of things.
Being a fairly superficial lot, what we really care about are people's faces and how attractive they are.
Are bigger breasts better?
When it comes to bosoms, it is often taken for granted that more is more - how else can you explain the popularity of models like Jordan or the sultry appeal of the cartoon figure Jessica Rabbit?
In fact, most studies contradict this. There is little evolutionary evidence to suggest that breast size has anything to do with fertility or health.
Studies into the ideal breast size are inconclusive, and the results vary according to personal taste and culture.
In terms of how it contributes to overall attractiveness, studies have repeatedly shown that breast size comes below both body weight and shape.
So, you have been told.
Is there such a thing as the perfect human body?
Marilyn Monroe, the Venus de Milo, Sophia Loren, Scarlett Johansson - at different times, these women have all been considered among the most desirable on Earth.
Quite apart from their beautiful faces, they all boast, or boasted, a low waist/hip ratio (WHR).
Used by our hunter-gatherer forefathers to judge the health and fecundity of women, the WHR explains why men find more curvy (but not necessarily overweight) figures such as Scarlett Johansson attractive.
To work out WHR, divide the waist measurement by the hip measurement.
Most women's WHR falls between 0.7 and 1.0. WHRs of 0.7 or 0.8 are most attractive, with attraction decreasing as the WHR increases.
Unlike breasts, where bigger doesn't mean better, attraction increases as WHR decreases, even if the waist is artificially cinched in with a belt or corset.
But a woman's WHR isn't necessarily lower the thinner she is; it's about how small her waist is compared with the hips.
"Young women can be chubby, but still have a low WHR," say the authors of The Psychology Of Physical Attraction.
"As women get older, their waists thicken and their fertility goes down in proportion to their age - that explains why a slim waist, a signal of fertility, is attractive."
A low WHR doesn't have universal appeal, though. A Tanzanian tribe, the Hadza, who subsist by foraging for wild foods, are unaffected by the female WHR. Another isolated tribe, the Matsigenka of southern Peru, simply prefer the larger lady.
It's all because of what we perceive as healthy. When resources were scarce, being overweight - and thus well fed - was good.
Today, being overweight is associated with health problems.
Can a man be too tall?
Women are always looking for someone tall, dark and handsome, right? No one specifies "short, mousy and ugly" in a personal ad.
But how much does a man's height matter? Taller men have more children than their averagely tall counterparts, and receive more replies to personal ads.
At 6ft 3in, Sacha Baron Cohen is a full foot taller than his fiancee Isla Fisher.
But don't worry, Mr Five Foot Nine (the average height of the UK male): many studies show that men of average height are more attractive and likeable than very tall men.
Above-average height may even indicate poor health.
Why are gay men always at the gym?
While lesbians reject body fascism, gay men embrace it with zeal.
Gay men are more likely to be unhappy with their bodies than straight men and are more likely to have an eating disorder. They also idealise slightly underweight bodies.
Gay men also tend to idealise upperbody strength - particularly well-defined biceps and abdominal muscles - over and above other physical aspects.
One theory is that having an overdeveloped musculature is a way for gay men (otherwise thought of as effeminate) to assert their masculinity and to distance themselves from being thought of as girly.
Should you wax?
Hairlessness on women is perceived as good because it indicates youth and fertility.
However, total hairlessness on women and men (eyebrows aside) is not as attractive, as it is a sign of pre-pubescence and, therefore, the inability to have children.
Male waxing makes little evolutionary sense, as chest hair shows masculinity, but such depilation is common in Western societies; a 2005 study found that 60 per cent of men regularly removed body hair.
Of course, if like David Beckham you are naturally hairless, it's not an issue.
Whether a man waxes is down to personal choice and is largely affected by culture.
The current obsession with female bikini waxes can be blamed on fashion - there's no reason we should find it attractive, and some would say they don't.
Are 'beer-goggles' a myth?
You know how it is; that man who, at midnight, looked like the dreamiest hunk in the world turns out the next day to look more like actor Steve Buscemi's ugly cousin.
Most people blame too much alcohol but, while being drunk doesn't help, it's not just hops that make you hop into bed with a monster.
A study of singles bars in 1979 found that as the evening wore on, people rated members of the opposite sex as more attractive.
The author of the study argued that as time went by and the risk of going home alone increased, the singles downgraded their criteria for attractiveness.
How interesting is pale?
In most pre-industrial societies, a tan indicated that the person in question worked outdoors, probably as a manual labourer, and had a low social status and income.
Historically, pale skin like Nicole Kidman's (above) - an indication that you were rich enough to sit indoors all day - has been revered as beautiful.
In the 20th century, having a tan (especially when the weather in your country is cold) became a sign that you were rich enough to fly off to Jamaica in the winter, and became desirable.
This has been complicated recently by the rise of budget airlines and tanning booths; an all-year tan no longer equals wealth.
When a skin tone (light or dark) becomes associated with low economic or social status, it ceases to be attractive.
Is beauty colour-blind?
Physical attraction is, pleasingly, not racist. Not taking into account personal prejudices and cultural pressures, all races can appeal to all other races - because what's more important than skin colour is the symmetry of a person's facial features and body.
Evolutionary psychologists argue that only the healthiest people are able to develop symmetry in their faces and bodies, which is why people find Will Smith or Brad Pitt attractive.
How do ugly boys get gorgeous girlfriends?
In lonely hearts adverts, men usually emphasise what they are looking for in a woman physically, whereas women look for wealth and status.
The difference in priorities might explain why the Formula One supremo Bernie Ecclestone is married to a stunningly tall wife, Slavica.
Women often find feminine features attractive on a man. Brad Pitt has plump lips and large eyes.
This is because women look for a trade-off between good mates and good fathers, and feminine features hint at better parenting skills.
Male facial hair - hot or not?
Studies in the 1970s and 1980s often came to opposite conclusions.
Bearded men are usually regarded as looking older and more masculine, dominant, courageous and confident, but that doesn't mean that women want to go to bed with them.
Some find beards a turn-off and associate them with being dirty. Beards have no basis in evolutionary history, so whether you like them depends on fashion and individual taste. Here's a handy guide: Johnny Depp, hot; Alan Sugar, not.
