Attraction is in the eye of the beholder. But what it looks like can depend on where the beholder lives

Forget the sporting debates. Among my friends, one of the most common Olympics discussion was: which sport produces the best body? The choice is as wide as Chris Hoy's majestic cycling thighs. A triangular but muscled swimmer. A less triangular but muscled diver. A no-apparent-faults diver or a 6ft 5in sprinter. Choices varied but not much, and most conformed to what scientists have discovered women want in a body and a man: a V-shaped body; broad hips; muscled but not too much. Of course, "best" really means "ideal". What people actually want in a partner though, is somewhat more complex. Fashions come and go (the angular facial features of Katharine Hepburn, for example, which looked best in black and white, have given way to oversized mouths and lips of Jolie and Roberts, which look better in colour), but some things stay the same: we want Mr and Mrs Average.

Researchers have found that, across cultures, more average facial features rate as attractive. Women, though, seek out more masculine features when they're ovulating, as they indicate a better genetic option (more feminine features, denoting kindness and co-operation, become more attractive when we are less fertile). What we dream about Brad Pitt's too-close eyes and small features; Angelina's cartoon lips may be something different altogether. Men, meanwhile, are less predictable than you'd think. They don't want heroin chic: heroin chicks won't reproduce. One survey found that 81 per cent of men in 58 cultures preferred women with a bit of fat on them, all the better for nurturing a foetus. And research using an "eye-tracking" machine shows that, though breasts are the first thing a man's eyes settle on, he will consistently pick a woman with a smaller waist-hip ratio, no matter what size her breasts are.


Indian English provides us with many delightful linguistic differences. A less delightful one is "wheatish complexion," a standard description in marriage ads aimed at either sex. Wheatish it's not brown, but it's not white is the ideal in a country of brown-skinned people, where 60 per cent of the cosmetics industry is devoted to skin-whitening creams, and where men have their own brand ("Fair and handsome", a masculine version of L'Oreal's top-selling "Fair and Lovely"). The reasons for such skin hatred are complex: it could be that peasants got tanned and the aristocrats didn't (the same reason why Elizabethan ladies poisoned their skin with lead to whiten it); or because of a traditional aesthetic preference in Indian society for Aryan skin.


There are some sacred cows about attraction. Women judge a partner on his status and resources; men look at different figures, usually the ones denoting cup size. In fact, a study of 10,000 Britons born in the UK in one week in March 1958 came to the conclusion that, for us, size matters. Women consistently picked taller men for mates, and a 6ft man had a much higher chance of having children than someone two inches shorter. Men, on the other hand, went for petite women, possibly because tall women reach their fertility peak later in life.


Globally, male athletes, actors and models are significantly more muscular than they used to be, heralding a shift in perceptions of desirability. Yet women are less attracted to the muscle-bound than men think. In one survey, by Harvard Medical School, Western women consistently picked an average male over an overly muscular one despite male expectation that they would pick bodies that carried 20-30 per cent more muscle than average. But Taiwanese men, in the same study, had a better grasp of reality: they consistently and correctly assumed that women didn't prefer muscle. That may be why the researchers found almost no evidence of anabolic steroid abuse in Taiwan, or anywhere else in the Pacific Rim.


Scientists may talk of waist-to-hip ratios and body mass indexes, as well as ectomorphs and mesomorphs, but in some African nations, female attractiveness can be summed up in two words: "a bottom." Alexander McCall Smith's Mma Ramotswe, politely but proudly described as "traditionally built" ,has put into print what any larger-bottomed western traveller will have understood from the wolf-whistles heard when walking down an African street. There is no room for bony bottoms here. The fuller, the riper, the better.


The traditional Australian aeshetic ideal tan, muscles, not much clothing, beach has been shaken by skin cancer. But in China, where pale skin has been the aesthetic ideal for centuries, skin preferences are changing. The country's new wealth has brought a flux of tanning salons along with it; 70 per cent of the customers are men. A glowing tan is supposed to denote prosperity and success.


In societies that didn't have Baywatch, a corpulent figure meant healthy eating, fertility, and beauty. In the Azawagh society of the Sahara, female fattening has been going on at least since the 14th century, when the great Arab traveller Ibn Battuta mentioned women famed for their white skin and their corpulence, and the 20th century traveller Mungo Park noted that an ideal woman was one who could not "walk without a slave under each arm to hold her." A perfect beauty was "a load for a camel". Anthropologist Rebecca Poponoe records that women still ingest large quantities of couscous and camel milk to put on desirable weight. In Fiji, however, where fat also traditionally means sexy, tastes are changing. Three years after television was introduced in 1995, Harvard researchers found that girls who watched TV more than three nights a week were 50 per cent more likely to have an eating disorder and describe themselves as ugly. A third were likelier to diet.


When the beauty company Dove polled 3,300 girls worldwide about their views on beauty, more than 90 per cent said they would like to change some aspect of their appearance and a quarter said they would consider plastic surgery. In the US, plastic surgery procedures have increased 59 per cent in the last decade; in the UK, they rose 12 per cent between 2006 and 2007. Experts blame reality TV including plastic surgery makeovers such as The Swan and the unforgiving detail of HDTV for the trend. When plastic surgeons surveyed first-time patients, they found that 57 per cent were "high-intensity" viewers of such shows, and four out of five patients admitted feeling influenced by TV.