"And the world's ugliest dog is... Wild Thang!" The crowd roars. The spectators at the Marin-Sonoma County Fair in California could not be happier with their champion.

Wild Thang is an eight-year-old PekingeseA toy dog breed originating from China. They were once favoured as companions by the Chinese Imperial court. with fuzzy fur and a flopping tongue. As a puppy he suffered from a virusA very small piece of material that causes disease. which nearly killed him, meaning his teeth never developed. 

So why exactly is Wild Thang considered ugly? It all comes down to a lack of symmetryHaving two matching halves. , say some scientists. 

For a long time, facial symmetry has been held up as a reliable indicator of physical attractiveness. Experts call it the "Evolutionary Advantage Theory"; examples of asymmetryWhen something is not symmetrical. suggest that an individual has issues that have affected their development, from mutationsChanges to the structure of genes. to disease.¹

In short, without even thinking about it, we link symmetry with good genesSections of DNA strands that act as a kind of instruction manual for a human being. There is still a great deal we do not understand about how they work. and physical health, and these are traitsA person's characteristics or qualities. we might want to pass on to our children. 

The symmetry theory has taken off in popular culture. On social media, filters promise to show people how symmetrical - and thus beautiful - they really are. 

Today, some scientists remain unconvinced by the symmetry theory. In real life, perfect symmetry can be boring, even unnervingMaking someone feel unsettled or disconcerted.. "If you create a perfect symmetrical face in the lab, those faces have very low beauty ratings," says UCLAUniversity of California, Los Angeles. psychologyThe scientific study of the mind and behaviour. professor Dahlia W Zaidel.²

In fact, throughout history, people have added imperfections in order to appear more real and attractive. In 18th Century Mexico, spots made from tortoiseshell were added to the forehead. Today, "fake freckles" are a TikTok trend. 

The desire for the real does not only exist in the beauty industry. Musicians will sometimes leave flaws in their songs. In Japan, the practice of kintsugi involves mending broken pots with gold. The object's flaws are not hidden, but highlighted.

Is it more attractive to be imperfect?

Yes: Human beings are by nature imperfect. It is these imperfections that make us organic and real. Somebody who was 100% perfect in all ways would simply be unnerving.

No: We are drawn to symmetry and perfection as a sign of good health. There are some traits that almost everyone finds attractive.

Or... The old saying goes: "Beauty is in the eye of the beholder." And it is true. What is considered "perfect" or "imperfect" has varied wildly throughout history. There is no one single example of a truly attractive person.