UK Edition
Could you track down your doppelganger?
I used to live on the south coast, and each day on my way into work I would stop off at the Brighton railway station kiosk for a caramel latte and an update on my "twin".
According to the affable barista behind the counter, a woman who looked "the image" of me would swing by 30 minutes before I arrived, and order an English Breakfast tea.
Further probing led him to admit she was actually blonde (I’m brunette) and fairly short (I’m nearly 5ft 10ins), and yet he clearly saw something in both of our faces that chimed enough to mention it.
I never met this woman, but the idea of a petite, less tardy, tea-clutching version of myself zipping up the Brighton-to-London-line was intriguing.
This week it emerged that Dublin City University student Niamh Geaney had started a campaign to find the "twins" of strangers on Facebook after discovering her own doppelganger through the social media site in only 16 days.
So are the streets of Britain lined with unwitting clones? Are there only a certain number of ways that features can line up on a face before the pattern starts repeating again?
Well, interestingly, science suggests that doppelgangers should not exist. Mathematically speaking, the number of variables in any face is so large that it would be virtually impossible to meet someone who looks identical to you.
In fact, nobody has even worked out how to measure the probability. Dr Garrett Hellenthal at the genetics institute of University College London doubts it could even be done.
The best guess of the science world is that we are like snowflakes. No two are the same, even if at first glance they all look small, white and spiky.
“The overall chance of finding someone who looks exactly like you is really very small,” said Sir Walter Bodmer, a professor of human genetics from the University of Oxford.
“The human face is extraordinarily unique. I mean think about it. The chance has to be quite low otherwise you would be bumping into people who looked like you all the time, and you don’t.”
When I posted my picture on Twitter and asked if anyone had come across my doppleganger the web, for once, was surprisingly quiet. One man suggested I look like Tracey Cox, the relationship expert (we have very similar hair) while another posted a picture of Joan Collins. I asked Facebook and got no response at all.
Mostly people do not come across doppelgangers of themselves. Someone else points out a likeness and, more often than not, the subject cannot see the similarity.
When retired priest Neil Richardson, 69, moved to Braintree, Essex he wasconstantly greeted by complete strangers who insisted on calling him John.
It turned out there was a retired headteacher, John Jemison, 74, living a few miles away who was the spitting image of Mr Richardson. Yet Mr Jemison struggled to see the likeness.
"I didn't instantly notice our resemblance,” he said. “My wife, however, did a double-take.”
Likewise when Montreal photographer Francois Brunelle revealed an exhibition of portraits of people who resembled each other, but weren’t biologically linked, the effect was startling. But, crucially, many of his subjects do not think they look similar at all.
"Often lookalikes depend on particular facial expressions, such as the big smile for the Obama lookalike you can find on the internet, or are strongly influenced by image parameters used to make the claim," says Professor Manfred Kayser, a forensic molecular biologist of the Erasmus MC University Medical Center Rotterdam.
"Often the true resemblance is much less than images taken under certain conditions show.
The other problem with delving into the science of doppelgangers. It’s entirely subjective. While one person sees a spooky resemblance, another person will not even notice a fleeting similarity.
Dr Dainele Podini, a forensic scientist and expert in facial recognition atGeorge Washington University in Washington believes that the way we view faces is ‘filtered by our own experiences.’
It's all to do with how individuals read faces, he claims. While some people start with the eyes, then move to the mouth and nose, others may being with the nose, then work to mouth and finally eyes. And that order change completely alters the perception of how you view a face.
We are also heavily influenced by context. If people are of a similar build, with matching hair-cuts and clothing it is easy to think they look alike. It is known in psychology as ‘verification bias.’ Once one thing makes sense we bend the facts so that everything else fits the mental picture we have built.
The fact that some people suffer from ‘face blindness’ or prosopagnosia is proof that there is a sliding scale of how well people can process identity.
What science does tell us is that genes are at the heart of what our face looks like. We know this because identical twins look the same and it’s easy to see that distinct physical traits are passed down through families.
Researchers at Bristol University have even identified five genes that code for specific facial features. For example, PAX3, a gene that regulates muscle-cell formation, controls the distance between the top of the nose and the right and left eyes.
People with mutations in PAX3 develop Waardenburg Syndrome, a rare genetic disorder characterized by wide-set eyes.
So it might be possible one day to work out the proportion of a population that has a set of particular genes and calculate the chance of running into someone else with that exact same genome. But the task would be vast.
“Like height, we expect that face shape is influenced by many hundreds/thousands of genes with small effects," said Dr Lavinia Paternoster, a genetic epidemiologist at the University of Bristol who helped carry out the gene study.
"We are nowhere near a position whereby we can predict a human face from someone's genetic code."
And even if we did share the exact gene sequence as a total stranger, our own personal experiences are altering how we look every day.
The last time I went to the doctor she immediately ticked the ‘non-smoker’ box on my health record. When I queried how she had known without asking, she said: “I can just tell.”
Lifestyle has a huge impact on how we look and can alter our appearance from day to day. Sun damage, injury and the ageing process itself all takes a huge toll.
Personally I sometimes feel I have a face made of Play-Doh which is bent and shaped by lack of sleep, too much alcohol or stress. We’ve all looked in the mirror and thought: “ I just don’t look like myself today.”
So the upshot is there probably isn’t an exact copy of you out in the world somewhere, the variables are just too great. And even if you do find someone who looks like you may not get on.
When Dr Nancy Segal of the Twin Studies Centre at California State University tested Brunelle’s subjects she found the portrait pairs had little in common.
But a real doppelganger may exist outside of our own universe. Some scientists now believe that we live in a multiverse where there are infinite possibilities and other ‘Earths’ where identical versions of ourselves are living out slight variations to our life. It means an identical copy of you has already read this story. And another is about to turn the page and begin.
In one multiverse I even bump into the blonde haired girl on the Brighton train. In fact, I probably already have. It’s just that I didn’t think she looked enough like me to take any notice.