Science has always told you that you have a twin lurking somewhere in the world. But the truth behind it is less than you can imagine. Forget about the movies. They may show twins and duplicates, but these are more real in Hollywood than in real life.
There aren't as many doppelgangers as believed. In a study by Teghan Lucas, a researcher at the University of Adelaide in Australia, almost 4,000 who were located in the ANSUR database show that surveying military personnel could not really help people to find an exact doppelganger, with the odds working out to less than a trillion.
The world is tottering under 7.4 billion people, yet it gives just a one in 135 chance of there being even one pair of doppelgangers.
By comparing eight traits among the photographs, experts were able to assess the distances between the eyes and ears and decided on the results.
The Forensic Science International in 2015 reduced people to a "singularity," which explained that "only one individual in a specific population has a particular set of characteristics." Seven out of eight traits needed to be matched in order to reach that singularity.
"Before you could always be questioned in a court of law, saying 'well what if someone else just looks like him?' Now we can say it's extremely unlikely," Teghan said.
The possibility of sharing your genes with another person who looks exactly like you is low. But while Teghan's study examines "exact measurements," you only require "approximations" to recognise a face.
The brain uses one part called the fusiform gyrus that leads to the creation of a "bigger, broader picture" to arrive at an analysis of someone's face. It helps people to recognise familiar faces better.
Personal evaluations are different too, says Scienceline. If you study another person's eyes initially, rather than their hair, your brain will lay the emphasis on unique regions in the brain, which would make people's observations of each other quite "subjective".
"Most people concentrate on superficial characteristics such as hairline, hair style, eyebrows," says Nick Fieller, a statistician involved in The Computer-Aided Facial Recognition Project. However, research shows that we tend to examine the eyes, mouth, and nose, in that order, rather than any other features.
Hence, the possibility of duplicating your looks would be quite low.
"There is only so much genetic diversity to go around," Michael Sheehan, an assistant professor of neurobiology and behavior at Cornell University, told LiveScience. "If you shuffle that deck of cards so many times, at some point, you get the same hand dealt to you twice."
So if you're unlucky---or perhaps lucky---you may not have a twin trying to hug or knife you.
