According to popular belief, the bizarre play of nature has led to the fact that somewhere on the planet there are at least six (in some sources - seven) people walking like two peas in a pod like us. We checked how correct this statement is.

You can read about this entertaining theory on resources such as Adme, "Komsomolskaya Pravda", Woman Journal, "Political expert", "Rambler", "Mirtesen", "Soviet sport", and many others. Moreover, in a number of sources (for example, "Channel One", "The Fourth Estate", "Arguments of the week") a reference is made to the scientific community (“scientists believe”, etc.). To confirm the theory in practice, several years ago there was created project Twin Strangers, with which you can upload your own photo and try to find your twins around the world.

In 2015, forensic anthropologist Tegan Lucas from the Universities of New South Wales and Flinders (Australia) published in "International Journal of Forensic Medicine" results from their study of nearly 4,000 individuals from the publicly available Anthropometric Survey of the United States (ANSUR) database on the U.S. military. Its main purpose was to calculate the probability of apprehending an innocent person based on a photograph of a criminal.

As a base metric, Lucas took eight parameters of the face and eight parameters of the rest of the body. Among the first were, for example, the length of the ears or the distance between the centers of the pupils of the eyes. The results were disappointing for fans of the theory - according to the study, even though there are 7.4 billion people on the planet, the chance of having at least one pair of doubles in the world based on eight facial parameters is only 1 in 135. If we take into account the rest of the body, then this chance drops by many orders of magnitude - physical complexion turned out to be an even more unique factor.

However, many of us periodically read news about doubles meeting by chance. How do they correlate with the results of research by Australian scientists? The fact is that this work used very strict principles: if one person’s ear height was 58 mm, and another’s was 59 mm, then this was interpreted as a mismatch. In visual perception, our brain does not record such subtleties, so people with facial features that are quite different in size may seem like doubles to us. In addition, there is another factor.

“Many of those who seem like doubles to us are people we don’t know very well,” explains doctor Michael Sheehan, neuroscientist from Cornell University (USA). “You are much more likely to see a double of your friend than your mother. You know your mother very well. If someone is like you, you can appreciate it,” he adds, noting that our eyes will notice differences with close people much earlier.

In addition, according to the doctor, one cannot ignore the age factor - at three years old he himself was like two peas in a pod, but now the difference is obvious.

One more thing study, conducted in 2019 by scientists at the University of California, proved a fact that people already guessed, but did not have a strict justification: representatives of a foreign race more often seem to be doubles than representatives of their own.

Thus, it all comes down to the question of who can be considered a double. “We can talk about both visual similarity and similarity from the point of view of a computer image recognition program,” - believes David Aldous, statistician at the University of California at Berkeley (USA). To recognize a person (even one who has seriously changed his appearance since the last meeting), the brain engages the so-called fusiform gyrus for bringing all facial features together. It is believed that such a comparison works much more efficiently than comparisons based on individual traits. However, this also reduces the importance of some of the finer details. Most people concentrate on superficial characteristics, such as hair length, hairstyle, eyebrows. At the same time, according to research, people look first at the eyes, then at the mouth and nose. In addition, it should be noted that obviously there are both people with the most common facial features and those with extremely rare types. For people in these two categories, the number of doubles will vary dramatically.

Where did the theory of six doubles come from? There is a version that it is nothing more than beautiful legend - allegedly seven twins are born simultaneously in different parts of the earth. And although it appeared on the World Wide Web quite late (not earlier than the 2010s), the abundance Indian sources on the topic references ethnic Indians to "grandfather's stories", as well as direct mention legends of this region - all this may indicate that the legend takes its roots in Hindu mythology. Nevertheless, there is no scientific confirmation of the theory of six doubles, as well as a strict definition of the concept of “twin.”