Are Doppelgängers Real? Revealing The Strange Science of Seeing Double

Your identity is ingrained in your face, infused in your features. Unless you’re a twin, your perception of yourself is probably so tied to your appearance that it’s tough to imagine a world where your looks aren’t altogether your own.

But ‘tough to imagine’ isn’t the same as ‘impossible.’ Despite what you assume about yourself and your description, there’s a small possibility that there’s someone out there who looks a lot like you: someone we would deem your ‘doppelgänger’ or ‘twin stranger.’

For hundreds of years, people have wondered what it means to have a doppelgänger, a distinct duplicate of them. For most of that time, the answer has been left to folklore and literature. But some scientists are starting to wonder themselves, and are arriving at their own scientifically supported answers. With that in mind, what is a doppelgänger, and how has the idea transformed over time? What does a meeting with a double mean, and what are our odds of finding one of our own?

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The idea of the doppelgänger is deeply ingrained, having inspired human imaginations throughout history. In folklore and literature, it is a double, or lookalike, of a living person. In some stories, they’re portrayed as paranormal phenomena: They’re spirits, specters, and apparitions of individuals that appear to those individuals and their family and friends. In other stories, they’re normal, natural individuals, only notable in their similarity to others, and in their use of that similarity — whether moral or immoral.

In the past, seeing someone’s double, including one’s own, was perceived as a deeply profound, deeply dangerous occurrence, though it isn’t typically treated with the same severity and superstition today. While some imbue such meetings with special meaning, most modern doppelgänger sightings are seen as something scientific: a consequence of psychology or coincidence of genetics. Still, the traditional meaning and mythology of the term warrant discussion, despite their diminishing influence on the trope today.

Tracing its origins to Germany, the term itself is a German loanword, literally translating to ‘double goer.’ It initially appeared in the 1790s in the book Siebenkäs by Jean Paul, who defined ‘doppelgänger,’ then ‘doppeltgänger,’ in the book’s footnotes as a term for those who “see themselves.” Initially used for lookalikes in German folklore and literature, the term now describes duplicates and doubles in an array of worldwide traditions.

In fact, though the term only emerged in the 1700s, the idea of the doppelgänger was well established, even then, in the tales of Germany, and of Europe as a whole. German legends had spirits and specters of the living, while English and Irish folklore featured fetches, lookalike apparitions whose appearance was a sure sign of future tragedy. In Scandinavia, the vardøger had a habit of appearing in places prior to a person’s actual arrival, and the activities of the Finnish etiäinen provided a timely teaser of a person’s future actions.

In all of these traditions, the appearance of the doppelgänger acted as an omen, foretelling future tragedies or performing a person’s actions in advance. Still, some spiritual doubles were worse warnings than others, with the German and Celtic traditions supposing that the appearance of a lookalike was a sign of impending doom, death, or sickness. See a fetch in the shadows, one such superstition said, and your life will last only as long as flames in your fireplace.

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Though there is no scientific support for these traditions, there is a budding body of research into the science of seeing, or being, double, as well as the science of similarity. Breaking doppelgänger sightings down, this research reveals an abundance of reasons why a person may think they’ve met their lookalike, ranging from the psychological to the genetic.

When it comes to psychology, doppelgängers aren’t always what they appear. Delusional misidentification syndromes, including delusions of doubles and subjective doubles, are closely associated with doppelgängers and can cause people to think they’ve seen duplicates of themselves or others. These syndromes are typically identified during the diagnosis of other disorders, such as schizophrenia, and are associated with hallucinations and heautoscopy, the sensation of seeing one’s own body as if from a distance.

Studies suggest that these syndromes can carry different concepts of doppelgängers. In some instances, the suspected double is thought to share a person’s appearance. In other instances, the suspected double is thought to share a person’s appearance, as well as their inner identity. In these cases, the duplicate’s similarity is so severe that they are not a lookalike of a particular person — they are a particular person.

Of course, doppelgänger sightings aren’t always a consequence of psychology. Aside from these relatively rare psychological phenomena is a simpler account of the twin stranger trope, one ingrained in our genes. Thanks to genetic coincidence, it’s completely possible for a pair of unrelated people to share similar traits, with some strangers seeming so similar that they’ve warranted scientific study.

Recently, for instance, a team of researchers recruited 32 pairs of lookalikes to study why they looked so similar. They found that the 16 pairs with more similar features shared more genes than the 16 pairs with fewer similar features, confirming the theory that lookalikes look alike thanks to their genetics. “These individuals share similar genotypes,” the researchers concluded of the lookalikes in a Cell Reports article in 2022, suggesting that their similarities are at least partially a consequence of chance.

Psychological doppelgängers — those brought by delusions of doubles — are sometimes signs of serious psychological conditions, and should therefore be taken seriously. Whether associated with schizophrenia, dementia, or some other disorder, these delusions may drive out-of-the-ordinary or dangerous behavior and thus demand a doctor’s advice and attention. But genetic doppelgängers aren’t at all dangerous — or any more dangerous than the average person. The only threat they pose is to a person’s sense of uniqueness.

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So, it’s possible, sure, but is it probable that you’ll find a stranger out there in the world with the same face as you? For years, scientists have sought out answers and had little luck.

In 2015, for instance, researchers assessed the faces of almost 4,000 people, determining the distances between facial features and the probabilities that those distances were widely shared. They found that the probability of sharing four with another person was less than one in a million, while the probability of sharing eight was less than one in a trillion. But distances were only shared if they were precisely the same, discounting the possibility of doppelgänger pairs with slight differences.

Research reveals that the average person is able to recognize and recall around 5,000 faces — not only by registering their specific measurements and subtle minutia, but also by seeing their sum, the whole of their features all at once. In other words, while systematic studies demand doppelgängers pairs be precisely the same, our own perception may not, meaning that scientists aren’t sure whether we all have a double (or multiple doubles) to call our own.

Depending on your perspective, that uncertainty could be a comfort or a concern. But if you’re one of the brave individuals on a mission to meet your double, there’s no need to despair: There are plenty of options available for you to find your lookalike — if there is, indeed, a lookalike to find.

A whole slew of websites and apps, including Twin Strangers and I Look Like You, advertise their ability to discover doppelgänger pairs within their user pools. All you need to do is upload a picture, and a twin stranger appears. A more organic method — plopping down on a park bench and waiting for a doppelgänger to wander past — is always another option, though it may take more patience. If a double does pass by, take it as a sign: not of impending doom, but of simple, serendipitous chance.

Read More: Don’t Give Up on Finding Your Doppelgänger

Our writers at Discovermagazine.com use peer-reviewed studies and high quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• Britannica. Doppelgänger.

• Google Books. The Doppelgänger: Double Visions in German Literature.

• Google Books. Craving Supernatural Creatures: German Fairy-Tale Figures in American Pop Culture.

• Google Books. Ritual, Belief and the Dead in Early Modern Britain and Ireland.

• Google Books. Scandinavian Folk Belief and Legend.

• Google Books. Finnish Folklore.

• Oxford Reference: A Dictionary of Celtic Mythology. Fetch.

• Cambridge University Press: Psychopathology of Rare and Unusual Syndromes. Delusional Misidentification Syndromes.

• Handbook of Clinical Neurology. Illusory Reduplications of the Human Body and Self.

• Cell Reports. Look-Alike Humans Identified by Facial Recognition Algorithms Show Genetic Similarities

• Forensic Science International. Are Human Faces Unique? A Metric Approach to Finding Single Individuals Without Duplicates in Large Samples.

• Proceedings of the Royal Society B. How Many Faces Do People Know?

• Scientific Reports. Holistic and Featural Processing’s Link to Face Recognition Varies by Individual and Task