We have all experienced it: meeting an acquaintance in a distant or unexpected place or discovering an unsuspected personal bond with a stranger, we are always very surprised. “The world is small”, they say. For real ?
What is our perception of coincidences? Why does what we believe to be an incredible coincidence happen more often than we think? “There are a lot of biases and cognitive processes that come together to explain this”, replies Nicolas Gauvrit, professor-researcher in cognitive sciences at the University of Lille. He is also the author, with Jean-Paul Delahaye of As if by chance, coincidences and the law of series (Book-and-book editions). But if coincidences surprise us, it might not be at all …
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A coincidence that is less than you think
“When we try to intuitively estimate a probability, we don’t take certain parameters into account”, notes Nicolas Gauvrit. sociological, for example. We often have friends from the same social background who travel at the same time and in the same kind of places. “These encounters are therefore not entirely random. “
For example, the holiday period is more favorable for some French people to travel. This increases the likelihood of meeting someone who also travels quite in the summer. “In the research community, some travel to conferences around the world. It is therefore more likely that a fortuitous meeting between two researchers will take place during the period in which there are multiple conferences. Rather at the beginning of the school year or just before the summer. “
Similarly, on vacation, we often go to tourist places where many people pass. The likelihood of seeing someone there is higher than in an uncrowded place.
Also, the more people you know or the more you have a profession in contact with the public, the more likely you are to meet people you know, even distant acquaintances.
Sometimes hidden explanations
“Some coincidences can sometimes have an explanation that we do not know”, continues Nicolas Gauvrit. In the case of casual encounters abroad, it can be a big promotion on flights or a fad for a destination. This increases the likelihood of meeting in an unexpected place without knowing why.
More generally, “Some things seem really surprising, even a little miraculous, but there is a very simple explanation. We simply don’t have the key to the mystery. “ Nicolas Gauvrit cites the example of Violet Jessop, a nurse “who present themselves as survivors of the main accidents of the three sister ships”L’Olympicthe titanic the British.
“At first glance, his story seems crazy. Websites say her fate was not to drown., describes the teacher-researcher. But she was an employee of the White Star line, the company that owns those three boats. Which relativizes the fact that she was always on board. “Furthermore, the first accident did not result in a shipwreck and there were no casualties. The most surprising thing is that she survived titanic , because the other shipwreck was much less deadly. “
Sometimes an explanation even eliminates all possibility. During an expedition to the Brazilian Amazon, the director of the Science Museum of Barcelona, who enjoys a clear and high view of the forest, sees flocks of birds, very distant from each other, suddenly flying away at the same time. The phenomenon is extraordinary. Even more incredible: it reproduces two more times before his eyes. “You ask: do these birds communicate in a network? Is there a kind of telepathy? Is this an unlikely coincidence? “Says Nicolas Gauvrit.
The director, in fact, understood what happened next: it was the final of the 1998 FIFA World Cup, the birds flew among the noisy reactions of the Brazilians, in their camps in the forest listening to the game. He cries every time a goal has been scored by France against Brazil! So there was a hidden explanation.
The phenomenon of “small worlds”
One aspect has been studied from a mathematical point of view: meeting someone with whom you have a mutual friend. “For example, we are on a plane, we talk to the next passenger and we …