In a world with over seven billion individuals, is it truly possible to trace a social connection between any two random people within just six steps? An international team of mathematicians has put the “six degrees of separation” theory to the test, and the results are amazing.
Kevin Bacon, the unofficial representative of this quirky social concept, may be just as surprised as the rest of us: The experts have confirmed that it really does take an average of six handshakes to connect any two individuals.
This mathematical revelation traces its origins back to 1967 when Professor Stanley Milgram of Harvard University conducted an innovative experiment.
Professor Milgram mailed 300 identical letters with similar instructions across the United States. The letters were intended to traverse specific social circles until they reached their named recipient.
The experiment unveiled a startling reality: the paths which criss-crossed and connected people across American society were astonishingly short, with the letters reaching their destination within about six exchanges.
In the decades since the experiment, multiple “six degrees of separation” investigations focused on subjects ranging from actor networks to Facebook friendships have produced the same results, showing that the average number of handshakes to link any two individuals is six.
But the pressing question remained: Why six? The answer has finally been revealed in a paper published in the journal Physical Review X. The study authors include researchers from Israel, Spain, Italy, Russia, Slovenia, and Chile.
The team looked into the dynamic equilibrium of human behavior, where there is a clash between the desire for social prominence and the associated costs of forming and maintaining social connections.
The researchers explained that people naturally gravitate towards central roles in social networks, carefully selecting associations that propel them into these positions. Yet, every new relationship demands an investment of time and energy, setting a tangible price on every connection.
The study paints the picture of a network filled with nodes or “rational agents” who continuously gauge the costs and benefits of their connections.
Each agent in this networked world is in a perpetual state of evaluation, constantly weighing the pros and cons of forging new connections versus maintaining existing ones, all in a bid to amplify their influence.
A press release from Bar-Ilan University said the research shows that social networks are a “dynamic beehive of individuals constantly playing the cost-benefit game, severing connections on the one hand, and establishing new ones on the other.”
“It’s a constant buzz driven by the ambition for social centrality. At the end, when this tug-of-war reaches an equilibrium, all individuals have secured their position in the network, a position that best balances between their drive for prominence and their limited budget for new friendships.”
“When we did the math, we discovered an amazing result: this process always ends with social paths centered around the number six. This is quite surprising. We need to understand that each individual in the network acts independently, without any knowledge or intention about the network as a whole,” explained study lead author Professor Baruch Barzel.
“But still, this self-driven game shapes the structure of the entire network. It leads to the small world phenomenon, and to the recurring pattern of six degrees.”
In the midst of a global health crisis like the COVID pandemic, understanding this six-step ripple effect can be pivotal. Consider the terrifying potential of a virus that, in just six infection cycles, could engulf the entire planet.
Interestingly, this research itself is a product of six nations converging in academic unity – a testament to our interconnected global fabric.
The study was funded by the Israel Science Foundation, the Israel-China ISF-NSFC joint research program, and the Bar-Ilan University Data Science Institute.
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