Six Degrees of Separation

You’re finally on a solo vacation somewhere thousands of miles away from home. To celebrate your much-anticipated getaway, you treat yourself to a meal out. As a solo traveller, you begin talking to your server, who’s born and raised locally, yet you soon find yourself with some surprising things in common. It turns out your server has a connection with a childhood friend of yours who lives on the street you grew up on. Amazed, you think to yourself, “It really is a small world after all.” 

The six degrees of separation theory proposes that everyone in the world—yes, everyone—is connected by a chain of no more than six social ties.1 This idea challenges our intuition about distance and isolation, suggesting that even across cultures, borders, and backgrounds, we're all part of a surprisingly tight-knit global network. This is not only evident when you’re in a distant land on vacation, but it can also be the case between any two individuals across the globe. 

Sounds strange, right? This would imply that you are six degrees or less away from everyone in the world, ranging from former President Barack Obama to a Hmong villager in Vietnam. This isn’t just a coincidental confirmation bias of the world being small when your server happens to know your neighbor—there is a science behind it, with a history of small worlds, social science research, and large-scale studies that we’ll dive into soon. Let’s take a closer look at how the six degrees of separation work when tracing back your connection to this apparent stranger:

While this example of the five intermediaries between you and your server abroad may feel farfetched, we can all recollect a time when we ended up being strangely connected through mutuals, whether in-person or virtually. Today, the six degrees may be decreasing to only three or four with the virtual ties that bring us closer to others online through our professions, communities, and common interests.2 Another common way to visualize degrees of separation is via a social graph, such as: 

Social Networks and the Science of Connection

Modern research in network science has validated aspects of the theory, revealing how hubs, weak ties, and clustering play a role in connecting distant individuals.³ These principles underpin platforms like LinkedIn and Facebook, where mutual connections often span continents. While the original experiment testing the theory of six degrees goes back to the 1960s, recent research by Microsoft shows how billions of digital conversations across tens of millions of people link us by the exact amount of 6.6 degrees of separation.⁴ Let’s zoom in on how some of these principles in the modern technological world relate to how separated we are from each other:³

Whether it’s the spread of ideas, social movements, or misinformation, the idea of six degrees of separation has profound implications for how behavior travels through networks. Understanding these dynamics helps marketers, policymakers, and behavioral scientists anticipate how messages ripple across populations. It's easier now than ever before to trace the six degrees (or fewer!), when decades ago it may have taken several long conversations and arduous phone calls to attempt to make the same connection. Looking into how this is possible and discovering what information influences collective behaviors through increasingly connected networks sheds light on the invisible forces impacting our daily experiences. Social media and other digital spaces have shown the potential for degrees of separation to become even fewer, and we may soon see how advancements in AI, machine learning, or other contemporary technologies manage to bring us even closer together.