Imagine you’re hosting a networking event for a hundred professionals who don’t know each other initially. You start by serving a selection of appetizers and drinks, and soon, people begin to form small conversation groups. Now, suppose you mention to Emma, one of your guests, that the exclusive, hand-crafted hors d’oeuvres in the unmarked trays are far superior to the ones on the decorative platters. If Emma only shares this tip with her immediate connections, the premium snacks remain relatively safe, since she’s only met a few people so far.

As the event progresses, guests will continue to mingle, creating indirect connections between those who haven’t yet met. For instance, while Alex hasn’t met Emma, they have both met Jordan, so there’s an indirect connection from Alex to Emma via Jordan. Over time, these connections will become more extensive, and the news about the exclusive hors d’oeuvres will spread from Emma to Jordan, and from Jordan to Alex, reaching a larger portion of the crowd.

In theory, if everyone eventually meets everyone else, all guests will end up sampling the premium snacks. However, if each interaction takes about ten minutes, meeting all ninety-nine others would take approximately sixteen hours. Thus, you might reasonably expect that some of the exclusive hors d’oeuvres will still be available by the end of the event.

Yet, you’d be mistaken. This scenario aligns with a well-known concept in network science called the “small-world phenomenon.” According to this theory, you don’t need to wait for everyone to meet everyone else for the information to spread rapidly. Once each person has met at least one other person, an invisible network starts to form, enabling the information about the premium snacks to reach almost everyone quickly. Consequently, it won’t be long before everyone has had a chance to try the best hors d’oeuvres.