Peculiar Pittsburgh

6 degrees of separation in Pittsburgh: Why it feels like you know everyone here

We want to hear about your craziest connections, too.

MJ Slaby

Ever strike up a conversation and realize the Pittsburgher you just met went to high school with your cousin? Or their significant other is a friend of your boss?

Pittsburgh’s often called a big city with a small town vibe (or a big, small city) and part of living in a small town is feeling like you know, well, everyone. (I’ve been in Pittsburgh less than a year, and that’s already true.) So The Incline tried to put a finger on why everyone seems to know everyone in Pittsburgh — one of the many things that makes Pittsburgh peculiar.

The Expert

Chris Warren is an associate professor of English at Carnegie Mellon University and project director of Six Degrees of Francis Bacon, which aims to track the relationships of Francis Bacon, William Shakespeare, Isaac Newton and others using documents from the years 1500 and 1700.

“Six Degrees of Francis Bacon tries to capture 63 different ways people in the sixteenth and seventeenth centuries were related to one another,” Warren told The Incline via email.

The social network project manages its data on the supercomputer Bridges at the Pittsburgh Supercomputing Center, a joint center between CMU and the University of Pittsburgh. (Yes, that’s the same supercomputer behind Libratus, the artificial intelligence that plays — and wins — at Heads-Up No-Limit Texas Hold’em.) Using the supercomputer allows the project to have a large data set of documents and makes it easier for users to access, said Nick Nystrom, senior director of research at the center.

And there’s a lot of similarities between social networks then and now, Warren wrote. He said there are family ties like parents and siblings, interpersonal ties, like rivals and friends, and financial ties, like debtor and creditor, he said. But Warren added there are ties that existed then that are less important or more rare now like “master/apprentice, for example.”

“People were connected in very similar ways that they are now, and, at the same time, it was a different world,” Warren said.

So what does he think of the social networks in 2017 Pittsburgh? He gave us two possible reasons behind that everyone-knows-everyone feeling.

1. ‘Birds of a feather’

“There’s a well-known principle in network science called homophily, aka ‘birds of a feather flock together,'” Warren said. So people who have things in common are the most likely to know each other.

But in Pittsburgh, there would be a split between the older population and the younger, new-to-the-city population working in tech, medicine and education, he said. The people in each of those groups are likely to know “a good chunk” of other people who are also in that group, Warren said.

“Within these groups, something called ‘triadic closure’ works very quickly,” he said. “If I know Ben and you know Ben, chances are, you and I are going to meet at some point through Ben — closing the triangle.”

2. A single connection

There is a way that people who have less in common can still be connected, furthering that everyone-knows-everyone feeling, Warren said.

“Even when there are tightly defined, relatively distant communities, there are often people — sometimes, a very few people — who join those communities together,” he said.

For example, think of a Pittsburgher you know who grew up here, left for college and then came back and is active in the community.

That person has what network scientists call “high ‘betweenness,'” Warren said.

“It isn’t necessarily that people with high betweenness know a lot of people — though they sometimes do — it’s who they know, it’s that they help stitch different communities together,” he said. “They’re the all-important bridges and connectors who make Pittsburgh feel like a small town.”

They cross over demographic boundaries — aka the longtime residents and the transient new Pittsburghers — and that is important for making the city feel like everyone knows one another, Warren said.

The Numbers

In March, the U.S. Census Bureau released estimates that labeled the Pittsburgh metropolitan statistical areas (seven counties) as the region with the second worse decline of all metro areas, reported the Post-Gazette. The area lost nearly 9,000 people between July 2015 and July 2016.

Christopher Briem, a University of Pittsburgh regional economist, explained two reasons for that to KDKA. First, there are more deaths than births each year, and second, is migration loss, Briem said. Yes, many people from Pittsburgh have been in Pittsburgh for a long time.

3. Location, location, location

“Many think Pittsburgh is, or has been, unusual in the rate at which people, or in particular young people, leave the region,” but it’s also “ranked very low in the rate at which people move into the region,” Briem told The Incline in an email. He gave this example of the longstanding older population:

Of the 50 largest metropolitan statistical areas by number of housing units, Pittsburgh tops the list for the highest percent of owner-occupied housing units where the owner has lived there since 1979 or earlier.  (The data comes from the U.S. Census Bureau’s American Community Survey five-year estimates from 2011 to 2015.)

Percentage of owner-occupied homes where the owner has lived there 36 years or more

Your Stories

We want to hear about your craziest connections and unbelievably close degrees of separation in Pittsburgh. Write to us (tips@theincline.com, subject: Connections), or tweet to us @theinclinepgh, and we might just feature your story in a future article.

Chances are you’ll know the other people in the story, too.