Duncan Watts on Friendship: I

I met with Duncan Watts the other day at Yahoo Research, nine blocks south of our BW offices in midtown. He’s a Columbia professor, a Yahoo researcher, and one of the leading experts on social networks. He wrote the book Six Degrees.

As I was going through my notes with him, I was thinking: There’s a blog post, there’s another… So I think I’ll do a short series of posts on my interview with him. (I’d blog the notes, but they’re hen scratched in a notebook)

First, a question: How many friends do you have? Regardless of how you interpret the word “friend,” Watts says, you’ll likely answer with a lowball number. “People are terrible at estimating,” he says. Since (until the age of Facebook) we didn’t keep track of casual friends, sociologists came up with ways to estimate our circles of friends and acquaintances.

* How many people named Stephanie do you know? * How many airline pilots do you know? * How many plumbers do you know?

They’d ask about 50 questions like this. And since they had the data on how many Stephanies, airline pilots, plumbers, etc. there were in society, they could calculate how many people their subjects knew by name. “In the early 90s,” he says, “it came out to an average of about 300. The upper limit was a couple of thousand.” These are about the same numbers people have on Facebook. The point: Facebook doesn’t add to the number of our friendships; it just keeps all the friends and acquaintances around.

By the way, Watts, who has been on leave from Columbia to work at Yahoo, is giving up his tenured position this spring. You might think that employment at Yahoo, which was targeted for takeover by Microsoft last year, is less secure than the Ivy League. But Watts is a leader in an extremely hot area of research. Plus, he’s got a book contract.

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