You might be familiar with the concept of Six Degrees of Separation, which refers to how closely connected we are with other random human beings, but did you ever think to leverage this connectivity to find long-lost friends on Facebook? An online friend of mine mentioned the other day that he was trying to find an old crew of friends whose surnames he had never known, and to whom he had no current connections. Now that’s quite a challenge, but it’s not impossible. If you’re looking to find forgotten friends on Facebook, there are a few simple techniques discussed below, after a quick overview of Six Degrees of Separation.

What is Six Degrees of Separation?

The ideas behind Six Degrees of Separation (SDS) are alternately attributed to the writings and research of several people; however, a significant influence on the SDS concept is the ”small world experiment” of American social psychologist Stanley Milgram. Milgram was studying (offline) social networks of Americans and the “average path lengths” between people — that is, how connected they were to each other. In a nutshell, he sent packages to several people at random in Omaha, Nebraska and asked them to forward their package to a stock broker in Boston, Mass. via someone else. They were not supposed to send their received package directly to the stockbroker, but rather to whomever they knew who was mostly likely in their mind to be able to continue redirecting a package. (Milgram also conducted other similar experiments, but actually with the intent of studying anti-social behavior.)

SDS suggests that any two humans are connected to each other by at most six steps or relationships. So if Person A and G know each other, they are one degree away from each other. If they don’t know each other, there are at most five other people in between A and G, forming a chain of six steps, or relationships. (E.g., A-B, B-C, C-D, D-E, E-F, F-G, where each letter represents a person, and each hyphen represents a connection between the two people specified.) The idea is that SDS applies for everyone in the world, no matter how remotely located they are or how far apart from each other, no matter how rich or poor, famous or unknown.

Other variations of SDS include Six Degrees of Kevin Bacon — which says that he has either worked with everyone in Hollywood or knows someone who knows someone who… knows someone who has — and the Erdos Number, which is a bit more complex and refers to a “collaborative distance” or professional lineage between mathematician Paul Erdos and other colleagues in the field. There’s even something known as the Erdos–Bacon number, which is an intersection of the two concepts. There are in fact scientists, actors and a few others who have a connection to both Kevin Bacon and Paul Erdos.

5 Tips for Finding Old Friends

It’s this idea of intersection — discussed in the last section — between two seemingly disparate social circles that could be a strong factor in helping find someone you once knew. It might be difficult to find that person if you don’t their last name — as in my colleague’s situation — but it is still possible. What’s more, when it comes to the online world and social media, it might be easier than you think. An analysis of 30 billion electronic conversations (instant messenger, email) amongst 240 million people by Microsoft [FTP link; PDF, 28 pgs] suggests that the concept of Six Degrees of Separation can be proven with hard data, and that in some virtual social circles, we’re even within as little as 3 degrees of connectedness online. (As an online writer since 2005, I’ve noticed the latter to be increasingly true for me, especially amongst other writers.)

Now that’s a fair bit of theory, above, though you don’t have to do anything too complex to find someone, aside from trying to make the right friend connections. The assumption here is that the person you’re seeking is actually on Facebook. The diagram below might help you to visualize how to expand your Facebook friends network while seeking that lost friend. At each stage, you are expanding your network by adding “friends” at the next degree of connectedness. So you start by “friend requesting” all the people that you know directly, especially anyone whom you think might know the lost friend, then add friends of a friend (FOAFs), then friends of FOAFs, etc. The tips are below the diagram.

Click image to see larger version

1. Common friends. Who else do you know who knows the person you’re trying to find? Are you friends with them on Facebook? If there’s more than one person in common in that social circle, make a list and seek them out on Facebook. Keep expanding the list by taking note of other people less connected than the core group (which you can use in tips #2 and 3, below).
2. Ask FOAFs. A FOAF is a “friend of a friend,” and are thus “2 degrees” away from you. I’ve reconnected with other people in the real world through FOAFs, and there’s no reason why this won’t work on Facebook. Make a list of the FOAFs of the person sought, if possible. If you don’t know any, try finding the friend of a FOAF (3 degrees). This list could be all you need, especially with Facebook continually adding new search features. For example, one new social search feature will display the names of people who are friends of friends that match your search string. So if you start typing, say, “Jo,” the dropdown list that appears will return a list of Facebook users with “jo” anywhere in their name, and who are either already your Facebook friend or a friend of a friend. Leverage this network in your search.
3. Intersection of social circles. Remember that kid in high school who always seemed to make friends amongst all the social cliques? Find people like that as the next step in your connection path. Reconnect with them on Facebook, get reacquainted, then ask them if they recall the person you’re trying to find. He or she may not know, but like the people in Stanley Milgram’s experiment, they might know someone who knows someone…
4. Interests. Facebook has many thousands of Group and Fan Pages. If you’ve written up a “personal interests” profile of the person you’re seeking, this may help you them via Page search. The new social search feature mentioned in tip #2 above gives an added bonus in the search results: the dropdown list also shows Fan and Group Pages that match your search text, whether you are a member, or a friend or a FOAF is a member. So if you can recall your lost friend’s favorite hobbies, that’s another possible lead for finding them. If you both went to the same learning institution, worked for the same employer, or had some other location-based commonality, scan relevant Groups and Fan Pages that way. I found a few old high school acquaintances by checking all the different Facebook Groups for my school (there were several, despite being a relatively small school). My find included people whose names I’d completely forgotten but that I could still recognize from their mostly unchanged faces.
5. Check other networks first. Sometimes people have nicknames that you know them by, but their Facebook profiles might have their real names. Or, you might know their real name but Facebook shows several other people with the same name, none of whom you recognize on first glance. I’ve sometimes found people on Facebook by first checking other social networks such as Twitter, or on search engines, or in blogs related to an interest they had. Sometimes those blogs, or image sharing sites like Flickr, have old photos that you might recognize. If you know that they definitely have some sort of online presence, you might find them elsewhere, then notice a clue that leads to their Facebook profile. (There might even be a big “Connect with me on Facebook” button.)

To wit, my now sister-in-law set up a special interest Group on Facebook in 2008, then set about trying to locate people in North America who shared the same cultural background as she (and I) did. She had a list of names to go on, but often the kids in our community only knew each other by nicknames. So she wasn’t always sure if she was contacting the right person. She applied some of the above techniques, starting with people she did know, and built up the Group to nearly 120 members, and reconnected to a few dozen more who are now her Facebook friends but not Group members. As a result, she’s also mostly responsible for many of the reconnections via Facebook in our shared cultural community. While many of us still don’t see each other more than once a year (around July 4th), and some of us haven’t seen each other for over 30 years, we are many of us reconnected at least on Facebook.

As an end result of all of my sister-in-law’s Facebook friending efforts, I also reconnected with her sister, after 12 years, and we ended up getting married. (Thanks, Facebook. And yes, geek that I am, my first proposal WAS over Facebook chat. She said, “No,” until I persisted. Let’s just say that some things you just cannot do justice to through social media, and have to do in real life.)