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Like, How Many Friends Does Facebook Need?

Facebook's new, disruptive "like" feature may also be a pre-emptive solution to a looming problem: the anthropological boundaries of friend management

me-grayGuest post By Edo "Amin" Elan, Product Designer,  The Product Point-of-View blog

Facebook’s new, disruptive "like" feature may also be a pre-emptive solution to a looming problem: the anthropological boundaries of friend management

According to the official stats, the average Facebook member now has 130 friends. Is this too many Friends? Can you have too many friends? In fact, you can. 130 is dangerously close to 150, also known in anthropology and social media as the Dunbar number.

Robin Dunbar, a British anthropologist and evolutionary biologist, argued in 1998 that there is a cognitive limit to the number of relations that any one primate can maintain. Researching gossip, grooming and human history Dunbar[1]formulated that people can only keep gossip with 150 people at any given time. According to Dunbar, “this limit is a direct function of relative neocortex size, and that this in turn limits group size … the limit imposed by neocortical processing capacity is simply on the number of individuals with whom a stable inter-personal relationship can be maintained.”

The Dunbar number is discussed in some length in Malcolm Gladwell’s "Tipping Point". Dunbar himself blames the Internet for simplifying his theories into a "Dunbar number", but the title of a recent (2010) anthology of his writings seems to wink to the Facebook generation: "How Many Friends Does One Person Need?" (see Dunbar speak here, mentioning Facebook).

It’s no surprise that the Dunbar number made its way to social media circles, and keeping within Dunbar number boundaries may already be one of the industry’s established "best practices". I first learned of the Dunbar number while reading a 2006 article by sociologist Danah Boyd, who researched Friendster and MySpace, among others. As Boyd noted back then, Friendser was acknowledging the Dunbar limit when it capped Friends at 150. With its current average at 130, Facebook might appear to some to be like a car running with steam shooting from under its hood.

To be fair to Boyd, she regarded Friendster’s practice as a misconception. In her 2006 "Friends, Friendsters, and MySpace Top 8" she pointed out that Friendsters were actually connecting to friends from the past with whom they are not currently engaging, so those past links should not be counted towards the 150 contact cognitive limit. That said, Boyd was far from suggesting complacency in the face of exploding friend numbers:

"Because social network sites do not provide physical walls for context, the context that users create is through their choice of Friends. They choose people that they know and other Friends that will support their perception of what public they are addressing through their presentation of self, bulletins, comments, and blog posts. This completely inverts the norms in early public social sites where interests or activities defined a group (Usenet, mailing list, chatroom, etc.) and people chose to participate based on their interest in the topic."

Escaping the Dunbar Curse

The recent Facebook "like" feature, released about two weeks ago, seems to be designed for creating precisely such contexts for social proximity. With a sufficient inventory of "like"s, Facebook should have plenty of options for contexts to differentiate between different kinds of friends. This should help to bail it out if 150 indeed turns out to be Dunbar’s Curse.

In her 2006 paper, Boyd says "While it was once possible to gather all cat lovers into one Usenet group, the size of this group would be beyond unbearable today". I couldn’t help but look into the couple-of-weeks-old Facebook "like" page for Cats– and found it had 53,544 people who "liked" it. Beyond unbearable? Sure, it’s difficult to carry any meaningful conversation in that size of community. But when I view the "Cats" page, all I see above the fold are posts that, indeed, include "Cats" but originate from my friends. So the "context", to use Boyd’s term, might have been created here – but its effect isn’t so much to generate conversation within the huge Cats group, as much as to enable the Cats context between me and my friends.

This correlates to my own experience as an interaction designer. Recently, when designing the interaction for an enterprise social network, I noticed that the more the social element was brought into the forefront, the less the total number count of participants in a "topic" mattered. What mattered was seeing that some "friends" are already participating in the topic. In fact, just a handful of friends interested in (or "liking") a  topic was sufficient to create significant peer pressure.

Simultaneously with launching "like", Facebook also continued quietly revising the news feed filters – another location sensitive to a growing contact book. In a previous post, from about a month ago, I noticed some interface confusion there. It’s now cleared.

Also note that friends lists have a prominent place in the "Account" menu in the current Facebook  layout. Editing those lists will become a more familiar, everyday activity as we learn to target our posts to "lists" (or in the future, "likes") instead of to all friends. My present Facebook policy is to accept any Facebook friend request arriving to my account, then to organize my hundreds of Facebook contacts in lists that look a lot like "Like"s.

Dunbar, by the way, did not provide a single number but a series. The first number was 5 (Bret Taylor, FriendFeed co-founder and Facebook Head of Platform Product, referred to this number as "the magic number" in the beginning of his F8 presentation).  But the next significant "friendship circle" beyond 150, Dunbar says, allows for a more shallow connection with up to 500 contacts. Last weekend, my Facebook friend count crossed that magic number. I’ll keep you posted.


Edo "Amin" Elan ( is a Product Designer in San Francisco, CA. Elan has been following social media from its inception to its global spread. His most recent project was designing the interaction for an enterprise social platform. He also likes to draw comic strips.

Interested in being a Guest Blogger on The Product Guy? Contact me.


  1. that was a very well written and interesting post.
    Social networking and the information load we are constantly exposed to is very fascinating, and I like the angle you approached the subject.
    Great job!


  2. I’ve never seen the Dunbar number and am not a psychologist and think that’s basically sort of arbitrary, but that seems about right for me. Most of my friends have about 150 – 200 facebook friends, though many facebook friendships as you point out could just be old-time acquaintances they rarely talk to. Twitter limits you to 5000 peoples’ tweets you can read in one day I think. I guess maybe thats why also caps the number of phone numbers you can track at 300 I think. I think there could be some innovation though in how social networks can help users cope with all of this information. Facebook has their streaming news updates but it doesn’t scale well for larger numbers of people.


  3. Nicholas Christakis did some good science int the 15 years he spent studying networks. Don’t miss his 18 minutes on TED!


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