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Dunbar's Number and the Future of Communications

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groomingOver the past year, I’ve wished more of my friends “Happy Birthday” than I had my entire life prior to that. This summer, I’ve checked in daily with numerous friends while they were on their vacations. And last week I accidentally ignited a debate among 16 of my friends over the article “Why Exercise Won’t Make You Thin.”

Of course, none of this happened in person, but via Facebook and Twitter. The asymmetrical and casual nature of social networks is allowing humans to engage in what Robin Dunbar has termed “social grooming” with increasingly larger groups — without investing increasingly larger amounts of time. The value of these communications improvements is so great that going forward, I expect significant increases in human and capital investments in this space.

Dunbar’s Number and Social Grooming

Dunbar argues that the number of people with whom humans can maintain a relationship is a function of neocortical size. He puts that number at ~150 — what’s known as Dunbar’s Number.  He further argues that language may have emerged as a device to more efficiently maintain those relationships, that while other animals maintain relationships through activities like physical grooming, which limits social productivity, language allows humans to engage in the far more efficient act of “social grooming.” For example, a brief watercooler discussion or a “Happy birthday” wish on Facebook replaces the need to spend a great deal of time physically grooming each other as a way to stay connected. Consequently we can achieve greater coordination and collaboration with comparatively less effort.

Over the past decade I have noticed a dramatic increase in the number of people with whom I stay connected, yet the time I spend on these activities hasn’t increased one bit. It seems like electronic communications and social networks are increasing Dunbar’s Number such that it’s now somewhat divorced from neocortical size.

What’s Next?

This trend will continue and probably even accelerate as a result of global broadband penetration, the proliferation of smartphones and high-bandwidth wireless data, the cheap availability of video and knowledge gains from these first-generation services. In an effort to peek into the future, I retained all communications over the course of a week in an attempt to identify a few opportunities for improvement.

1. Smart Email

Even after removing what was clearly spam, only 25 percent of the email messages I received over the 7-day period were from a real person directed solely to me. Why do I need an email every time Netflix ships me a DVD and every time I return one (asking for a rating)?  There must be a better way for Netflix (and everyone else) to notify and collect feedback. Ditto for billing — phone service, cable, online services and so on.  Why can’t my email client figure out what’s an invite and queue those up in once place?  Can’t the online mail guys figure out what’s public vs. private and somehow how help me auto-filter my mail (e.g. when Apple blasts a message to 10 million people, that’s not a one-one-one communication — file it in a “MyBrands” folder or the like). Shouldn’t it be easier for a consumer to quickly (visually) identify a personal communication from a group conversation from a notification?  And why is voice mail a separate category from email?

2. Next-Generation Collaboration

An even larger category of email messages can be categorized as collaboration. Whether in the form of a blast to a large group of people (and the many subsequent replies) or a discussion amongst just five people, email today is not currently well suited for conversations with multiple people. Nor is instant messaging, SMS, video conferencing, the telephone or voice mail. Why aren’t all conversations threaded? Why can’t I edit something after it’s been “sent” in a server-based computing world? Why is sharing documents and managing collective editing so difficult? How can we merge audio and video bits together the way do with text? When will we be able to approximate the ubiquitous hallway conversation online? Perhaps the recently announced Google Wave will be the answer, or the foundation of one? Sococo may also offer some insight into what the future holds.

3. Location-Based Groups

Whenever I’m stuck in traffic these days, I do a quick search on Twitter to figure out why.  It would be nice to be automatically “subscribed” to my location to find out what’s going on. Speaking of driving, I’d love to be able to broadcast a message to everyone in my area when a car is blocking my garage door. Such dynamic and temporal location-based groups will finally be enabled by pervasive GPS and other location-based techniques. Facebook used domains to do “network” authentication (e.g.; might someone use location to do location-based authentication?

With every improvement it feels like the pace of innovation will slow, but then something new turns up. This will surely be the case in the communications space in the coming years, whether it’s one of these ideas or, more likely, something crazy that nobody has thought of to date.  And Dunbar’s number will continue to grow, only great new communications products will be the factor rather than human evolution.

Mike Speiser is a Managing Director at Sutter Hill Ventures. His thoughts on technology, economics and entrepreneurship will appear at this time every week.

26 Responses to “Dunbar's Number and the Future of Communications”

  1. Mike –

    An interesting article, and that hits close to the core of my current project. A few points:

    First, I think the number of relationships we categorize as “close” in a familial or near-familial context (e.g. childhood friends) has to be bounded by some constant. It will vary from person to person, but when you get right down to it you’ve only got 24 hours in your day, and your attention span is a limited commodity. That said, we are not close to hitting that limit, and aforementioned technologies are helping us push our capabilities. We may not necessarily make more new close friends, but we be able to maintain strong friendships with ones you’ve established through new media of interaction ( and I stress that particular use of the word media).

    Secondly, I think that any discussion of the value of expanding your network should also bring to attention the inherent value of weak connections. These are people who are not close to you, but on the borders of your social circle. These are the people you meet at networking events, at work, or even at your country club if that’s your thing. They have real benefit because they can set up introductions to new social circles.

    @banu, I think that discount factor has always been there, regardless of what new medium you are talking about. I still think handwritten letters have more significance than email, but I nonetheless find emails from my contacts to still be important. And some day, that distinction will cease to exist. After all I don’t receive telegraphs. And some day, a tweet will have as much meaning as an email, inasmuch as it informs your view of someone you know.

    None of this is new, but I thought I would just mention it.



  2. I am not familiar with Dunbar’s number, but it probably has something to do with the natural size of a village. 150 is the number of people a person can know well and count on as a “contact”. This is someone a person can know, like, and trust.

    Social media allows a person to know lots of folks not so well, and perhaps much of social media communications does not subtract from this number.

  3. another great article .

    I agree cost of maintaining a connection is going down but my question is does that translate into more connections of value ? I dont think so .My logic is since connetion cost is going to down to every body the person at the reciveing end of connection will invariably discount that factor in determining weather connection is significant or not . which leads to status quo .

    so Birthday wish left on facebook is not the same as birthday wish delivered by calling that person .the person who is reciving birthday wish will treat those wishes seprately.
    my point is number of birtday wish might increase but the value of conncetion does not .

  4. Ciao Mike.

    Seems the Dunbar’s number persist in social network era. You can read this article from Economist :

    “The cost the transaction costs of keeping track of someone is not primarily the effort of actually speaking with them. Rather, it is the cost of remembering their name, what they do, what they think, and how they have related to you in the past” says Jake Young, a neuroscientist.

  5. I agree there’s still tons of room for improvement in communication. It annoys me that so many “new and improved” search engines just bring up more stuff that’s recent, instead of narrowing down for me what’s relevant (and possibly old – like by a week!)

    I also have a comment on Dunbar’s number – I know many people critique this argument by saying that FB just allows us to spend more time with people we don’t know well. I find that as my life changes (high school, college, first job, b-school, hobbies, another job, sports, marriage, kids) I have close friends that I know well but don’t have time to stay in touch with. Facebook has allowed me to reconnect and keep up with them (those that are on FB, that is). It’s been a gem – not superficial at all. It does mean I don’t “friend” everyone I meet, though. That’s MY way of filtering the search engine!

  6. Nice article with some good thought starters. Question: Do we think that Dunbar’s number will ever change from 150 as social networking technology becomes smarter and is able to apply intelligent filtering and routing to continuously improve the signal to noise ratio?

    Imagine if Dunbar’s number shifted exponentially over time in a Moore’s Law kind of fashion?