The Marginalian
The Marginalian

Beyond the Dunbar Number: Picking Dunbar’s Brain

In 1992, anthropologist and evolutionary biologist Robin Dunbar proposed Dunbar’s Number — a theoretical cognitive limit on the number of people with whom we can maintain viable social relationships. He pinned that number at 148, or roughly 150. But how does this translate to today’s social media environment of 400-friend Facebook profiles — does it help us beat Dunbar’s number?

We asked the iconic British social anthropologist himself, who addresses the issue further in his new book, How Many Friends Does One Person Need? — we highly recommend it.

The amount of time we invest in a relationship is proportionate to its quality. Face-to-face relationships are simply unmatched by online ones. “A touch is worth a 1000 words any day,” says Dunbar. But what online relationships are good for is to stall the decay of a relationship.

If you don’t go to the pub sooner or later, it will die.” ~ Dunbar

But what of all those huge numbers of online friends, aren’t they worth something? Perhaps kinship. The difference between friendship and kinship is that kin won’t fall apart with time and distance, “you can abuse your kin and they’ll still come,” says Dunbar.

Dunbar argues that having lots of kin means having fewer friends. Imagine your time-budget devoted to relationships as a pie. When you start handing out slices of your time to your friends, if too many people crowd around, no one gets a proper slice. Kinship is more about similar social groups, interests, geographical locations, whereas a friend, defined by Dunbar, is a person you can have a personal reciprocated relationship where you are willing to do each other favors.

Have humans always been able to handle 150 personal relationships? Dunbar explains that our brains have grown over time to handle our more complex relationships. The most taxing on our brain is the romantic kind (monogamous). Pair-bonded species have unusually big brains to do all the work.

Romance is very hard work and extremely costing to maintain.” ~ Dunbar

Will our brains continue to evolve to accommodate this hyper-connectivity? The brain accounts for only 2 percent of your total body weight, but uses 20 percent of your daily energy.

Hold on, someone just tweeted me…

Filip Matous hosts a pop-philosophy video show at He currently lives in London and is always seeking to find the next interesting person to interview.

Published March 2, 2010




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