Dunbar’s Number

No matter how many “friends” you have on Facebook, it is impossible to increase the size of your social circle, reports Drake Bennett in Bloomberg Businessweek (1/14/13). This limiting factor is known as Dunbar’s Number, which holds that most people “cannot maintain many more than 150 meaningful relationships.” Its originator, Robin Dunbar, arrived at the number after two decades of research found “groupings of 150″ in a wide range of circumstances — from clans of hunter-gatherers to military units to religious sects. In business, WL Gore builds a new office when “a branch exceeds 150 employees.”

The number, says Robin, correlates to brain size. He actually “plotted the size of the neocortex” of various primates “against the size of the group it lived in: The bigger the neocortex, the larger the group a primate could handle.” When he plugged the neocortex of the human brain into his formula, the resulting number was 147.8. Dave Morin believes that this number is inalterable. Facebook, for example, enables up to 5,000 potential connections but the average user has just 190 connections. “What Dunbar’s research represents is that no matter how the march of technology goes on, fundamentally we’re all human, and being human has limits,” says Dave.

Based on this, Dave founded Path, a social networking site that limits its users to no more than 150 connections. “Fundamentally, once you go beyond this number of people you can keep in your head, you begin to filter yourself,” says Dave. Critics argue that Dunbar’s Number is inaccurate because people have different kinds of friends that matter for different reasons. Robin counters that he’s only talking about friends with whom there is a basic emotional bond. Asana, a task-management software company, meanwhile offers technology designed to help work teams keep track of and understand each other without necessarily conversing, with a goal of increasing Dunbar’s Number in the process.