Teams and the Magical Number 150

We like to claim that some institutions are “too big to fail.” Can the same be said of teams?

Turns out that bigger isn’t always better, especially when it comes to team size. Not only can large teams put a freeze on workplace culture, they sometimes create silos that stifle collaboration and threaten a company’s ability to innovate and grow – all because of the magical number 150.

Take the case of W.L. Gore and Associates, whose signature product – Gore-Tex – shows up everywhere from waterproof rain gear and wetsuits to vascular grafts and fade-resistant manuscripts. When the company boomed in the early 1960s, adding employees and factories at a rapid pace, its founder, Bill Gore, suddenly realized that he couldn’t name all of the workers assembled on his floor. So Gore made a spot decision: He would cap the number of workers in any factory at 150. Once a facility expanded beyond 150 people, he would build a new one, which is exactly what happened: As the company grew, so did its facilities – each one limited to about 150 active workers.  

Gore came up with that figure on a hunch, but it turns out 150 is no random number. Almost three decades later, a British evolutionary psychologist named Robin Dunbar discovered that humans can maintain on average no more than 150 meaningful relationships, based on the size of the neocortex, the part of the brain responsible for conscious thought and language. We naturally maintain relationships through what Dunbar calls “social grooming” – exchanging daily signals that help us bond with one another, whether that’s sharing face-to-face laughter and gossip or splashing virtual posts across social media. These gestures hold our friendship groups together, but only up to a point. Once groups exceed 150 people, Dunbar argues, they can be kept together only through coercion and bureaucracy – and even then, may eventually slip into dysfunction.

There may be a universal principle at work. Anthropologists and social scientists alike have spotted “Dunbar’s number” across wildly different groups and settings. The average number of soldiers in a basic military company? 150. The average number of Christmas cards Brits mailed to friends in a 2000 study on friendship in the U.K.? 150. Your typical number of Twitter followers or Facebook friends? You guessed it: 150. From Neolithic farming villages to multinational corporations, 150 seems to be the optimal size for groups to stick together. It’s the sweet spot for social bonding. Or, as Rich Karlgaard and Michael Malone put in in their book, Team Genius: It’s the number of people you would not feel embarrassed about joining uninvited for a drink if you happened to bump into them individually at a bar.

Even Dunbar admits that his magical number may have limits, but it does carry interesting implications for organizing and leading teams. When groups become too large, they can lead to diminished individual effort, or what psychologists call “social loafing.” (Anyone who has experienced the misfortune of doing a group project knows exactly what I mean.) There’s also a cost to team morale, known as “relational loss.” As the size of a team grows, individual members sense a loss in the support and resources available to them and become discouraged, leading to a decline in productivity and work outcomes. When credit and blame are harder to assign, workers may also feel disconnected from their jobs. All of this might be summed up best by the “two pizza” rule of Amazon CEO Jeff Bezos, which holds that if the group needs more than two pizzas for lunch, it’s too big.

That’s not to say that large groups always produce outsized problems. Research shows that bigger groups are sometimes better off than smaller ones, especially for certain design and manufacturing tasks, which require more complex problem-solving and analysis. Larger group structures can also create a broader information pool that delivers the right amount of oversight and dynamic thinking, thereby reducing tunnel vision and the margin of human error.

The trick, it seems, is to strike the right balance between work outcomes and working conditions – ensuring that teams are sized in such a way that allows people to get the job done but still feel connected to one another. Dunbar’s number offers an intriguing perspective on teams, but ultimately reinforces the old wisdom practiced by great organizations: Big enough to serve you, small enough to know you.

This blog is adapted from Joe’s new book, “The Feedback Fix: Dump the Past, Embrace the Future, and Lead the Way to Change,” now available from Rowman & Littlefield.

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