Later On

A blog written for those whose interests more or less match mine.

The Dunbar Number

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It’s 150, of all things. Read this (fascinating) article in Bloomberg Businessweek by Drake Bennet for an explanation. The article begins:

A little more than 10 years ago, the evolutionary psychologist Robin Dunbar began a study of the Christmas-card-sending habits of the English. This was in the days before online social networks made friends and “likes” as countable as miles on an odometer, and Dunbar wanted a proxy for meaningful social connection. He was curious to see not only how many people a person knew, but also how many people he or she cared about. The best way to find those connections, he decided, was to follow holiday cards. After all, sending them is an investment: You either have to know the address or get it; you have to buy the card or have it made from exactly the right collage of adorable family photos; you have to write something, buy a stamp, and put the envelope in the mail. These are not huge costs, but most people won’t incur them for just anybody.

Working with the anthropologist Russell Hill, Dunbar pieced together the average English household’s network of yuletide cheer. The researchers were able to report, for example, that about a quarter of cards went to relatives, nearly two-thirds to friends, and 8 percent to colleagues. The primary finding of the study, however, was a single number: the total population of the households each set of cards went out to. That number was 153.5, or roughly 150.

This was exactly the number that Dunbar expected. Over the past two decades, he and other like-minded researchers have discovered groupings of 150 nearly everywhere they looked. Anthropologists studying the world’s remaining hunter-gatherer societies have found that clans tend to have 150 members. Throughout Western military history, the size of the company—the smallest autonomous military unit—has hovered around 150. The self-governing communes of the Hutterites, an Anabaptist sect similar to the Amish and the Mennonites, always split when they grow larger than 150. So do the offices of W.L. Gore & Associates, the materials firm famous for innovative products such as Gore-Tex and for its radically nonhierarchical management structure. When a branch exceeds 150 employees, the company breaks it in two and builds a new office.

For Dunbar, there’s a simple explanation for this: . . .

Continue reading.

Written by LeisureGuy

14 January 2013 at 9:00 am

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