How Many Close Friends Can One Person Really Have?

Look at your phone contacts carefully. How many of those people are you really close to?

   British anthropologist Robin Dunbar previously determined that humans can be emotionally close to about 150 people because the size of our brains determines the number of people we can have meaningful relationships with.

Out of that group, up to five can be a person's best friends. The next closest layer contains an additional 10, the next an extra 35, and the final group another 100. These are known as the Dunbar layers.

In new research, Dunbar, who is at the University of Oxford in the U.K., and some colleagues analyzed mobile phone calls, measuring the frequency of calls between individuals to determine the strength of their relationships.

The data examined six billion calls made by 35 million people in an unnamed European country in 2007 before the widespread use of smartphones and social networks such as Facebook, Twitter and Instagram.

The MIT Technology Review reports that individuals had an average of four people in their closest circle, 11 in the next, 30 in the next, and 129 in their outermost circle of friends.

The research shows, "These numbers are a little smaller than the conventional numbers for Dunbar layers, but within their natural range of variation."

Plus, the numbers could be smaller because cell phone data includes only part of a person’s total social interactions.

Researchers also determined that some people have extra layers of friendship, which could mean "introverts and extroverts have a different number of layers of friends."

In sum, there is strong evidence for the existence of the innermost and outermost layers of friendship but some variability for the size of the intermediate layers.