Do Most People Have a Lot of Close Friends?

History is filled with famous equations and fantastic friendships, but perhaps only one man, Robin Dunbar, has come up with a way to combine them. A British anthropologist, Dunbar gained some fame in the 1990s when he created "Dunbar's number," a theory that proposes that people can only handle about 150 social relationships at any one time. But more recently, Dunbar has furthered his friendship focus. In 2007, he and a group of fellow researchers analyzed 35 million people in Europe conversing via six billion phone calls. They came to the conclusion that within that wide social circle, people have an average of only five close friends. They also found that most people have an additional 10 friends who are one step away from being "close," and 35 others with whom they are tighter than the remaining 100 people in their social group. Despite the depth of the analysis, Dunbar says he has more work to do, especially in light of the changing social scene that has developed alongside the rise of smart phones and social media.

Friends, family, and furry creatures:

• Dunbar's number has been informally defined as "the number of people you would not feel embarrassed about joining uninvited for a drink if you happened to bump into them in a bar."
• Research suggests that when it comes to personal health, friendships become more important than family as we get older.
• Studies show that besides humans, other animals capable of true friendship include primates, elephants, horses, camels, dolphins, and whales.