Friendship is one of life’s most important healthy pleasures, and one too often taken for granted. A Harvard study found that having no friends (or feeling lonely) is as deadly as smoking, suggesting we ought to pay more attention to who we surround ourselves with.
The theory of Dunbar’s Number posits that 150 is the number of perpetually changing friends and family members with whom any one person can maintain stable relationships (e.g. that you would invite to a large party). This research is solid, as it has been repeated in many settings and across species. The main idea is that our social capital is finite—we can handle only so many relationships at one time.
While you may have far fewer than 150 of these people in your life, your brain really can’t hold a close connection with more than 150, Dunbar’s research shows.
Within that group, your closest 5 relationships seem to be most crucial when it comes to your mental and physical health. These are the people who are confidantes and who you would call at 4 am for help. Most of us can only maintain five intimate relationships at once and quality matters more than quantity especially as you get older.
For the sake of your health, you need friends—ideally the really close kind you see (not virtually) on a regular basis. But even one very good friend can improve your life in profound ways.
Since we are the average of the 5 people we spend the most time with, audit and cherish the people around you. Make sure that you’re spending time with people who are in line with what you want for your own life. As Woodrow Wilson has said, “Friendship is the only cement that will ever hold the world together.”