你需要多少个朋友？上课的时候有时候讲到类似友谊的话题的时候会问下同学，是不是有交心的朋友的话题。其实不是调侃，是真的很好奇现在年轻人对于朋友的定义。How Many Friends Do You Really Need

关于朋友数量有个常被提到的数字是Dunbar 数字，来自于英国心理学家Robin Dunbar：人们能维系的关系数量上限是150（后面研究说可以更多）；亲密关系的数量是5人。

The best-known theory of how many friends people can (though not necessarily should) have comes from British psychologist and anthropologist Robin Dunbar. What has come to be known as Dunbar’s number contends that humans are only cognitively able to maintain about 150 connections at once (subsequent research has put the number higher). That includes an inner circle of about five close friends, followed by larger concentric circles of more casual types of friends.

出于减少孤独感的考虑，不管是朋友，还是家人，人至少需要一个交心的人。

If your goal is simply to mitigate the harmful impact loneliness can have on your health, what matters most is having at least one important person in your life — whether that’s a partner, a parent, a friend or someone else, said Jeffrey Hall, a professor of communication studies at the University of Kansas.

要从友谊里提高生活质量的，有研究说3个，也有说6个。

One 2016 study suggested people who have six or more friends have improved health throughout their lives, while a 2020 study by Suzanne Degges-White, professor and chair of the Counseling and Higher Education department at Northern Illinois University, found that middle-aged women who had three or more friends tended to have higher levels of overall life satisfaction.

当然到底需要几位朋友，看个人的需求，如果你想体验一些新的东西，那么交个朋友是比较合适的，只是要深交一位朋友，差不多需要200小时的投入。

Dr. Hall’s research suggests that on average, very close friendships tend to take around 200 hours to develop. Quantity and quality go hand-in-hand.