人们总认为生命中有一群重要到无法替代的人，他们陪伴着自己走过春夏秋冬。这些人也许是至亲，是亲人，是情人，亦或者是其他。但不管他们是谁，在我们经历重大变故时，首先想到的倾诉对象便是他们。但这是真的吗？又或者说当我们经历人生转折点后，这些重要的人也发生了变化？

Those are the questions addressed by a trio of sociologists. They wondered whether our core groups may be less permanent than we believe. To find out, they looked at the specific example of starting graduate school. The entire cohort of students beginning their graduate studies in a humanities department, a social science department, and a lab science department participated in the research. Within a month of the start of their first year, all of the students answered this question:

“From time to time, most people discuss important matters with other people. Looking back over the last six months – who are the people with whom you discussed matters important to you?” They could name as many people as they wanted. The people they named were considered their core discussion networks.

All of the students were asked the same question six months later, and then a third time six months after that.

So how, if at all, did the students’ core discussion networks change over the course of the year after they started graduate school?

First, students tended to add a person from their cohort (the people who started in their graduate program the same time they did) to their core discussion network. A fellow student became someone to whom they would turn when they had something important on their mind and wanted to discuss it.

There is no limit on the number of people we can turn to when we want to talk. So the students could have added a fellow student to their core group without demoting anyone who was already in their network. But that’s not what happened. Instead, the new person in their network replaced someone else. Over the course of the year, 31 out of the 37 graduate students replaced at least one person in their core group.

Change was the norm. Over the twelve months, not one person’s core network stayed the same, with the same number of people in it as when they started the grad program, and with no replacements. Within the first six months, only one person’s network stayed the same, but then by the end of the following six months, the network changed.