What would you say if someone asked you how many friends you have? Every person defines what they call a friend in their own way. Some feel that their friends are those with whom they grew up and went to high school, while others consider their acquaintances on social media to be their friends. It is said that the average person is capable of maintaining relationships with approximately 150 other people – this is the number of people whose names and personalities they will remember if they run into them on the street*. Some research suggests that this number shrinks to four when talking about intimate relationships, which includes people who are important to an individual and with whom one is able to carry on non-urgent conversations about life and other such topics. This is called the “core group.”
Before the rise of social media, interpersonal relationships were maintained through direct contact. In the current day, many people over the age of 50 maintain relationships with around 150 people (e.g.relatives, neighbors, and co-workers) made through traditional social practices such as family gatherings,local associations, and company connections. For people in these generations, the offline social network still lives strong. In contrast, many Japanese people in their 20s and 30s were raised in highly anonymous urban environments, and have entered the workforce in an era in which fewer people are living in extended family groups, and the system of lifelong employment is collapsing. For this generation, social media has played a major role in helping people maintain relationships with approximately 150 others, as social media requires no direct contact.
For those people living their lives within offline networks, being outside of that framework of online social norms results in isolation because there is no other means of maintaining relationships there. In addition, it is difficult for that group to view social media as a way of maintaining relationships. For this reason, they feel that online relationships among people in their 30s and younger are weaker than the relationships they enjoy. However, whether online or not, the number of people in an individualʼs core group is the same for both types of network.
Sachio Ishida is an associate professor of sociology at the Faculty of Urban Innovation at Asia University, and he is researching this idea of core groups. Social networks have elements that are optional,while there are fewer options when engaging with offl ine networks, such as when attending a gathering between family members. In addition, your neighborhood and work-related connections depend on where you live, the company you work for, and what kind of work you do. Social media, on the other hand,provides many more options than one gets from neighborhood and work connections, even considering the many random encounters one has in larger urban areas. That being said, there seems to be an increasingly excessive number of options available in online networks, and no scientific analysis of what constitutes a core group connection. If empirical research can successfully clarify this point with concrete evidence, we may be able to build a basis on which we can consider what types of online networks should be used by society. In other words, we may learn what our new social norms should look like. As a sociologist, Ishida is working on social issues in our increasingly borderless world, with an eye to the future of urban society.
* This value is called Dunbarʼs number after British evolutionary psychologist Robin Dunbar, who first proposed it.
石田幸生准教授（亜細亜大学 都市創造学部 都市創造学科）