Daily activities can help social networks evolve, but lasting ties take more

Almost every big life change, whether it’s starting a new school, changing jobs, or moving, elicits the same advice: get involved and make friends. Although there is some truth in this advice, according to a study conducted by an international team, participating in activities is not enough to develop a social network.

The researchers, led by Makoto Chikaraishi, a professor at the Graduate School of Advanced Science and Engineering at Hiroshima University, evaluated the current scientific literature on social networks (the concentric, overlapping circles of connections between individuals) and developed a new framework to account for the dynamic nature of the evolution of these networks.

They published their work, which included simulated scenarios on the impact of various policies, such as those that restricted social interactions during COVID-19, on social media, on August 27 in Transportation.

The scattered seeds of social media only grow when nourished

“Social media is dynamic, not static,” Chikaraishi said. “We decided to think of social media as adaptive networks that evolve with daily activities. We found that activities disperse countless ‘seeds,’ but few of them grow into lasting connections and that policies shape the soil in which they take root.”

To better understand the evolution of social networks, researchers surveyed newly enrolled international students at the University of Tokyo in spring 2019, asking them for details about each person’s social network, specifically who they spend their free time with. Next, the students completed a three-week joint activity diary. Each participant reported details of the joint activities carried out, including the names and other details of those involved.

Activities were divided into four types: going to an event, going out to eat, attending a party, and other leisure activities such as hiking. After three weeks, the researchers surveyed respondents again on their social networks.

Although the sample was small, with only 16 respondents, Chikaraishi said it provided a basis for developing a framework. They found that the 16 people made 1,344 activity engagement decisions over 21 days, resulting in 435 joint activities or activities in which more than one of the people participated. Of the 435 joint activities, 550 new encounters were made and 183 of these new connections were described in the second social media survey.

On average across participants, international students recorded approximately 86 dating events over three weeks (not single individuals, as repeat meetings and prior acquaintances were included), while only 13 unique friendships lasted.

Using this information, the team developed a framework to simulate this data and found that these networks were dynamic and could evolve. To further explore the framework, the team developed a baseline simulation including 200 international students from 10 countries.

“Our empirical results show that the proposed framework can successfully trace the growth of international students’ social networks,” Chikaraishi said. “We also show that the model can be used to draw policy conclusions: we confirmed that restrictions on outdoor activities would significantly limit social network expansion. The simulation shows that banning social activities can reduce network growth by almost a third.”

Next, the researchers said they plan to extend their adaptive network framework and integrate it with transportation simulations and large datasets.

“Recognizing social networks as adaptive systems opens new avenues for evaluating urban and transportation policies through their social consequences,” Chikaraishi said. “Our ultimate goal with this work is to provide policymakers with a tool that connects mobility, urban design and social resilience, ensuring that cities are planned not only for movement, but also for connection and community.”