Do the Young Live in a "Smaller World" Than the Old? Age-Specific Degrees of Separation in Human Communication

TL;DR

This study reveals that younger individuals are more interconnected within their age group and with other generations, forming smaller social worlds, while older individuals are more isolated, affecting information spread and social dynamics.

Contribution

It introduces the concept of age-specific small worlds in communication networks, highlighting how age influences social connectivity and network structure.

Findings

Young people live in the smallest social worlds across age groups.

Older individuals are more separated from their peers and other generations.

Age-specific small worlds are robust across various data checks.

Abstract

In this paper, we investigate the phenomenon of "age-specific small worlds" using data from a large-scale mobile communication network approximating interaction patterns at societal scale. Rather than asking whether two random individuals are separated by a small number of links, we ask whether individuals in specific age groups live in a small world in relation to individuals from other age groups. Our analysis shows that there is systematic variation in this age-relative small world effect. Young people live in the "smallest world," being separated from other young people and their parent's generation via a smaller number of intermediaries than older individuals. The oldest people live in the "least small world," being separated from their same age peers and their younger counterparts by a larger number of intermediaries. Variation in the small world effect is specific to age as a node attribute (being absent in the case of gender) and is consistently observed under several data robustness checks. The discovery of age-specific small worlds is consistent with well-known social mechanisms affecting the way age interacts with network connectivity and the relative prevalence of kin ties and non-kin ties observed in this network. This social pattern has significant implications for our understanding of generation-specific dynamics of information cascades, diffusion phenomena, and the spread of fads and fashions.