The paper “Evidence of equilibrium dynamics in human social networks evolving in time”, co-authored by LASIGE’s integrated researcher Andreia Sofia Teixeira, was published in the journal Communications Physics (SCIMAGO Q1). This research was led by researchers at Universidad Carlos III de Madrid.

The research explores how networks of social relationships evolve over time, addressing the lack of longitudinal analyses of social networks grounded in mathematical modelling. The authors analyse a dataset tracking the social interactions of 900 individuals over four years. Despite shifts in individual relationships, the macroscopic structure of the network remains stable, fluctuating within predictable bounds. They link this stability to the concept of equilibrium in statistical physics. Specifically, the authors show that the probabilities governing link dynamics are stationary over time, and that key network features align with equilibrium predictions. Moreover, the dynamics also satisfy the detailed balance condition. This equilibrium persists despite ongoing turnover, as individuals join, leave, and shift connections. This suggests that equilibrium arises not from specific individuals but from the balancing act of human needs, cognitive limits, and social pressures. Practically, this equilibrium simplifies data collection, supports methods relying on single network snapshots (like Exponential Random Graph Models), and aids in designing interventions for social challenges. Theoretically, it offers insights into collective human behaviour, revealing how emergent properties of complex social systems can be captured by simple mathematical models.

The paper is available here.