Social interactions play a key role in shaping opinion formation, and can lead to a self-organized collective state with a winning opinion. However, random factors are always present and can produce changes of opinion independently of the interactions, and as such can hinder the ability of the social group to converge to consensus. An additional factor, termed “aging”, can significantly influence opinion dynamics. Aging reflects the increased resistance of individuals to change their opinion over time, such that changes of mind can become less likely the longer an agent has adopted a given opinion state. In recent research [1,2], we have has delved into the impact of aging on two standard opinion models with pairwise interactions and random changes. One of the studied models, the voter model, represents a two-state dynamics driven by simple social contagion, the other, a kinetic exchange model, introduces a neutral state, where the resulting opinion depends on the prior viewpoints of both interacting agents. Additionally, random opinion shifts occur independently of interactions. Aging introduces a diminishing probability of opinion change over time, which we take into account through different kernels (exponential and power-law decays with age).By performing a comparative analysis based on mean-field analytical predictions and agent-based simulations, we elucidate the effects of aging on both models. Notably, we observe a non-monotonic relationship between the critical value of the noise intensity for consensus and the aging rate. Surprisingly, optimal consensus emerges at an intermediate aging rate, highlighting the nuanced role aging plays in opinion formation. In certain scenarios, aging facilitates consensus, while in others, it poses a barrier to reaching a dominant viewpoint.

[1] Aging in some opinion formation models: a comparative study, J Llabres, S Oliver-Bonafoux, C Anteneodo, R Toral, Physics 2024, 6, 515-528 (2024)

[2] Noisy kinetic-exchange opinion model with aging,AR Vieira, J Llabrés, R Toral, C Anteneodo. Physical Review E 109 (6), 064119 (2024)