Dynamical processes that emulate human behavior have been the focus of many studies, where social relationships and interactions are typically considered as an underlying structure. As shown recently in various contexts, it is moreover important to take into account the fact that individuals do not interact only in pairs but also in larger groups . Social interactions are indeed a natural testing ground for higher-order approaches. In this talk, I will discuss the effects of group interactions on social systems dynamics. In particular, I will generalize two models of social contagion and norm evolution, initially introduced and studied on graphs, and now extended as dynamical processes on hypergraphs. Leveraging real-world interaction data and analytical insights, I will show the emergence of novel phenomena, such as discontinuous transitions and critical mass effects induced by higher-order interactions . After allowing for the presence of a committed minority, I will show that the ability of committed individuals to overturn an existing norm is non-monotonic with the number of participants in higher-order interactions . These results provide theoretical support to the observation that extremely small minorities can overcome the opinion of the corresponding large majority of the population. Finally, I will propose a measure of hyper-coreness to characterize the centrality of nodes in hypergraphs, and show how different seeding strategies can play a crucial role in dynamical processes driven by group interactions [4,5]. Overall, the findings confirm the relevance of exploring network representations beyond pairwise interactions when modeling social phenomena .
 Battiston, F., Cencetti, G., Iacopini, I., Latora, V., … & Petri, G. (2020). Networks beyond pairwise interactions: structure and dynamics. Physics Reports, 874, 1-92.
 Iacopini, I., Petri, G., Barrat, A., & Latora, V. (2019). Simplicial models of social contagion. Nature Communications, 10(1), 1-9.
 Iacopini, I., Petri, G., Baronchelli, A., & Barrat, A. (2022). Group interactions modulate critical mass dynamics in social convention. Communications Physics, 5(1), 1-10.
 St-Onge, G., Iacopini, I., Latora, V., Barrat, A., Petri, G., Allard, A., & Hébert-Dufresne, L. (2022). Influential groups for seeding and sustaining nonlinear contagion in heterogeneous hypergraphs. Communications Physics, 5(1), 1-16.
 Mancastroppa, M., Iacopini, I., Petri, G., & Barrat, A. (2023) Hyper-cores promote localization and efficient seeding in higher-order processes. ArXiv:2301.04235.