Oral: Memory and Personality Shape Opinon Polarization

Memory of and response to past events are important keys to understanding behavior in living systems. Memory-based response leads to important biological phenomena, from the chemotaxis of bacteria based on chemical concentration changes to opinion polarization in human societies based on the history of past events. We equip spinning robots with $+/-$ spins resembling two opinions in a society with memory to store perceived spins of other agents. We find that when agents try to follow the majority, their collective behavior is governed by a critical memory threshold, below which the two spin populations coexist and above which spontaneous symmetry breaking (polarization) of the spins is inevitable. Further, depending on how each agent treats past events, what we call personality, the polarization can be static or dynamic in time, even chaotic. For instance, introducing stubborn constant agents (curmudgeons) can assimilate all other agents; introducing agents always going against the majority (contrarians) can oscillate the demography intermittently. We show a theory mapping opinion polarization into a dynamic potential landscape to explain these phenomena. Such an interpretation of social dynamics by physics techniques perhaps could provide novel perspectives on the political instability in the world today and insights into active matter with intelligence.