The first shall be last: Selection-driven minority becomes majority

Street demonstrations occur across the world. In Rio de Janeiro, in June/July 2013, they reach beyond one million people. A wrathful reader of O Globo, a leading newspaper in the same city, published a letter (Ferreira (2011)  [10]) where many social questions are stated and answered Yes or No. These million people of street demonstrations share opinion consensus about a similar set of social issues. But they did not reach this consensus within such a huge numbered meeting. Earlier, they have met in diverse small groups where some of them could be convinced to change their mind by other few fellows. Suddenly, a macroscopic consensus emerges. Many other big manifestations are widespread all over the world in recent times, and are supposed to remain in the future. The interesting questions are: (1) How a binary-option opinion distributed among some population evolves in time, through local changes that occurred within small-group meetings? and (2) Is there some natural selection rule acting upon? Here, we address these questions through an agent-based model.