Serge Galam (CEVIPOF-Center for Political Research, Sciences PO & CNRS) | Do humans behave like atoms? An answer from sociophysics |


This provocative question sounds out of place and indeed is out of place if it concerns a comparison between a human and an atom. However, it takes on its full meaning if being understood as “do human obeys quantitative laws like atoms do? And if yes, could these laws be identified and put into equations?” The subsidiary question which immediately follows this question is “can we predict social and political events, at least some of them?”. Sociophysics answers yes to those three questions,

But what is sociophysics? It is a newly established field of research among physicists to address a wide range of social and political phenomena, which result from individual human interactions. The approach is similar to statistical physics, which studies the macroscopic properties of inert matter starting from interactions between its microscopic constituents.

I will illustrate sociophysics with the case of opinion dynamics. Indeed, opinion dynamics is today a major driver of policy making, in particular with both the ubiquity of social medias and the scale of contemporary global challenges. In this talk I consider a community of heterogeneous agents, floaters and inflexibles (stubborn), having to choose between two discrete competing choices via open discussion among them. The dynamics is monitored using repeated local updates of individual opinions in small size groups of randomly distributed agents. At each distribution of agents, local majority rules are applied within the discussing groups. However, while floaters update their choices along the local majority, inflexibles keep on their choices. The effect of shared prejudices is also incorporated quite naturally within groups at a tie where floaters select unconsciously a tie breaking local choice, which is in tune with their activated prejudice, while being convinced that it was done at random. 

The dynamics is found to be either a tipping point dynamics with two competing attractors or a single attractor dynamics. In the case of the tipping point, what matters is the initial support to grow or shrink with each attractor yielding an overwhelming majority in favor of one of the two choices. The associated dynamics is unbalanced with tipping points which can be located at very low values of initial support for one of the two choices and very high value for the other choice. The results are unexpected and counter-intuitive, in particular highlighting both phenomena of minority spreading and polarization. Novel and disturbing strategies to win a democratic public debate can be designed. Predictions can be made about elections.




R. Brazil, The physics of public opinion, Physics World, January issue (2020)

S. Galam, Minority Opinion Spreading in Random Geometry, Eur. Phys. J. B25, Rapid Note 403-406 (2002)

S. Galam, Heterogeneous beliefs, segregation, and extremism in the making of public opinions.Physical Review E71, 046123 (2005)

S. Galam and F. Jacobs, The role of inflexible minorities in the breaking of democratic opinion dynamics, Physica A381, 366–376 (2007)

S. Galam, Sociophysics: A Physicist’s Modeling of Psycho-political Phenomena, Springer (2012)

When: March 30, 2022 02:00 PM (Israel Standard Time).

Where: Over Zoom