In a study published recently in Nature Communications Physics, a team from the University of Fribourg led by Dr. Matúš Medo apply the methods of complex systems physics to the problem of misinformation in the age of the Internet. Their study shows how erroneous opinions can emerge naturally in a system where information sources are very numerous.

In forming our opinion on a subject, we sometimes research it in depth. But most of the time this would take far too long, so we rely on sources we regard as reliable. How foolproof is this method? How does it deal with misinformation? This is what Dr. Matúš Medo, physicist and complex systems specialist at the University of Fribourg, asked himself.

«It all started from a personal experience,» he explains. «Reading about the situation in Venezuela, I wondered whose side to take, that of the protesters or that of the government.» Like most of us, Matúš Medo did not invest the time needed to be really conversant with the history and details of the situation. He formed his opinion based on those of involved parties such as other nations, for example. «I found that the countries I trusted supported one party and the ones I distrusted supported the other. So that was the way I formed my opinion.»

A fragile method in the age of the Internet
Matúš Medo then asked himself whether this way of forming an opinion was reliable. As a physicist, he combined computer simulations and theoretical calculations in order to investigate this question. He and his colleagues found that this method, while it was relatively reliable as long as the number of subjects on which one wanted to form an opinion was small, became unstable when this number increased. In a complex system where the subjects are extremely numerous, the same point of departure can lead to diametrically opposed conclusions. Honest citizens trying to form an opinion can thus arrive at an erroneous conclusion. What is worse, they then become a source of misinformation themselves.

Opinion Polarisation
Experts have extensively studied the spread of false information in systems such as social media networks, within which a source, often ill-intentioned, spreads a piece of false information that then goes viral. But the study carried out by Matúš Medo's team has identified a factor that can even affect a system in which all the participants are acting in good faith and honestly trying to form an opinion. Their study shows that once the number of opinions is high enough, misinformation can arise and spread naturally. The system even tends to «polarise» into two groups of opposing sources of information that no longer trust each other - a well-known phenomenon in social networks.

«Our results provide ways to better understand misinformation and the spread of false information in the age of the Internet,» concludes Matúš Medo. «They suggest that the more complex the world becomes, the more likely it is that our simple methods of forming opinions can lead us astray and cause us to form erroneous opinions. The models show that this can be countered by investing effort in increasing the number of reliable opinions. This underscores the importance of critical thinking in today's hyperconnected society of information and opinion overload.»

Article: Medo, M., Mariani, M.S. & Lü, L. «The fragility of opinion formation in a complex world», Nature Commun Phys 4, 75 (2021).