Vox Populi vox dei

An exhibition at the Cité des sciences in Paris has the theme: “The crowd, an object of science.”

This exhibition is proposed by two researchers Mehdi Moussaid (1) and Coralie Chevalier (2) . It highlights the effect of group dynamics on decision-making (3) .

Confrontation, the emergence of solutions

Mehdi Moussaid reports an interesting experience on this subject:

  • A one-to-one chess game is organized against hundreds of players who must decide together against the one playing alone. We have, in the end, a collective performance superior to the average level of the players who participate in this experiment. This makes it possible to verify the allegations of the proponents of collective intelligence.
  • This researcher also reports on a collective intelligence experiment organized by David Becker who posed a research question in the field of biochemistry. 200,000 people started thinking and after 5 days a viable solution was found.
  • Another experiment that might seem improbable: We take a crowd of individuals who are asked a question for which there is an answer (for example how many elevators in the Empire State Building). We interview a million people and we average the answers. We will then come across the correct answer (73).
  • Here is an experiment that I had the opportunity to carry out in a school more than 30 years ago and that everyone can easily reproduce: We take a piece of wood about 1 meter long but no one knows the exact length. We are asked to evaluate the length of this piece of wood to as many people as possible. We will then highlight that although the difference in the answers is very large (the difference between the lowest answer and the highest answer), the average of the answers is strangely close to reality.
  • These experiments can be compared to the work of Kurt Lewin (4). Kurt Lewin, among other inventors of the concept of group dynamics, had shown that creating interactions and confrontations between several potential women customers for household products was more effective in triggering a purchase gesture than most advertising campaigns.

Beyond the pooling of information, it is the confrontational aspect that seems to have a significant effect on decision-making. This form of collective intelligence highlights the function of confrontation to make a thought evolve. We can see an inner confrontation unfolding (the inner forum in its primary sense of inner forum). The same confrontation with oneself that the client leads to his therapist.

Interactions between people have an effect of transforming the representations of each, especially if confrontation is allowed. This reality is staged in a masterful way in Sidney Lumet’s film: twelve angry men (5).

If we allow the actors of a situation to exchange, discuss and argue, then each individual gets closer to the right answer. Beyond the search for a better score than the opposing group, the interest of this confrontation is to develop individual points of view as well as collective decisions.

This is an effect put forward by the psychologist Hugo Mercier (6).

We can also see the effects of collective confrontation on decision-making: we have shown in learning company approaches that when confrontation is allowed by instituting it as part of the job, collective decisions are better and the commitment of the actors is maximum.

Democracy, a space of established confrontation

It will be noted that the institution of confrontation is the very basis of democratic functioning: in the French legislative system, the two assemblies are each in themselves a place of confrontation between elected representatives. And the transition from one room to another is also a process of confrontation.

We can hypothesize that decisions concerning collectives can only be taken after an established confrontation. If the experts and the scientists were legitimate to make decisions concerning the common life, one would not need democracy to govern. We will remember what Clemenceau said: “War is too serious a thing to entrust to soldiers.” Beyond the apparent joke, there is an obvious reality: expertise is made to produce information but rarely to make decisions, mainly in situations of uncertainty.

We saw this recently in the covid crisis; the uncertainty was such that no expertise could claim to provide a certain solution whose results could be foreseeable. In this sense, the trials made of certain politicians in their management of the crisis may seem somewhat unfair. In such uncertainty, we have only the choice of wandering and trial and error. If we really wanted to reproach them for something, it could have been for having prevented the debates, which was not the case.

In this sense the decisions taken in a democratic system are, for the most part, the most viable and appropriate decisions.

The art of talking

The use of confrontation to transform opinions can take quite unexpected forms (7). Many countries have seized on the phenomenon of television series to influence their public opinion. This is what India has done in particular to allow the development of contraception and more recently as a means of mobilizing women in the fight against the archaic patriarchy which slows down the economic development of the country (8).

If we look closely, beyond the appearance of the fight of good against evil, these series designed to influence opinions, stage confrontations. This promotes intrapsychic debate (the inner forum for the individual) and also promotes debate within families or communities.

Those who affirm that democratic institutions are a waste of energy, time and money do not see how these instances, by producing confrontation, allow a collective to self-regulate and self-determine as little harm as possible. .

But if the possibility of confrontation is necessary, it is not sufficient. We can clearly see this in current social debates where the manipulation of certain populations allows leaders like Trump or Bolsonaro to emerge. The education of citizens remains the necessary condition and a constant concern for the existence of confrontations which are something other than battles of slogans reflecting the fear and ignorance of those who bear them. Because in this case vox populi can become vox diaboli.


1 Mehdi Moussaid, researcher in cognitive science at the Max Planck Institute and curator of the exhibition; author of fouloscopie: what the crowd says about us.

2 Coralie Chevalier, curator of the exhibition. cognitive science researcher at Normal Sup.

Pdf document on the Crowds exhibition

3 We will listen with interest to the Radio France podcast on this exhibition: The mechanics of crowds – France Inter

4 Kurt Lewin (1890-1947), American psychologist specializing in social psychology and behaviorism, a major player in the school of human relations. For more details on Kurt Lewin’s experience, Permission marketing

5 https://fr.wikipedia.org/wiki/Douze_Hommes_en_col%C3%A8re_(film)

Hugo Mercier. Jean Nicod Institute IJN Laboratory ESC. Team SOCIAL COGNITION: FROM BRAIN TO SOCIETY.
Personal website. https://sites.google.com/site/hugomercier/

6 Series and Politics – When fiction contributes to public opinion

7 How the “I, Woman, I Can Accomplish Anything” series is waking up feminism in India

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Vox Populi vox dei