Tim Rogers

Overturning Consensus in Animals and Humans

Effective collective decision-making in human and animal groups requires robust mechanisms to form consensus, typically via feedback loops in which individuals adapt their behaviour based on their perception of others. Such behaviour has been observed and theorised across scales from nucleosomes to entire societies. Of equal importance, but far less well studied, is the question of how consensus is overturned. In many contexts it is vital that group decisions do not remain fixed in the face of new evidence; echo-chamber effects must be suppressed so that the collective preferences which are expressed are not too strongly entrenched. In this talk I will discuss a new mathematical theory for how consensus can be overturned in symmetric binary choice problems, and compare the theoretical predictions to experiments with human and animal groups.