Table 1.

Outstanding questions.

— Can behavioural change be engineered? Can we foster social consensus on beneficial behavioural norms, such as practices of environmental sustainability or social inclusion? Conversely, how can negative yet widespread norms—from bullying to corruption—be eradicated? — How can we contrast the formation of online self-organizing communities, or ‘echo-chambers’? How can the connectivity of a social network be increased? How robust are these echo-chambers? How do overlapping echo-chambers interact? — How can committed minorities be put to use to induce social change? Can their role be tested in the laboratory? Are the properties of the network structure in social interactions a key factor for the effectiveness of committed minorities? — How are online social networks changing the mechanisms of social consensus? What is the interaction between online and offline paths to consensus? What is the role of centralized and decentralized mechanisms of information production on the formation of social consensus? How does consensus emerge on new ways to attribute and store values such as cryptocurrencies?