People protest for many reasons, yet we don’t know how effective protests are

On the 17th October, over 20,000 people marched on Parliament Square in London. Why do people take to the streets, and does it make a difference? Interwoven issues of grievances, efficacy, identity, emotions and social embeddedness help answer why. However, there’s a gap in our understanding of when and how demonstrations affect political agendas. Here, Jacquelien van Stekelenburg identifies key mechanisms which have both direct and indirect effects on important players.