Moving the First Mover: Campaigns, Social Influence and Political Behaviour

Social influence - where socially-connected individuals exert a causal effect on each other's behaviour - has been used to explain a broad range of political phenomena: from global waves of revolutions to turnout in elections. Both academics and practitioners believe that the effects of political movements and campaigns can be amplified through social networks when elites can move their supporters to exert social influence. Social influence can spread exponentially when individuals pass on messages to their own networks. Thus, social influence provides the potential for the actions of political actors to cascade widely and suddenly.

Despite the breadth of the literature on social influence and political behaviour, most of the work has been observational and has thus struggled to convincingly distinguish social influence from homophilic selection and common-cause explanations of why socially connected individuals change their behaviour at the same time. More recently, field experiments have been used to show that the effects of direct campaign contact spill over in social networks. The random delivery of exogenous treatments to networks in these experiments distinguishes influence from selection effects. However, these studies have so far stopped short of exploring what mediates the spillover of campaign effects.

This project will examine the behaviours that mediate social influence. Such behaviours include interpersonal political discussion, online political communication, and the public display of political affiliations with lawn signs and posters. I will examine what motivates these behaviours, whether they causally influence individuals' social connections, and how political campaigns strategically mobilize these behaviours amongst their supporters to initiate social influence. Conceptualising social influence as a resource that campaigns can mobilize from their supporters, I will develop a theoretical model of campaign-initiated social influence.

As well as descriptive research on how campaigns ask their supporters to exert social influence, and the different types of behaviours that individuals carry out, I will use field experiments in collaboration with political campaigns in the UK to empirically validate my model. This project will contribute to our understanding of how public opinion and political participation are socially conditioned. Understanding the mechanisms of how individuals influence each other, as well as the extent to which political actors can initiate processes of social influence, is useful for explaining why mass cascades of political and social change occur so suddenly.