How Election Polls Shape Voting Behaviour

This article investigates how election information such as opinion polls can influence voting intention. The bandwagon effect claims that voters ‘float along’: a party experiencing increased support receives more support, and vice versa. Through a large national survey experiment, evidence is found of a bandwagon effect among Danish voters. When voters are exposed to a news story describing either an upwards or downwards movement for either a small or large party, they tend to move their voting intentions in the according direction. The effect is strongest in the positive direction – that is, when a party experiences increased support, more follows. Consistent effects are found across two different parties for a diverse national sample in a political context very different from earlier research on the bandwagon effects. Considering previous research and the fact that evidence is not found that suggests that the effect of polls vary across sociodemographic groups, the results imply that bandwagon behaviour is based not on social or political contingencies, such as media or political institution, but on fundamentals of political cognition.