Getting Public Opinion on their Side? How Social Movements Shape Public Opinion.

How do social movements with their protest actions succeed in winning public support? I theorize how particular features of protest can persuade citizens to align their views with demonstrators. In particular, I argue that broadcasting an attractive collective identity by means of diverse, worthy, united, numerous and committed participants (dWUNC) triggers supportive reactions of observers through increasing identification with the protesters. As most observers witness protest indirectly via media coverage, I exposed respondents to manipulated television news items of a protest event in two video vignette experiments. Study 1 scrutinizes the effect of dWUNC displays on a representative sample of Belgian citizens exposed to an asylum seeker demonstration. Study 2 replicates this design in the US for the Black Lives Matter issue of police brutality. Both studies show that predispositions of citizens strongly affect their favorability towards protesters. On top of strong receiver effects, the manipulated features of the protest succeed in affecting citizen’s opinion formation too. In both experiments a consistent pattern of feature effects is found: demonstrations that mobilized diverse participants, who behaved worthy and acted in unison, elicited more supportive reactions. Study 2 adds that the effect of protest features is in part mediated by increasing identification with the demonstrators. Together, these findings contribute to our knowledge on how social movements and advocacy groups can affect public preferences.