Résumé : Citizens with populist sentiments are dissatisfied with the current workings ofdemocracy. They yearn for changes in the democratic process that ensure the generalwill of the people is implemented, rather than politics being dominated by an elite.One potential solution to this dissatisfaction, rooted in early concepts of Atheniandemocracy and gaining increasing scholarly attention over the last decades, aredemocratic innovations. These innovations give a more central role to citizens in thedemocratic process, potentially addressing populist grievances.In this thesis, I examine how democratic innovations affect the populist attitudesof participating citizens. I first assess whether populist attitudes are changeable,or whether they remain stable regardless of the context. Using sociopsychologicalinsights, I develop a theoretical model of populism among individuals, revealing thatpopulism is conceptually ambiguous: it is not a classic attitude nor a stable ideology.I use panel data from the Netherlands and Great Britain spanning approximatelyfour years to study whether populist attitudes change over time. The data show thatpopulist attitudes fluctuate, mainly in response to changes in democratic satisfaction.Increased satisfaction with democracy is associated with a decrease in populistattitudes. This suggests that changes in the democratic process that make citizensmore satisfied with democracy could reduce populist attitudes.Next, I investigate whether democratic innovations impact populist attitudes and why.As a first step, collaborating with Carolien van Ham and Kristof Jacobs, we conduct ameta-analysis of 100 studies on democratic innovations' effects on participants. Wefind that mini-publics positively affect citizens' attitudes and capabilities, but thereis a knowledge gap regarding the effects of participatory processes, referendums,and citizens' initiatives. Many studies lack pre-participation measurements or areconducted at the aggregate level, making it hard to trace individual-level effects.To study changes in populist attitudes at the individual level, I expand on thetheoretical model of populism to include mechanisms by which democraticinnovations might affect populist attitudes. The model suggests that citizens withhigh populist attitudes, or so-called populist citizens, might be affected differentlythan those with low populist attitudes, or so-called non-populist citizens. I thenuse this model to empirically assess the impact of participatory budgeting (PB) onparticipants' populist attitudes. Analysing pre- and post-participation surveys fromfour cases in the Netherlands, Rosa Kindt and I find that populist citizens significantlydecrease their populist attitudes after participation, while non-populist citizensremain unaffected. Thus, PBs might address the democratic demands of populistcitizens more effectively than those of non-populist citizens.199SUMMARY IN ENGLISHTo further understand how participation in democratic innovations affects populistattitudes, I analyse 35 interviews with both populist and non-populist participants. Theanalysis confirms that populist and non-populist citizens experience PBs differently.Populist citizens focus on the authorities' intentions and sincerity, the inclusion ofpolitically marginalised groups, and the process's impact on policy-making. Nonpopulist citizens value opportunities for deeper discussions to find common interestsand emphasise the representativeness of participants. These findings indicatethat democratic innovations that address populist citizens' democratic desires canpotentially appease populist dissatisfaction.However, since participants in democratic innovations tend to be older, moreeducated and more politically interested, it could be that the populist participants aredifferent from populist citizens in the wider population and that these findings onlyapply to these ‘usual suspects’. By comparing descriptive data from participants andthe wider population, I find that populist citizens are as likely as non-populist citizensto show up to a participatory process. Nevertheless, the participating populist citizensare older, more educated, and more trusting in political actors than those in the widerpopulation. This means that one should be careful in generalising the findings of thisthesis to the entire population.This thesis’ findings contribute to both the study of populism and democraticinnovations. It builds a theoretical model of populist attitudes, presenting evidencethat these attitudes are changeable. A major driver of populist attitudes change isdemocratic satisfaction. When populist citizens are exposed to democratic reformsthat appeal to their democratic demands, their populist attitudes decrease. Thissuggests that populist attitudes signal a perceived democratic deficit, and play asignificant role in how citizens interact with the democratic process. For the field ofdemocratic innovations, the thesis shows that mini-publics affect participants inthe expected positive way, but highlights gaps in our understanding of participatoryprocesses, referendums and citizens' initiatives’ effects on participants. Thetheoretical model of attitude change developed in this thesis can be applied toother democratic innovations. The model predicts and the empirical analyses showthat democratic innovations have different effects on populist and non-populistcitizens. Moreover, these groups experience democratic innovations in a differentway. Therefore, there is no 'one-size-fits-all' approach to democratic innovations inparticular, or to democracy in general, and our democratic systems should be adaptedto meet those diverse democratic needs.