The Hot Politics Lab has contributed to the conceptual development of populism, and an understanding of its psychological roots. In, for example, this paper Matthijs Rooduijn contributes to the conceptual development of populism, as well as setting a future research agenda. In joint work we find that the personality trait Agreeableness predicts populist voting. Across countries, and different left-wing or right-wing populist parties, we find that low Agreeable individuals are more likely to support populists. Using a survey experiment we find that in particular anti-establishment rhetoric links Agreeableness to populist voting.