Since the Great Recession of 2008, populist or openly Eurosceptic parties – such as the Front National, Syriza, Golden Dawn, the Five Star Movement, the Northern League, Podemos, Jobbik, Law and Justice, the UK Independence Party, or the Party for Freedom – have scored major electoral successes around Europe and the developed world. The aim of this project is to investigate this phenomenon with the lenses of behavioral political economy, a blossoming field at the intersection of behavioral economics and political economy, which applies insights from cognitive psychology and methodological tools from microeconomics to understand the causes and consequences of political behavior. The project pushes this research frontier forward by addressing two fundamental issues that can shed light on the puzzling pattern of support for populism: the heterogeneity and time (in)stability of preferences and cognitive abilities; and the role of limited attention in shaping preferences and information processing. In particular, this project has two ambitious goals. The first major goal is to understand citizens’ economic preferences, social preferences and cognitive abilities, how they vary over space and time, and how they affect political behavior and the support for populist policies. The key novelty of my approach is to collect empirical evidence from representative samples of European citizens and to combine large surveys with state-of-the-art techniques from experimental and behavioral economics. The second major goal is to understand how politicians’ incentives are affected by the cognitive abilities and unstable preferences of their electorate, and how this matters for the supply of populist policies. The key novelty of my approach is to introduce a fundamental lesson from cognitive psychology in theoretical models of politics: voters have limited attention, think in context and the environment in which they operate influences their preferences and beliefs