Four essays on bounded rationality in behavioral economics and finance.

Summary This thesis addresses the topic of bounded rationality through four chapters, combining theoretical models, laboratory experiments and statistical and econometric analyses. In the first two chapters, we test the validity of new models in economics that use the mathematical formalism of quantum mechanics to account for cognitive biases. In chapter 1, we consider models explaining the order effect and derive new experimental predictions. In Chapter 2, we propose an original experiment to test a wide range of quantum models that account for the conjunction error. Both groups of models fail our empirical tests. We then discuss possible ways to improve these models. Chapter 3 explores how individuals process successive, complex and abundant economic information. Our experimental results show the inability of subjects to combine such information, which confirms the fuzzy trace theory. Finally, Chapter 4 is a chapter of experimental finance. It studies how buying on margin (respectively selling short) increases (decreases) the price level, volatility, market heterogeneity and price expectations of traders as well as how it changes trading strategies. Our results highlight the clear consequences of each of these techniques separately, and identify unexpected phenomena when they are combined. Our analyses pave the way for regulators to take better account of these destabilizing interactions.