Essays on behavioral and experimental economics

Tuomas Nurminen will defend his doctoral dissertation “Essays on behavioral and experimental economics” on June 23, 2026.

This composite dissertation consists of three essays that use laboratory experiments to study problems in public and health economics. The essays explore three economic settings in which trust, trustworthiness, and the misreporting of private information are fundamental factors: markets for credence goods, tax reporting, and voluntary cooperation under low observability. While the essays examine different contexts and distinct applied questions, incentives for fraud arising from asymmetric information play a central role in each of them. Taken together, the dissertation identifies patterns of economic behavior that are difficult to explain using standard economic theory and demonstrates how incorporating insights from behavioral economics can help explain economic phenomena.

Essay 1 explores markets for credence goods, such as healthcare and repair services. These markets are characterized by severe information asymmetries between customers and expert sellers regarding the quality of the good that best fits the customer’s needs – and even regarding which quality was actually provided. These asymmetries create incentives for experts to defraud customers, for example by providing unnecessarily high-quality and expensive services. The essay examines whether expert sellers exploit customer reputation in their provision decisions and how this affects market efficiency and profits. The results suggest that sellers defraud more often customers with a trusting reputation, but only when customers are uncertain whether their reputation is observable.

The second essay studies the effects of different tax reporting institutions on sales tax evasion and market outcomes in competitive markets. The essay first shows that when sellers can unilaterally evade taxes, evasion is frequent, yet prices are higher than predicted by standard theory, implying that buyers bear most of the effective tax burden. The essay then demonstrates that third-party reporting is an effective tool for deterring tax evasion. Finally, it argues that the presence of sellers motivated by lying aversion and social image concerns can best explain these findings.
Essay 3 studies two low-cost interventions that could be used to promote cooperation in social dilemma settings characterized by free-riding and low observability of actions. The essay shows that providing individuals with a focal cooperation level through a morally charged “norm-nudge” can drastically increase cooperation, even without affecting monetary incentives or limiting the choice set. The results are consistent with the idea that the focal point helps conditional cooperators to coordinate their behavior. By contrast, non-verifiable ex post communication does not improve cooperation rates.