PhD defence D.R. (David) Gonzalez Jimenez

Below is a brief summary of the dissertation:

This thesis studies how people form expectations when the future is uncertain, and how that affects their decisions. It combines a large field experiment, controlled lab experiments, and a new method to measure beliefs.

The first part looks at online security. In a nationwide project with small and medium-sized firms in the Netherlands, more than 30,000 employees received realistic fake phishing emails. When people clicked, they were shown that it was a test and got tips on how to spot such emails. In the short run, they became more careful and were less likely to click again. However, this effect weakened over time. Personal traits such as patience and willingness to take risks were more important than the type of company.

The second part uses lab experiments to compare learning from clear written information with learning from personal experience and feedback. Learning from experience makes people update their beliefs in a more sensible direction, but also makes them treat different uncertain situations more similarly when things feel vague.

The third part shows that stereotypes, for example about gender and field of study, change how uncertain people feel, even when they see the same numbers.

Finally, the thesis introduces a simple betting method that helps researchers measure people’s expectations more accurately.