Research and Teaching Fields
Primary: Behavioral Economics, Experimental Economics
Secondary: Microeconomic Theory
Email: m.kozakiewicz@fs.de
Working Papers
Experimental Evidence on Misguided Learning
[pdf] [appendix] [instructions (German)]
This paper studies how people form beliefs in environments with multiple unknown parameters, some of which are relevant to agents' self-esteem. In particular, we examine how initial bias in beliefs about an ego-relevant characteristic affects learning about the state of the world. Using data from a laboratory experiment, we demonstrate that the learning process of an overconfident agent is self-defeating: the agent repeatedly takes suboptimal actions, misinterprets the output, and forms increasingly mistaken beliefs about the state. Therefore, we corroborate the theory of misguided learning formulated by Heidhues et al. (2018). We provide the first empirical evidence that allowing a biased agent to experiment and acquire new information is not only ineffective but in some cases counterproductive. Furthermore, we move beyond the theory as we examine how learning about multiple parameters evolves in ego-relevant and ego-neutral environments.
Belief-Based Utility and Signal Interpretation
[New version coming soon!] [pdf (old version)]
Do people perceive favorable feedback in a different way than unfavorable one? After a decade of research, there is no definite answer. The existing literature disagrees not only on the magnitude but also the direction of the bias (Benjamin, 2019). In this paper, I propose a new experimental paradigm to identify motivated distortion of beliefs about signal informativeness. The new design allows me to better capture the asymmetry in response to "good" and "bad" news. The data reveals that participants perceive favorable signals as much more likely to be informative. Furthermore, I introduce a new control condition to uncover the underlying mechanism. Participants in the control group evaluated informativeness of a signal ex-ante, conditioned on possible signal realizations. By comparing beliefs reported after a signal to the reports stated ex-ante, I show that participants distort their perception in a motivated way after receiving a signal. The results cast a new light on the origins of overconfidence, pointing towards the role of affect (or utility from beliefs shifted by the signal) in asymmetric updating.
Hope for the best, prepare for the worst: signal anticipation and ex-ante belief manipulation
[Draft available upon request]
In this paper, I experimentally test a model of belief choice with reference-dependent utility. The basic idea is that people can "prepare themselves" for the arrival of new information by adopting overly pessimistic beliefs. By distorting her prior beliefs, an agent can 1) hedge against a painful downward shift in beliefs after a negative signal and 2) enhance a pleasant surprise from a positive signal. To test the model, I designed a lab experiment in which subjects solve an IQ test and subsequently report beliefs about their relative performance. I introduce an exogenous variation in subjects' expectations over the upcoming signal, which allows me to identify belief manipulation. The results confirm the main predictions of the model, substantiating the claim that utility from beliefs is reference-dependent. Furthermore, I examine a previously unexplored link between gain-loss attitudes and overconfidence, and confirm it in the data.
Work in Progress
Estimating Belief-Based Utility Using Experimental Data
Does the world get crazier or is it just me? Learning about ability and an external parameter