2021 Theses Doctoral
Essays in Information and Behavioral Economics
This dissertation studies problems in individual and collective decision making. Chapter 1 examines how information providers may compete to influence the actions of one or many decision makers. This chapter studies a Bayesian Persuasion game with multiple senders who have access to conditionally independent experiments (and possibly others). Senders have zero-sum preferences over what information is revealed. The main results characterize when any set of states can be pooled in equilibrium and, as a consequence, when the state is (fully) revealed in every equilibrium. The state must be fully revealed in every equilibrium if and only if sender utility functions satisfy a ‘global nonlinearity’ condition. In the binary-state case, the state is fully revealed in every equilibrium if and only if some sender has nontrivial preferences. Our main takeaway is that ‘most’ zero-sum sender preferences result in full revelation. We discuss a number of extensions and variations.
Chapter 2 studies Liquid Democracy (LD), a voting system which combines aspects of direct democracy (DD) and representative democracy (RD) and is becoming more widely used for collective decision making. In LD, for every decision each voter is endowed with a vote and can cast it themselves or delegate it to another voter. We study information aggregation under LD in a common-interest jury voting game with heterogenously well-informed voters. There is an incentive for a voter i to delegate to someone better informed; but delegation has a cost: if i delegates her vote, she can no longer express her own private information by voting. Delegation trades off empowering better information and making use of more information. Under some conditions, efficiency requires the number of votes held by each nondelegator to optimally reflect how well informed they are. Under efficiency LD improves welfare over DD and RD, especially in medium-sized committees. However LD also admits inefficient equilibria characterized by a small number of voters holding a large share of votes. Such equilibria can do worse than DD and can fail to aggregate information asymptotically. We discuss the implications of our results for implementing LD.
For many years, psychologists have discussed the possibility of choice overload: large choice sets can be detrimental to a chooser’s wellbeing. The existence of such a phenomenon would have profound impact on both the positive and normative study of economic decision making, yet recent meta studies have reported mixed evidence. In Chapter 3, we argue that existing tests of choice overload - as measured by an increased probability of choosing a default option - are likely to be significantly under powered because ceteris parabus we should expect the default alternative to be chosen less often in larger choice sets. We propose a more powerful test based on richer data and characterization theorems for the Random Utility Model. These new approaches come with significant econometric challenges, which we show how to address. We apply the resulting tests to an exploratory data set of choices over lotteries.
This item is currently under embargo. It will be available starting 2026-06-07.
More About This Work
- Academic Units
- Thesis Advisors
- Kartik, Navin
- Ph.D., Columbia University
- Published Here
- June 15, 2021