Self-selection of Information and Belief Update: An Experiment on COVID-19 Vaccine Information Acquisition

TL;DR

This study uses a randomized experiment in Taiwan to examine how individuals' self-selected information influences belief updating about COVID-19 vaccines, revealing that people update beliefs more when they choose the information they receive.

Contribution

It introduces an experimental method to disentangle information selection from exposure, showing that self-selected information significantly impacts belief change.

Findings

Subjects prefer information about vaccines they perceive as more effective.

Belief updating is larger when individuals choose the information they receive.

Endogenous information demand influences persuasion beyond mere information availability.

Abstract

How does the endogenous selection of information shape belief formation? In observational settings, individuals only consume information they choose, making it impossible to observe how they would respond to information they actively avoid. We address this identification challenge using a randomized experiment on COVID-19 vaccines in Taiwan. After eliciting subjects' preferences over vaccine-specific reports, we randomly assign them to receive either their chosen or unchosen information, orthogonalizing selection from exposure. We find subjects are more likely to select information about vaccines they already perceive as more effective. Conditional on receiving information, belief updating is substantially larger when the information was self-selected, even after controlling for prior-posterior disagreement. These findings highlight endogenous information demand as a central determinant of persuasion, suggesting that increasing information availability alone may be insufficient when individuals rationally filter out options they perceive as less relevant to their decision-making.