by Salvatore Nunnari and Giovanni Montanari
This paper presents a model of selective exposure to information and an experiment to test its predictions. An agent interested in learning about an uncertain state of the world can acquire information from one of two sources which have opposite biases: when informed on the state, they report it truthfully; when uninformed, they report their favorite state. When sources have the same reliability, a Bayesian agent is better off seeking confirmatory information. On the other hand, it is optimal to seek contradictory information if and only if the source biased against the prior is sufficiently more reliable. We test these predictions with an online experiment. When sources are symmetrically reliable, subjects are more likely to seek confirmatory information but they listen to the other side too frequently. When sources are asymmetrically reliable, subjects are more likely to consult the more reliable source even when prior beliefs are strongly unbalanced and listening to the less reliable source is more informative. Moreover, subjects follow contradictory advice sub-optimally; are too trusting of information in line with a source bias; and too skeptic of information misaligned with a source bias. Our experiment suggests that biases in information processing and simple heuristics - e.g., listen to the more reliable source - are important drivers of the endogenous acquisition of information.
JEL Codes: C91, D81, D83, D91
Keywords: Choice under Uncertainty, Information Acquisition, Bayesian Updating, Selective Exposure, Conrmation Bias, Limited Attention, Online Experiment