Essays in political economy of media and communication
Massachusetts Institute of Technology. Department of Economics.
Benjamin A. Olken and Daron Acemoglu.
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This thesis consists of three chapters on the role of media and communication in forming political opinions of news consumers and politicians. In the first chapter, I study the causal link between the public's self-selective exposure to like-minded partisan media and polarization. I first present a parsimonious model to formalize a traditionally neglected channel through which media selection leads to reduced polarization. In a world where the media heavily distorts signals with its own partisan preferences, familiarity with media biases is vitally important. By choosing like-minded partisan media, news consumers are exposed to familiar news sources. This may enable them to arrive at better estimates of the underlying truth, which can contribute to an alleviation of polarization. The predictions of this model are supported by experimental evidence collected from a South Korean mobile news application that I created and used to set up an RCT. The users of the app were given access to curated articles on key political issues and were regularly asked about their views on those issues. Some randomly selected users were allowed to select the news source from which to read an article; others were given randomly selected articles. The users who selected their news sources showed larger changes in their policy views and were less likely to have radical policy views-an alleviation of polarization-in comparison with those who read randomly provided articles. The belief updating and media selection patterns are consistent with the model's predictions, suggesting that the mechanism explained in the model is plausible. The findings suggest that the designers of news curation algorithms and their regulators should consider the readers' familiarity with news sources and its consequences on polarization. The second chapter, coauthored with Matt Lowe, investigates whether there would be less polarization if politicians were physically integrated. This chapter tackles this question by exploiting random seating in Iceland's national Parliament. Since almost all voting is along party lines, we use a text-based measure of language similarity to proxy for the similarity of beliefs between any two politicians. Using this measure, we find an in-coalition effect: language similarity is greater for two politicians that share the same political coalition (government coalition or opposition) than for two politicians that do not, suggesting that the measure captures meaningful partisan differences in language. Next, we find that when two MPs randomly sit next to each other, their language similarity in the next parliamentary session (when no longer sitting together) is significantly higher, an effect that is roughly 16 to 25 percent of the size of the in-coalition effect. The persistence of effects suggests that politicians are learning from their neighbors, not just facing transient social pressure. However, this learning does not reflect the exchange of ideas across the aisle.- The effects are large for neighbors in the same coalition group, at 29 to 53 percent of the in-coalition effect, with no evidence of learning from neighbors in the other group. Based on this evidence, integration of legislative chambers would likely slow down, but not prevent, the ingroup homogenization of political language. The third chapter examines how the news media affects news consumers' perceptions about the importance of political issues via their editorial choices of which articles to emphasize, and how such an agenda setting effectcan influence readers' political attitudes. This chapter reports on a preliminary analysis of a pilot study of a randomized controlled trial conducted on Amazon Mechanical Turk (MTurk). There are two potential causal mechanisms through which editorial choices of article prominence can influence subjective issue importance-(i) readers' behavioral biases such as cognitive fatigue and short-term memory congestion can lead to selection of salient articles at prominent positions (salience), (ii) prominence of articles reflects the subjective issue importance of news editors, which can guide the readers to select to read such articles (guidance). I find both salience and guidance mechanisms to influence article selection. There is suggestive evidence that article selection, and subsequent exposure to the content, results in changes in readers' subjective issue importance. This pilot study successfully reveals important-yet surmountable-limitations of the study; lessons from the pilot study will be incorporated in the full-scale experiment.
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Economics, 2018.Cataloged from PDF version of thesis.Includes bibliographical references (pages 155-164).
DepartmentMassachusetts Institute of Technology. Department of Economics.; Massachusetts Institute of Technology. Department of Economics
Massachusetts Institute of Technology