Social media and democratic deliberation

Lewis, Nick (2025) Social media and democratic deliberation. PhD thesis, London School of Economics and Political Science.

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Abstract

The internet continues to have a profound influence upon political communication. Have social media changed the language we use to talk about politics, made particular voices more prominent in online discussions, or even led people to turn away from democratic deliberation entirely? In three distinct papers, this thesis explores each of these questions in turn, making the following theoretical, methodological, and practical contributions. First, using a novel dataset of 4 million tweets, paper 1 shows how political elites in the United Kingdom have used increasingly emotive rhetoric over time on Twitter. I argue this changing rhetorical behaviour has been influenced by, and rewarded with, greater engagement. Paper 2 also employs new data, linking a nationally-representative survey of the UK population with Twitter accounts, to show that people who discuss politics on Twitter are more ideologically and affectively extreme than those who do not. These findings have important implications for understanding who we are most likely to hear in online political discussion, and for increasingly-polarised online political debate. Finally, in a pre-registered lab-in-the-field experiment on Facebook, I argue that people disengage from discussing contentious political issues in groups of people with contrasting opinions and beliefs. In conducting a real-world experiment which attempts to causally identify why people turn away from political discussion, this study represents a methodological advance on existing survey-based research, and understanding the key drivers of online self-censorship may help mitigate some of its most negative consequences. Overall, these findings contribute to our understanding of how social media is influencing the scope and tone of democratic debate.

Item Type:	Thesis (PhD)
Additional Information:	© 2025 Nick Lewis
Library of Congress subject classification:	J Political Science > JA Political science (General) J Political Science > JC Political theory J Political Science > JN Political institutions (Europe) > JN101 Great Britain P Language and Literature > P Philology. Linguistics
Sets:	Departments > Government
Supervisor:	Hobolt, Sara and Berliner, Daniel
URI:	http://etheses.lse.ac.uk/id/eprint/4830

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