The Internet has given new opportunities to those who wish to interfere and disrupt society through the systematic manipulation of social media. One goal of these cyber-enabled information operations is to increase polarisation in Western societies by stoking both sides of controversial debates. Whether these operations are successful remains unclear. This paper describes how novel applications of computational techniques can be used to test the impact of historical activity from the Russian Internet Research Agency (IRA) on two social media platforms: Twitter and Reddit. We show that activity originating from the Russian IRA had a measurable effect on the subsequent conversations of genuine users. On Twitter, increases in Russian IRA activity predicted subsequent increases in the degree of polarisation of the conversation surrounding the Black Lives Matter movement. On Reddit, comment threads started by Russian IRA accounts contained more toxic language and identity-based attacks. We use causal analysis modelling to further show that Russian IRA activity in existing threads caused measurable changes in the conversational quality of the following 25-100 posts. By developing methods to measure the impact of information operations in online conversations and demonstrating a measurable effect on genuine conversations, our study provides an important step in developing effective countermeasures.

Keywords—information operations, social media, social psychology, group polarisation, disinformation, strategic communications 

About the Authors 

John D. Gallacher is a Cyber Security DPhil student at the University of Oxford working with the department of Experimental Psychology and the Oxford Internet Institute. 

Dr Marc W. Heerdink is an Assistant Professor of Social Psychology at the University of Amsterdam, where he also obtained his PhD, and a former visiting postdoc at the University of Oxford. 


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