Understanding the Roles of Humans, algorithms, and cyborgs in political polarization

Recent studies revealed more increasingly political polarization in the distribution and consumption of political news. Political polarization demonstrates the disagreement between people aligned with different ideologies or political parties (e.g. left vs. right, Democrats vs. Republicans). Increasingly political polarization can have negative effects on our society; for example, extreme cases influenced by the left/right ideology can lead to massive bombing or shooting incidents. Thus, through four different research streams this thesis will help people to understand the roles of humans, algorithms, and cyborgs in political polarization.

In terms of humans, prior research has shown that people are mainly consuming news conforming to their pre-existing beliefs. People also prefer to have homophilous social interactions. Both of these lead to political polarization. Thus, to help inform the political slant of news people consume, we develop a lightweight and scalable news slant measurement using Twitter. Moreover, utilizing this method to estimate each Twitter user as a Republican or Democrat, we analyze political discourse on Twitter communications in the combination of three aspects including political affiliation, personality perception, and policy discussion around several main candidates from both parties during the 2016 U.S. presidential election.

In terms of algorithms, researchers have recently started to question whether algorithms create distinct personalized experiences for users, which can unintentionally contribute to a more polarized society. Thus, it is important to study the roles of personalization algorithms employed by search engines and social media in reinforcing pre-existing biases. To this end, we examine the personalization of Google News Search based on the users’ browsing history, especially when it comes from the users with different political biases.

In terms of cyborgs, there have been numerous reports of widespread misinformation campaigns during the 2016 U.S. presidential election. Of particular notes, there are reports which identified the efforts to manipulate social media (e.g. Twitter, Facebook) by the Russian state-sponsored accounts. These external manipulations by cyborgs cause significant pressure on social media services to mitigate spam, abuse, and political polarization on their platforms. Specifically, Twitter publicly acknowledged the exploitation of their platform and has since conducted aggressive cleanups to suspend the involved accounts. To shed light on Twitter’s countermeasures, we conduct a postmortem analysis of about one million Twitter accounts who engaged in the 2016 U.S. presidential election but were later suspended by Twitter.