Decoding Political Polarization in Social Media Interactions
Giulio Pecile, Niccolò Di Marco, Matteo Cinelli, Walter Quattrociocchi
TL;DR
The paper addresses how political polarization manifests in social media by quantifying selective exposure in large-scale Facebook interactions with news pages across five bias categories. It uses Shannon entropy to measure concentration of engagement and two null models—strong and weak randomizations—to test whether political bias drives page-level selectivity beyond simple popularity. Key findings show pervasive leaning-driven selectivity, particularly among center-left users, with pages and biases interacting to shape engagement patterns; center-left and centrist likes are especially informative of political affiliation. The work provides a robust framework for analyzing ideological fragmentation online and offers methods for distinguishing bias-driven behavior from random or popularity-based effects, with implications for understanding echo chambers and designing interventions.
Abstract
Social media platforms significantly influence ideological divisions by enabling users to select information that aligns with their beliefs and avoid opposing viewpoints. Analyzing approximately 47 million Facebook posts, this study investigates the interactions of around 170 million users with news pages, revealing distinct patterns based on political orientations. While users generally prefer content that reflects their political biases, the extent of engagement varies even among individuals with similar ideological leanings. Specifically, political biases heavily influence commenting behaviors, particularly among users leaning towards the center-left and the right. Conversely, the 'likes' from center-left and centrist users are more indicative of their political affiliations. This research illuminates the complex relationship between social media behavior and political polarization, offering new insights into the manifestation of ideological divisions online.
