Ideological and Temporal Components of Network Polarization in Online Political Participatory Media

TL;DR

This paper empirically examines online political network polarization on politnetz.ch, revealing strong intra-party cohesion, temporal increases near elections, and links between social structure and ideology.

Contribution

It introduces a multiplex network analysis of online political interactions, highlighting how different interaction layers and temporal dynamics relate to polarization and ideology.

Findings

Supports are highly polarized along party lines.

Likes polarization increases near elections.

Party social structures correlate with ideological positions.

Abstract

Political polarization is traditionally analyzed through the ideological stances of groups and parties, but it also has a behavioral component that manifests in the interactions between individuals. We present an empirical analysis of the digital traces of politicians in politnetz.ch, a Swiss online platform focused on political activity, in which politicians interact by creating support links, comments, and likes. We analyze network polarization as the level of intra- party cohesion with respect to inter-party connectivity, finding that supports show a very strongly polarized structure with respect to party alignment. The analysis of this multiplex network shows that each layer of interaction contains relevant information, where comment groups follow topics related to Swiss politics. Our analysis reveals that polarization in the layer of likes evolves in time, increasing close to the federal elections of 2011. Furthermore, we analyze the internal social network of each party through metrics related to hierarchical structures, information efficiency, and social resilience. Our results suggest that the online social structure of a party is related to its ideology, and reveal that the degree of connectivity across two parties increases when they are close in the ideological space of a multi-party system.