Communication ties and political polarization in the Dutch parliamentarians’ Twitter network
Marc Esteve Del ValleA growing body of research has examined issues related to the formation of networked communication ties (González-Bailón & Wang, 2016; Esteve Del Valle & Borge, 2018) and political polarization (Barberá et al, 2015; Takikawa & Nagayoshi, 2017) in online political networks, but few studies have analyzed how new media are affecting communications among parliamentarians (Esteve Del Valle & Borge, 2017). This despite the fact that the understanding of the implications of the changes among MPs’ communications is key to evaluate how new media affect parliamentary debates. To fill this lacuna, this study answers the following two questions related to MPs’ use of Twitter: first, what are the network characteristics and the MPs’ attributes influencing MPs’ likelihood of forming communication ties in Twitter parliamentary networks? And second, are MPs’ communications in online parliamentary Twitter networks foregrounding political polarization?
To answer these questions, we collected all the mentions (N= 7,352) tweeted by Dutch parliamentarians (144 MPs out of 150, that is, 96% of all the Dutch MPs) over one year (2016). We chose that period because we did not want the results of our study to be affected by electoral contests. Moreover, we decided to study the Dutch MPs’ mentions Twitter network because previous research has shown that while the following-follower and the retweet networks are concentrated on popular parliamentarians and highly polarized (Conover et al., 2011; Hsu & Park, 2012; Yoon & Park, 2014), the mention network is more decentralized, shows more cross-party and cross-ideological connections (Esteve Del Valle & Borge, 2018), and is more reflective of MPs’ personalized communication behavior (Thamm & Bleier, 2013). We employed Exponential Random Graph (ERG) models (Hunter et al, 2008; Lusher et al., 2012) to discover the network mechanisms (reciprocity, popularity, and brokerage) and the MPs’ attributes (political position, party, participation in the parliamentary commissions, seniority, location, gender, and age) facilitating communication ties among Dutch parliamentarians. Furthermore, we measured party polarization by calculating the external-internal (E-I) index (Krackhardt & Stern, 1988) of the Dutch MPs’ mentions.
We found evidence that Dutch MPs’ communication ties arise from network dynamics (reciprocity, brokerage and popularity) and from MPs’ political position, participation in the parliamentary commission, location, age and gender. Moreover, we discovered a high degree of cross-party and cross-ideological interactions in the Dutch MPs’ mentions Twitter network.
This study provides empirical evidence for understanding social media networks and how they are challenging communications in parliament. The tools used in this research can also be applied to the analysis of other parliamentary and political networks. Furthermore, we seek to explain parliamentarians’ communication ties through a set of network parameters, MPs’ characteristics, and cross-ideological interactions. As far as we know, this is the first study that explains the Dutch online parliamentary network by means of network dynamics, MPs’ attributes and cross-ideological interactions.