Diversifying channels or diversifying information? Panel data analysis of polarization in the contentious pension reform

Escalating political polarization has threatened democratic governance, but how can we reduce polarization? Existing literature holds opposite views on the effects of newly emerged social media platforms, debating whether the increase in online channel diversification or the influence of echo-chamber exposure may further change the landscape of political polarization. We hypothesize an interactive effect between channel and information diversification, proposing that the extent to which additional information channels reduce issue polarization is contingent on the diversification of information to which individuals are exposed through multiple online channels. This article utilizes valuable panel data (n = 688) from an unlikely case, examining civil servants’ attitudes toward Taiwan’s Civil Service Pension Reform in 2018, wherein pre-reform polarization among civil servants culminated in deadly protests. Analysis of the ordinal logit models suggests that increased channel diversification mitigates issue polarization for individuals who remain within a homogeneous information environment, but exposure to diverse and conflicting information across multiple channels intensifies polarization. The result is robust through various tests. Our findings highlight the heterogeneous effect of channel and information diversification on issue polarization and offer both theoretical and practical implications for understanding the mechanisms through which information environments shape policy perceptions.