Textual Time Capsule: A Text-Based Approach for Elite Polarization over 130 Years

• In Event: Understanding Legislative Debates

Abstract

Increased polarization has long been lamented as a sign of democratic instability and erosion. It is a phenomenon constantly postulated to have increased in the past few decades. However, this has yet to be studied over a prolonged period, and Switzerland is no exception. Thus, we ask whether this claim still holds when studying polarization over the past 130 years in the Swiss parliament. The Swiss parliament represents an interesting case to study, given its multi-party environment with weak party cohesion and a strong sense of consensus.
To achieve this, we employ text embeddings to compute multi-dimensional representations of Swiss parliament members based on the legislative bills introduced from 1891 to today. We build upon the SwissBERT model, a Switzerland-specific model based on the XMOD architecture. Furthermore, to enhance the model’s understanding of language structure and context, we fine-tune SwissBERT using masked language modeling (MLM) on parliamentary texts, encompassing speeches and bill texts. Additionally, we train the embeddings to predict party class. Finally, we employ a multi-dimensional variance-based polarization measure to study polarization trends in the Swiss Parliament over 120 years. Our findings indicate that, while polarization has indeed increased, this trend began in the 1970s and reached its peak in the 1990s. Furthermore, we show how polarization varies across different political topics over 120 years.

Authors

• Sophia Schlosser

• Laurence Brandenberger