Potential and Pitfalls of Audio as Data for Political Research: Alignment, Features, and Classification Models

Political science is a field rich in multimodal information sources, from televised debates to parliamentary briefings. This paper bridges a gap between computer and political science in multimodal data analysis using audio. The adoption of multimodal analyses in political science (e.g., video/audio with text-as-data approaches) has been relatively slow due to unequal distribution of computational power and skills needed. We provide solutions to challenges encountered when analyzing audio, advancing the potential for multimodal data analysis in political science. Using a dataset of all televised U.S. presidential debates from 1960 to 2020, we focus on three features encountered when analyzing audio data: low-level descriptors (LLDs), such as pitch or energy; Mel-frequency cepstral coefficients (MFCCs); and audio embeddings/encodings, like Wav2Vec. We showcase four applications: (a) forced alignment of audio text using MFCCs, time-stamping transcripts, and speaker information; (b) speech characterization using LLDs; (c) custom-made classification models with audio embeddings and MFCCs; and (d) emotional recognition models using Wav2Vec for classification of discrete emotions and their valence-arousal dominance. We provide explanations to help understand how these features can be applied for different political research questions and advice on vigilance to naive interpretation, for both experienced researchers and those who want to start working with audio.