Detection of Conspiracy Theories Beyond Keyword Bias in German-Language Telegram Using Large Language Models

Milena Pustet, Elisabeth Steffen, Helena Mihaljevic


Abstract
The automated detection of conspiracy theories online typically relies on supervised learning. However, creating respective training data requires expertise, time and mental resilience, given the often harmful content. Moreover, available datasets are predominantly in English and often keyword-based, introducing a token-level bias into the models. Our work addresses the task of detecting conspiracy theories in German Telegram messages. We compare the performance of supervised fine-tuning approaches using BERT-like models with prompt-based approaches using Llama2, GPT-3.5, and GPT-4 which require little or no additional training data. We use a dataset of ∼4, 000 messages collected during the COVID-19 pandemic, without the use of keyword filters.Our findings demonstrate that both approaches can be leveraged effectively: For supervised fine-tuning, we report an F1 score of ∼ 0.8 for the positive class, making our model comparable to recent models trained on keyword-focused English corpora. We demonstrate our model’s adaptability to intra-domain temporal shifts, achieving F1 scores of ∼0.7. Among prompting variants, the best model is GPT-4, achieving an F1 score of ∼0.8 for the positive class in a zero-shot setting and equipped with a custom conspiracy theory definition.
Anthology ID:
2024.woah-1.2
Volume:
Proceedings of the 8th Workshop on Online Abuse and Harms (WOAH 2024)
Month:
June
Year:
2024
Address:
Mexico City, Mexico
Editors:
Yi-Ling Chung, Zeerak Talat, Debora Nozza, Flor Miriam Plaza-del-Arco, Paul Röttger, Aida Mostafazadeh Davani, Agostina Calabrese
Venues:
WOAH | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
13–27
Language:
URL:
https://preview.aclanthology.org/fix-sig-urls/2024.woah-1.2/
DOI:
10.18653/v1/2024.woah-1.2
Bibkey:
Cite (ACL):
Milena Pustet, Elisabeth Steffen, and Helena Mihaljevic. 2024. Detection of Conspiracy Theories Beyond Keyword Bias in German-Language Telegram Using Large Language Models. In Proceedings of the 8th Workshop on Online Abuse and Harms (WOAH 2024), pages 13–27, Mexico City, Mexico. Association for Computational Linguistics.
Cite (Informal):
Detection of Conspiracy Theories Beyond Keyword Bias in German-Language Telegram Using Large Language Models (Pustet et al., WOAH 2024)
Copy Citation:
PDF:
https://preview.aclanthology.org/fix-sig-urls/2024.woah-1.2.pdf