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From Tweets to Model-Based Causal Spans: Noise-Robust Transformers for Social Media Sentiment Analysis in the Age of LLMs
Proceedings of the The 39th Canadian Conference on Artificial Intelligence, PMLR 318:880-887, 2026.
Abstract
Social media text is short, noisy, and rapidly evolving. Transformer-based sentiment models like BERTweet are brittle under lexical noise and offer limited explainability. We propose the Noise-Robust Causal Transformer (NRCT), which augments BERTweet with a contrastive objective that aligns semantically equivalent but lexically perturbed tweets, and a causal attention head trained to highlight sparse token spans that drive the model’s prediction. On Sentiment140 and TweetEval-Sentiment, NRCT matches clean accuracy, improves macro-F1 under synthetic noise, and produces token rationales that are more faithful than standard attention (higher deletion/insertion AUC). NRCT offers a practical trade-off be- tween accuracy, robustness, and model-based interpretability for social media sentiment analysis.