Reducing Spurious Correlations for Aspect-Based Sentiment Analysis with Variational Information Bottleneck and Contrastive Learning

The literature on aspect-based sentiment analysis (ABSA) has been overwhelmed by deep neural networks, yielding state-of-the-art results for ABSA. However, these deep models are susceptible to learning spurious correlations between input features and output labels, which in general suffer from poor robustness and generalization. In this paper, we propose a novel Contrastive Variational Information Bottleneck framework (called CVIB) to reduce spurious correlations for ABSA. The proposed CVIB framework is composed of an original network and a self-pruned network, and these two networks are optimized simultaneously via contrastive learning. Concretely, we employ the Variational Information Bottleneck (VIB) principle to learn an informative and compressed network (self-pruned network) from the original network, which discards the superfluous patterns or spurious correlations between input features and prediction labels. Then, self-pruning contrastive learning is devised to pull together semantically similar positive pairs and push away dissimilar pairs, where the representations of the anchor learned by the original and self-pruned networks respectively are regarded as a positive pair while the representations of two different sentences within a mini-batch are treated as a negative pair. Extensive experiments on five benchmark ABSA datasets demonstrate that our CVIB method achieves better performance than the strong competitors in terms of overall prediction performance, robustness, and generalization.