Improving Implicit Sentiment Learning via Local Sentiment Aggregation

Aspect-based sentiment classification (ABSC) has revealed the potential dependency of sentiment polarities among different aspects. Our study further explores this phenomenon, positing that adjacent aspects often exhibit similar sentiments, a concept we term "aspect sentiment coherency." We argue that the current research landscape has not fully appreciated the significance of modeling aspect sentiment coherency. To address this gap, we introduce a local sentiment aggregation paradigm (LSA) that facilitates fine-grained sentiment coherency modeling. This approach enables the extraction of implicit sentiments for aspects lacking explicit sentiment descriptions. Leveraging gradient descent, we design a differential-weighted sentiment aggregation window that guides the modeling of aspect sentiment coherency. Experimental results affirm the efficacy of LSA in learning sentiment coherency, as it achieves state-of-the-art performance across three public datasets, thus significantly enhancing existing ABSC models. We have made our code available, providing a ready tool for existing methods to harness the potential of sentiment coherency information.