Consistency-Aware Gated Fusion with Mamba for Multimodal Sentiment Analysis
Multimodal sentiment analysis has attracted increasing attention due to the prevalence of text-image content on social media. A central challenge is to design fusion mechanisms that are both expressive and parameter-efficient, especially for small-scale datasets where heavy cross-modal attention can easily overfit. In this paper, we present Consistency-Aware Gated Fusion (CAGF), a lightweight and fusion module tailored to Mamba-based architectures. Our key idea is to exploit Mamba's bidirectional scanning mechanism: forward and backward hidden states from text and image encoders are concatenated to form enhanced representations, and a cosine-based semantic consistency score is computed between modalities. This score is then passed through a fixed sigmoid gate to adaptively weight text and image features, without introducing any additional learnable parameters. CAGF is plug-and-play compatible with dual-stream Mamba encoders and incurs negligible computational overhead compared with attention-based fusion. Experiments on the MVSA-Single dataset show that CAGF achieves state-of-the-art performance (Acc=82.54%, F1=84.82%), outperforming strong multimodal baselines such as CLIP, MISA, DLF, AoM, and SFTTR, while remaining more efficient and interpretable. Extensive ablations and sensitivity analyses further validate that bidirectional scanning, enhanced representations, and consistency-aware gating are all critical to the observed gains.