Multi-Level Counterfactual Contrast for Visual Commonsense Reasoning

Given a question about an image, a Visual Commonsense Reasoning (VCR) model needs to provide not only a correct answer, but also a rationale to justify the answer. It is a challenging task due to the requirements of diverse visual content understanding, abstract language comprehending, and complicated inter-modality relationship reasoning. To solve above challenges, previous methods either resort to holistic attention mechanism or explore transformer-based model with pre-training, which, however, cannot perform comprehensive understanding and usually suffer from heavy computing burden. In this paper, we propose a novel multi-level counterfactual contrastive learning network for VCR by jointly modeling the hierarchical visual contents and the inter-modality relationships between the visual and linguistic domains. The proposed method enjoys several merits. First, with sufficient instance-level, imagelevel, and semantic-level contrastive learning, our model can extract discriminative features and perform comprehensive understanding for the image and linguistic expressions. Second, taking advantage of counterfactual thinking, we can generate informative factual and counterfactual samples for contrastive learning, resulting in stronger perception ability of our model. Third, an auxiliary contrast module is incorporated into our method to directly optimize the answer prediction in VCR, which further facilitates the representation learning. Extensive experiments on the VCR dataset demonstrate that our approach performs favorably against the state-of-the-arts.