Perceive before Respond: Improving Sticker Response Selection by Emotion Distillation and Hard Mining

In online chatting, people increasingly prefer using stickers to supplement or replace text for replies, as sticker images can express vivid and varied emotions. The Sticker Response Selection (SRS) task aims to predict the sticker image that is most relevant to the history dialogue. Previous researches explore the semantic similarity between context and stickers, overlooking both unimodal and cross-modal emotional information. In this paper, we propose a 'Perceive before Respond' (PBR) training paradigm. PBR perceives sticker emotions through a knowledge distillation module. Variety representations of each emotion category are acquired from the large-scale sticker emotion recognition dataset and distilled into our model to enhance emotion comprehension. We further distinguish stickers with similar subject elements under the same topic. We perform contrastive learning at both inter- and intra-topic levels to obtain discriminative and diverse sticker representations. In addition, we improve the hard negative sampling method for image-text matching based on cross-modal sentiment association, conducting hard sample mining from both semantic similarity and sentiment polarity similarity for sticker-to-dialogue and dialogue-to-sticker. Extensive experiments verify the effectiveness of each proposed component. Ablation experiments on different backbone networks demonstrate the generality of our approach. Our code is released on https://github.com/wuyou-xia/Perceive-before-Respond.