Model-Driven Validation of Visual Explanations for Multimodal Emotion Recognition

Abstract

Abstract AI-based emotion recognition approaches may benefit from the integration of multimodal data, but their explainability and validation is still a critical challenge. Indeed, the limited neurophysiological understanding of novel multimodal features, e.g. brain-heart interaction, can be insufficient to assess whether the AI-extracted physiological insights (i.e., the model explanations) accurately reflect the real underlying physiological processes. To validate the explanations obtained by an AI-based model in this context, we introduce a novel framework that autonomously identifies the optimal explanations for a black-box model used in emotion recognition. Our approach leverages a convolutional neural network to process BHI features, which are derived from EEG and HRV data and rearranged as images. A model-agnostic methodology is employed to extract local explanations, which are then dynamically evaluated to select the most accurate for representing specific emotional states. The effectiveness of the proposed framework is evaluated across multiple classification tasks, including up to 9-level arousal and valence emotion classification, as well as nine discrete emotions classification, using the MAHNOB-HCI and DEAP datasets. The system achieved remarkable accuracy levels, consistently reaching approximately 97–98% across all tasks. Furthermore, our dynamic selection framework revealed that Integrated Gradients outperformed other state-of-the-art explainable AI approaches in reliably capturing global explanations.