Information theory links multimodal learning challenges and methods
Dependency, Compression, and Synergy: A Unified Information-Theoretic View of Multimodal Learning
Information Theory
Summary
Multimodal learning combines different types of information like images, text, and audio into one system. The authors connect three math ideas—mutual information, information bottleneck, and partial information decomposition—that explain how these types of data share and keep useful details. They studied many recent works and organized them around key problems like aligning data, combining it efficiently, and understanding their interactions. Their work helps to see different methods as points in a bigger framework and suggests new ways to build future systems.
What this means in practice
- •For healthcare data teams: Improve multimodal patient data integration by selecting methods based on shared and unique information insights from this survey.
- •For robotics engineers: Design robot perception systems by applying information-theoretic trade-offs in sensor fusion and data compression highlighted in this work.
A survey. It maps existing work.
Authors
Liangjian Wen, Linjie Li, Jiang Duan, Yong Dai, Jianzhuang Liu, Zhao Kang
Abstract
Recent advances in multimodal foundation models have intensified the need to understand how different modalities share, preserve, and complement information. Mutual Information (MI), the Information Bottleneck (IB), and Partial Information Decomposition (PID) provide complementary perspectives, yet existing studies often treat them as isolated tools. This survey presents an information-theoretic perspective connecting these principles as progressively refined views of multimodal information processing: MI characterizes inter-modal dependency, IB explains task-oriented information preservation under compression, and PID decomposes preserved information into redundancy, uniqueness, and synergy. We review 170 recent studies (2018--2026) and 12 foundational works, organizing multimodal learning around four challenges: cross-modal alignment, information-efficient fusion, interaction-type characterization, and scaling to multimodal foundation models. Rather than using application domains as primary taxonomy axes, we interpret healthcare, robotics, recommendation systems, affective computing, and wireless communications as empirical validations of these information principles. Beyond taxonomy, we organize existing multimodal paradigms within a single information-theoretic coordinate system -- the Generalized Multimodal Information Lagrangian -- in which they occupy exact or approximate parameter corners, and whose unoccupied regions name candidate method families the literature has not yet built. We further discuss how emerging multimodal foundation models instantiate these principles at scale and identify open challenges including scalable information estimation in high-dimensional settings, standardized evaluation across information-theoretic methods, combinatorial complexity of multimodal PID, and the transition from post-hoc information analysis toward information-aware multimodal learning.