A Systematic Review of 128 Spontaneous and Dynamic Facial Expression Databases

In the past decade, spontaneous and dynamic facial expression databases (FEDBs) have expanded rapidly, advancing emotion research beyond static, posed expressions. Yet existing reviews remain fragmented due to limited search strategies and a lack of systematic methods. This article synthesizes 128 spontaneous and dynamic FEDBs, examining their conceptual, technical, and practical dimensions. It summarizes how emotions are represented, measured, and validated across diverse populations; how databases vary in composition, recording methods, and modalities; and how accessibility, usability, and ethics shape their use. By integrating these perspectives, the review consolidates current knowledge, identifies methodological gaps, and outlines directions for developing more diverse and ecologically valid FEDBs that better capture the complexity of human emotion.