Emotional Adaptation Theory: A Three-Layer Theoretical Framework with Dynamic Balance as the Ideal Standard

Objective: Emotion regulation research has long been constrained by a fundamental fallacy that equates emotional calmness with emotional health. Traditional single-target interventions treat the elimination of emotion as equivalent to clinical cure, while neglecting that healthy emotional system function relies on flexible alternation between sympathetic and parasympathetic dominance. This study aims to establish a unified theoretical framework that explains the generative mechanism, adaptive function, and health standard of emotion, while addressing core limitations of the predictive coding framework.Methods: This research systematically constructs a three-layer theoretical system centered on adaptation as the core goal, adaptive command as the implementation mechanism, and dynamic balance as the ideal standard. It integrates a dual-loop emotion operation mechanism, interoceptive reuse model, six-dimensional assessment system, and dual quantitative tools, with the emotional dynamic balance coefficient θ as the core quantitative indicator. The attractor property of θ=0.5 is rigorously proven via the Lyapunov stability theorem, and four strongly falsifiable predictions with clear verification protocols are proposed.Results: The framework systematically revises five core limitations of the predictive coding account of emotion, and provides a unified explanation for three long-standing central debates in contemporary emotion psychology: the nature-versus-construction debate on emotion origins, the existence of physiological fingerprints for discrete emotions, and the reality of non-cognitive emotions. It also offers a principled theoretical anchor for the ongoing paradigm shift from static homeostasis to dynamic balance in clinical intervention guidelines (e.g., National Institute for Health and Care Excellence [NICE], 2025).Conclusions: Emotion is a global, dual-system adaptive command initiated by the central nervous system to synchronize psychological behavior and somatic physiology for adaptive matching between internal and external environments. The ideal health standard of the emotional system is the dynamic functional alternation between sympathetic-dominant and parasympathetic-dominant emotional states (θ≈0.5), rather than static affect-free homeostasis. This theory achieves the integration and transcendence of basic emotion theory, constructionism, and the predictive coding framework, with both formal rigor and clinical applicability.