The Brain's Financial System: A Game Theory of Dopamine, Serotonin, and the Lateral Habenula[大脑财务系统]

Dopamine, serotonin, and the lateral habenula have long been mislabeled as the "pleasure molecule," "mood stabilizer," and "anti-reward center." These labels obscure a deeper truth: they constitute the brain's built-in decision-value evaluation system—a precise Brain Financial System. This book presents a unified framework that redefines the three systems as: · Dopamine = Benefit Expectation · Serotonin = Loss Expectation · Lateral Habenula = Cost Expectation Together, they report to the "CEO"—the prefrontal cortex—which computes Decision Net Value: Decision Net Value = Benefit Expectation − Loss Expectation − Cost Expectation If net value is positive, act; if negative, refrain; if near zero, hesitate. This formula is not a metaphor—it is a neural computation model supported by independent experimental evidence: dopamine reward prediction error (Schultz, 1997), serotonin loss assessment (Colwell, 2024; Neukam, 2018; ATD experiments), and lateral habenula cost accounting (Sevigny, 2021). The book further extends this framework to explain a range of phenomena: · The Buffett Threshold: the tipping point at which expected benefit exceeds expected loss, determining whether decisions lean toward risk-taking or conservatism; · The Anti-Fishing Circuit: when reward disappears, the lateral habenula triggers a healthy "stop investing" program (Post, 2022); · The Despair Circuit: when the lateral habenula becomes locked in burst-firing, cost signals are fixed at infinity, rendering net value negative for all options—the neural essence of learned helplessness (Yang, 2018); · The Serotonin No-Go Executor: serotonin, via 5-HT2C receptors, activates D2-MSNs to physically apply the brake at the action level (Malenka & Cardozo Pinto, 2026; Härmson, 2021); · The Dual-Baseline Theory: the tonic levels of dopamine and serotonin jointly determine emotional immunity, delayed gratification capacity, and decision stability. The book also applies this framework to explain social and pathological phenomena—the overjustification effect, involution, workplace apathetic disengagement, drug addiction, anxiety disorders, and depression—and discusses its practical implications for education, workplace management, business, and the boundaries of artificial intelligence. The brain is not a passive emotional machine—it is a holding company with its own Reward Department, Risk Department, and Cost Department. Understanding how this system operates is the starting point for understanding human decision-making—and when it fails. Keywords: Brain Financial System; dopamine; serotonin; lateral habenula; benefit expectation; loss expectation; cost expectation; decision net value; Buffett Threshold; Anti-Fishing Circuit; Despair Circuit; dual-baseline theory 中文摘要 多巴胺、血清素和外侧缰核被长期误解为“快乐分子”、“情绪稳定剂”和“反奖赏中心”。这些标签掩盖了一个更深层的真相:它们构成了大脑内置的决策价值评估系统——一个精密的大脑财务系统。 本书提出一个统一框架,将三个系统重新定义为: · 多巴胺 = 预期收益(Benefit Expectation) · 血清素 = 预期亏损(Loss Expectation) · 外侧缰核 = 预期成本(Cost Expectation)