2025

Understanding Reinforcement Learning from Human Feedback (RLHF)

Reinforcement Learning from Human Feedback (RLHF) is a powerful machine learning technique that enhances the alignment of artificial intelligence (AI) systems with human preferences. By integrating human feedback into the training process, RLHF has become a cornerstone for fine-tuning large language models (LLMs) such as GPT-4 and Claude, enabling them to generate more accurate, helpful, and contextually appropriate outputs.

How RLHF Works

RLHF involves a three-phase process that combines supervised learning and reinforcement learning:

1. Supervised Pretraining: The model is pretrained on large-scale datasets using supervised learning objectives like next-word prediction. This phase establishes the model's foundational understanding of language and context.

2. Reward Model Training: A reward model is trained to evaluate the quality of the AI's outputs based on human feedback. Human annotators rank or score responses, providing a signal for what constitutes "good" or "bad" behavior. These rankings are used to train the reward model, which predicts scores for unseen outputs.

3. Reinforcement Learning Fine-Tuning: Using reinforcement learning techniques—most commonly Proximal Policy Optimization (PPO)—the language model is fine-tuned to optimize its outputs according to the reward model's guidance. This iterative process ensures that the AI aligns more closely with human preferences over time.

Key Challenges and Limitations of RLHF

Despite its effectiveness, RLHF faces several challenges that can limit its performance and scalability:

1. Subjectivity in Human Feedback: Human preferences are diverse and context-dependent, leading to inconsistencies in feedback. Annotators may unintentionally introduce biases or errors due to fatigue or personal perspectives.

2. Bias Amplification: If the training data or human feedback contains biases, these can be reinforced during the RLHF process, potentially leading to harmful or unfair outputs.

3. Reward Model Misalignment: The reward model may fail to capture complex human preferences accurately, leading to "reward hacking," where the AI optimizes for superficial metrics rather than genuine understanding.

4. Mode Collapse: Over-optimization during RLHF can reduce diversity in responses, as the model tends to prioritize high-scoring but repetitive outputs over creative or varied ones.

5. High Computational Costs: RLHF is resource-intensive, requiring significant computational power for training large models and handling complex dataflows across multiple GPUs.

6. Adversarial Vulnerabilities: RLHF-trained models remain susceptible to adversarial attacks that exploit weaknesses in their safeguards, potentially causing them to generate harmful or unintended content.

Examples of RLHF Implementations

Several prominent AI systems have successfully implemented RLHF:

• OpenAI's GPT Models: GPT-4 was fine-tuned using RLHF to improve its conversational abilities while adhering to ethical guidelines. Human feedback helps refine its capacity for producing accurate and safe responses.

• Anthropic's Claude: Anthropic employs RLHF alongside principles-based alignment techniques to ensure its models prioritize helpfulness, honesty, and harmlessness in their outputs.

• Google Gemini: Gemini integrates RLHF into its training pipeline to enhance its generative capabilities while aligning with user expectations and safety standards.

Future Directions for RLHF

To address current limitations and unlock the full potential of RLHF, researchers are exploring several promising directions:

1. Improved Reward Models: Developing more sophisticated reward models capable of capturing nuanced human preferences will reduce issues like reward hacking and misalignment.

2. Efficient Training Techniques: Optimizing resource allocation and leveraging techniques like distributed training can help mitigate the high computational costs associated with RLHF.

3. Robustness Against Bias and Adversarial Attacks: Incorporating methods like adversarial training and fairness-aware feedback mechanisms can enhance the safety and reliability of RLHF-trained models.

4. Scalability Across Domains: Expanding RLHF beyond conversational AI into areas like code generation, mathematical reasoning, or multimodal tasks will broaden its applicability.

Conclusion

Reinforcement Learning from Human Feedback has revolutionized how AI systems align with human values and expectations. By combining human intuition with advanced reinforcement learning algorithms, RLHF ensures that large language models generate outputs that are not only accurate but also aligned with ethical standards. However, addressing its limitations—such as bias amplification, computational inefficiencies, and adversarial vulnerabilities—will be critical for advancing this technique further. With ongoing research and innovation, RLHF holds immense potential for shaping safer and more effective AI systems across diverse applications.

了解來自人類反饋的強化學習（RLHF）

來自人類反饋的強化學習（Reinforcement Learning from Human Feedback，簡稱 RLHF）是一種強大的機器學習技術，旨在使人工智慧（AI）系統更好地符合人類偏好。透過在訓練過程中整合人類反饋，RLHF 成為微調大型語言模型（LLMs）的核心方法，例如 GPT-4 和 Claude，使它們能生成更準確、有用且符合上下文的輸出。

RLHF 的工作原理

RLHF 包含三個主要階段，結合了監督學習和強化學習：

1. 監督預訓練： 模型通過監督學習目標（如下一個詞預測）在大規模數據集上進行預訓練。這一階段建立了模型對語言和上下文的基本理解。

2. 獎勵模型訓練： 使用人類反饋訓練一個獎勵模型，用於評估 AI 輸出的質量。人工標註者根據預定標準（如準確性、幫助性或倫理性）對回應進行排名或打分，這些排名用於訓練獎勵模型，以便對未見的輸出進行預測。

3. 強化學習微調： 使用強化學習技術（最常用的是近端策略優化算法 Proximal Policy Optimization，簡稱 PPO），根據獎勵模型的指導對語言模型進行微調。這一迭代過程確保 AI 能夠更好地符合人類偏好。

RLHF 的主要挑戰與限制

儘管 RLHF 成效顯著，但它仍面臨一些挑戰，可能會限制其性能和可擴展性：

1. 人類反饋的主觀性： 人類偏好多樣且依賴於上下文，導致反饋不一致。標註者可能因疲倦或個人觀點而引入偏差或錯誤。

2. 偏差放大： 如果訓練數據或人類反饋中存在偏差，這些偏差可能在 RLHF 過程中被放大，導致有害或不公平的輸出。

3. 獎勵模型不匹配： 獎勵模型可能無法準確捕捉複雜的人類偏好，導致「獎勵作弊」，即 AI 優化表面指標而非真正理解。

4. 模式崩塌： 在 RLHF 過程中過度優化可能減少輸出的多樣性，因為模型傾向於優先生成高分但重複的回應，而非創造性或多樣化的回應。

5. 高計算成本： RLHF 是資源密集型，需要大量計算能力來訓練大型模型並處理跨多個 GPU 的複雜數據流。

6. 對抗性漏洞： RLHF 訓練的模型容易受到對抗性攻擊，利用其防護措施中的弱點生成有害或意外內容。

RLHF 的實例應用

以下是一些成功實施 RLHF 的知名 AI 系統：

• OpenAI 的 GPT 模型： GPT-4 通過 RLHF 微調，提高其對話能力，同時遵守道德指南。人類反饋幫助改進其生成準確且安全回應的能力。

• Anthropic 的 Claude： Anthropic 使用 RLHF 和基於原則的對齊技術，確保其模型優先生成有幫助、誠實且無害的輸出。

• Google Gemini： Gemini 在其訓練管道中整合了 RLHF，以增強生成能力，同時符合用戶期望和安全標準。

RLHF 的未來方向

為了解決現有限制並充分發揮 RLHF 的潛力，研究者正在探索以下幾個方向：

1. 改進獎勵模型： 開發能夠捕捉細微人類偏好的更先進獎勵模型，以減少「獎勵作弊」和不匹配問題。

2. 高效訓練技術： 優化資源分配並利用分布式訓練等技術，有助於降低 RLHF 的高計算成本。

3. 抵禦偏差與對抗性攻擊： 引入對抗性訓練和公平感知反饋機制，可提高 RLHF 訓練模型的安全性和可靠性。

4. 跨領域擴展能力： 將 RLHF 從對話式 AI 擴展到代碼生成、數學推理或多模態任務等領域，可拓寬其應用範圍。

結論

來自人類反饋的強化學習已經徹底改變了 AI 系統如何與人類價值和期望保持一致。通過結合人類直覺和先進的強化學習算法，RLHF 確保大型語言模型生成不僅準確，而且符合倫理標準的輸出。然而，要推動這項技術進一步發展，需要解決其限制，例如偏差放大、計算效率低下以及對抗性漏洞。隨著持續研究和創新，RLHF 在塑造更安全、更高效的 AI 系統方面具有巨大的潛力，可廣泛應用於各種場景。

Discover Your Best Self

Have you ever paused to ask yourself: "Am I truly living as my best self?" Each of us holds immense potential, waiting to be unlocked through self-awareness, meaningful connections, continuous learning, and purposeful growth. Your journey toward discovering your best self begins today—and it promises to be one of the most rewarding adventures you'll ever embark upon.

Imagine the power of capturing your thoughts, dreams, and reflections in writing. Journaling isn't just a habit—it's an empowering practice that can transform your life. Every word you write is a step toward clarity and self-discovery. When you journal regularly, you create a personal roadmap that helps you track your growth, celebrate your victories, and learn from challenges along the way. Whether you choose a beautifully crafted notebook or a handy journaling app on your phone, make it a daily ritual. The insights you gain today will become invaluable treasures tomorrow.

Remember, you're not alone on this journey. The people around you profoundly shape who you become. Just as physical exercise builds strength in your body, spending quality time with positive and inspiring people strengthens your emotional and intellectual well-being. Research has shown that we feel happiest when we spend meaningful time with family and friends—so make these connections a priority! Surround yourself with people who uplift and inspire you. Be open to new friendships and unexpected encounters; inspiration often arrives when we least expect it—in casual conversations, group activities, or even while waiting in line at the grocery store.

Your mind craves growth as much as your body craves movement. Never stop learning! Lifelong learning is not only a pathway to success but also essential for maintaining mental sharpness and vitality throughout life. Today’s world offers countless opportunities to learn in ways that fit your lifestyle—structured online courses, engaging podcasts, insightful videos, or inspiring books and articles. Seek out experts around you who can mentor and guide you toward deeper understanding. Science confirms that continuously challenging your brain by acquiring new skills or knowledge keeps your mind vibrant, delays aging, and reduces the risk of cognitive decline. Embrace learning as an exciting adventure rather than an obligation.

When it comes to career success, remember that there's no shortcut—but there is one powerful mindset that can accelerate your progress: becoming a "sponge." On my very first day working at a consulting firm, a wise consulant shared profound advice: "In life, you're either growing or sinking—there's no standing still." This applies to every profession. Adopt a sponge-like attitude by absorbing wisdom from everyone around you—colleagues, mentors, clients—and you'll continuously evolve into your best self. Career growth isn't just about promotions or titles; it's about constant personal development.

Finally, remember the importance of balance in life. If work consumes all your energy and time, setbacks can feel overwhelming. But imagine structuring your day differently: eight hours for sleep, eight hours for work, and eight hours dedicated entirely to leisure activities and relationships. Imagine filling those leisure hours with joyful interactions with loved ones (proven by Harvard's Adult Development Study as essential for happiness), hobbies you're passionate about (scientifically linked to increased well-being), a peaceful home environment, and meaningful personal goals you're excited to pursue. With such balance in place, setbacks at work become minor inconveniences rather than devastating blows.

Today is the perfect day to begin this journey toward discovering your best self! Start journaling consistently to gain clarity; nurture relationships that energize and inspire; commit yourself passionately to lifelong learning; embrace career growth with enthusiasm; and maintain balance so every aspect of life thrives harmoniously together. Your greatest potential is waiting within you—ready for you to unlock it fully. Take action now: Your future self will thank you!

發現最好的自己

你是否曾經停下來問自己：「我真的在以最好的狀態生活嗎？」我們每個人都擁有無限的潛力，等待透過自我覺察、有意義的連結、持續學習以及有目標的成長來釋放出來。你的旅程從今天開始，這將會是你人生中最值得期待且回報豐厚的冒險之一。

想像一下，把你的想法、夢想和反思記錄下來的力量。寫日記不僅僅是一種習慣——它是一種能夠改變你生活的強大實踐。你寫下的每一個字，都是邁向清晰與自我探索的一步。當你養成定期寫日記的習慣時，你便創造了一張屬於自己的成長地圖，幫助你追蹤進步、慶祝成就，並從挑戰中學習。不論是選擇一本精美的筆記本，還是下載一款方便的日記應用程式，都讓它成為你的每日儀式。今天獲得的洞察力，將成為明天無價的寶藏。

請記住，在這段旅程中，你並不孤單。周圍的人對你的成長有著深遠的影響。正如身體需要運動來增強力量，與積極且鼓舞人心的人共度時光也能增強你的情感與智慧。研究顯示，當我們與家人或朋友共度有意義的時光時，我們感到最幸福——因此，把這些聯繫放在優先位置吧！讓自己被那些激勵你、啟發你的人包圍。對新友誼和意外相遇保持開放態度；靈感往往在我們最意想不到的時候到來——可能是在輕鬆的對話中、團隊活動中，甚至是在超市排隊時。

你的心靈渴望成長，就像你的身體渴望運動一樣。永遠不要停止學習！終身學習不僅是通往成功的途徑，也是保持頭腦敏銳和活力的重要關鍵。在當今世界，有無數適合你生活方式的學習機會——結構化的線上課程、引人入勝的播客、有啟發性的影片或令人振奮的書籍和文章。尋找身邊能指導你深入理解領域的專家作為導師。科學證明，不斷挑戰自己的大腦以獲取新技能或知識，不僅能讓頭腦保持活躍，還能延緩衰老並降低認知能力下降的風險。將學習視為一場令人興奮的冒險，而不是一項義務。

談到職業成功時，請記住：沒有捷徑，但有一種強大的心態可以加速你的進步，那就是成為一塊「海綿」。在我第一天進入一家諮詢公司的時候，一位睿智的顧問給了我深刻的建議：「在生活中，你不是在成長，就是在退步——沒有停滯不前。」這句話適用於每一個職業領域。通過吸收周圍每個人的智慧——同事、導師、客戶——你將不斷進化，朝著最好的自己邁進。職業成長不僅僅是升遷或頭銜，而是持續不斷地自我提升。

最後，請記住生活中的平衡至關重要。如果工作佔據了你所有的精力和時間，那麼挫折可能會令人難以承受。但試想一下，如果你以不同方式安排一天：八小時睡眠、八小時工作，以及八小時完全投入於休閒活動和人際關係。想像一下，把這些休閒時間用於與親人愉快互動（哈佛成人發展研究證明這是幸福的重要因素）、投入熱愛的興趣（已被科學證明能提升幸福感）、營造一個平靜舒適的家庭環境，以及追求讓你充滿激情的個人目標。在這樣平衡充實的人生中，工作上的挫折只會是微不足道的小插曲，而非毀滅性的打擊。

今天就是開始這段旅程的最佳時機！養成寫日記來獲得清晰思路；培養能激勵和啟發你的關係；全心投入終身學習；以熱情擁抱職業上的成長；並保持生活各方面和諧共存的平衡。你最大的潛力正在內心深處等待著被完全釋放出來。現在就行動吧：未來的自己一定會感謝今天努力前行的你！

Overcoming the Fear of Moving Abroad

Have you ever dreamed of moving abroad to start a new chapter in your life, yet found yourself hesitating at the thought of leaving your comfort zone? You're not alone. Many of us feel drawn toward exciting opportunities overseas—whether for career growth, education, or simply a fresh start—but uncertainty and fear often hold us back.

As someone originally from Hong Kong who has embarked on two international moves—first to Brisbane, Australia (December 2012–June 2014), and later to Singapore (September 2020–present)—I understand firsthand the psychological struggles involved in making such life-changing decisions. Each move brought excitement and anticipation, but also anxiety about leaving behind family, friends, and familiar surroundings. Questions filled my mind: Would I find suitable employment? Could I adapt to a new culture? Would I regret leaving behind the stability I'd built?

These feelings are rooted deeply in human psychology, specifically in a concept known as "loss aversion." Nobel Prize-winning psychologist Daniel Kahneman and his colleague Amos Tversky introduced this idea to explain why we fear losses more intensely than we value equivalent gains. Simply put, the pain of losing something familiar often outweighs the excitement of gaining something new—even if the potential rewards are substantial.

Loss aversion explains why many people hesitate to migrate, despite clear opportunities abroad. The uncertainty of finding employment, adapting culturally, or building new social networks can feel daunting. Even small risks associated with migration can seem overwhelming when viewed through this psychological lens.

Beyond loss aversion, another hidden psychological factor influences our hesitation: our desire to maintain a positive self-image. Most of us prefer seeing ourselves as intelligent, responsible individuals rather than foolish or irresponsible ones. Taking risks means potentially exposing ourselves to failure or disappointment—something we instinctively avoid. For instance, someone capable of migrating but choosing not to do so might comfort themselves by imagining hypothetical success: "If I had moved abroad, surely I would have succeeded." By not taking action, they preserve this comforting illusion indefinitely.

Yet here's the truth I've discovered through personal experience: stepping outside your comfort zone and embracing uncertainty can lead to incredible personal growth and fulfillment. My time in Australia taught me invaluable lessons about adaptability and resilience. Overcoming initial challenges boosted my confidence and broadened my perspective on life. Years later, when contemplating my move to Singapore amidst global uncertainties in 2020, these earlier experiences gave me strength and courage to once again embrace change.

Today, living in Singapore has rewarded me beyond expectations—professionally enriching experiences combined with vibrant cultural immersion have reinforced my belief that calculated risks often yield profound rewards. Migration is indeed an adventure—one filled with uncertainty and occasional setbacks—but it also offers unparalleled opportunities for personal development and lasting fulfillment.

If you're considering moving abroad but find yourself hesitating due to fear or uncertainty, remember this: life is inherently unpredictable; no decision comes without risk. However, by confronting our fears directly rather than allowing them to control us subconsciously through loss aversion or self-image preservation tactics, we open ourselves fully toward growth opportunities waiting just beyond our comfort zones.

Ultimately, the greatest risk may be never taking one at all. So when opportunities arise that could transform your life for the better—embrace them courageously. Your future self will thank you for having taken that bold first step into a world filled with possibility and adventure.

克服移居海外的恐懼

你是否曾經夢想過移居海外，開啟人生的新篇章，卻因為害怕離開舒適圈而猶豫不決？你並不孤單。許多人都渴望海外的精彩機會——無論是職業發展、教育提升，還是單純追求一個嶄新的開始——但不確定性和恐懼往往讓我們止步不前。

作為一名出生於香港的人，我曾經歷過兩次國際搬遷——第一次是在2012年12月至2014年6月移居澳洲布里斯本，第二次則是在2020年9月至今定居於新加坡。我深刻體會到做出如此改變人生的重大決定時所面臨的心理掙扎。每一次搬遷都帶來了興奮和期待，但同時也伴隨著對離開家人、朋友以及熟悉環境的焦慮。腦海中充滿了各種問題：我能否找到合適的工作？我能否適應新的文化？我會不會後悔放棄原有的穩定生活？

這些感受深深植根於人類心理學中一個名為「損失厭惡」的概念。諾貝爾獎得主丹尼爾·康納曼（Daniel Kahneman）和他的同事阿莫斯·特沃斯基（Amos Tversky）提出了這一理論，用以解釋我們為什麼害怕失去的痛苦遠遠超過獲得等值收益的喜悅。簡而言之，失去熟悉事物的痛苦往往超過獲得新事物的興奮，即使潛在回報非常可觀。

損失厭惡解釋了為什麼許多人在面對明顯的海外機會時仍然猶豫不決。找到工作、適應文化或建立新的人際網絡的不確定性可能令人望而卻步。即使是與移民相關的小風險，在損失厭惡的心理框架下，也可能顯得難以承受。

除了損失厭惡之外，另一個隱藏的心理因素也影響著我們的猶豫：那就是維持正面的自我形象。我們大多數人都希望自己被視為聰明、負責任的人，而不是愚蠢或不負責任的人。冒險意味著可能暴露自己的失敗或失望——這是我們本能上想要避免的。例如，一個有能力移民但選擇不行動的人可能會用假想成功來安慰自己：「如果我移民了，我一定會成功。」通過不採取行動，他們可以無限期地保留這種令人安慰的幻想。

然而，通過我的親身經歷，我發現了一個真相：走出舒適圈並擁抱不確定性，可以帶來令人難以置信的個人成長和滿足。我在澳洲的生活教會了我適應能力和韌性的重要性。克服最初的挑戰增強了我的信心，也拓寬了我的人生視野。多年後，在2020年全球局勢不穩定之際，我再次考慮移居新加坡時，早期經驗給了我力量和勇氣，再次擁抱改變。

如今，在新加坡生活已經給了我超出預期的回報——專業上的豐富經歷與充滿活力的文化融合，使我更加堅信計劃周全的冒險往往能帶來深刻的回報。移民確實是一場冒險——充滿著不確定性和偶爾的挫折——但它也提供了無與倫比的個人成長和持久滿足感。

如果你正在考慮移居海外，但因恐懼或不確定性而猶豫不決，請記住：生活本質上就是不可預測的，每一個決定都伴隨著風險。然而，通過直接面對恐懼，而不是讓它們在潛意識中控制我們，我們可以完全敞開心扉去迎接舒適圈之外等待著我們的成長機會。

最終，最大的風險可能就是永遠不去冒險。所以當有機會出現，可以改變你的生活時——勇敢地擁抱它吧！未來的自己一定會感謝你踏出了那充滿可能性和冒險精神的一步。

Lessons from the Smoot-Hawley Act of 1930

As we enter 2025, President Trump's renewed embrace of tariffs has once again sparked fears of economic turmoil. His administration's latest tariff measures—imposing duties as high as 25% on imports from China, Canada, Mexico, and the European Union—have already rattled markets and economists alike. With recession warnings growing louder, it is crucial to recall historical lessons from America's past experience with protectionism, particularly the infamous Smoot-Hawley Tariff Act of 1930.

The Smoot-Hawley Tariff Act of 1930 is often cited as one of the most damaging trade policies in American history. Signed into law by President Herbert Hoover during the early stages of the Great Depression, this act dramatically raised tariffs on over 20,000 imported goods. Initially intended to protect American industries and farmers, it instead triggered retaliatory tariffs from trading partners worldwide. The result was catastrophic: U.S. exports plunged by more than 60%, global trade shrank by approximately two-thirds, and unemployment soared to unprecedented levels. While historians debate whether Smoot-Hawley directly caused the Great Depression, economists broadly agree it significantly worsened the crisis by shrinking global trade and harming export-dependent industries. Countries such as Canada retaliated by imposing tariffs on U.S. goods, further depressing U.S. exports and deepening economic distress.

Fast forward nearly a century later, and President Trump appears determined to repeat history's mistakes. His recent tariff announcements have already triggered sharp declines in stock markets. Economists are increasingly sounding alarms about an imminent recession, attributing rising risks primarily to these aggressive tariff policies. Goldman Sachs recently increased their estimate of recession probability from 15% to 20%, while Moody's Analytics placed it even higher at 35%. The immediate consequences are clear: Trump's tariffs will significantly raise prices for American consumers and businesses. According to recent analyses, the average tariff rate on all imports could rise from a baseline level of 2.5% in 2024 to an alarming 13.8%—the highest since 1939. This translates into an estimated annual loss of approximately $109 billion for the U.S. economy alone. These rising costs will disproportionately affect everyday American families through higher prices for basic goods and services. For example, new tariffs on Canada and Mexico alone could lead to an annual economic loss exceeding $109 billion. Moreover, retaliatory tariffs from trading partners such as China—already targeting key U.S. agricultural exports—will further compound these losses and threaten employment in vulnerable sectors.

Economists widely agree that Trump's aggressive tariff strategy could trigger a recession in the United States in 2025. The recent stock market plunge following announcements of new tariffs underscores investor anxiety about slowing growth prospects due to escalating trade tensions. Consumer confidence has also sharply declined amid worries about higher costs for everyday goods and uncertainty for businesses planning investments and hiring decisions. While Trump argues that these tariffs represent a necessary "transition" period toward economic strength and self-sufficiency, economists warn that history offers critical lessons against such optimism. The Smoot-Hawley experience vividly demonstrates how escalating trade barriers can backfire dramatically—causing severe economic contraction rather than prosperity.

Economists Arnaud Costinot and Andrés Rodríguez-Clare have highlighted that while trade benefits large economies like the U.S., these benefits are relatively modest overall. Their influential research shows that only about eight cents out of every dollar spent by Americans goes toward imported goods. Blocking all imports would indeed make America poorer—but perhaps not drastically so. However, this does not mean tariffs are harmless. Even small disruptions can trigger outsized negative effects through retaliatory measures and lost business confidence. Trump's current policies risk repeating the mistakes of Smoot-Hawley by provoking retaliation from major trading partners—potentially causing substantial declines in exports, employment losses in manufacturing sectors, and reduced overall economic growth.

The historical parallels between Trump's tariff strategy today and the Smoot-Hawley Tariff Act nearly a century ago are striking—and alarming. While Trump insists his policies will ultimately benefit America economically, evidence from both history and contemporary economic analyses strongly suggests otherwise. By raising prices for consumers, disrupting supply chains, provoking retaliation from trading partners, and creating market uncertainty, Trump's tariffs risk tipping the U.S. economy into recession in 2025—a scenario he himself has refused to rule out. As we learned painfully during the Great Depression era, protectionist trade wars rarely end well. As we navigate this uncertain economic landscape in 2025, policymakers would be wise to heed history's warnings: protectionism may promise short-term gains but often delivers long-term pain.

1930年斯姆特霍利關稅法案的歷史教訓

進入2025年，美國總統川普再度大力推行關稅政策，引發各界對經濟動盪的擔憂。他的政府近期對中國、加拿大、墨西哥和歐盟等貿易夥伴的進口商品徵收高達25%的關稅，已經嚴重衝擊金融市場，令經濟學家們深感憂慮。隨著經濟衰退的警訊越來越明顯，我們有必要回顧歷史上美國實施保護主義政策的教訓，尤其是臭名昭著的1930年《斯姆特霍利關稅法案》（Smoot-Hawley Tariff Act）。

1930年的《斯姆特霍利關稅法案》被視為美國史上最具破壞性的貿易政策之一。該法案由胡佛總統在大蕭條初期簽署生效，對超過兩萬種進口商品大幅提高關稅。這項措施原本旨在保護美國本土產業及農民，卻意外引發全球貿易夥伴的報復性關稅措施，造成嚴重後果：美國出口量暴跌超過60%，全球貿易規模萎縮約三分之二，失業率飆升至前所未見的高點。雖然歷史學家對於該法案是否直接導致大蕭條仍有爭議，但經濟學家普遍認為，它無疑加劇了這場危機，使全球貿易萎縮，重創依賴出口的產業。加拿大等國家隨後對美國商品實施報復性關稅，更進一步打擊美國出口，加深經濟困境。

時隔近一個世紀後，川普總統似乎決意重蹈覆轍。他近期宣布的新一輪關稅措施已導致股市急劇下跌。經濟學家紛紛警告，美國正面臨即將到來的經濟衰退風險，而這種風險主要源自川普政府激進的關稅政策。高盛（Goldman Sachs）最近將美國陷入衰退的可能性預測從15%調升至20%，穆迪分析（Moody's Analytics）則將此機率估計得更高，達到35%。這些新關稅措施所帶來的直接影響十分明顯：美國消費者和企業將面臨顯著上升的成本壓力。根據最新分析，美國所有進口商品的平均關稅水平可能從2024年的2.5%基準，大幅攀升至13.8%，創下自1939年以來的新高。這意味著每年將給美國經濟帶來約1,090億美元的損失。此外，這些不斷上升的成本將透過日常生活用品和服務價格上漲，對一般美國家庭造成不成比例的衝擊。例如，僅針對加拿大和墨西哥的新一輪關稅，每年就可能造成超過1,090億美元的經濟損失。此外，中國等貿易夥伴已開始對美國農產品出口實施報復性關稅措施，更進一步加劇這些損失，威脅脆弱產業中的就業機會。

多數經濟學家一致認為，川普政府激烈推行的關稅策略，很可能在2025年引發美國經濟衰退。近期股市在新一輪關稅宣布後的大幅下跌，凸顯出投資人對於貿易緊張局勢升級所帶來成長放緩風險的憂慮。同時，由於民眾擔心日常用品價格上漲，以及企業投資和招聘決策面臨不確定性，美國消費者信心也明顯下滑。儘管川普聲稱這些措施只是邁向經濟強大與自給自足過程中必要的「過渡期」，但經濟學家警告說，歷史教訓清楚地表明了這種樂觀想法的不切實際。《斯姆特霍利法案》的歷史教訓生動地提醒我們，不斷升級的貿易壁壘往往適得其反，不僅無法帶來繁榮，反而會嚴重拖累整體經濟。

經濟學家科斯蒂諾（Arnaud Costinot）與羅德里格斯-克萊爾（Andrés Rodríguez-Clare）的研究指出，雖然貿易對像美國這樣的大型經濟體有益，但整體而言其實收益有限。他們具影響力的研究表明，美國消費者每花費一美元中，大約只有八美分用於購買進口商品。如果完全停止所有進口，美國確實會變得比較窮，但也不至於急劇惡化。然而，這並不意味著提高關稅是無害之舉。即使是小規模干擾，也可能透過報復性措施和企業信心喪失，引發更大的負面效應。目前川普政府推行的政策正冒著重蹈《斯姆特霍利法案》覆轍的風險，引發主要貿易夥伴報復性措施，大幅降低出口量、製造業就業機會流失，以及整體經濟成長放緩。

川普當前推行的關稅策略與近百年前《斯姆特霍利法案》的歷史相似之處令人震驚，也令人擔憂。儘管川普堅稱他的政策最終將使美國受益，但無論從歷史還是當代經濟分析看來，都強烈表明事實並非如此。透過提高消費者物價、破壞供應鏈、引發貿易夥伴報復，以及製造市場不確定性，川普政府2025年的關稅政策正讓美國經濟陷入衰退邊緣——而他本人也從未排除這種可能性。如同我們從大蕭條時代痛苦學到的一樣：保護主義貿易戰很少有好結果。在面臨2025年充滿不確定性的經濟環境中，美國決策者應謹記歷史教訓：保護主義或許能帶來短期利益，但往往會帶來長期痛苦。

Lessons from Nixon's Shock and Stagflation

In 2025, investors face significant uncertainty due to President Trump's aggressive and unpredictable tariff policies. With tariffs imposed on major trading partners such as Canada, Mexico, and China, economists warn of rising inflation and slowing economic growth—conditions reminiscent of the stagflation era triggered by President Nixon's policies in the 1970s. Understanding how Nixon's economic measures contributed to stagflation can offer valuable insights into navigating today's turbulent market environment.

President Trump's recent tariff decisions—including a 25% tariff on Canadian and Mexican imports and a doubling of tariffs on Chinese goods—have sparked fears of stagflation (high inflation coupled with stagnant growth). Economists from Morgan Stanley and Goldman Sachs have revised down U.S. GDP growth forecasts for 2025, citing increased inflationary pressures and reduced economic growth due to these tariffs. While a full-blown recession isn't imminent, economists warn that prolonged tariffs could lead to higher consumer prices, slower growth, and rising unemployment—a classic stagflation scenario. This situation bears resemblance to the "Nixon Shock" of 1971, when President Richard Nixon abruptly ended the dollar's convertibility into gold, imposed wage-price controls, and introduced import surcharges. These measures disrupted international trade relations, created currency instability, and eventually contributed significantly to the stagflation crisis of the 1970s.

Given the parallels between today's tariff-driven uncertainty and Nixon-era economic disruptions, investors should adopt prudent strategies to protect their portfolios. Diversification is essential during periods of policy uncertainty; investors should spread their investments across multiple asset classes—stocks, bonds, commodities, real estate—to mitigate risk from any single sector or market. Commodities typically perform well during inflationary periods caused by tariffs or trade disruptions. Precious metals like gold provide a hedge against currency volatility and inflation risks. Energy commodities such as oil or agricultural products can benefit from price increases during supply-side shocks.

Treasury Inflation-Protected Securities (TIPS) adjust their principal based on inflation rates, offering protection against rising prices caused by tariffs. Defensive sectors—consumer staples, healthcare, utilities—typically maintain stability during economic turbulence because their products remain essential regardless of economic conditions. Higher inflation expectations driven by tariffs can negatively impact long-duration bonds; thus, investors should shift toward short-term bonds or cash equivalents to reduce sensitivity to rising interest rates. Real estate investments or Real Estate Investment Trusts (REITs) often perform well during inflationary periods due to rental income adjustments linked to inflation. Stocks in defensive sectors with stable earnings streams typically outperform cyclical or growth-oriented stocks during periods of economic uncertainty and stagflation fears.

The Nixon Shock triggered an era of stagflation in the 1970s by creating currency instability, price distortions through wage-price controls, and exacerbating supply-side shocks in energy markets. Investors who successfully navigated that period emphasized tangible assets like gold, commodities, defensive equities, real estate holdings, and international diversification. Today's investors facing similar uncertainties under Trump's tariff policy should apply these historical lessons: gold remains an effective hedge against currency volatility and inflation today; international diversification can provide protection against currency fluctuations.

While economists warn that Trump's tariff policies create significant market volatility and raise concerns about potential stagflation scenarios similar to those following Nixon's Shock, a full-blown recession is not yet imminent. Investors should remain disciplined by maintaining diversified portfolios across asset classes; prioritizing commodities, inflation-protected bonds (TIPS), defensive equities, real estate investments; reducing exposure to long-duration bonds vulnerable to rising interest rates; and considering international diversification for currency protection. By applying lessons learned from historical episodes like the Nixon Shock—and carefully selecting asset classes resilient to stagflationary pressures—investors can better navigate today's uncertain environment under Trump's tariff-driven economic landscape.

Lessons from Nixon's Shock and Stagflation