在20世纪的大部分时间里，凯恩斯主义者主张通过政府管理总需求来防止重演1930年代大萧条的大规模失业，而以米尔顿·弗里德曼（Milton Friedman）为首的货币主义者则认为应固定货币供应量，否则刺激就业将导致类似1970年代大通胀的物价持续上涨。如今，大多数央行行长属于第三阵营“新凯恩斯主义”。10月12日，斯坦福大学的罗伯特·霍尔（Robert Hall）和哥伦比亚大学的迈克尔·伍德福德（Michael Woodford）因在“微观基础”上重建宏观经济学而共同获得诺贝尔经济学奖，分享1200万瑞典克朗（约合120万美元）奖金。继1995年诺贝尔奖得主罗伯特·卢卡斯（Robert Lucas）提出批评后，他们摒弃了过去自上而下分析经济统计总量的做法，转而从个人和企业的决策行为出发自下而上构建模型。

霍尔研究了消费者如何根据对未来终身收入的预期来平滑支出，认为个人消费随时间的变化就像醉汉回家一样，虽因突发冲击而随机摇摆，但总体方向一致。伍德福德则借鉴20世纪初瑞典经济学家克努特·维克塞尔（Knut Wicksell）的纯信贷经济模型，将其理论称为“新维克塞尔主义”，主张央行应使利率与由技术进步和储蓄者耐心决定的投资“自然”回报率保持一致，以避免通胀繁荣或通缩循环。伍德福德于2003年出版的《利率与价格》结合了“价格粘性”和“不完全竞争”概念，成为现代央行行长的圣经，其出版恰逢低通胀、稳增长的“大缓和”时期。然而，这两种模型都存在缺陷：自然利率无法直接观测且会随人工智能等新技术投资热潮而迅速变化，模型也忽略了金融部门和投资者风险偏好，大缓和最终在2008年金融危机中终结；同时，现实中的消费者往往对疫情刺激支票等意外之财反应过度，却对持久的经济变化反应不足。

此次诺贝尔奖颁发之际，伍德福德的框架正面临新的理论和现实压力。新维克塞尔主义建议央行提前沟通其应对经济繁荣或衰退的“反应函数”，以便市场实时预测利率，但美联储新任主席凯文·沃什（Kevin Warsh）担心这会导致市场与央行互相观望的“镜像大厅”效应，认为保持一点利率不确定性反而有益。此外，当今央行正疲于应对从疫情到乌克兰及伊朗战争等一系列供给侧冲击，富裕国家的高额债务负担也引发了利用利率管理借贷成本而非控制通胀的担忧，迫使利率制定者在政治经济学的现实中就容忍多少通胀和失业率做出艰难抉择。

Throughout much of the 20th century, Keynesians argued that governments should manage aggregate demand to prevent 1930s-style mass unemployment, whereas Milton Friedman’s monetarists favoured fixing the money supply to avoid 1970s-style inflation. Today, most central bankers identify as New Keynesians, and on October 12th the Nobel memorial prize in economics—worth SKr12m ($1.2m)—was awarded to two pioneers of the movement: Stanford University’s Robert Hall and Columbia University’s Michael Woodford. Responding to a critique by 1995 Nobel laureate Robert Lucas, the duo broke with top-down models of statistical aggregates and instead rebuilt macroeconomics bottom-up on “microfoundations” rooted in individual and business decision-making.

Mr Hall modelled how forward-looking consumers “smooth” spending based on perceived lifetime income, causing consumption over time to resemble a drunk walking home—straying randomly in response to unforeseen jolts while staggering in a consistent direction. Drawing on turn-of-the-20th-century Swedish economist Knut Wicksell, Mr Woodford developed a “neo-Wicksellian” credit-economy framework arguing that central banks should align interest rates with the “natural” rate of return on investment—shaped by technological progress and savers’ patience—to prevent inflationary booms or deflationary spirals. His 2003 book, “Interest and Prices”, incorporated “sticky prices” and “imperfect competition” to become a bible for central bankers during the stable Great Moderation. Yet both models have flaws: the unobservable natural rate shifts rapidly with tech booms like artificial intelligence, and ignoring financial risk-taking preceded the Great Moderation’s end in the 2008 financial crisis; meanwhile, real consumers overreact to windfalls like covid stimulus cheques and underreact to persistent shifts.

The prize arrives as Mr Woodford’s framework faces fresh theoretical and practical challenges. While neo-Wicksellian theory advises central banks to communicate their “reaction function” in advance so markets can anticipate rates, new Federal Reserve chair Kevin Warsh warns this creates a “hall of mirrors” between markets and central banks, arguing that some rate uncertainty is beneficial. Furthermore, modern central bankers must navigate supply-side shocks from the pandemic and wars in Ukraine and Iran, alongside high rich-world debt burdens that risk pressuring rate-setters to manage government borrowing costs rather than inflation.

Source: A Nobel prize for how to keep economies on even keel

Subtitle: Two “New Keynesians”, Robert Hall and Michael Woodford, win the highest honour in economics

Dateline: Oct 15th 2026\n