貧富不均造成經濟大蕭條

How income inequality contributed to the Great Recession

Source: Till van Treeck guardian.co.uk, Wednesday 9 May 2012

Higher inequality, combined with easy credit, can pressure the lower and middle class to keep up with consumers at the top

過高的貧富不均衡，與寬鬆的信貸政策相結合，使低層和中產階級跟上上流消費者有壓力。

A house in Denver lies empty and under foreclosure as the sub-prime crisis hits the US in 2007. Photograph: Sipa Pres/Rex Features

2007年的美國深受次貸危機衝擊，位在丹佛的房子仍舊乏人問津，(抵押人)已失去回贖權。攝影：Sipa Pres/Rex

The idea that the Great Recession of 2008 may have been caused not just by careless banking but also social inequality is currently all the rage among macroeconomists.

目前所有宏觀經濟學家之間的憤怒是認為2008年的大衰退不只是粗心的金融體系，也有是因社會不公的想法所造成。

Much of the impetus for the current debate stems from the widely discussed 2010 book Fault Lines, written by Raghuram Rajan, a former chief economist of the International Monetary Fund. Rajan argues that many lower- and middle-class consumers in the United States have reacted to the stagnation of their real incomes since the early 1980s by reducing saving and increasing debt. This has temporarily kept private consumption and thus aggregate demand and employment high, but also contributed to the creation of the credit bubble which eventually burst.

許多當前的辯論，有很大程度是源於2010年一本書:Fault Lines裡廣泛討論的，該書是由國際貨幣基金組織前首席經濟學家Raghuram Rajan所著。Rajan質疑認為，自20世紀80年代初以來，在美國的許多低收入和中產階級消費者因儲蓄減少和債務增加而反應不景氣，他們的實際收入停滯不前。這使得暫時維持私人消費，從而攏聚總需求和提高就業，但也助長造成信貸泡沫最終破滅。

In Rajan 's view, a large portion of the blame for this falls on misguided government policies, which promoted the expansion of credit to households. But the "Rajan hypothesis" also contradicts the dominant textbook theories of consumption, which see no link between persistent income inequality and aggregate private consumption, and hence no need for government action stimulating consumption demand and jobs in response to higher inequality.

Rajan認為，將很大一部分歸咎指責於錯誤的政府政策指引，促使家庭的信貸擴張。但“Rajan假設”， 反駁了目前主導的教科書裡的消費理論－即看不出持續性的收入不均衡和總私人消費之間的聯繫，因此政府沒有必要採取行動刺激消費需求和就業以回應較高的不平衡。

These theories, known as the permanent income or life-cycle hypotheses, are based on the assumption that consumers form rational expectations about their long-term income. Short-term fluctuations of income due to, say, unexpected job loss, or lower than average stock market returns, have only a limited impact on current consumption since households expect them to be only temporary. According to this view, households can insure against windfall losses through efficient credit markets and "smooth" their consumption over the longer term.

這些理論，以稱永久性收入或生命週期的假設著名，此是基於消費者對他們的長期收入形成理性預期的假定。收入的短期波動，比方說，意外失去工作，或低於股票市場平均回報值，如果家庭希望並預期這些事只是暫時的那只對當前消費的影響有限，因為。根據這種觀點，住戶可以藉由有效的信貸市場，並“緩和”較長時期內需要的消費以對抗意外之財的損失。

Up until the crisis, a very influential view inspired by this standard theory was that the rise in measured inequality since the early 1980s reflected temporary, not permanent, inequality. It was argued, for instance, that the information technologies of the "new economy" brought about more rapid structural change, faster labour turnover and thus higher job insecurity than in previous decades – leading to higher short-term risks and opportunities for workers and investors, but not necessarily higher inequality of lifetime incomes. The idea was that rising personal credit was an efficient market response to higher temporary earnings dispersion. Most economists therefore welcomed the deregulation of the credit market.

此直到危機，一個非常有影響力的觀點受標準的理論啟發了，自20世紀80年代初以來衡量不均衡的上升，反映了暫時的，非永久性的，不平等。有人認為爭議，例如，比過去幾十年來“新經濟”的信息技術帶來更迅速的結構性變化，勞動力流動加快，從而更高的工作不安全感- 導致工人和投資者更高的短期風險和機會，但卻不一定是較高的終生收入的不平等。當時的想法是提升個人信用是一個有效的市場反應分散更高的臨時收入風險。因此，信貸市場的放鬆管制受到大多數經濟學家的歡迎。

In 1996, Alan Greenspan, then chairman of the Federal Reserve Bank, noted in response to growing concerns about rising inequality that "wellbeing is determined by things people consume [and] disparities in consumption … do not appear to have widened nearly as much as income disparities". In a similar vein, Fabrizio Perri and Dirk Krueger suggested in an influential scholarly article published in 2006 that "consumers could, and in fact did, make stronger use of credit markets exactly when they needed to (starting in the mid-1970s), in order to insulate consumption from bigger income fluctuations".

在1996年，聯邦儲備銀行主席Alan Greenspan，關注到日益嚴重的不均衡提升的反應在“福利是決定在人民消費不同的產品…並沒有出現像收入不等那樣的擴大性“。同樣的脈絡，Fabrizio Perri和Dirk Krueger的建議在2006年發表在一個具影響力的學術文章，“消費者可以也確實作了，在他們需要時確切開始使用信貸市場(起於在20世紀70年代中期)，是為隔離避免受更大收入者消費波動的影響。

However, recent empirical work, for instance by Emmanuel Saez and others, strongly suggests that the rise in inequality over the past decades has been largely due to the permanent rather than transitory components of income. In other words, many households have lived beyond their means and were lured into dubious credit they could not afford.

然而，最近的實證工作，由Emmanuel Saez和其他的實例，強烈表明，在過去幾十年的崛起中的不平等在很大程度上是由於永久性而非暫時性收入的組成部分。換句話說，許多家庭生活入不敷出，被誘騙運用到他們受存疑的信用度。

There are alternatives to the outdated paradigm of rational consumers and efficient financial markets. In particular, there is the  relative income hypothesis, first formally stated by James Duesenberry back in the 1940s and more recently developed by behavioural and Keynesian economists: it says that consumers care about their consumption relative to others as a signal of social status. This means that higher inequality can lead to increased pressure for the lower and middle class to keep up with consumers at the top. Similarly, the basic Keynesian insight that middle-class incomes need to grow in line with productivity in order to sustain robust aggregate demand appears today more relevant than ever.

運用過往合理性的消費者或有效率的金融市場的典範。尤其是相對收入假說，此早在20世紀40年代由James Duesenberry第一次正式發表和最近發展的行為學及凱恩斯主義的經濟學家說，消費者關心他們的消費相對於他人的消費以作為一種社會地位的信號。這意味著更高的貧富不均可能導致較低和中產階級為跟上頂端消費者的壓力增加。同樣，基本凱因斯主義者洞察出，中產階級需增加生長所需要的生產力以增長收入，以維持強勁的總需求在現今比以往任何時候都更切題。

There is ample evidence that, especially in the US, households reacted to higher inequality by working longer hours, lowering savings, and increasing debt in an attempt to maintain their relative consumption status. Up to a point this allowed them to pay for medical bills, the ever-increasing costs of children's college education and a house; but eventually the bubble burst. The situation is not dissimilar in the UK.

尤其是在美國，有充分的證據顯示，住戶延長工作時間，降低儲蓄，增加債務等反應企圖保持其相對的消費狀況而造成更高的不均衡。在某種程度上，這使他們能夠支付醫療費用，孩子的大學教育和房子的日益增加的成本，但最終泡沫破滅。在英國，情況沒有什麼不同。

The renewed interest among economists in inequality as a macroeconomic risk is highly encouraging. Undoubtedly more research is needed to pin down the macroeconomic implications of inequality under different country-specific circumstances. But it should be clear that, in hindsight, the dominant textbook economic theories of consumption look almost as toxic as some of the credit products that ultimately caused the crisis.

經濟學家對能修復此不均衡作為宏觀經濟風險的興趣是非常令人鼓舞的。無疑的更多的研究需要確定宏觀經濟在不同國家的具體情況牽連的影響。但應該明確的是，以後見之明，消費經濟理論佔主導地位的教科書看起來幾乎和最終導致危機的一些信貸產品一樣有毒。

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