第三十四章货币政策与财政政策对总需求的影响TheInfluenceofMonetaryandFiscalPolicyonAggregateDemand1总需求AggregateDemand除了货币与财政政策以外，有许多因素影响总需求。Manyfactorsinfluenceaggregatedemandbesidesmonetaryandfiscalpolicy.特别的，家庭与商业企业希望的支出决定了对于物品与服务的总体需求。Inparticular,desiredspendingbyhouseholdsandbusinessfirmsdeterminestheoveralldemandforgoodsandservices.2总需求AggregateDemand当希望的支出改变，总需求移动，导致短期产出与就业的波动。Whendesiredspendingchanges,aggregatedemandshifts,causingshort-runfluctuationsinoutputandemployment.货币与财政政策有时能用以弥补这些移动，稳定经济。Monetaryandfiscalpolicyaresometimesusedtooffsetthoseshiftsandstabilizetheeconomy.3货币政策如何影响总需求HowMonetaryPolicyInfluencesAggregateDemand总需求曲线向下倾斜有三个原因Theaggregatedemandcurveslopesdownwardforthreereasons:‹财富效应Thewealtheffect‹利率效应Theinterest-rateeffect‹汇率效应Theexchange-rateeffect4货币政策如何影响总需求HowMonetaryPolicyInfluencesAggregateDemand对美国经济来说，总需求曲线向下倾斜的最重要原因是利率效应。FortheU.S.economy,themostimportantreasonforthedownwardslopeoftheaggregate-demandcurveistheinterest-rateeffect.解释价格水平对总需求曲线的影响——利率效应，与解释货币政策对总需求曲线的影响都用到了同一个理论。5流动性偏好理论TheTheoryofLiquidityPreference凯恩斯发展了流动性偏好理论，以解释决定经济的利率的因素。Keynesdevelopedthetheoryofliquiditypreferenceinordertoexplainwhatfactorsdeterminetheeconomy’sinterestrate.按照这一理论，利率调整以平衡货币供求。Accordingtothetheory,theinterestrateadjuststobalancethesupplyanddemandformoney.6货币供给MoneySupply货币供给由中央银行（美国的Fed）通过以下途径进行控制：ThemoneysupplyiscontrolledbytheFedthrough:‹公开市场运作Open-marketoperations‹改变法定准备金Changingthereserverequirements‹改变贴现率Changingthediscountrate7货币供给MoneySupply货币供给的数量不依赖于利率，因为它被Fed固定住了。BecauseitisfixedbytheFed,thequantityofmoneysupplieddoesnotdependontheinterestrate.固定的货币供给用一条垂直的供给曲线来表示。Thefixedmoneysupplyisrepresentedbyaverticalsupplycurve.8货币需求MoneyDemand货币需求决定于若干因素。Moneydemandisdeterminedbyseveralfactors.按照流动性偏好理论，一个最为重要的因素是利率。Accordingtothetheoryofliquiditypreference,oneofthemostimportantfactorsistheinterestrate.9货币需求MoneyDemand人们选择持有货币而不是带来更高