学生在微观经济学中学到，商品的需求曲线显示了商品价格与消费者需求的商品数量之间的关系 – 即愿意，准备好并且能够购买 – 具有负斜率。这种负斜率反映了这样一种观察结果：人们在价格越来越低时需要更多的商品，反之亦然。 （这被称为需求定律。）相比之下，宏观经济学中使用的总需求曲线显示了一个经济体的总体（即平均）价格水平之间的关系，通常由GDP平减指数表示，与所有价格水平相当。经济中要求的商品。 （请注意，在这种背景下，“商品”在技术上指的是商品和服务。）具体而言，总需求曲线显示实际GDP，其在均衡中表示经济中的总产出和总收入的横轴。 （从技术上讲，在总需求的背景下，横轴上的Y代表总支出。）事实证明，总需求曲线也向下倾斜，在价格和数量之间存在类似的负相关关系。一个好的。然而，总需求曲线具有负斜率的原因是完全不同的。在很多情况下，人们在价格上涨时会消耗较少的特定商品，因为他们有动力替代其他因价格上涨而变得相对便宜的商品。然而，在总体水平上，这有点难以做到 – 尽管并非完全不可能，因为在某些情况下消费者可以替代进口商品。因此，总需求曲线必须因不同原因而向下倾斜。事实上，总需求曲线表现出这种模式有三个原因：财富效应，利率效应和汇率效应。当一个经济体的整体价格水平下降时，消费者的购买力会增加，因为他们所拥有的每一美元都比以往更进一步。在实际水平上，购买力的增加与财富的增加相似，因此购买力的增加使消费者想要消费更多也不足为奇。由于消费是GDP的一个组成部分（因此也是总需求的一个组成部分），因此价格水平下降导致的购买力增加导致总需求增加。相反，总体价格水平的提高降低了消费者的购买力，使他们感觉不那么富裕，因此减少了消费者想要购买的商品数量，导致总需求减少。虽然较低的价格确实会鼓励消费者增加消费，但通常的情况是，购买商品数量的增加仍然会使消费者留下比以前更多的钱。然后将剩余的钱存起并借给公司和家庭用于投资目的。 “可贷资金”市场与任何其他市场一样响应供需力量，可贷资金的“价格”是实际利率。因此，消费者储蓄的增加导致可贷资金的供应增加，这降低了实际利率并增加了经济投资水平。由于投资是GDP的一个类别（因此是总需求的一个组成部分），因此价格水平的下降会导致总需求的增加。相反，总体价格水平的提高往往会减少消费者节省的金额，从而降低储蓄供应量，提高实际利率，并降低投资数量。投资减少导致总需求减少。
Students learn in microeconomics that the demand curve for commodities shows the relationship between commodity prices and the number of commodities demanded by consumers – that is, willingness, ready and able to buy – with a negative slope. This negative slope reflects the observation that people need more goods when prices are getting lower and lower, and vice versa. (This is called the law of demand.) In contrast, the aggregate demand curve used in macroeconomics shows the relationship between the overall (ie, average) price levels of an economy, usually expressed by the GDP deflator, and All price levels are comparable. Goods required in the economy. (Note that in this context, “commodities” are technically referred to as goods and services.) Specifically, the aggregate demand curve shows real GDP, which represents the total output and total income in the economy in equilibrium. Horizontal axis. (Technically, in the context of aggregate demand, Y on the horizontal axis represents total expenditure.) It turns out that the aggregate demand curve also slopes downward, with a similar negative correlation between price and quantity. A good one. However, the reason why the aggregate demand curve has a negative slope is completely different. In many cases, people consume less specific commodities when prices rise because they have the incentive to replace other commodities that are relatively cheaper due to rising prices. However, at the overall level, this is a bit difficult to do – although not entirely impossible, because in some cases consumers can replace imported goods. Therefore, the aggregate demand curve must be tilted downward for different reasons. In fact, the aggregate demand curve shows that this model has three reasons: the wealth effect, the interest rate effect, and the exchange rate effect. When the overall price level of an economy declines, the purchasing power of consumers will increase because every dollar they own is going further than ever. At a practical level, the increase in purchasing power is similar to the increase in wealth, so it is not surprising that the increase in purchasing power makes consumers want to consume more. Since consumption is an integral part of GDP (and therefore an integral part of aggregate demand), the increase in purchasing power due to lower price levels leads to an increase in aggregate demand. Conversely, an increase in the overall price level reduces the purchasing power of consumers, making them feel less affluent, thus reducing the number of items consumers want to buy, resulting in a reduction in aggregate demand. While lower prices do encourage consumers to increase consumption, it is often the case that an increase in the number of items purchased will still leave consumers with more money than before. The remaining money is then saved and loaned to companies and households for investment purposes. The “loanable funds” market responds to the supply and demand forces like any other market. The “price” of the loanable funds is the actual interest rate. As a result, the increase in consumer savings has led to an increase in the supply of loanable funds, which has lowered real interest rates and increased the level of economic investment. Since investment is a category of GDP (and therefore an integral part of aggregate demand), a decline in the price level leads to an increase in aggregate demand. Conversely, an increase in overall price levels tends to reduce the amount of money saved by consumers, thereby reducing the supply of savings, raising real interest rates, and reducing the amount of investment. The reduction in investment has led to a reduction in aggregate demand.