第21章消费者选择理论.ppt-上海杉达学院.ppt

21.5 结论: 人们真的这样想吗？ 人们并不是在画出预算约束线和无差别曲线之后，再来做消费决策。 但他们力图在资源有限的情况下，做出能最大化他们满意程度的决策。 本章的理论只是作为消费者如何做决策的一个比喻。 它很好地解释了许多情况下的消费者行为，也为更高深的经济分析提供了基础。 At A, Hurley has few fish, so an additional fish is very valuable to him. At B, Hurley already has lots of fish, so an additional one is not as valuable to him. Hurley has more fish at B than at A, so an extra fish would be less valuable at B than at A. When the two goods are close but not perfect substitutes (like Coke and Pepsi), indifference curves are slightly bowed. When the two goods are close but not perfect complements (like hot dogs and buns), indifference curves are very bowed, having a very sharp (but not quite 90-degree) angle. Later in this PowerPoint chapter, an Active Learning exercise asks students to illustrate the substitution effect for these two cases. They will see that a relative price change causes a much bigger movement along an indifference curve when the goods are substitutes than when they are complements. Consumer optimization is another example of “thinking at the margin.” Remember that MRS = marginal value of the good on the X-axis (fish) in terms of the good on Y-axis (mangos). If MRS Pf/Pm, the value of another fish is greater than its cost, so Hurley can make himself happier by decreasing his mango purchases and using the proceeds to buy another fish. If MRS Pf/Pm, the value of another fish is less than its cost, so Hurley should move along his budget line to a bundle with less fish and more mangos to make himself happier. In Active Learning 2, students determined that an increase in the price of a good pivots the budget constraint inward. Here, the price of a good is falling, so the budget line pivots outward. * Why the interest rate determines the relative price of current in terms of future consumption: If you reduce current consumption by $1, and save this $1, then your future consumption will rise by $(1 + r), where r denotes the interest rate. Simila