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These arguments about the shapes of indifference curves and about higher or lower levels of utility do not require any numerical estimates of utility, either by the individual or by anyone else. They are only based on the assumptions that when people have less of one good they need more of another good to make up for it, if they are keeping the same level of utility, and that as people have more of a good, the marginal utility they receive from additional units of that good will diminish. Given these gentle assumptions, a field of indifference curves can be mapped out to describe the preferences of any individual.

The Individuality of Indifference Curves

Each person determines their own preferences and utility. Thus, while indifference curves have the same general shape—they slope down, and the slope is steeper on the left and flatter on the right—the specific shape of indifference curves can be different for every person. [link] , for example, applies only to Lilly’s preferences. Indifference curves for other people would probably travel through different points.

Utility-maximizing with indifference curves

People seek the highest level of utility, which means that they wish to be on the highest possible indifference curve. However, people are limited by their budget constraints, which show what tradeoffs are actually possible.

Maximizing Utility at the Highest Indifference Curve

Return to the situation of Lilly’s choice between paperback books and doughnuts. Say that books cost $6, doughnuts are 50 cents each, and that Lilly has $60 to spend. This information provides the basis for the budget line shown in [link] . Along with the budget line are shown the three indifference curves from [link] . What is Lilly’s utility-maximizing choice? Several possibilities are identified in the diagram.

Indifference curves and a budget constraint

The graph shows indifferences curves Ul, Um, and Uh which highlight the following choices based on her options of books (the x-axis) and doughnuts (the y-axis): A (2, 120); B (3, 84); F (5, 100); G (6, 48); H (3, 70).
Lilly’s preferences are shown by the indifference curves. Lilly’s budget constraint, given the prices of books and doughnuts and her income, is shown by the straight line. Lilly’s optimal choice will be point B, where the budget line is tangent to the indifference curve Um. Lilly would have more utility at a point like F on the higher indifference curve Uh, but the budget line does not touch the higher indifference curve Uh at any point, so she cannot afford this choice. A choice like G is affordable to Lilly, but it lies on indifference curve Ul and thus provides less utility than choice B, which is on indifference curve Um.

The choice of F with five books and 100 doughnuts is highly desirable, since it is on the highest indifference curve Uh of those shown in the diagram. However, it is not affordable given Lilly’s budget constraint. The choice of H with three books and 70 doughnuts on indifference curve Ul is a wasteful choice, since it is inside Lilly’s budget set, and as a utility-maximizer, Lilly will always prefer a choice on the budget constraint itself. Choices B and G are both on the opportunity set. However, choice G of six books and 48 doughnuts is on lower indifference curve Ul than choice B of three books and 84 doughnuts, which is on the indifference curve Um. If Lilly were to start at choice G, and then thought about whether the marginal utility she was deriving from doughnuts and books, she would decide that some additional doughnuts and fewer books would make her happier—which would cause her to move toward her preferred choice B. Given the combination of Lilly’s personal preferences, as identified by her indifference curves, and Lilly’s opportunity set, which is determined by prices and income, B will be her utility-maximizing choice.

Questions & Answers

What is captalizeg
Saminu Reply
What is socializing
What is socializing
What is socializing
what is demand
Oforiwaa Reply
demand is the quantity of a good that consumers are willing and able to purchase at various prices during a given period of time.
what is opportunity cost
Aboubakar Reply
what is gini coefficient?
Khalipha Reply
Never heard of that!!!!
ive heard about it Actually i know it..
In that case, you have to help us.
Another name for Absolute cost advantage
fatimah Reply
what is the difference between demand and supply
Peter Reply
what is the national income
Kamara Reply
oils and resources
it is the sum of all incomes earned by factors of production usually a year
What's current account?
Che Reply
Demand refers to goods and services that the buyer is willing and able to buy at a price over a period of time
Can it be possible to have two level of comparative advantage in a country ?
Louise Reply
.no.its not possible
Why ?
I think no possible
No resources are scare for a country to have a comparative advantage and it discourages external trade
each country are meant to Specialize on 1 production activities
why do oligopoly increase on the elastic segment of the demand curve
Tintswalo Reply
what is all about production possibility curve
Nice Reply
help me about the assumption of possibility curve
-The quantity and quality of economic resources are fixed. -only two types of goods can be produce out of this resources (that is,producer and consumer goods). -Resources are fully utilised. -The resources are mobile. -The state of technology is constant.
What is utility
chisom Reply
it is the satisfaction derived from d consumption of goods and services
what is opportunity cost
what is the meaning of money and inflation
Tinuke Reply
Money can be define as anything acceptable as a medium of exchange and mean of payment
inflation is when everything seemed to cost so much less
Inflation is d persistent rise in level of goods and services in a country
Inflation is the persistent increase in d general price level of goods n services
what is a bar chart
Godwin Reply
what's economic
John Reply
Economics can be define as a study of how human beings make decisions in the face of scarcity it can also be define as using one wealth to make more wealth
Or in Nigerian way Economics is a science (social science) which studies human behavior as a relationship between Ends and Scarce which have alternative uses
Economics is the study of how human make decision in the face of scarcity

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Source:  OpenStax, Principles of economics. OpenStax CNX. Sep 19, 2014 Download for free at http://legacy.cnx.org/content/col11613/1.11
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