Theory of Consumer Behavior
Chapter 4 – Theory of Consumer Behavior
Economics 11 – UPLB
Prepared by T.B. Paris, Jr. December 11, 2007
Theory of Consumer Behavior
Useful for understanding the demand side of the market. Utility - amount of satisfaction derived from the consumption of a commodity ….measurement units utils Utility concepts
cardinal utility - assumes that we can assign values for utility, (Jevons, Walras, and Marshall). E.g., derive 100 utils from eating a slice of pizza ordinal utility approach - does not assign values, instead works with a ranking of preferences. (Pareto, Hicks, Slutsky)
Total utility and marginal utility
Total utility (TU) - the overall level of satisfaction derived from consuming a good or service Marginal utility (MU) additional satisfaction that an individual derives from consuming an additional unit of a good or service.
∆ TU MU = ∆Q
Total utility and marginal utility
Example (Table 4.1): Q 0 1 2 3 4 5 6 7 TU 0 20 27 32 35 35 34 30 36 MU --20 7 5 3 0 -1 -4
TU, in general, increases with Q At some point, TU can start falling with Q (see Q = 6) If TU is increasing, MU > 0 From Q = 1 onwards, MU is declining principle of diminishing marginal utility As more and more of a good are consumed, the process of consumption will (at some point) yield smaller and smaller additions to utility
Total Utility Curve
TU 35 Total utility(in utils) 30 25 20 15 10 5 0 1 2 3 4 5 Quantity 6 Q Figure 4.1
Marginal Utility Curve
MU Marginal utility (in utils) 20 15 10 5 0 -5 Figure 4.2 1 2 3 4 5 6 Quantity Q
Consumer Equilibrium
So far, we have assumed that any amount of goods and services are always available for consumption In reality, consumers face constraints (income and prices):
Limited consumers income or budget Goods can be obtained at a price
Some simplifying assumptions
Consumer’s objective: to maximize his/her utility subject to income constraint 2 goods
Economics 11 – UPLB
Prepared by T.B. Paris, Jr. December 11, 2007
Theory of Consumer Behavior
Useful for understanding the demand side of the market. Utility - amount of satisfaction derived from the consumption of a commodity ….measurement units utils Utility concepts
cardinal utility - assumes that we can assign values for utility, (Jevons, Walras, and Marshall). E.g., derive 100 utils from eating a slice of pizza ordinal utility approach - does not assign values, instead works with a ranking of preferences. (Pareto, Hicks, Slutsky)
Total utility and marginal utility
Total utility (TU) - the overall level of satisfaction derived from consuming a good or service Marginal utility (MU) additional satisfaction that an individual derives from consuming an additional unit of a good or service.
∆ TU MU = ∆Q
Total utility and marginal utility
Example (Table 4.1): Q 0 1 2 3 4 5 6 7 TU 0 20 27 32 35 35 34 30 36 MU --20 7 5 3 0 -1 -4
TU, in general, increases with Q At some point, TU can start falling with Q (see Q = 6) If TU is increasing, MU > 0 From Q = 1 onwards, MU is declining principle of diminishing marginal utility As more and more of a good are consumed, the process of consumption will (at some point) yield smaller and smaller additions to utility
Total Utility Curve
TU 35 Total utility(in utils) 30 25 20 15 10 5 0 1 2 3 4 5 Quantity 6 Q Figure 4.1
Marginal Utility Curve
MU Marginal utility (in utils) 20 15 10 5 0 -5 Figure 4.2 1 2 3 4 5 6 Quantity Q
Consumer Equilibrium
So far, we have assumed that any amount of goods and services are always available for consumption In reality, consumers face constraints (income and prices):
Limited consumers income or budget Goods can be obtained at a price
Some simplifying assumptions
Consumer’s objective: to maximize his/her utility subject to income constraint 2 goods