Introduction to the dual-self model of choiceDr. Russell James IIIUniversity of Georgia

An alternative modelPrevious discussion shows that the rational, utility-maximizing assumption for consumers is not always true.So, now what?Throw it out the door?But, it often makes accurate predictionsA modification from behavioral economics

“Our theory proposes that many sorts of decision problems should be viewed as a game between a sequence of short-run impulsive selves and a long-run patient self.”Drew Fudenburg (Harvard U.) and David K. Levine (Washington U.), 2006, A dual-self model of impulse control. American Economic Review, 96(5), 1449-1476.

Fudenberg & Levine (2006)Long-run (patient) selfThis side tries to maximize utility across timeShort-run (impulsive) selvesSequential selves that exist only for a brief timeEach cares only about immediate experience

This side tries to maximize utility across time

Sequential selves that exist only for a brief time

Each cares only about immediate experience

Experiment Time!This is real. One of you will be picked to receive one of the choices you selected.

Choice OnePick oneYou can receive $1.00 (cash) on the second to last day of this class.You can receive $1.05 (cash) on the last day of this class.

Choice TwoPick one. One week prior to the last day of class, you can have during class eitherTangerineChocolate BarThe dollar value of both is identical. (Of course, the tangerine is a healthier choice.)

It’s now time!Get ready, someone is about to get a nice giveaway!

Choice ThreePick one. Right now, you can have eitherTangerineChocolate BarThe dollar value of both is identical. (Of course, the tangerine is a healthier choice.)

Choice FourPick oneYou can receive $1.00 (cash) right now.You can receive $1.05 (cash) during the next meeting of this class.

Research ResultsRead & van Leeuwen (1998). 200 participants. People who were not hungry, chose the unhealthy snack for delivery in one week 26% of the timeThey chose the unhealthy snack for immediate consumption 70% of the time←Next WeekRight Now -> 26%70%

Dual-selfLong-run (patient) selfThis side tries to maximize utility across timeShort-run (impulsive) selvesSequential selves that exist only for a brief timeEach cares only about immediate experience

This side tries to maximize utility across time

Sequential selves that exist only for a brief time

Each cares only about immediate experience

DiscussionShort-run (impulsive) selvesDoes the short-run self care aboutFuture consumption next week?Future health consequences? Immediate consumption choice?←Next WeekRight Now -> 26%70%

Future consumption next week?

Future health consequences?

Immediate consumption choice?

DiscussionDiscuss with a neighbor and vote in a moment.Does this result fit better with simple rational decision-making or a two-system approach? Simple rational decision makingTwo system “dual-self” decision making (long-run/patient self and short-run/impulsive selves)←Next WeekRight Now -> 26%70%

Class vote comparisonHow many voted for chocolate at the end of the semester?Fall 2009 – 62.7% (n=86)How many voted for chocolate right now?Fall 2009 – 64.8% (n=74)

Hyperbolic discountingWould you rather receive $100 right now or $101 in a week? Most people choose $100 right now. But when the choice is between $100 a year from now and $101 in a year and a week from now, most people choose $101 in a year and a week. This is time inconsistent, as both choices involve delaying by one week for $1.Note also that choosing $100 right now implies an interest rate charge of 1% per week or APR of 52%

DiscussionShort-run (impulsive) selvesDoes the short-run self care aboutImmediate money?Two different future money options? Now v. laterLater v. much later

Immediate money?

Two different future money options?

Class vote comparisonHow many voted to take the $1 on the second to last day of the class (instead of $1.05 on the last day)?Fall ‘09: 32.2% (n=87)How many voted to take the $1 right now (instead of $1.05 in the next class meeting)?Fall ‘09: 66.3% (n=86)What is the implied interest rate being charged to those who chose the immediate $1?Next class in 2 days. 5% difference. APR = (365/2) X 5% ≈912%

Thoughts to ponderCould the willingness of some to ignore a 920% interest rate for immediate reward have implications for consumer use of credit?Could the variations in the healthiness of food choices have implications for consumer food choices?More later…

Slides by: Russell James III, J.D., Ph.D.Asst. Professor, Department of Housing & Consumer Economics, University of GeorgiaPlease use these slides! If you think you might use anything here in a classroom, please CLICK HEREto let me know. Thanks!The outline for this behavioral economicsseries is at rjames.myweb.uga.edu/outline.htm