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Reverse Preference Reversals for Short Front-End Delays. Ay ş e Öncüler INSEAD, France (joint work with Serdar Sayman, Koc U., Turkey). Time Inconsistency. Discounted Utility Model (Koopmans, 1960) Stationarity in Discounting: If (x, t)~(y, t*), then (x, t+j)~(y, t*+j)
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Reverse Preference Reversals for Short Front-End Delays Ayşe Öncüler INSEAD, France (joint work with Serdar Sayman, Koc U., Turkey)
Time Inconsistency • Discounted Utility Model (Koopmans, 1960) Stationarity in Discounting: If (x, t)~(y, t*), then (x, t+j)~(y, t*+j) • A set of experimental evidence on (regular) time inconsistency, starting with Thaler (1981), Benzion et al (1989): Individuals prefer the later-larger reward (LL) at the beginning but closer to the date, switch to the sooner-smaller one (SS).
present value SS LL time Time Inconsistency (Regular) Time Inconsistency Prefer LL Prefer SS
Time Inconsistency • Discounted Utility Model (Koopmans, 1960) Stationarity in Discounting: If (x, t)~(y, t*), then (x, t+j)~(y, t*+j) • A set of experimental evidence on (regular) time inconsistency, starting with Thaler (1981), Benzion et al (1989): Individuals prefer the later-larger reward (LL) at the beginning but closer to the date, switch to the sooner-smaller one (SS). • Current study provides evidence on reverse time inconsistency: Individuals aim for the sooner-smaller reward and over time, they switch to the later-larger one Experimental evidence and a possible explanation
Time Inconsistency (Regular) Time Inconsistency (Reverse) Time Inconsistency present value present value LL SS SS LL SS LL time SS LL time Example: Vacation plans of workaholics Example: Dieting, Christmas clubs
Experimental Design Hypothetical Real Payoffs Loyalty Programs Study 1 Study 3 Monetary Payoffs Study 4 Study 2
Study 1: Hypothetical Loyalty Program • Aim: To check for regular/reverse time inconsistency • INSEAD, Singapore (n=97) and Koc U., Turkey (n=100) • Hypothetical scenarios on retailer loyalty programs • Local supermarket offers a $10 check if the buyer makes $100 purchases. Reward is $25 when the cumulative purchase is $200 • Subjects’ favorite movie theater offers a free ticket after 3 movie attendances or 2 free tickets after 5 attendances • 2 conditions: beginning of program, midway through
Study 1 Results - INSEAD Movie Supermarket RTI TI RTI TI Beginning A: $10 after $100 B: $25 after $200 Midway A: $10 today ($100 completed) B: $25 after $100 more ($200 total) Beginning A: 1 ticket after 3 B: 2 tickets after 5 Midway A: 1 ticket now (3 completed) B: 2 tickets after 2 more (5 total)
Study 1 Results – Koc Uni. Movie Supermarket RTI ~TI RTI Beginning A: $10 after $100 B: $25 after $200 Midway A: $10 today ($100 completed) B: $25 after $100 more ($200 total) Beginning A: 1 ticket after 3 B: 2 tickets after 5 Midway A: 1 ticket now (3 completed) B: 2 tickets after 2 more (5 total)
Study 1- Conclusion • Overall, no significant time inconsistency in either direction • Some women exhibited regular TI- becoming more impatient for imminent reward • Men exhibited reverse TI- deferring an imminent reward • Possible pitfall: Effort required for payoff • Next: Choice task between two monetary payoffs
Study 2: Hypothetical Monetary Outcomes • Aim: to check time inconsistency for choice task between two monetary outcomes to be received at different time periods • 2 pairs of outcomes ($7-$10 and $20-$25) • 4 pairs of time periods
Study 2 - Results (Koc U., n1 = 70, n2 = 60, btw ss) % preferring to wait RTI RTI RTI RTI
Study 2 - Results cont. (Koc U., n1 = 70, n2 = 60, btw ss) % preferring to wait RTI RTI RTI RTI
Study 2- Conclusion • No gender difference • We observe RTI in almost all cases • % subjects preferring to wait decreases with delay • Replicated at INSEAD (n=67) • Possible pitfall: Not longitudinal • Next: Real payoffs
Study 3: Real Payoffs, Loyalty Program • Aim: To check for regular/reverse time inconsistency in an incentive-compatible design • INSEAD, Fontainebleau (n=47) • During the experiment, the campus café offered a two-level reward program: students and staff could receive 1 croissant after buying 10 croissants, or could receive 2 croissants after 15 croissants. Customers are given a patronage card which bears an ID number. This card is shown when they make purchases, and the purchases are recorded on the card by means of a stamp. • Intended choices are elicited at the beginning • Purchase and promotion redemption is recorded for 6 weeks
Study 3 – Results (n=47, within-ss) % preferring to wait (B) Male Female TOTAL A: 1 free crois. after 10 B: 2 free crois. after 15 70% 25% 51% A: 1 free crois after 10 purchased B: 2 free crois. after 5 more 56% 95% 72% RTI RTI TI
Study 3- Conclusion • At the beginning, most men reported preferring later/larger reward but some switched to sooner/smaller reward during the experiment (Regular Time Inconsistency) • At the beginning, most women reported preferring sooner/smaller reward but they switched to later/larger reward during the experiment (Reverse Time Inconsistency) • Overall, there seems to be some evidence on RTI and TI 40% RTI 19% TI 41% consistent with earlier preference
Study 4: Real Payoffs, Monetary Outcomes • Replication of Study 2 with real payoffs, n=38, France • 2 pairs of outcomes, 3 pairs of time periods
Study 4 - Results (INSEAD, n=38, within ss) % preferring to wait RTI RTI RTI
Study 4 – Results cont. (INSEAD, n=38, within ss) % preferring to wait RTI TI
Study 4 - Results • for €7 vs. €10: both females and males exhibit RTI • for €20 vs. €25: for small time periods RTI, for larger periods females exhibit TI
Main Result Evidence for “reverse” time inconsistency… For loyalty programs: Men exhibit RTI for hypothetical rewards; women exhibit RTI for real rewards For neutral payoffs: It depends on the relative size of SS and LL and the time interval between them Main conclusion: Intertemporal preferences are richer than previously recognized
Discussion What can explain reverse time-inconsistency? • Utility from delayed consumption (savoring, Loewenstein 1987) • Effort Uncertainty (sunk cost of time, Soman 2003) • Affect • Form of discounting (elicitation study shows some subjects exhibit a modified discounting behaviour)
Conclusion • An explicit identification of reverse time-inconsistency • Also observed in some recent experiments • Sholten and Read (2005), Airoldi et al (2005), Attema et al (2006) • Implications in many domains: Loyalty programs, bank loan schedules, etc