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T I M E D I S C O U N T I N G
For example, people are often consistent in recognizing the need to maintain a
diet. Yet they periodically violate their own desired course of action—often rec-
ognizing even at the moment of doing so that they are not behaving in their own
self-interest.
Yet a third type of multiple-self model draws connections between intertempo-
ral choice and models of multiperson strategic interactions (Elster 1985). The es-
sential insight that these models capture is that, much like cooperation in a social
dilemma, self-control often requires the cooperation of a series of temporally sit-
uated selves. When one self “defects” by opting for immediate gratification, the
consequence can be a kind of unraveling or “falling off the wagon” when subse-
quent selves follow the precedent.
Few of these multiple-self models have been expressed formally, and even
fewer have been used to derive testable implications that go much beyond the in-
tuitions that inspired them in the first place. However, perhaps it is unfair to criti-
cize the models for these shortcomings. These models are probably best viewed
as metaphors intended to highlight specific aspects of intertemporal choice.
Specifically, multiple-self models have been used to make sense of the wide range
of self-control strategies that people use to regulate their own future behavior.
Moreover, these models provided much of the inspiration for more recent formal
models of sophisticated hyperbolic discounting (following Laibson 1994, 1997).
TEMPTATION UTILITY
Most models of intertemporal choice—indeed, most models of choice in any
framework—assume that options not chosen are irrelevant to a person’s well-
being. In a recent paper, Gul and Pesendorfer (2001) posit that people have
“temptation preferences,” wherein they experience disutility from not choosing
the option that is most enjoyable now. Their theory implies that a person might be
better off if some particularly tempting option were not available, even if he or
she doesn’t choose that option. As a result, the person may be willing to pay in
advance to eliminate that option, or in other words, he or she may have a prefer-
ence for commitment.
COMBINING INSIGHTS FROM DIFFERENT MODELS
Many behavioral models of intertemporal choice focus on a single modification
to the DU model and explore the additional realism produced by that single mod-
ification. Yet many empirical phenomena reflect the interaction of multiple phe-
nomena. For instance, a preference for improvement may interact with hyperbolic
discounting to produce preferences for U-shaped sequences—for example, for
jobs that offer a signing bonus and a salary that increases gradually over time. As
discussed by Loewenstein and Prelec (1993), in the short term, the preference-
for-improvement motive is swamped by the high discount rates, but as the discount
rate falls over time, the preference-for-improvement motive may gain ascendance
and cause a net preference for an increasing payment sequence.
As another example, introducing visceral influences into models of hyperbolic
discounting may more fully account for the phenomenology of impulsive choices.
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