This paper discusses the discounted utility (DU) model: its historical development, underlying assumptions, and "anomalies" - the empirical regularities that are inconsistent with its theoretical predictions. We then summarize the alternate theoretical formulations that have been advanced to address these anomalies. We also review three decades of empirical research on intertemporal choice, and discuss reasons for the spectacular variation in implicit discount rates across studies. Throughout the paper, we stress the importance of distinguishing time preference, per se, from many other considerations that also influence intertemporal choices.

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Time Discounting and Time Preference: A Critical Review

Procrastination is a prevalent and pernicious form of self-regulatory failure that is not entirely understood. Hence, the relevant conceptual, theoretical, and empirical work is reviewed, drawing upon correlational, experimental, and qualitative findings. A meta-analysis of procrastination’s possible causes and effects, based on 691 correlations, reveals that neuroticism, rebelliousness, and sensation seeking show only a weak connection. Strong and consistent predictors of procrastination were task aversiveness, task delay, selfefficacy, and impulsiveness, as well as conscientiousness and its facets of self-control, distractibility, organization, and achievement motivation. These effects prove consistent with temporal motivation theory, an integrative hybrid of expectancy theory and hyperbolic discounting. Continued research into procrastination should not be delayed, especially because its prevalence appears to be growing.

/pdf/the-nature-of-procrastination-a-meta-analytic-and-546ofkfr8u.pdf

The nature of procrastination: A meta-analytic and theoretical review of quintessential self-regulatory failure.

http://boccignone.di.unimi.it/CompAff2015_files/SomaticMarkerBecharaDamasio.pdf

The somatic marker hypothesis: A neural theory of economic decision

Fifty-six heroin addicts and 60 age-matched controls were offered choices between monetary rewards ($11-$80) available immediately and larger rewards ($25-$85) available after delays ranging from 1 week to 6 months. Participants had a 1-in-6 chance of winning a reward that they chose on one randomly selected trial. Delay-discounting rates were estimated from the pattern of participants' choices. The discounting model of impulsiveness (Ainslie, 1975) implies that delay-discounting rates are positively correlated with impulsiveness. On average, heroin addicts' discount rates were twice those of controls (p = .004), and discount rates were positively correlated with impulsivity as measured by self-report questionnaires (p < .05). The results lend external validity to the delay-discounting rate as a measure of impulsiveness, a characteristic associated with substance abuse.

Heroin addicts have higher discount rates for delayed rewards than non-drug-using controls.

When choosing between delayed or uncertain outcomes, individuals discount the value of such outcomes on the basis of the expected time to or the likelihood of their occurrence. In an integrative review of the expanding experimental literature on discounting, the authors show that although the same form of hyperbola-like function describes discounting of both delayed and probabilistic outcomes, a variety of recent findings are inconsistent with a single-process account. The authors also review studies that compare discounting in different populations and discuss the theoretical and practical implications of the findings. The present effort illustrates the value of studying choice involving both delayed and probabilistic outcomes within a general discounting framework that uses similar experimental procedures and a common analytical approach.

/pdf/a-discounting-framework-for-choice-with-delayed-and-2di0vonnl8.pdf

A discounting framework for choice with delayed and probabilistic rewards.

In this study, children, young adults, and older adults chose between immediate and delayed hypothetical monetary rewards The amount of the delayed reward was held constant while its delay was varied All three age groups showed delay discounting, that is, the amount of an immediate reward judged to be of equal value to the delayed reward decreased as a function of delay The rate of discounting was highest for children and lowest for older adults, predicting a life-span developmental trend toward increased self-control Discounting of delayed rewards by all three age groups was well described by a single function with age-sensitive parameters (all R2s > 94) Thus, even though there are quantitative age differences in delay discounting, the existence of an age-invariant form of discount function suggests that the process of choosing between rewards of different amounts and delays is qualitatively similar across the life span

/pdf/discounting-of-delayed-rewards-a-life-span-comparison-4h7plbihnj.pdf

Discounting of Delayed Rewards: A Life-Span Comparison

This study examined the effects of age and income temporal discounting (i.e. the decrease in the subjective value of a reward as the delay to its receipt increases). The value of delayed hypothetical monetary rewards was discounted at similar rates by adults of different ages but similar income levels, but at different rates by adults of similar age but different income levels. Specifically, lower income older adults showed a greater degree of temporal discounting than did either upper income older adults or upper income younger adults, but there were no age differences in discounting between the upper income groups. Comparison of these findings with those of a previous study (Green, Fry, & Myerson, 1994) suggests that impulsivity in decision making declines rapidly in young adulthood, reaching stable levels in the 30s. Further, age and income appear to interact in determining the impulsivity of decision making by adults.

Astrid F Fry

Papers

Discounting of Delayed Rewards: A Life-Span Comparison

Temporal discounting in choice between delayed rewards: the role of age and income.