The domain effect in delay discounting: The roles of fungibility and perishability

102

Steep delay discounting is characterized by a preference for small immediate outcomes relative to larger delayed outcomes and is predictive of drug abuse, risky sexual behaviors, and other maladaptive behaviors. Nancy M. Petry was a pioneer in delay discounting research who demonstrated that people discount delayed monetary gains less steeply than they discount substances with abuse liability. Subsequent research found steep discounting for not only drugs, but other nonmonetary outcomes such as food, sex, and health. In this systematic review, we evaluate the hypotheses proposed to explain differences in discounting as a function of the type of outcome and explore the trait-and state-like nature of delay discounting. We found overwhelming evidence for the state-like quality of delay discounting: Consistent with Petry and others' work, nonmonetary outcomes are discounted more steeply than monetary outcomes. We propose two hypotheses that together may account for this effect: Decreasing Future Preference and Decreasing Future Worth. We also found clear evidence that delay discounting has trait-like qualities: People who steeply discount monetary outcomes steeply discount nonmonetary outcomes as well. The implication is that changing delay discounting for one outcome could change discounting for other outcomes.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Delay discounting of different outcomes: Review and theory

Odum

Becker

Haynes

et al. 2020

102

“…This explanation is especially relevant because perishability may have differed between the food choices. Holt, Glodowski, Smits‐Seemann, and Tiry () found greater discounting of food outcomes when the food item was perishable compared to when the food item was nonperishable. Further research should determine if informing participants that they do not have to eat all of their food choice at that moment but can instead prepare to store surplus food reduces the proportion of participants that choose a smaller amount in the now condition.…”

Section: Discussionmentioning

confidence: 99%

The effects of outcome unit framing on delay discounting

DeHart

Friedel

Frye

et al. 2018

We examined the effects of outcome framing on delay discounting. In Experiment 1, participants completed four delay-discounting tasks. In one monetary task, money was framed in units of dollars (＄50), and in the other, money was framed in units of handfuls of quarters (equal to ＄50). In one food task, food was framed in clear units of food (e.g., 100 M&Ms), and in the other, food was framed in units of servings (e.g., 10 servings of M&Ms). When money was framed in units of dollars, participants discounted less by delay compared to discounting of handfuls of quarters. When food was framed as clear units, participants also discounted less compared to how they discounted servings. In Experiment 2, participants completed two delay-discounting tasks for dollars and quarters (e.g., ＄50 or 200 quarters) to determine if the results of Experiment 1 were due to the differences in handling costs. In one delay-discounting task, money was framed in units of dollars. In the other delay-discounting task, money was framed in units of quarters. There was no difference in how participants discounted delayed money framed as dollars or quarters. Clear unit framing may result in less discounting by delay than fuzzy unit framing.

“…Specifically, rates of discounting are less steep for money compared to that of directly consumable rewards like beer, candy, and soda (Estle, Green, Myerson, & Holt, 2007). Further, the functions of fungibility and perishability have an effect on rates of discounting separately from reinforcer type (Holt, Glodowski, Smits-Seemann, & Tiry, 2016); though, fungibility may be further mediated by individual preference (Stuppy-Sullivan, Tormohlen, & Yi, 2016). Regardless, fungibility may play a role in producing the magnitude effect in humans-a factor that is difficult to study with nonhuman animals but perhaps possible via a token economy.…”

Section: Discussionmentioning

confidence: 99%

Delay discounting in the pigeon: In search of a magnitude effect

Holt

Wolf

2019

Self Cite

The magnitude effect, where larger outcomes are discounted proportionally less than smaller outcomes, is a well‐established phenomenon in delay discounting by human participants. To this point in the literature magnitude effects have not been reliably evidenced in nonhuman animals. , however, used a concurrent‐chains arrangement with pigeon and found evidence for a magnitude effect. Grace et al. suggested that in many delay discounting experimental arrangements with nonhuman animals (e.g., adjusting amount, adjusting delay) the organism is not given the opportunity to directly compare outcomes of different sizes. They suggest that because of the lack of direct comparison it is difficult for the organism to determine the relative size of each outcome, which in turn mutes the effect of the amount differences between outcomes. As a test of this “comparison hypothesis,” the present experiment was conducted to assess whether the magnitude effect would be evidenced in pigeon when using an adjusting amount procedure where outcomes of different amounts were presented proximally. In the present arrangement, pigeons were presented two choice panels in an operant chamber where each panel was associated with an independent adjusting amount delay discounting task, but with differing outcome amounts (i.e., a 32‐food pellet panel and an 8‐food pellet panel). In this arrangement the choice panels alternated in their availability within a session from trial block to trial block. The present findings indicate no reliable effect of amount, even when the outcomes were proximal and thus readily comparable. This result suggests that the lack of magnitude effect is not driven by the organism's ability to compare the difference in amount between choice alternatives.