Evaluating the effect of delay spacing on delay discounting: carry‐over effects on steepness and the form of the discounting function

Abstract

Most delay discounting studies use tasks that arrange delay progressions in which the spacing between consecutive delays becomes progressively larger. To date, little research has examined delay discounting using other progressions. The present study assessed whether the form or steepness of discounting varied across different delay progressions. Human participants completed three discounting tasks with delay progressions that varied in the time between consecutive delays: a standard (increasing duration between delays), linear (equal duration between delays), and an inverse progression (decreasing duration between delays). Steepness of discounting was generally reduced, and remained so, following experience with the inverse progression. Effects of the delay progression on the best fitting equation were order-dependent. Overall the hyperbola model provided better fits, but the exponential model performed better with data from the inverse progression. Regardless, differences in which model fit best were often small. The finding that the best fitting model was dependent, in some cases, on the delay progression suggests that a single quantitative model of discounting may not be applicable to describe discounting across all procedural contexts. Ultimately, changes in steepness of discounting following experience with the inverse progression appeared similar to anchoring effects, whose mechanism will require further study to delineate.

The effect of “should” and “would” instructions on delay discounting of rewards for self and others

“…This pattern of effects is consistent with that apparent in the group-level discounting curves. Rung et al (2019) manipulated the sequence of delays participants made choices about and also observed significant effects for conditions completed later in the session but not those completed first.…”

“…This meant that all participants were aware of all possible instruction types across all conditions, holding this factor constant across conditions and condition orders. Rung et al (2019) suggested a similar approach to follow up their study in which their experimental manipulation affected discounting rates only in conditions that participants completed later in the session.…”

“…Delay discounting is affected by condition x order interactions suggesting recent decision type affects subsequent choices (Malkoc & Zauberman, 2006;Malkoc, Zauberman, & Bettman, 2010;Olsen, Macaskill, & Hunt, 2018;Rung, Frye, DeHart, & Odum, 2019;Yi, Stuppy-Sullivan, Pickover, & Landes, 2017). People make a variety of different delay-amount trade-off decisions throughout day-to-day life, and order effects thus raise the intriguing possibility that everyday decision making is also affected by the decision frames an individual has recently encountered.…”

Association of the altered sense of time in the seconds-to-minute range with intertemporal choices across time-horizons.

“…Scholars have argued that it is crucial to combine timing and intertemporal choice research (Lucci, 2013;Rung, Frye, DeHart, & Odum, 2019;Schultz, 2010;Wittmann & Paulus, 2008). In this paper, we have shown that accounting for subjects' timing helps to predict discounting, but only using variation in time perception to explain variance in short delay tasks and when timing and discounting are proximally assessed.…”

Sequential delay and probability discounting tasks in mice reveal anchoring effects partially attributable to decision noise

“…While we designed our tasks to capture adaptations in value and decision noise, some caveats come with the sequential design of our tasks. Delay and probability discounting rates are significantly impacted by the order of presentation of delayed or probabilistic uncertainties and could also be affected by whether animals experience delay or probability discounting first (Rung, Frye, et al, 2019;St Onge et al, 2010;Tanno et al, 2014). It is worth noting mice did stabilize in their performance in delay discounting, despite experiencing two different orders of delay.…”