Within-subject comparison of degree of delay discounting using titrating and fixed sequence procedures

Abstract

Different procedures are often used across experiments to estimate the degree of delay discounting, a common measure of impulsivity. In all procedures, participants indicate their choice between a reward available immediately and one available after a delay. The present experiment determined whether there are differences in the degree of discounting for a hypothetical $100 produced by a procedure that titrates the immediate amount (titrating sequence procedure) versus a procedure that presents a fixed sequence of immediate amounts (fixed sequence procedure) using a within-subject design. The adult human participants showed no significant differences in degree of discounting between procedures as assessed by a hyperboloid model and the Area Under the Curve. Furthermore, the Area Under the Curve values from the two procedures showed a strong positive correlation. These findings suggest there may be no systematic difference between the degree of delay discounting as estimated by the titrating sequence and fixed sequence procedures. Given the apparent similarities in the results, it appears researchers may be justified in basing their choice of which procedure to use on convenience.

Nicotine deprivation, temporal discounting and choice consistency in heavy smokers

“…Deprivation might specifically affect the valuation of immediate rewards, which could not be detected with our task design (a fixed 10s immediate reward is contrasted with varying delayed rewards). However, Rodzon, Berry, & Odum (2011) found that participants do not discount differently between both task designs. Finally, a recent study by Yi and Landes (2012) with 28 participants (FTND scores M ¼ 6.4; SD ¼1.35) tested both large hypothetical and small real delayed rewards and replicated the pattern of the two previous studies: Hypothetical larger rewards ($1000) were discounted more steeply after nicotine deprivation, while real smaller ($50) rewards were not.…”

The Value of Clean Air: Comparing Discounting of Delayed Air Quality and Money Across Magnitudes

“…The delay-discounting task was an adjusting amount task (Du, Green, & Myerson, 2002; Frye, Galizio, Friedel, DeHart, & Odum, 2016; Rodzon, Berry, & Odum, 2011), and the procedures used are similar to those reported in Friedel et al (2016). In a trial of the delay-discounting task, participants made a choice between a smaller hypothetical amount of an outcome that was to be delivered immediately and a larger hypothetical amount of that same outcome that was to be delivered after a delay.…”

“…For each outcome and each delay to receiving that outcome, the amount of the immediate outcome decreased in a fixed sequence (see e.g., Rodzon et al, 2011). The values used for the small magnitude discounting tasks (both monetary and air quality) were 100, 99, 95, 90, 85, 80, 70, 60, 50, 40, 30, 20, 15, 10, 5, and 1 either dollar(s) or day(s) of improved air quality.…”

Delay discounting: Trait variable?

“…Robles et al (2009) obtained a moderate relation between the degree of discounting as determined by different sequences of presentation of the choices between the immediate and delayed outcomes (ascending vs. descending outcome amounts; ρ = .44). The degree of delay discounting was strongly correlated between versions of the task that used fixed versus titrating amount sequences of presentation of the choices between the immediate and delayed outcomes ( r = .81; Rodzon et al, 2011). Other studies have also reported good correlations between the degree of discounting obtained using alternate methods (e.g., Epstein et al, 2003; Kowal et al, 2007).…”