Delay discounting, the tendency to choose a smaller-sooner reward over a larger-later reward, has been conceptualized either as a personal preference or as a rational thinking component. In this study (N = 397), the associations between monetary delay discounting – constructed as a rational thinking task – and cognitive individual difference measures were examined. Participants with higher general cognitive ability, cognitive reflection, scientific reasoning, and objective numeracy had a weaker tendency to discount delayed rewards, the opposite was true for those with higher intuitive thinking disposition and bias susceptibility. Bias susceptibility predicted delay discounting over and above all other cognitive predictors. The results partially support the assumption about a common basis of delay discounting and susceptibility to cognitive biases (as a rational thinking indicator). Because of the relatively low explained variance in delay discounting by cognitive variables, however, ample room is left for other potential predictors in the monetary delay discounting tasks.
The involvement of the prefrontal cortex in intertemporal choices has been long recognized. Using neurostimulation techniques, recent studies have indicated that the left dorsolateral prefrontal cortex (DLPFC) influences performance on intertemporal choice tasks. The present pilot study is aimed to explore further the DLPFC’s role in intertemporal choices by assessing the influence of individual levels of impulsivity on modulating the stimulation’s effects. Thirteen subjects participated in a within-subjects experiment. During the three sessions, participants received 20 minutes of transcranial direct current stimulation (tDCS; either sham, anodal, or cathodal) and were administered the Intertemporal Choice Task. Then, they completed the Barratt Impulsivity Scale and the Dickman Impulsivity Inventory. Using a repeated-measure generalized linear model, we explored the effects of stimulation on intertemporal choice (either immediate or delayed reward) on impulsive responses, defined as quick answers. The individual level of impulsivity was included in the model as a covariate. According to the results, participants made a greater number of impulsive choices favouring immediate rewards after cathodal stimulation of the left DLPFC. Additionally, a moderating role of individual impulsivity emerged. This study provides support for the involvement of the left DLPFC in intertemporal choices. We contend that the role of individual differences should be further explored to obtain a better understanding of intertemporal choice behaviour.
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.