Delay discounting and intelligence: A meta-analysis

Delay discounting (DD), the tendency to prefer smaller, sooner rewards to larger, later ones, is an important indicator of self-control. Assessments of DD superficially require individuals to make choices based on motivational processes. However, several lines of evidence suggest that DD may be systematically related to cognitive ability. We sought to provide a definitive assessment of the relation between DD and intelligence via quantitative research synthesis. A comprehensive literature search in two electronic databases yielded 24 eligible studies with 26 effect sizes in total. Meta-analysis revealed that, across studies, higher intelligence was associated with lower DD (randonn effects model weighted mean r=-0.23). Studies using reward schemes in which payoffs were subject to chance (i.e., involving either a chance of receiving one choice or random selection of one choice) showed weaker associations between DD and intelligence than did studies in which payoffs were all hypothetical or all real. Other moderator analyses revealed no influence of DD measure, DD choice paradigm, or intelligence type. There was no evidence of publication bias. Given clear evidence for a negative relation between DD and intelligence, investigating the processes that support or moderate this relation would be worthwhile. (C) 2007 Elsevier Inc. All rights reserved.