This study investigated whether age and ADHD symptoms affected choice preferences in children and adolescents when they chose between (1) small immediate rewards and larger delayed rewards and (2) small certain rewards and larger probabilistic uncertain rewards. A temporal discounting (TD) task and a probabilistic discounting (PD) task were used to measure the degree to which the subjective value of a large reward decreased as one had to wait longer for it (TD), and as the probability of obtaining it decreased (PD). Rewards used were small amounts of money. In the TD task, the large reward (10 cents) was delayed by between 0 and 30 s, and the immediate reward varied in magnitude (0-10 cents). In the PD task, receipt of the large reward (10 cents) varied in likelihood, with probabilities of 0, 0.25, 0.5, 0.75, and 1.0 used, and the certain reward varied in magnitude (0-10 cents). Age and diagnostic group did not affect the degree of PD of rewards: All participants made choices so that total gains were maximized. As predicted, young children, aged 6-11 years (n = 25) demonstrated steeper TD of rewards than adolescents, aged 12-17 years (n = 21). This effect remained significant even when choosing the immediate reward did not shorten overall task duration. This, together with the lack of interaction between TD task version and age, suggests that steeper discounting in young children is driven by reward immediacy and not by delay aversion. Contrary to our predictions, participants with ADHD (n = 22) did not demonstrate steeper TD of rewards than controls (n = 24). These results raise the possibility that strong preferences for small immediate rewards in ADHD, as found in previous research, depend on factors such as total maximum gain and the use of fixed versus varied delay durations. The decrease in TD as observed in adolescents compared to children may be related to developmental changes in the (dorsolateral) prefrontal cortex. Future research needs to investigate these possibilities.
|Number of pages||12|
|State||Published - 2006|
Bibliographical noteFunding Information:
This work was partially supported by NIMH grant MH0660393. We gratefully acknowledge B.J. Casey, Keith Ditkowski, Monique Ernst, Richard Gallagher, and Mary Solanto for their help with and useful discussions about task development; Harriet de Wit for useful advise; Lori Evans, Vilma Gabbay, Glenn Hirsch, Mark Krushelnycky, Steven Kurtz, Melvin Oatis, and Maurizio Zamebenedetti for assistance in recruiting participants; most of all, the participants and their parents.
- Attention-deficit/hyperactivity disorder
- Probabilistic discounting
- Temporal discounting
ASJC Scopus subject areas
- Experimental and Cognitive Psychology
- Cognitive Neuroscience
- Behavioral Neuroscience