Impulsivity, self‐control, and delay discounting in persons with acquired brain injury

Abstract

The present paper describes two studies in which participants with and without acquired brain injuries were compared on a temporal discounting task involving various hypothetical amounts of money available at varying delay values. During Experiment 1, both groups of participants were presented with choices between amounts of money ranging from 1 to 1000 US dollars at delays from 1 week to 10 years. The results obtained from this procedure were consistent with previous models of temporal delay discounting for control group participants, yet not for the majority of the participants with acquired brain injuries. During Experiment 2, adjustments in hypothetical amounts and delays were made whereby the amounts of money ranged from 1 to 20 US dollars at delays from 1 day to 1 year. These manipulations yielded data generally consistent with temporal delay discounting models previously reported in the published literature. The utility of using delay discounting procedures as a means of assessing impulsivity in persons with acquired brain injuries is presented.

Adolescent smokers rate delayed rewards as less certain than adolescent nonsmokers

“…Delay-discounting data for 11% of the sample (9 participants; 5 smokers) were not included in analyses for failure to meet data-validity criteria (see Dixon et al, 2003;2005). To be retained, a participant's discounting data were required to have indifference points that decreased in monetary value over at least two successive delays and to also not have indifference points that increased in monetary value more than once over successive delays.…”

Investing in the Future: Stimulation of the Medial Prefrontal Cortex Reduces Discounting of Delayed Rewards

“…The DD task is a behavioral analytic approach to understand how each individual makes a choice between a smaller reward given immediately and a larger reward given after a time delay, thus assessing the degree of cognitive impulsivity or self-control (Dixon et al, 2005). The task was composed of 120 trials; in each trial, the amounts of monetary reward for immediate and delay options are decided by the fixed k value and the delay time based on the hyperbolic function of delay discount, V ¼ A/(1 þ kD), where V is the value of the delayed outcome (ie, the indifference value), A is the delayed reward, D is the length of the delay, and k expresses the steepness of the discount function (Mitchell, 1999;Richards et al, 1999;de Wit et al, 2002).…”

Intertemporal Decision Making After Brain Injury: Amount-Dependent Steeper Discounting after Frontal Cortex Damage

“…The only explanation found for the lack of the magnitude effect in the clinical control group, is the possibility that the relatively small difference between discounted amounts could contribute to two things: a relatively small magnitude effect in groups, and a different trend in patients with frontal lobe damage. We used such amounts to make them as meaningful and easy to imagine to participants as possible, and based our approach on the study by Dixon et al (2005) that showed that when the reward is too large, patients with brain damage, may discount it in a more unsystematic way. Also, according to Sellitto et al, 2010 it is worthy to test delay discounting rate in patients with ventromedial orbitofrontal cortex (vmOFC) damage to obtain more insight to the neural mechanism of discounting.…”

“…This also applies to the processes of discounting, which can provide conceptual space for impulsive behavior (Dixon et al, 2005;McHugh & Wood, 2008;Sellitto, Ciaramelli & di Pellegrino, 2010;Peters & D'Esposito, 2016). The first empirical attempts to relate brain damage to impulsivity investigated the overall effect of the brain injury itself, regardless of specific localization.…”