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Unformatted text preview: Impulsive Decision Making and Working Memory John M. Hinson, Tina L. Jameson, and Paul Whitney Washington State University Decision making that favors short-term over long-term consequences of action, defined as impulsive or temporally myopic, may be related to individual differences in the executive functions of working memory (WM). In the first 2 experiments, participants made delay discounting (DD) judgments under different WM load conditions. In a 3rd experiment, participants high or low on standardized measures of impulsiveness and dysexecutive function were asked to make DD judgments. A final experiment examined WM load effects on DD when monetary rewards were real rather than hypothetical. The results showed that higher WM load led to greater discounting of delayed monetary rewards. Further, a strong direct relation was found between measures of impulsiveness, dysexecutive function, and discounting of delayed rewards. Thus, limits on WM function, either intrinsic or extrinsic, are predictive of a more impulsive decision-making style. When making decisions or choices involving known outcomes, people typically weight the value of an outcome by the time it takes to obtain the outcome. The value of a desirable or undesir- able consequence will typically decrease as the consequence be- comes more remote in time (Green, Myerson, & McFadden, 1997; Green, Myerson, & Ostaszewski, 1999). Not surprisingly, reward (or punishment) that is available immediately has more impact on performance than reward (or punishment) that is delayed (Myerson & Green, 1995; Rachlin, 1989). This aspect of decision making is referred to as delay discounting (DD). First examined in the field of economics, DD has been the subject of intensive study by psychologists over the past 3 decades (e.g., Green et al., 1997; Kirby & Marakovic, 1995; Loewenstein, 1992; Loewenstein & Prelec, 1992; Rachlin, Raineri, & Cross, 1991). Although DD can be studied in many ways, a popular method of laboratory study is to offer people hypothetical choices between sums of money. A person chooses between a smaller amount that is available immediately and a larger amount that will be available after a specified delay. With repeated choices, an individual delay discounting function can be obtained on the basis of the observed subjective equality between choices differing in amount and delay. This delay discounting function describes pre- cisely how value declines with delay for a specific individual. For the overwhelming majority of people, DD is well charac- terized by a specific mathematical function. Economists originally argued that value should decline as an exponential function of delay. However, psychologists have shown that preference for immediate versus delayed consequences is better modeled by the hyperbolic discounting function (Ahlbrecht & Weber, 1995; Green et al., 1997, 1999; Prelec & Loewenstein, 1991). Although there is debate about which hyperbolic function best accounts for discount-...
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This note was uploaded on 06/16/2009 for the course PSYCH 120 taught by Professor Hald during the Spring '09 term at Berkeley.
- Spring '09
- Working Memory