When working memory isn't effective: The role of working memory constraints on rates of delayed discounting and substance-use problems

Research has demonstrated that individuals who pathologically engage in addictive behaviors are in general more impulsive, as suggested by their tendency to discount larger rewards that are delayed in time in favor of immediate, albeit smaller rewards. Additionally, some evidence exists that placing constraints on working memory during the decision making process increased an individual's preference for immediate reward. These findings, taken together, have led some to hypothesize that addictive behavioral disorders might result from working memory deficits because the inability to effectively process real-world discounting tasks (e.g., deciding between the immediate gratification associated with substance use despite the potentially larger rewards associated with abstinence that are displaced further in time). However, recent research indicates that individuals do not necessarily become more impulsive with increasing constraints on working memory; rather, individuals became more variable in their responding. Stately differently, increasing working memory constraints rendered the individual less likely to behave (i.e., decide) in a consistent manner. However, the mechanism by which working memory constraints create variance in responding, as well as the way in which working memory deficits influence the onset and maintenance of addictive behaviors, if not through increasing impulsivity, is currently unclear. The purpose of the current chapter is to specify the process by which working memory constraints create inconsistency in responses during discounting tasks, and use this theoretical account to explain the relationship between working memory deficits and the etiology and maintenance of addictive behavioral disorders. Theoretical and methodological implications regarding basic and applied research on working memory, impulsivity, and their relationship to addictive behaviors are discussed.