Impulsive choice can be defined as a failure to maximize total gains when choosing between options that are available at different times. This failure is often ascribed to overly-fast discounting of delayed options (i.e., the value of delayed options is decreased as a function of the delay). Such behavior is thought to be a key component of many broader issues concerning society, such as scholastic failure, debt, aggression, and various mental disorders like addiction. Impulsive choice stands out as a topic that has been, and must be, studied through multiple scientific disciplines: psychologists have measured impulsivity through a wide variety of tasks in a number of populations (e.g., children, non-human animals); neurobiologists have identified neural systems and brain structures that seem to affect impulsive choice; and psychopharmacologists have examined the influence of pharmacological agents on impulsive behavior. In the face of these varied lines of work, there is growing agreement that impulsivity is a multi-dimensional phenomenon that is unlikely to be understood through any single approach.
Intellectual Merit:
This project is an interdisciplinary approach to studying impulsivity that integrates tools and concepts from psychology, neuroscience, and behavioral ecology that helps to elucidate both the mechanisms involved in impulsivity, as well as the evolutionary causes of such behavior. Specifically, this project extends and tests the ecological rationality hypothesis, which states that impulsive choice is the product of placing evolved cognitive mechanisms for foraging into evolutionarily novel situations in the laboratory (such as standard delay-discounting tasks in which subjects choose between a smaller-sooner option and a larger-later option). Foraging behavior can be thought of as a series of choices to either stay in a patch of resources and exploit it or leave the patch to look for other possibilities. This project (i) replicates this basic finding in a new species by developing a new methodology for assessing impulsive choice in rats, (ii) further investigates the discrepancy between how decisions are made in the two types of tasks, and (iii) gains a detailed understanding of the neural mechanisms involved in choice by comparing neural representations of value during decisions in both types of task.
Broader Impacts:
Because this project exists at the intersection of several disciplines, the results and the new methods that are developed are of interest to a wide variety of scientists (e.g., psychologists, economists, biologists); and because a deeper understanding of impulsive choice may benefit the study of several mental disorders (e.g., addiction, attention-deficit/hyperactivity disorder) and other major societal concerns, the results are also of interest to those developing treatment and policy.
