Document Type

Contribution to Book

Journal/Book Title/Conference

Impulsivity: The Behavioral and Neurological Science of Discounting


American Psychological Association

Publication Date


First Page


Last Page



Given the importance of research findings and the potential of further research to aid in the prediction and control of impulsivity, the primary focus of this chapter (and this book) is on choice and the failure of future events to affect current decisions. In this primer chapter, we consider two types of impulsive choice: (a) preferring a smaller-sooner reward while forgoing a larger-later one and (b) preferring a larger-later aversive outcome over a smaller-sooner one. The first of these is exemplified by the toy-pilfering child with whom we opened this chapter. Taking the toy is immediately rewarded, but it is a short-lived reward because the caretaker soon returns the toy to the victimized peer. Undoubtedly, the child would prefer to play with the toy for a longer period of time, but waiting until the toy is dropped by the peer seems a weak reinforcer when compared with brief access now. To put an economic term on this phenomenon, the child appears to have discounted the value of the delayed but otherwise preferred reward. Delay discounting describes the process of devaluing behavioral outcomes, be they rewarding or aversive events, that happen in the future (and perhaps the past; see chap. 7, this volume). This chapter provides a primer in delay discounting; it is intended for readers who have only a limited background in the procedures, measures, and outcomes of studies examining this form of impulsive choice. Following an overview of the delay-discounting process, its quantification, and its implications for the human condition, emphasis is placed on procedures (and critiques of these procedures). The remainder of the book is concerned with experimental findings, and for the most part, we do not review these here.


Originally published by the American Psychological Association.