Impulsivity, Impatience, and Risk Taking—8:45 am-9:30 am
|Sunday, March 27, 2011|
|8:45 AM–12:00 PM |
|Area: SCI; Domain: Experimental Analysis|
|Instruction Level: Intermediate|
|CE Instructor: Amy Odum, Ph.D.|
|Chair: Amy Odum (Utah State University)|
|LEONARD GREEN (Washington University)|
|Leonard Green received his undergraduate degree from the City College of New York (CCNY) and his Ph.D. from the State University of New York at Stony Brook. After completing post-doctoral research, Green ventured west of the Mississippi (although he thought he was still east of the river) where he is now professor of psychology at Washington University in St. Louis. He also serves as director of undergraduate studies for the psychology department. Green's research concerns choice and decision making in rats, pigeons, and people, with a particular interest in models of self-control, impulsivity, choice and decision making, and basic learning processes. In addition, he is one of the developers of "behavioral economics," a transdisciplinary field that combines the experimental methodology of psychology with the theoretical constructs of economics. He has published over 150 articles and book chapters, is co-author of the book Economic Choice Theory: An Experimental Analysis of Animal Behavior (Cambridge University Press), and editor of Advances in Behavioral Economics, the third volume of which is subtitled Substance Use and Abuse. He has been editor of the Journal of the Experimental Analysis of Behavior, associate editor of the Pavlovian Journal of Biological Science, and consulting editor for Behavior and Philosophy. Green's research has been funded by the National Institutes of Health, National Institute on Aging, and the McDonnell Center for Higher Brain Function. He serves on the executive board of the Society for the Quantitative Analysis of Behavior (SQAB), and was recently elected a fellow of the Association for Behavior Analysis International (ABAI) and the Association for Psychological Science (APS). He is president of the Society for the Experimental Analysis of Behavior. Len also is on the board of MO-FEAT, Missouri Families for Effective Autism Treatment. His awards and honors include: Council of Students of Arts and Sciences Award, "In Recognition of Outstanding Teaching and University Service" Distinguished Faculty Award from Washington University of St. Louis Special Recognition for Excellence in Mentoring from the Graduate Student Senate ArtSci Council Faculty Award.|
People discount the value of delayed or uncertain outcomes. That is, the subjective values of delayed and uncertain outcomes decrease depending on how delayed or how unlikely they are. How steeply individuals discount is thought to reflect how impulsive they are. From this perspective, steep discounting of delayed outcomes (which fails to maximize long-term welfare) and shallow discounting of probabilistic outcomes (which fails to adequately take risk into account) reflect similar decision-making processes and the same trait of impulsivity. However, several manipulations differentially affect delay and probability discounting, and correlational studies show that how steeply one discounts delayed rewards is relatively independent of how steeply one discounts probabilistic rewards. Thus, calling them both "impulsivity" may serve only to indicate that they can both cause people real problems. To study such problems, animal models frequently are needed, and indeed, animals' discounting seems similar to human discounting, although there are differences, some more apparent than real. People reportedly discount delayed rewards on a time scale of weeks or months rather than seconds as in animals, but when choices involve real, consumable rewards, people are as impatient as animals. Interestingly, correlational analyses reveal people's discounting of real, consumable rewards on a small time scale and hypothetical money on a large time scale are uncorrelated, suggesting that even within delay discounting, there may be multiple "impulsivities," each of which is important for understanding a different aspect of decision-making.
|Dr. James MacKillop received his Ph.D. in clinical psychology from the State University of New York at Binghamton and was a clinical intern and postdoctoral fellow at the Center for Alcohol and Addiction Studies at Brown University. He is currently an assistant professor in the Psychology Department at the University of Georgia and an adjunct assistant professor at the Center for Alcohol and Addiction Studies. Dr. MacKillop uses behavioral economics as a framework for understanding addictive behavior in general and applies the approach to alcoholism, nicotine dependence, and pathological gambling in particular. Specific foci include investigating the roles of impulsive delay discounting and excessive drug demand in addictive behavior on multiple levels of analysis. His research applies a translational approach, seeking to apply insights from behavioral, neurobiological, and genetic research to clinical interventions and other applied contexts. He has published more than 60 journal articles, book chapters, and other works in this area and his research is funded by the National Institute on Alcohol Abuse and Alcoholism, the National Institute on Drug Abuse, the Robert Wood Johnson Foundation, and the Alcoholic Beverage Medical Research Foundation, among others.|
Delayed reward discounting (DRD) is a behavioral economic index of impulsivity. Numerous studies reported more impulsive DRD in groups exhibiting addictive behavior compared to control groups. This presentation will synthesize findings across the literature using a meta-analysis of these studies. Specifically, the meta-analysis will characterize: (a) overall patterns of findings, qualitatively and quantitatively; (b) systematic variability by sample and study type; and, (c) possible small study (publication) bias. Literature reviews identified 310 candidate articles from which 47 studies reporting 67 comparisons were identified (total N = 56,013). From the total comparisons identified, a highly statistically significant but small magnitude effect was evident with extremely high heterogeneity of effect size. Based on systematic observed differences, large studies assessing DRD with a small number of self-report items were removed and an analysis of 60 comparisons (n = 3,329) using equivalent methods and exhibiting acceptable heterogeneity revealed a highly significant medium magnitude effect. Further analyses revealed significantly larger effect sizes for studies using clinical samples (d = .62) compared to studies using nonclinical samples (d = .44). Indices of small study bias among the various comparisons suggested varying levels of influence by unpublished findings, ranging from minimal to moderate. These results reveal consistent evidence of more impulsive DRD in individuals exhibiting addictive behavior that is of medium effect size in general and significantly larger in individuals who meet criteria for an addictive disorder. Moreover, these findings suggest that multi-item assessments of DRD that offer more precise estimates of discounting are more sensitive to group differences. However, the studies reviewed use cross-sectional designs that do not permit a clear inference of whether these differences are causative (etiological) or consequential (symptomatic) of addictive behavior. To address this, several lines of research will be reviewed, including: (a) longitudinal evidence of DRD predicting addictive behavior; (b) evidence of the temporal stability of DRD; (c) evidence of DRD predicting clinical outcomes; (d) evidence from animal studies bearing on etiology; and (e) evidence of genetic influences on DRD and related phenotypes. On balance, most of the studies in these areas suggest that DRD plays an etiological role but there is also evidence these areas suggest that DRD plays an etiological role but there is also evidence that DRD is further exacerbated by drug abuse and aspects of addiction, such as withdrawal and craving. A potentially interactive and recursive process will be discussed.
|Howard Rachlin obtained a Ph.D. in psychology at Harvard University in 1965. He is currently a research professor and an Emeritus Distinguished Professor of Psychology at the State University of New York at Stony Brook. He has published more than 100 articles, written six books including Behavior And Mind (Oxford University Press, 1994) and The Science of Self-Control (Harvard University Press, 2000), and edited two others. He has served on study sections for The National Institutes of Health (NIH) and The National Science Foundation (NSF). He is on the editorial boards of six journals. Since he received his Ph.D. his research (on choice, self-control, social cooperation, and experimental economics) has been continuously supported by grants from NIH and NSF including an NIH MERIT award. Among other honors he has been elected fellow at the American Psychological Society and the Society of Experimental Psychologists. He has been the recipient of a James McKeen Cattell Fellowship (1975-76), and an Award for the Impact of Science on Application from the Society for the Advancement of Behavior Analysis (2005). He was a visiting scholar at the Russell Sage Foundation (1988-89) and an invited speaker at the Nobel Symposium on Behavioral and Experimental Economics, Stockholm, Sweden (2001).|
A human delay discount function measures overlap between the interests of a person now and that same person's interest later; the steeper a person's delay discount function is, the more impulsive (less restrained) she is. A human social discount function measures overlap between the interests of a person now and those of another person now; the steeper a person's social discount function is, the more selfish (less altruistic) he is. Just as delay discount functions are obtained by asking people to choose between smaller rewards for themselves now and larger rewards for themselves at later times, social discount functions are obtained by asking people to choose between smaller rewards for themselves now and larger rewards for other people now at various social distances. In typical game theory analyses, each player is assumed to value only immediate or delayed rewards with delayed rewards being discounted. Looking at games from the viewpoint of social discounting, benefits from immediate and discounted delayed rewards to the player would be supplemented by discounted rewards to the other player or players. Given social discounting, degree of cooperation by Player-A would be predicted to increase as a function of the amount of reward to the other players or the number of other players receiving benefits (all else held constant), consequent on cooperation. This prediction was confirmed in experimental tests.
Leonard Green, James MacKillop, and Howard Rachlin will participate in a panel discussion and answer questions on the topics presented in Cluster 3.
Session Moderator: Amy Odum.
|Target Audience: |
|Learning Objectives: available onsite|