Chapter 9 - Junk Time: Pathological Behavior as the Interaction of Evolutionary and Cultural Forces

Abstract

This chapter discusses several points about discounting and its relationship to drug dependence. It shows that discounting appears to be an evolved psychological mechanism that appears to have been exapted in the process of drug dependence. It also shows that discounting has a developmental course that coincides with the onset of drug dependence and with the maturing-out phenomenon often observed in the drug dependent. It makes an argument that discounting may be influenced by culture and that this notion is consistent with the increases in the prevalence of certain disorders observed across the 20th century, especially drug dependence. Exaggerated discounting is directly observed in the drug dependent. In particular, drug dependent individuals discount future monetary rewards more than matched controls and drug dependents discount the drug of dependence more than money. Discounting can theoretically account for reversals in preference, often termed loss of control, which are considered indicative of drug dependence. The chapter includes the data from a recent study in which discounting appeared to be a reversible effect of drug use. Collectively, these observations support the notion that discounting is a behavioral process that may be driven by evolutionarily old brain systems selected to secure vital resources, and these processes appear to be commandeered in drug dependence. As a commandeered process, discounting could be a normal source of pathological behavior.