The behavioral economics and neuroeconomics of reinforcer pathologies: implications for etiology and treatment of addiction

Abstract

The current paper presents a novel approach to understanding and treating addiction. Drawing from work in behavioral economics and developments in the new field of neuroeconomics, we describe addiction as pathological patterns of responding resulting from the persistently high valuation of a reinforcer and/or an excessive preference for the immediate consumption of that reinforcer. We further suggest that, as indicated by the competing neurobehavioral decision systems theory, these patterns of pathological choice and consumption result from an imbalance between two distinct neurobehavioral systems. Specifically, pathological patterns of responding result from hyperactivity in the evolutionarily older impulsive system (which values immediate and low-cost reinforcers) and/or hypoactivity in the more recently evolved executive system (which is involved in the valuation of delayed reinforcers). This approach is then used to explain five phenomena that we believe any adequate theory of addiction must address.

Fig. 1

Demand data for cigarette puffs (solid circles) and monetary awards (open circles) plotted on the same graph. Note the double-logarithmic axes. Consumption (self-administrations) is plotted as a function of price (fixed ratio [FR], schedule requirement). For the left panelthe monetary award amount self-administered per each reinforcer that was earned by completing an FR schedule requirement was $0.05. For the right panelthis amount was $0.25. The same cigarette puff data are plotted in the left and right panels. Greater elasticity of demand for the monetary award reinforcers compared with the cigarette puff reinforcers is illustrated by the more precipitous decline in consumption of the monetary award reinforcers to zero in spite of the greater consumption of those reinforcers at lower prices. The duplication of the cigarette puffs curve in both panels serves as a common frame of reference that reveals a greater elasticity of demand for the $0.05 reinforcers than for the $0.25 reinforcers. This illustrates the comparatively greater reinforcer value of the $0.25 reinforcers and the greater extent to which that reinforcing commodity might be described as pathological. (From Johnson MW, Bickel WK: Replacing relative reinforcing efficacy with behavioral economic demand curves. J Exp Anal Behav 2006, 85, 73–93. Copyright 2006 by the Society for the Experimental Analysis of Behavior, Inc.)

Fig. 2

Median indifference points from hypothetical choices between large delayed and small immediate heroin and monetary rewards. The top graph shows data from opioid-dependent and control participants’ choices between monetary rewards. The bottom graph shows data from opioid-dependent participants’ choices between monetary rewards and between heroin amounts. The indifference points reflect the present value of larger, more delayed rewards (i.e., the value of delayed rewards stated in immediate-reward units). So that heroin and monetary rewards could be compared on a common axis, the vertical axis shows the percentage of the large delayed reward. Higher discounting rates are characterized by steeper overall slopes and closer proximity of the fitted curve to the axes. The top graph illustrates a greater discounting rate for monetary rewards by opioid-dependent participants than controls. The bottom graph illustrates a greater discounting rate for heroin rewards than for monetary rewards by opioid-dependent participants. (From Madden GJ, Petry NM, Badger GJ, Bickel WK: Impulsive and self-control choices in opioid-dependent patients and non-drug-using control participants: drug and monetary rewards. Experimental and Clinical Psychopharmacology 1997, 5, 256–262. Published by the American Psychological Association. Reprinted with permission.)

Fig. 3

Potential interactions between differing strengths of the impulsive and executive decision systems. Note that the shaded area indicates the risk of addiction. (From Bickel WK, Mueller ET, Jarmolowicz DP: What is addiction? In Addictions: A Comprehensive Guidebook, Second Edition. Edited by McCrady B, Epstein E. 2011 (in press) Copyright 2011 by and by permission of Oxford University Press, Inc. [http://www.oup.com].)