Abstract

Lewis ascribes the stubborn persistence of addictions to habit, itself a normal process that does not imply lack of responsiveness to motivation. However, he suggests that more dynamic processes may be involved, for instance that “our recurrently focused brains inevitably self-organize.” Given hyperbolic delay discounting, a reward-seeking internal marketplace model describes two processes, also normal in themselves, that may give rise to the “deep attachment” to addictive activities that he describes: People learn to interpret current choices as test cases for how they can expect to choose in the future, thus recruiting additional incentive against a universal tendency to temporarily prefer smaller, sooner to larger, later rewards. However, when this incentive is not enough, the same interpretation creates incentive to abandon the failed area, leading to the abstinence violation effect and a localized weak will. Normal human value does not come entirely, or even mainly, from expectation of external rewards, but is generated endogenously in imagination. Hyperbolic discounting provides an account of how we learn to cultivate the hedonic importance of occasions for endogenous reward by building appetite. In this account, expectations of the far future have to be rewarded endogenously if they are be as important as currently rewarded alternatives; and this importance is prone to collapse. Both will and hedonic importance are recursive and thus hard to study by controlled experiment, but do represent modelable, reward-based hypotheses about the dynamic nature of habit.