The Evolutionary Theory of Behavior Dynamics Predicts Delay Discounting.

Delay discounting is a behavioral phenomenon in which the subjective value of a reinforcer decreases as the reinforcer becomes more delayed. Two procedures are commonly used to assess how the value of a reinforcer changes as a function of delay: adjusting-delay and adjusting-amount. The evolutionary theory of behavior dynamics (ETBD) is a complex systems theory that uses an algorithm based on Darwinian principles of natural selection to animate artificial organisms. The behavior of artificial organisms animated by the theory are its predictions, and the theory has been shown to make accurate predictions about how living organisms behave in a variety of experimental arrangements. In the present article, we generated predictions with the ETBD for adjusting-delay and adjusting-amount procedures and evaluated whether these predictions align with live-organism delay discounting. The predictions were generated using modified procedures that could be conducted with continuous choice arrangements rather than discrete trials; however, despite these procedural differences, the ETBD's predictions were generally consistent with equations known to describe live-organism delay discounting well. This suggests that the ETBD might be used to generate other predictions that could expand our understanding of delay discounting.