An associability decay model of paradoxical choice

Paradoxical choices in human and nonhuman animals represent substantial deviations from rational models of behavior; such deviations often demand models that incorporate multiple perspectives, including psychology, biology, and economics. The past couple of decades have seen an increased interest in the paradoxical choice of pigeons in 2-armed bandit tasks (2ABT) developed by Zentall and colleagues. In these 2ABTs, pigeons, but not rats, systematically choose an alternative that yields less reward over multiple trials but provides more information on events within a trial, over an alternative that yields more reward over trials but provides less information on events within a trial. Although current computational models account for much of the extant data generated in studies on 2ABT choice, they do not explain, in a trial-by-trial basis, how pigeons learn to ignore some stimuli and not others in 2ABTs. To address the provenance of this differential allocation of attention, a simple model composed of Bush-Mosteller linear operators and a Pearce-Hall-like associability mechanism is proposed. This model, referred to as the Associability Decay Model (ADM) of paradoxical choice, adequately accounts for the performance of pigeons and rats in 2ABTs. The ADM yields an untested prediction that is inconsistent with other computational models of 2ABT performance, and offers potential explanations for why differences in motivation, social enrichment, and impulsivity alter the degree to which pigeons systematically choose information despite earning fewer rewards. The success of the ADM shows that a relatively simple dynamic trial-by-trial model can account for much of the extant paradoxical-choice data while identifying opportunities for further study and refinement of models of 2ABT performance.