title: An improved cognitive model of the Iowa and Soochow Gambling Tasks with regard to model fitting performance and tests of parameter consistency.
abstract: The Iowa Gambling Task (IGT) and the Soochow Gambling Task (SGT) are two experience-based risky decision-making tasks for examining decision-making deficits in clinical populations. Several cognitive models, including the expectancy-valence learning (EVL) model and the prospect valence learning (PVL) model, have been developed to disentangle the motivational, cognitive, and response processes underlying the explicit choices in these tasks. The purpose of the current study was to develop an improved model that can fit empirical data better than the EVL and PVL models and, in addition, produce more consistent parameter estimates across the IGT and SGT. Twenty-six opiate users (mean age 34.23; SD 8.79) and 27 control participants (mean age 35; SD 10.44) completed both tasks. Eighteen cognitive models varying in evaluation, updating, and choice rules were fit to individual data and their performances were compared to that of a statistical baseline model to find a best fitting model. The results showed that the model combining the prospect utility function treating gains and losses separately, the decay-reinforcement updating rule, and the trial-independent choice rule performed the best in both tasks. Furthermore, the winning model produced more consistent individual parameter estimates across the two tasks than any of the other models.
authors: Decision Research Laboratory, Department of Psychological and Brain Sciences, Indiana University , Bloomington, IN, USA ; Center for Adaptive Rationality, Max Planck Institute for Human Development Berlin, Germany.
authors: Junyi
authors: J
authors: Dai
authors: Department of Psychiatry, University of Pittsburgh School of Medicine Pittsburgh, PA, USA.
authors: Rebecca
authors: R
authors: Kerestes
authors: Department of Psychological Sciences, Monash University Clayton, VIC, Australia.
authors: Daniel J
authors: DJ
authors: Upton
authors: Decision Research Laboratory, Department of Psychological and Brain Sciences, Indiana University , Bloomington, IN, USA.
authors: Jerome R
authors: JR
authors: Busemeyer
authors: Department of Psychological Sciences, Monash University Clayton, VIC, Australia.
authors: Julie C
authors: JC
authors: Stout
keywords: Iowa Gambling Task; Soochow Gambling Task; cognitive modeling; opiate users; parameter consistency