Decisions under ambiguity and decisions under risk: correlations with executive functions and comparisons of two different gambling tasks with implicit and explicit rules.

We conducted two experiments with healthy subjects to investigate the possible relationships between Iowa Gambling Task (IGT) performance and executive functions as well as IGT performance and decision-making in a task with explicit rules, the Game of Dice Task (GDT). Results indicated that only the last trials of the IGT were correlated with executive functions and GDT performance. We suggest that the IGT taps into two mechanisms of decision-making: decisions under ambiguity in the first trials and decisions under risk in the latter trials. Results have impact on the interpretation of deficient IGT performance in patients with frontal lobe dysfunctions.