Figure 1.

A, General outline of a trial in the card-betting task. The task contained four decks of cards. Each deck had a predefined probability of winning of either 75, 60, 40, or 25%. On each trial, subjects had to choose one of the four decks. Participants were unaware of the probability assigned to each deck. B, Subjects' performance during fMRI scanning. Separation into two groups was based on subjects' choices on the two HP decks (75 and 60%) in the last 40 trials of the task. C–E, Postexperiment ratings show significant interaction between groups (learners and nonlearners) in pleasantness ratings (C) and preference rankings (D). E, In the probability assessment question, a significant linear trend is seen in the learners group but not in the nonlearners group.