Fig. 1. The 6-Armed bandit task.

a. Trial structure of the 6-armed bandit task. On each trial, six bandit options were displayed. A number pad was used to select a single bandit and the selected bandit was outlined in white. Then, the reward value of the selected bandit on that trial was displayed onscreen. b. The hidden reward values during the first 20 trials of the 6-armed bandit task. On the y-axis are the values of each of the 6 bandit options per trial. Each bandit option began with an initial value of 50, and values for subsequent trials were randomly adjusted by a biased random walk. Only when a bandit is selected by the player is the bandit’s value revealed. The selections made by a single control participant are shown as black squares.