Reversal learning task.

A: Exemplary trial sequence of experimental reversal learning task. Participants were instructed to choose the card that they thought would lead to a monetary reward. After they chose one of the two cards, the corresponding card was highlighted and feedback was displayed. The feedback consisted of either a 10 Eurocents coin for a win outcome, or a crossed 10 Eurocents for a loss outcome. B: The time series of the underlying reward probability of one of the two stimuli. The reward probability of the more rewarding stimuli at any time step was set to 0.8 and a punishment probability to 0.2 (and vice versa for the other stimulus). Reward contingencies remained stable for the first 55 trials (pre-reversal phase) and for the last 35 trials (post-reversal phase). In between, reward contingencies changed four times (reversal phase).