Figure 1

Schematic illustration of the R-R task. Stimulus and event timing as well as the response layout is depicted. Participants responded by using the numerical pad on a keyboard. The buttons of “1”, “4” and “7” were used for left responses, and “3”, “6” and “9” for right responses. Participants were instructed to use their left index finger on the left side of the pad, and their right index finger on the right side of the pad. For standard trials, stimuli are presented with white font color, green color was used for surprise trials (only rewarded group, top). In the no reward group (bottom), white font color was used.