Fig. 1.

(A) Schematic illustration of one trial sequence for the VWM tasks. At the beginning of each trial, the reward value (0, 10 or 50 Japanese yen) was presented in the reward instruction period. This task required the participants to memorize the colors of three or six disks in the sample display, maintain them for the 2-s retention interval, and judge whether a single probe disk in the test display matched one sample disk in the same location. After the judgment, the feedback stimulus, which indicated whether the answer was correct (O) or false (X), was presented, and the total reward was then presented as the purple bar graph. (B) The estimated VWM capacity under conditions of the different numbers of objects (three or six) and reward values (0, 10 or 50). Error bars depict the standard error of the mean.