Humans Can Adopt Optimal Discounting Strategy under Real-Time Constraints
Figure 2
At each trial the subject must select either a white or a yellow mosaic after the fixation cross turns red (“Go” signal). Each button press (green disk) adds a number of colored patches to the selected mosaic. In the example shown here, if the white mosaic is selected, the subject receives 5 yen in two steps of 1.5 s each. If the yellow mosaic is selected, the subject receives 20 yen in four steps. The position of the squares (left or right) was changed randomly at each step. For each trial, the initial numbers of black patches for both mosaics were randomly drawn from uniform distributions, and indicated different delays. The ITI, which corresponds to the reward display, was fixed (one time step). Thus, just after the reward display, a new trial began. The subjects had a total of 700 time steps to maximize their total gain.