Dynamic combination of sensory and reward information under time pressure
(A) The timeline of the sequential-sampling task used in Experiment 1. After fixation, two color targets and a peripheral white arc appeared on the screen. The peripheral arc represented the available time. Subsequently, the fixation cross was replaced by green and red dots, which appeared randomly around the center of the screen while the size of the peripheral arc started to decrease. After deciding the dominant color of the dots and submitting their response, subjects had to wait until the timer reached zero, so there was no advantage in responding early. Finally, reward feedback was displayed, and the local accumulated reward points were updated accordingly. (B) The timeline of Experiment 2 in which the peripheral arc represented the remaining reward over time. Following the appearance of the fixation cross and information about the maximum reward (50 and 100 points), subjects were presented with a diminishing arc informing them about the rate of reward decrease on a given trial. The rest of the trial was similar to Experiment 1. (C) The timeline of the time-dependent gambling task used in Experiment 3. Similar to Experiment 2, after the fixation cross and maximum reward points, subjects were presented with a diminishing arc informing them about the rate of reward decrease on each trial. A central yellow bar represented the probability of reward (between 0.5 and 1.0), while the peripheral arc indicated the amount of reward. The subjects’ task was to accept the presented time-dependent gamble at any point during a trial, and reward feedback (reward or no reward with a magnitude depending on the time of response) was provided at the end of each trial.