Fig. 1: Motion direction discrimination with post-decision wagering.

a Task design. On each trial, monkeys viewed a patch of randomly moving dots and made a decision about the net direction of motion. Stimulus strength and duration varied randomly from trial to trial. On half of the trials, only the right and left direction targets were shown (large red dots). The motion stimulus was followed by a delay period. The central fixation point (small red dot) disappeared at the end of the delay (Go cue), instructing the monkey to report perceived motion direction with a saccadic eye movement to one of the two direction targets. Choosing the correct target yielded a large reward, whereas choosing the incorrect target resulted in a short timeout. On the other half of the trials, a third target (sure target, shown as a blue dot) appeared on the screen during the delay period. Choosing this target after the Go cue yielded a guaranteed but smaller reward than choosing the correct direction target. b Accuracy as a function of motion strength and duration for the two monkeys (M1 and M2). For the motion strength plots, trials are pooled across all durations. For the motion duration plots, trials are pooled across all strengths. Solid lines show the accuracy on trials where the sure target was not presented (M1 motion strength plot: n = 6174 ± 112 per data point; M1 motion duration plot: n = 3720 per data point; M2 motion strength plot: n = 5035 ± 56 per data point; M2 motion duration plot: n = 2530 per data point). Dashed lines show the accuracy on trials where the sure target was shown but the monkey chose one of the high-stakes direction targets (M1 motion strength plot: n = 4148 ± 1314 per data point; M1 motion duration plot: n = 2261 per data point; M2 motion strength plot: n = 3376 ± 917 per data point; M2 motion duration plot: n = 1557 per data point). c Probability of choosing the sure target for different motion strengths and durations for monkeys M1 and M2 (M1 motion strength plot: n = 6195 ± 113 per data point; M1 motion duration plot: n = 4315 per data point; M2 motion strength plot: n = 5081 ± 79 per data point; M2 motion duration plot: n = 3031 per data point). Error bars indicate standard error of the mean (s.e.m.).