Figure 1.

Visualization of the reward offer titration. Each block contained six trials, always beginning with Offer 1, which was a $1.00 reward for performing a black (+20 dB signal-to-noise ratio [SNR]) trial or a $2.00 reward for performing a trial at a more difficult SNR. Each subsequent offer was determined by the participant's previous choice; if the harder SNR was chosen, then the lower reward offer would increase, and if the easier SNR was chosen, then the lower reward offer would decrease. The amount of change to the lower reward offer halved in each trial. In the diagram, the higher effort condition is green, but the actual color displayed to participants corresponded to one of the five higher effort SNRs (+4, 0, −4, −8, or −12 dB; shown in the lower panel of the figure). The color of the higher effort condition changed in each block, but the titration process was the same across conditions.