Figure 2.

a, b, One trial of the ball betting task (a) and bin betting task (b). Prior information: the two gray triangles gave incomplete prior information on the probability of the rewarded ball (ball betting task) or the rewarded bin (bin betting task). Sampling: between one and nine balls were drawn with replacement and shown in the center of the screen. Betting: participants placed a bet by moving a vertical gray line on the scale. Auction: the computer selected a price at random and displayed it by moving a vertical violet line; the outcome of the auction was revealed simultaneously. Final outcome: an additional ball was drawn in the ball betting task and the bin was revealed in the bin betting task. Feedback: payoff and net payoff were displayed.