Figure 1. Procedure for each trial: The instruction page was presented for ten seconds at the beginning of each run.

During the four-second presentation of the multiplication or rule-finding problem, the participants were required to decide which of the two results was greater. After a two-second inter-stimulus interval (ISI), the participants received a 2-second positive or negative feedback stimulus contingent upon their answer. The subsequent trial was presented after a randomized inter-trial interval (ITI) lasting 1–15 seconds (M = 4 seconds).