Figure 2.

Study 1 results. (a) RTs normalized to the first practice block RT (P1) to control for any pre-existing differences in performance. There was an interaction between tDCS group and block, such that the cathodal group was significantly slower at P4 than the other two groups. (b) The average number of key press errors during practice and transfer sessions. There was a main effect of tDCS during transfer (p = 0.045) such that the cathodal group made fewer errors than the other two groups after receiving stimulation. (The large variance for the sham group at T1 is owing to one participant who approached 0% accuracy during this block, suggesting fingers were shifted over the wrong keys. The participant's accuracy subsequently improved enough to meet the criteria for inclusion in data analysis.) The practice session consists of P1 through P6, where the number indicates the block. The transfer session consists of T1 through T6.