highly significantp < 0.001
The pre-test performance covariate was highly significant, F (1,37) = 2695.3, p < 0.001, η p 2 = 0.754 (zero-order correlation between the pre-test and the post-test performance were comparable between the tDCS conditions: Pearson r = 0.89 and r = 0.83, for the sham and the active stimulation, respectively).