Fig. 3. Effect of tDCS stimulation over mPFC on the Test Phase.

a Performance accuracy (%) across blocks on social and non-social condition of different tDCS groups. b Reaction time (ms) across blocks on social and non-social condition of different tDCS groups. c Confidence rating on social and non-social condition of different tDCS groups. The y-axis of (a), (b), and (c) indicate the raw performance data, with each dot representing an individual participant. The significance levels compare social and non-social conditions. d tDCS modulation of Social compared to Non-social hierarchy learning performance accuracy (left) and reaction time (right) across blocks during Test phase. e tDCS modulation of Social compared to Non-social hierarchy learning confidence rating across blocks. The y-axis of (d) and (e) indicates the raw performance data of social minus non-social condition, with each dot representing an individual participant. The significance levels compare effects among Cathode, Sham, and Anode stimulation on the differences between social and non-social conditions. All significance levels labeled were estimated by the marginal average effect across all individuals and time periods in the panel regression (Accuracy and Reaction time N = 128: Cathode=42, Sham=44, Anode=42; Confidence rating N = 118: Cathode=41, Sham=38, Anode=39, see Methods for detailed; * indicates p < 0.05, ** indicates p < 0.005, *** indicates p < 0.001, ns indicates non-significant). Error bars indicate standard error of the mean.