Figure 4

tACS protocol and experiment design for Experiment 2.
tACS was applied via two electrodes (5 × 5 cm2) over the left temporal (T5) and parietal (CP1) sites and a reference rubber electrode (5 × 7 cm2) over the right cheek. The stimulation waveform was sinusoidal at 40 Hz without DC offset at intensity of 1.5 mA (peak to peak) and the relative phase difference between the two electrodes (red) was set to 0°. Each participant performed on two different days (at least one week apart), one with sham (30 s) and one with active tACS (20 min), with counterbalanced order. On each day, the shape-only and shape-color binding trials were conducted in an interleaved block design.