Difference waves for stimulus interference and response interference. Difference waves for stimulus interference (SI – C) and response interference (RI-SI) for each of the four age groups at midline electrodes CPz, Pz, Oz, and electrode PO7. These waves were computed to determine the latency windows of stimulus interference and response interference. Gray-colored bars indicate the two effects (described in the text) for stimulus interference and response interference. For stimulus interference the effect overlapping the negative component (N4) and the positive component (P3) is shown at CPz. The first and the second gray bar indicate the latency window used for adults (260–400 ms) and children (400–560 ms), respectively. The P1 effect for stimulus interference is shown at Oz at a similar latency window for children and adults (80–140 ms). For response interference the effect at the P3-like component lateralized over parietal sites is shown at PO7. The second gray bar indicates the latency window (440–540 ms) used for all the groups; the first gray bar indicates the earlier latency window (300–440 ms) during which the effect already started in 10–12 year-olds. The late response interference effect at the descending flank of the P3 is indicated at Pz. The first and the second gray bar overlap and indicate the latency window used for adults (680–800 ms) and children (700–960 ms), respectively. The effects were not limited to the electrodes shown here; see the text for the exact selection of electrodes used in statistical tests.