Figure 4

Stimulus interference effects on occipital P1 amplitude (80–140 ms). Grand-averaged ERPs for congruent (C) and stimulus incongruent (SI) conditions at an occipital average of electrodes (Oz, O2, PO8) in each of the four age groups. The arrow indicates the P1 component. Topographical maps of the voltage difference for the SI minus C condition (blue: negative difference; red: positive difference) indicating stimulus interference show a negative amplitude difference (80–140 ms) at central and right-hemispheric occipital sites reflecting an amplitude reduction of the P1 component that was most pronounced in 6–7 year-olds.