Experiment 1: ERPs to non-symbolic stimuli separated by numerical value. (a & b) These figures depict brain responses to the numerosities 1, 4, 6, and 9 used in the dot displays in Experiment 1 for the right inferior parietal electrodes. These data strongly suggest that the N1 effect observed in figure 4 is due to differences in the N1 component for small numerical values. (c) The mean amplitudes during the N1 time window decrease significantly with increasing numerical value between 1 and 6. (d) In this figure, the mean amplitudes for each numerosity during the P2p time window are grouped by distance. Small numerical values show a significantly smaller P2p amplitude than large numerical values when distance is held constant.