The effect of numerical distance and stimulus probability on ERP components elicited by numerical incongruencies in mental addition

The dN3 in mental addition is most probably identical to the arithmetic N400 effect reported earlier in mental multiplication. The distance effect in latency may be a correlate of the discrimination of correct vs. incorrect results. A parietally localized probability effect (right greater than left) was found in the N3 amplitude. The dN3 was insensitive to the probability manipulation. In accord with its insensitivity to stimulus probability, the dN3 seems to be more related to the N400 than to the N2b. Posterior attentional processes sensitive to the allocation of attentional resources may have contributed to the topography of the dN3. The N3 is more related to the detection of expectation violation, while the P3 reflects the ease of identifying stimulus categories.