45-90 msec

Figure 4A shows that, in all the discrimination conditions, the ERPs elicited between about 45 and 90 msec post-stimulus significantly differ from those evoked in the No-discrimination condition at a number of central electrodes. In both the Intentional-age and -gender conditions, the differences began around 40 msec and were highly significant (p<0.01 or p<0.001) from about 45 to 90 msec latency over a wide central region (Fig. 4A, 2nd and 3rd blocks; mean amplitudes of the effects over 45-90 msec: -0.52 µV and -0.49 µV, respectively; see Table 2). In the Incidental-age condition, the differences were more restricted in space and time (Fig. 4A, 1st block), but their mean amplitude over 45-90 msec (-0.35 µV) was still significant (see Table 2). The topographies of the differences in the three conditions are depicted in Figure 3B-D, line a, at an illustrative (65 msec) latency.