Timing conditions for the two experiments are illustrated. The first three dot pairs in the upper sequence correspond to the samples that were illustrated in Figure 2, panels A, B and C, respectively. Each dot in the display set was flashed only once for 0.1 ms, this being T1. T2 was the interval from offset of one member of the pair till onset of the other member. For Exp. 1 this was 0 ms, and for Exp. 2 the value varied between 0 and 1.5 ms. T3 was the interval between successive pairs. In Exp. 1 it varied between 0 and 6 ms, and in Exp 2 it was kept constant at 3 ms.