In Exp. 1, each dot of the display set was flashed for a duration of 0.1 ms, and there was no temporal separation between members of each pair. The temporal separation of pairs was varied from 0 to 8 ms. The time line has been expanded for the illustration of Exp. 2, most of it being used to illustrate the alternative intervals at which the second member of a given pair would be positioned. In this example, the pair formed by dots 33 and 34 are separated for an interval that varied between 0 and 1.5 ms, and the spacing between one pair and the successive pair (dots 71 and 72 in this illustration) was a constant 3 ms for all pairs in the display set.