Figure 2

A. The duration that a given LED was illuminated was 0.1 ms. This is designated as T1. B. The dots within a given subset were displayed sequentially with a pulse spacing of 0.1 ms, measured from onset to onset. C. Here the pulse sequences for the odd and even subsets are illustrated like beads on a string. The time required to display a given subset varied with subset size, with the longest interval being 6.6 ms. The temporal separation of the two subsets, designated as T3, varied as a function of room illumination. The ranges for the T3 interval were: bright (0–40 ms); dim (0–80 ms); dark (0–160 ms).