Target selection time by set size. A: cumulative distributions of selection time across neurons for set sizes 2 (black), 4 (dashed), and 8 (gray). B: stacked histogram of differences in selection time between set sizes 4 and 2 (dark gray), 8 and 2 (gray), and 4 and 2 (light gray), for monkey Q. Most of the histogram falls to the right of zero, indicated by the dashed vertical line. C: the same as in B, but for monkey S.