As expected, the coefficient corresponding to stimulus number was negative (i.e., higher performance was observed for displays with fewer stimuli), and highly significant for all monkeys (regression analysis, subject EL: p = 7.9 × 10 −22 , subject NI: p = 0.0197; subject DA: p = 0.0011, subject CA: p = 1.98 × 10 −9 ).
A slightly negative coefficient was present for the distance variable, suggesting a small preference for spread out displays, however this effect failed to reach significance for the shape task (regression analysis, p = 0.085).
split displays pooled together) and the difference did not reach statistical significance ( p > 0.8).
Still, we did observe an overall trend toward higher performance for displays where all stimuli were distributed between the two fields vs. present in the same field.