Fig. 3.

Performance of monkeys on target displacement detection task. A: psychometric curves for the target displacement detection task (leftward and rightward 8° saccades) for monkey Fln. As in Fig. 2, the size of each data point (filled circles) represents the number of trials at that target displacement, saccade direction, and experimental condition (gray, Step condition; black, Blank-step condition). B and C summarize the perceptual bias and threshold for both monkeys for leftward (left) and rightward (right) saccades. Vertical error bars represent SE across the 5 experimental sessions for each monkey. For the data from the 2 monkeys combined (Both) the error bar shows the sample variance. Results were similar to humans except that for monkeys perceptual threshold was not significantly different in Step and Blank-step conditions.