Figure 7.

Experiment 3: (a–c) reciprobit plots of saccadic latency, for a gap and step task for three observers. The target was a black spot and ‘fixation’ targets were Gaussian patches placed 4° above and below the centre of the screen. Median latencies for the curves were: (a) subject A (step: 188, 186, 189 ms; gap: 175, 172, 160 ms); (b) subject B (step: 266, 266, 261 ms, gap: 246, 249, 236 ms); and (c) subject C (step: 147, 146, 151 ms, gap: 141, 140, 135 ms; step task: open circles, open squares and open triangles; gap task: filled circles, filled squares and filled triangles (+S, +M, Lum), respectively). A significant gap effect was present for all stimulus conditions for all three subjects (subjects A and B, p<0.001; subject C p=0.01, 0.02 and <0.001 for +S, +M and Lum, respectively).