Figure 3

Oriented faces speed up reaction times for congruent choices. Plots of saccadic reaction times as function of the duration of presentation of the central stimuli. Data pooled over the three animals (monkeys M1, M2, M3) and choice direction. Saccadic reaction times indicating congruent choices were significantly shorter compared to the incongruent ones up to 400 ms of presentation duration (Wilcoxon rank-sum test, 100 ms: zval = −4.8221, p < 0.001; 200 ms: zval = −3.8449, p < 0.001; 300 ms: zval = −2.0341, p = 0.04; 400 ms: zval = −2.4745, p = 0.01). The individual plots are fitted with 2nd degree polynomial functions in an attempt to improve the visibility. The two fits that showed a significant dependence of saccade latency on the presentation duration of the central stimulus were the one for congruent choices prompted by oriented faces and the one for neutral disk stimuli. The former exhibited a gradual increase with duration from a substantially shorted reaction time for a duration of 100 ms (adjusted r² = 0.86). The latter, on the other hand, showed a gradual decrease with duration (adjusted r² = 0.89).