Foveal stimulation and saccadic latencies.

We investigated how a postsaccadic visual error affects the latency of the subsequent saccade. Observers made sequences of saccades directed to a single object or three separate objects, which could be displaced backward or onward during the primary saccade. The results showed an increase of second saccade latency after a backward displacement and a decrease of second saccade latency after an onward displacement. Moreover, second saccade latencies were particularly short after an onward displacement which resulted in a primary saccade landing position outside the boundary of the objects. We interpret the latency differences in terms of known effects within the saccadic system, specifically the sensitivity to the pattern of visual stimulation, particularly at and near the fovea, and the inverse correlation between secondary saccade amplitudes and secondary saccade latencies.