How Longer Saccade Latencies Lead to a Competition for Salience

It has been suggested that independent bottom-up and top-down processes govern saccadic selection. However, recent findings are hard to explain in such terms. We hypothesized that differences in visual-processing time can explain these findings, and we tested this using search displays containing two deviating elements, one requiring a short processing time and one requiring a long processing time. Following short saccade latencies, the deviation requiring less processing time was selected most frequently. This bias disappeared following long saccade latencies. Our results suggest that an element that attracts eye movements following short saccade latencies does so because it is the only element processed at that time. The temporal constraints of processing visual information therefore seem to be a determining factor in saccadic selection. Thus, relative saliency is a time-dependent phenomenon.