Perceptual task drives later fixations and long latency saccades, while early fixations and short latency saccades are more automatic.

Abstract

We used a simple stimulus, dissociating perceptually relevant information in space, to differentiate between bottom-up and task-driven fixations. Six participants viewed a dynamic scene showing the reaction of an elastic object fixed to the ceiling being hit. In one condition they had to judge the object's stiffness and in the other condition its lightness. The results show that initial fixations tend to land in the centre of an object, independent of the task. After the initial fixation, participants tended to look at task diagnostic regions. This fixation behaviour correlates with high perceptual performance. Similarly, low-latency saccades lead to fixations that do not depend on the task, whereas higher latency does.