mechanism. 

To investigate inhibitory tagging, saccadic momentum, and facilitation of return, we recorded observers’ scanpaths on natural scenes starting from one of two predefined start- ing positions close to either side of the monitor. Participants were forced to maintain fixation at an initial location in an image for one second under gaze-contingent monitor- ing. Under the hypothesis that spatial inhibitory tagging is active at the starting position, we expected observers (i) to leave their starting positions when fixation markers disap- peared, and (ii) not to return immediately to the region of the experimentally controlled starting position. Since we hypothesized that both behaviors depend on the saliency of the region of the starting position, we classified natural images into three categories with left-sided and right-sided saliency asymmetry as well as images with an approximately symmetrical saliency distribution. We expected that initial fixations stay closer to the starting position when the starting position was in the more salient region of a scene; alternatively, gaze was expected to move immediately to the opposite side of a scene, when the starting position was in the less salient region of the scene. According to the saccadic momentum and facilitation of return hypothesis, we expected a behavior where subsequent eye movements depend on the direction of the first saccade. With the typical center bias we assume that the gaze had to shift to the center and, subsequently, either maintain direction and move to the opposite image side (saccadic momentum) or return close to the starting position (facilitation of return). 

Below we report scanpath patterns where gaze positions of the participants moved further away from the starting position than predicted by the empirical saliency map or a saccadic momentum mechanism. Next, we compare experimental data with numerical simulations from a range of stochastic models, a model reproducing the saccadic momentum mech- 

