Influence of initial fixation position 23 the first two fixations are equal. Next, we analysed the mean horizontal distance for all simulations. Figure 7g presents the mean horizontal distance for experimental data in comparison to data generated by the computational models, averaged over image types and starting positions. The most straightforward model is based on random sampling from the ex- perimentally observed fixation density. The MHD curve indicates that this model cannot produce an overshoot to the image side opposite to the starting position. A model that samples fixation positions randomly from a 2D gaussian-weighted density map is too slow in leaving the starting position, which is indicated by the shallow slope of the MHD curve. While the Gaussian-weighted model is psychologically more plausible because of its limited attentional span, the density map model is more compatible with the exper- imental data. Although the saccadic momentum model contains the same initial three fixations as the data, it can not reproduce the overshoot from the data. In contrast to the other models, the dynamical SceneWalk model (Engbert et al., 2015) can reproduce the overshoot component of the MHD curves in the time interval between 1.5 s and 2 s. The SceneWalk model uses inhibitory tagging that drives the eye towards the image side opposite of the starting position by inhibiting selection of saccade targets close to the starting position of the scanpath. Since model parameters of the SceneWalk model were taken from the published version and not adjusted to the current experimental data, we changed the exponent of the inhibition map from γ = . 3 to . 2 (see Eq. 2 in Methods) in a second simulation. This parameter was also adjusted by hand in the previous version of the model. We see that the overshoot of the MHD curve from the Scene Walk Model with an adjusted inhibition size is in good agreement with the overshoot observed in the experimental data. These simulations suggest that the overshoot produced by the model is primarily caused by the inhibitory tagging mechanism.