Temporal evolution of the central fixation bias 31 Figure 9 . a) Distance to image center over time for the empirical data and the SceneWalk StartMap model for the different pre-trial fixation times in Experiment 1. b) Influence of the initial saccade latency on the distance to image center on the second fixation for the empirical data and the SceneWalk StartMap model in Experiment 1. experiments. Next, we investigated the temporal evolution of the DTC for different pre-trial fixation times for the SceneWalk StartMap model (Fig. 9a). The SceneWalk StartMap model only took the initial saccade latency after image onset into account. This produced a qualitatively similar pattern for the different pre-trial fixation times as seen in the data. The qualitative progression for most pre-trial fixation times and experiments was similar to what was observed empirically. It is eminent though that the central fixation tendency produced by the model was too weak when compared to the data. This was probably a result of the method and the fixations used for the parameter estimation (see discussion). Finally, we evaluated the relation between latencies of the first saccade and DTC of the second fixation (Fig. 9b). Again this influence was only visible in the SceneWalk StartMap model as the other models do not incorporate a mechanism that depends on the initial saccade latency. The SceneWalk StartMap model produced a result pattern similar to Data SceneWalkStartMap 0 1000 2000 6 8 10 6 8 10 time [ms] distance to image center [°] Data SceneWalkStartMap 500 1000 1500 2000 3 4 5 6 7 8 9 3 4 5 6 7 8 9 initial saccade latency [ms] distance to center on second fixation [°] pre−tr ial fixation time [s] 0 0.125 0.25 0.5 1 a b