13 Temporal evolution of the central fixation bias Figure 3 . Experiment 2. a) Mean distance to center over time ( DTC ( t )) for the five different pre-trial fixation times with starting positions on a donut shaped ring around the image center. Confidence intervals indicate standard errors as described by Cousineau (2005). b) Mean dis- tance to center of the second fixation as a result of initial saccade latency and pre-trial fixation time. Bins represent quintiles of the saccade latency distribution. Errorbars are the standard error of the mean. too close nor too far away from the center so that fixations could be directed both towards and away from the center. In addition, the donut shaped ring of starting positions made the initial starting position less predictable. This setup was thus slightly different to the experiment conducted by Tatler (2007) where the initial starting position was randomly chosen from a circle (fixed radius) around the image center. Distance to Center over Time . In Experiment 2, where the starting positions were located on a ring around the image center, the eyes moved initially even further towards the image center in the 0 ms pre-trial condition (black curve in Fig. 3a was the only curve with a Results 4 6 8 10 0 2000 4000 time [ms] distance to image center [°] pre−trial fixation time [s] 0 0.125 0.25 0.5 1 3 4 5 6 500 1000 1500 2000 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