9 Temporal evolution of the central fixation bias Figure 1 . Schematic illustration of the experimental procedure of Experiment 1 with a starting position close to the left border of the screen. After a short fixation check of 200 ms (Fixation Check 1) the image is presented. A second fixation check between 0 and 1000 ms controls if par- ticipants move their eyes after image onset. After a succesful second fixation check, participants are allowed to freely move their eyes. was visible throughout the whole observation time of 5 s. A second group of participants in the 0 ms condition (Block 2) did not replicate the stronger CFB through the whole observation time. In addition, there was a gradual reduction of the CFB for pre-trial fixation times from 125 ms to 250 ms (red and green curve). DTC for pre-trial fixation times of 250 and 500 ms hardly differed (green vs. blue curve). The minimum for the pre-trial fixation time of 1000 ms occured later in time because of disproportionately long saccade latencies of the first saccade after a forced fixation on the fixation cross of 1000 ms (cyan curve). Distance to Center on the second fixation . Figure 2b shows the influence of initial saccade latency on the mean DTC of the second fixation for the five pre-trial fixation times. Each bin represents a quintile of the distribution of saccade latencies in each condition. A clear relation between DTC of the second fixation and latency of the initial saccade is visible Fixation Check 1  5 s of free observation Fixation Check 2  (0;125;250;500;1000ms)