Rothkegel et al. 10 Figure 2 . Experiment 1. a) Mean distance to center over time ( DTC ( t )) for the five different pre-trial fixation times with starting positions close to the border of the screen. Confidence intervals indicate standard errors as described by Cousineau (2005). Block 1 represents partici- pants 1-20, Block 2 participants 21-40 who were originally tested as a follow up experiment to consolidate the results. b) Mean distance to center of the second fixation as a result of initial fix- ation duration. Error bars are 95% confidence intervals of 1000 bootstrap samples as suggested by Efron and Tibshirani (1994). for the pre-trial fixation times of 0 ms and 125 ms. Overall, short saccade latencies led to a small average DTC (i.e., a strong initial CFB) whereas long latencies led to a larger average DTC (i.e., a less pronounced initial CFB). Table 1 shows the output of the LMM for Experiment 1. The DTC for a pre-trial fixation time of 0 ms is significantly lower than the average DTC and for a pre-trial fixation time of 500 ms it is significantly higher. This means that a saccade immediately after a sudden image onset led to the strongest overall CFB in this experiment. The initial saccade latency is highly significant regardless of the pre-trial fixation time. The model also shows that an interaction between saccade latency and pre-trial fixation time exists. If the image appears directly after a succesfull fixation check (pre-trial fixation of 0 ms) the 4 6 8 10 0 2000 4000 time [ms] distance to image center [°] block 1 1+2 2 pre−trial fixation time [s] 0 0.125 0.25 0.5 1 3 4 5 6 7 500 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