Fig. 5.

Experiment 2. FreezeEye tracker: Refixation dispersion. Panels A, B, and C show refixation positions for P1, P2 and P3. Note that the center of the collection of refixations does not necessarily coincide with the center of the fixation marker. As for many eye trackers, the zero is a choice. Here, the first sample of the recording was set to (0,0). We do this because we are only interested in the dispersion. On top of the refixation positions we plotted the BCEA ellipse (so small that it is difficult to see). The BCEA measures 0.006 deg$_{}^2$ (P1), 0.035 deg$_{}^2$ (P2) and 0.038 deg$_{}^2$ (P3). For all participants, the refixation dispersion is much smaller than for the corrected fixation positions of the EyeLink 1000 plus. The BCEA is respectively 25 (P1), 4 (P2) and 8 (P3) times smaller