Fig. 6.

The proportion of trials for which the eye-tracker reported data for two eyes (black), one eye (dark grey), or no data (light gray) is plotted over time for each eye-tracker for the three head orientation tasks. Ideal performance would be to have data from two eyes throughout the trial. The red vertical lines indicate the beeps that instructed the participants to rotate their head while remaining fixated at 1 s and rotate back at 3 s